JP5569021B2 - Method for manufacturing photoelectric conversion element - Google Patents

Description

  The present invention relates to a method for producing a photoelectric conversion element containing an electron extraction layer.

As a configuration of the organic thin film solar cell, a method is known in which a buffer layer is sandwiched between electrodes and an organic semiconductor layer instead of directly joining them. Since the total thickness of the organic semiconductor layer is generally very thin, about 100 nm, the surface of the transparent electrode (ITO) or the like is not sufficiently smooth, and there is a possibility of short-circuiting unless a buffer layer is provided.
Until now, 2,9-dimethyl-4,7- has been used as an electron extraction layer, which is a kind of buffer layer.
When using organic compounds such as diphenyl-1,10-phenanthroline (BCP) and phosphine oxide compounds (Non-patent Document 1, Patent Document 1), and inorganic compounds such as lithium fluoride (LiF) and titania oxide (TiOx) (Non-Patent Documents 2 and 3) have been reported.

Furthermore, after all the layers of the photoelectric conversion element are stacked, an attempt has been made to improve the characteristics of the photoelectric conversion element by heat-treating the entire element.
Regarding a solar cell using a low molecular vapor deposition type organic semiconductor layer, Patent Document 2 discloses an electrode once deposited for an element using copper phthalocyanine (CuPc) as a p-type semiconductor and a perylene derivative as an n-type semiconductor. It is described that after peeling off from the semiconductor layer once, bathocuproin (BCP) is vapor-deposited as a buffer layer, a silver (Ag) electrode is vapor-deposited thereon, and then heat treatment is performed to improve the performance. . Non-Patent Document 4 discusses an element using copper phthalocyanine (CuPc) as a p-type semiconductor and C60 as an n-type semiconductor. In this document, conversion efficiency is reduced by applying heat treatment after depositing a silver electrode in an element in which a C60 layer doped with decamethylcobaltene and a BCP layer are inserted between an organic semiconductor layer and a silver electrode. .92% of devices have been achieved. With this technology, it is described that the open circuit voltage (Voc) and the short circuit current (Jsc) are hardly changed, and the conversion efficiency is improved by 24% compared to before the heat treatment by improving the fill factor (FF). ing. Patent Document 3 discloses a photoelectric conversion element without poly (3-hexylthiophene-2,5-diyl) (hereinafter referred to as P3HT) as a p-type semiconductor, a fullerene derivative, and an electron extraction layer as an n-type semiconductor. It was reported that what was sealed by pasting a transparent glass substrate with a sealant was heat-treated at 150 ° C. for 5 minutes, and the photoelectric conversion efficiency after the heat treatment was 1.4 to 1.9%. Yes.

JP 2006-073583 A US2005 / 0061364 Gazette International Publication WO2009 / 008323 Pamphlet

Organic Electronics 2008, 9 p. 656-660 Sol. Energy Mater. Sol. Cells 2005, 86, 499-516 Sol. Energy Mater. Sol. Cells 2008, 92 p. 1476-1482 C. K. Chan et al .: Appl. Phys. Lett. 94, 203306, 2009

  According to the study of the present inventor, in the photoelectric conversion element containing BCP or LiF, which is known as an electron extraction layer, after the entire layer of the photoelectric conversion element is laminated, the entire element is subjected to heat treatment. Later, it was found that the photoelectric conversion efficiency dropped rapidly. Especially in solar cell applications, durability under high temperature conditions is required, so it is expected that a decrease in photoelectric conversion efficiency due to heat treatment of the entire element will not be durable under high temperature conditions, and practical application This is a problem.

  As a result of intensive studies to solve the above-described problems, the present inventors have determined that a photoelectric conversion element having an electron extraction layer containing a specific compound includes a substrate of the photoelectric conversion element, a pair of electrodes, an organic active layer, and an electron extraction layer. A process for heating after laminating (this process is sometimes referred to as an annealing process) has been found, and a manufacturing method for improving the photoelectric conversion efficiency and obtaining a durable photoelectric conversion element has been found, thereby achieving the present invention. It came to do.

That is, the gist of the present invention is as follows.
[1] A substrate, at least a pair of electrodes formed on the substrate, an organic active layer formed between the pair of electrodes, and an electron extraction layer containing a compound represented by the following general formula (I) and a method of manufacturing a photoelectric conversion element, on said substrate, said pair of electrodes, a method for manufacturing a photoelectric conversion element characterized in that it comprises a step of heating after laminating the organic active layer and the electron extraction layer .
Wherein, R ¹ to R ² represent each independently may condensation which may have a substituent polycyclic aromatic group or an aromatic radical, n represents an integer of 1 or more. R ³ is an aromatic group. X is an oxygen atom or a sulfur atom.

Wherein, R ¹ to R ² represent each independently may condensation which may have a substituent polycyclic aromatic group or an aromatic radical, n represents an integer of 1 or more. R ³ is an aromatic group. X is an oxygen atom or a sulfur atom.
[2] The method for producing a photoelectric conversion element according to [1], wherein the organic active layer is formed by a coating method.
[3] The method for producing a photoelectric conversion element according to the temperature of the heating to the process is a fifty to two hundred and eighty ° C. [1] or [2].

  ADVANTAGE OF THE INVENTION According to this invention, the adhesiveness of a semiconductor layer and an electron taking-out layer and / or the adhesiveness of an electron taking-out layer and an electrode can be improved, and the photoelectric conversion element which photoelectric conversion efficiency improves can be provided.

It is sectional drawing which shows typically the structure of the photoelectric conversion element as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell module as one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail.
The description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and is not specified in these contents unless it exceeds the gist of the present invention.
<Photoelectric conversion element>
The photoelectric conversion element according to the present invention has at least one pair of electrodes, a semiconductor layer, and a buffer layer. The semiconductor layer and the buffer layer are disposed between the electrodes. FIG. 1 shows a photoelectric conversion element used in a general organic thin film solar cell, but is not limited thereto.

<Buffer layer>
The buffer layer can be classified into a hole extraction layer and an electron extraction layer, and can be provided between the organic active layer and the electrode, respectively.
<Electronic extraction layer>
The material of the electron extraction layer according to the present invention is characterized by using a compound represented by the following general formula (I).

Wherein, R ¹ to R ² represent each independently may condensation which may have a substituent polycyclic aromatic group or an aromatic radical, n represents an integer of 1 or more. R ³ is an aromatic group. X is an oxygen atom or a sulfur atom.
In the formula, R ¹ and R ² are each independently a condensed polycyclic aromatic group or aromatic group which may have a substituent. Aromatic groups include phenyl, naphthyl, phenanthryl, biphenylenyl, triphenylene, anthryl, pyrenyl, fluorenyl, azulenyl, acenaphthenyl, fluoranthenyl, naphthacenyl, perylenyl, pentacenyl, Aromatic hydrocarbon group such as triphenylenyl group, pyridyl group, thienyl group, furyl group, pyrrole group, oxazole group, thiazole group, oxadiazole group, thiadiazole group, pyrazyl group, pyrimidyl group, pyrazoyl group, imidazoyl group, benzothienyl Group, dibenzofuryl group, dibenzothienyl group, phenylcarbazoyl, phenoxathienyl group, xanthenyl group, benzofuranyl group, thianthenyl group, indolizinyl group, phenoxazinyl group, phenothiazinyl group, acridinini Group, phenanthridinyl group, quinolyl group, isoquinolyl group, indolyl group, an aromatic heterocyclic group such as a quinoxalinyl group. Preferably, aromatic hydrocarbon groups such as phenyl group, naphthyl group, phenanthryl group, triphenylene group, anthryl group, pyrenyl group, fluorenyl group, acenaphthenyl group, fluoranthenyl group, perylenyl group, triphenylenyl group; pyridyl group, pyrazyl group , Pyrimidyl group, pyrazoyl group, quinolyl group, isoquinolyl group, imidazoyl group, acridinyl group, phenanthridinyl group, quinoxalinyl group, dibenzofuryl group, dibenzothienyl group, phenylcarbazoyl group, xanthenyl group, phenoxazinyl group, etc. It is a group.

  The ring forming the condensed polycyclic aromatic group is preferably a cyclic alkyl group which may have a substituent, an aromatic hydrocarbon group which may have a substituent, or a substituent. An aromatic heterocyclic group. Specific examples of the cyclic alkyl group include a cyclopentyl group and a cyclohexyl group. A specific example of the aromatic hydrocarbon group is a phenyl group. Specific examples of the aromatic heterocyclic group include a pyridyl group, thienyl group, furyl group, pyrrole group, oxazole group, thiazole group, oxadiazole group, thiadiazole group, pyrazyl group, pyrimidyl group, pyrazoyl group, as specific examples. An imidazolyl group, and the like. As the aromatic heterocyclic group, a pyridyl group and a thienyl group are preferable.

The condensed polycyclic aromatic group is a group in which the ring is condensed. Preferably, condensed polycyclic hydrocarbon groups such as phenanthryl group, anthryl group, pyrenyl group, fluoranthenyl group, naphthacenyl group, perylenyl group, pentacenyl group, triphenylenyl group, phenoxazinyl group, phenothiazinyl group, acridinyl group, phenanthate A lysinyl group, and the like.
Among them, a phosphine oxide compound substituted with an aryl group and a phosphine sulfide compound substituted with an aryl group are preferable, and a triaryl phosphine oxide compound, a triaryl phosphine sulfide compound, and two diaryl phosphine oxide units are more preferable. Aromatic hydrocarbon compounds having two or more diarylphosphine sulfide units, triarylphosphine oxide compounds composed of aryl substituted with fluorine atoms or perfluoroalkyl groups, two diarylphosphine oxide units An aromatic hydrocarbon compound having the above. In addition to the above materials, alkali metal or alkaline earth metal may be doped.

  Specific examples of the compound include the following.

  The compound represented by the general formula (I) according to the present invention is not particularly limited, but is preferably a compound having a glass transition temperature (hereinafter sometimes referred to as Tg) of 80 ° C. or higher. More preferably, it is 100 ° C. or higher, and more preferably 120 ° C. or higher. The upper limit is not particularly limited, and some compounds do not have a glass transition temperature, which is preferable because it has high thermal stability.

  If the glass transition temperature is too low, when used in the electron extraction layer of a photoelectric conversion element, the material of the electron extraction layer changes between an amorphous state and a crystalline state within the operating temperature range, and the state changes to provide an electron extraction layer. Stability is lost. When the glass transition temperature is too low, when used in a photoelectric conversion element, the electron extraction layer material is likely to be in a crystalline state within the operating temperature range, and there is a possibility that defects in the electron extraction layer can be formed.

  The glass transition temperature according to the present invention is defined as the point at which the specific heat of an organic compound in an amorphous state is changed to a temperature at which local molecular motion is initiated by thermal energy. When the temperature further increases, the solid structure changes and crystallization occurs (the temperature at this time is defined as the crystallization temperature (Tc)). When the temperature rises further, it generally melts at the melting point (Tm) and changes to a liquid state. However, the molecules may be decomposed or sublimated at a high temperature, and their phase transition may not be observed. What is necessary is just to measure a glass transition temperature by a well-known method, for example, DSC method is mentioned.

The material of the electron extraction layer of the present invention may be doped with an alkali metal or an alkaline earth metal in addition to the compound represented by the general formula (I).
The thickness of the electron extraction layer is not particularly limited, but is preferably 0.01 nm or more and 40 nm or less. More preferably, it is 20 nm or less. There is a problem that it is difficult to take out too large electrons and the photoelectric conversion efficiency is lowered, and when it is too small, there is a problem that the function as a material of the buffer layer is not achieved.

  The adhesion between the electron extraction layer and the electrode and / or the electron extraction layer and the semiconductor layer is important in terms of durability. When the device is operated for a long time, the layer is stressed due to changes in temperature or mechanical properties of the material.If the adhesion is poor, the laminated structure may be peeled off, resulting in deterioration of characteristics. Conceivable. Interlayer adhesion is considered to increase as the surface energy of the layer increases.

<Hole extraction layer>
The material of the hole extraction layer is not particularly limited as long as it is a material capable of improving the efficiency of extracting holes from the organic active layer to the electrode. Specifically, polythiophene, polypyrrole, polyacetylene, triphenylenediamine polypyrrole, polyaniline and the like doped with a conductive polymer such as sulfonic acid and / or iodine, a conductive organic compound such as arylamine, a p-type semiconductor described later, and the like. . Among them, a conductive polymer doped with sulfonic acid is preferable, and PEDOT / PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. A thin film of metal such as gold, indium, silver or palladium can also be used. Furthermore, a thin film of metal or the like may be formed alone or in combination with the above organic material.

The thickness of the hole extraction layer is not particularly limited, but is usually 10 nm or more, preferably 30 nm or more, and usually 200 nm or less. If it is too thin, the uniformity is not sufficient and a short circuit tends to occur.
In general, poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) is used as a hole extraction layer on the transparent electrode (ITO) surface. Although it contributes to the improvement of characteristics, PEDOT: PSS has poor stability to heat and light, and structural breakdown occurs with heat and light irradiation. The decomposition component of PEDOT: PSS diffuses to the electron extraction electrode (Al) side and may cause unstable operation and short circuit. Although the mechanism of action is not yet clear, the electron extraction layer containing the inorganic compound of the present invention and an organic compound having a glass transition temperature (Tg) of 80 ° C. or more is applied to the electrode (Al) side of the decomposition component of PEDOT: PSS. One of the factors is considered to be improving durability and the like by blocking the transition.

  The hole extraction layer and the electron extraction layer are disposed so as to sandwich the organic active layer between a pair of electrodes. That is, when the photoelectric conversion element according to the present invention includes both the hole extraction layer and the electron extraction layer, the electrode, the hole extraction layer, the active layer, the electron extraction layer, and the electrode are arranged in this order. When the photoelectric conversion element according to the present invention includes an electron extraction layer and does not include a hole extraction layer, the electrode, the active layer, the electron extraction layer, and the electrode are arranged in this order. The stacking order of the hole extraction layer and the electron extraction layer may be reversed, or at least one of the hole extraction layer and the electron extraction layer may be composed of a plurality of different films.

  There is no restriction | limiting in the formation method of a hole taking-out layer and an electron taking-out layer. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or inkjet. When a semiconductor material is used for the hole extraction layer, the precursor may be converted into a semiconductor material after forming the layer using the precursor, similarly to the low molecular weight compound of the organic active layer.

<Electrode>
In the photoelectric conversion element according to the present invention, any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Further, it is preferable that the transparent electrode has a solar ray transmittance of 70% or more in order to allow the transparent electrode to pass through and allow light to reach the organic active layer. The light transmittance can be measured with a normal spectrophotometer.

  The material used for the transparent electrode is not particularly limited as long as it has conductivity. For example, nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide ( IZO), conductive metal oxides such as titanium oxide, indium oxide, and zinc oxide, metals such as gold, platinum, silver, and chromium and alloys thereof, polythiophene derivatives doped with polystyrene sulfonic acid, polypyrrole and Examples thereof include conductive polymers doped with iodine or the like in polyaniline. These electrode materials may be used alone, or a plurality of materials may be mixed and used. Especially, it is preferable to use transparent electrodes, such as oxides, such as ITO, a tin oxide, a zinc oxide, and an indium zinc oxide (IZO), in the electrode in the position which light permeate | transmits. Alternatively, a material having a high work function such as ITO (indium tin oxide), tin oxide, zinc oxide, gold, cobalt, nickel, or platinum may be used in combination with aluminum, silver, lithium, indium, calcium, magnesium, or the like. .

  The film thickness of the transparent electrode is not limited and can be arbitrarily selected according to the resistance value. However, it is preferably 10 nm or more, particularly 50 nm or more, and usually 1000 nm or less, particularly 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. If the electrode is too thick, the transparency may decrease and the cost may be high. If the electrode is too thin, the series resistance may be large and the performance may be deteriorated.

The sheet resistance of the transparent electrode is 300Ω / □ or less, more preferably 200Ω / □ or less, from the viewpoint of increasing the short-circuit current.
The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, it is preferable to use an electrode material suitable for collecting holes and electrons for the electrode.
Examples of the electrode material suitable for collecting holes include materials having a high work function such as Au and ITO. On the other hand, an electrode material suitable for collecting electrons includes a material having a low work function such as Al.

In addition, there is no restriction | limiting in the formation method of an electrode. For example, it can be formed by a dry process such as vacuum deposition or sputtering. Further, for example, it can be formed by a wet process using a conductive ink or the like. At this time, any conductive ink can be used. For example, a conductive polymer, a metal particle dispersion, or the like can be used.
Furthermore, two or more electrodes may be stacked, and characteristics (electric characteristics, wetting characteristics, etc.) due to surface treatment may be improved.

  The counter electrode is preferably a metal such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium and magnesium, and alloys thereof, lithium fluoride, fluorine. Examples thereof include inorganic salts such as cesium oxide, metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. From the viewpoint of electrode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals are preferable.

The film thickness of the counter electrode is not limited and can be arbitrarily selected according to the resistance value. However, it is preferably 10 nm or more, particularly 50 nm or more, and usually 1000 nm or less, particularly 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less.
There is no restriction | limiting also in the formation method of a counter electrode. For example, it can be formed by a dry process such as vacuum deposition, electron beam, sputtering, plating, or CVD. Further, for example, it can be formed by a wet process such as ion plating coating, sol-gel, spin coating, and ink jet. At this time, any conductive ink can be used. For example, a conductive polymer, a metal particle dispersion, or the like can be used. Further, two or more electrodes may be laminated, and characteristics (electric characteristics, wetting characteristics, etc.) may be improved by surface treatment.

<Board>
The photoelectric conversion element according to the present invention usually has a substrate serving as a support. That is, an electrode, an organic active layer, and a buffer layer are formed on the substrate. The material of the substrate (substrate material) is arbitrary as long as the effects of the present invention are not significantly impaired. Preferable examples of the substrate material include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine Resin films, polyolefins such as vinyl chloride and polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, epoxy resin and other organic materials; paper, synthetic paper and other paper materials; stainless steel, Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as titanium or aluminum to impart insulation.

Examples of the glass include soda glass, blue plate glass, and alkali-free glass. As for the glass material, alkali-free glass is preferred because it is better that there are fewer ions eluted from the glass.
There is no restriction | limiting in the shape of a board | substrate, For example, shapes, such as a board, a film, a sheet | seat, can be used. There is no limitation on the thickness of the substrate. However, it is preferably 5 μm or more, especially 20 μm or more, and usually 20 mm or less, especially 10 mm or less. If the substrate is too thin, the strength of the semiconductor device may be insufficient, and if the substrate is too thick, the cost may be increased or the weight may be increased. Further, when the substrate is glass, if it is too thin, the mechanical strength is reduced and the substrate is easily broken. More preferably, it is 0.1 mm or more. Moreover, since weight will become heavy when too thick, Preferably it is 1 cm or less and 0.5 cm or less.

<Organic active layer>
In the photoelectric conversion element according to the present invention, the organic active layer includes a p-type semiconductor and an n-type semiconductor. In the photoelectric conversion element, light is absorbed by the organic active layer, electricity is generated at the interface between the p-type semiconductor and the n-type semiconductor, and the generated electricity is extracted from the electrode.
The layer structure of the organic active layer is a thin film stacked type in which a p-type semiconductor and an n-type semiconductor are stacked, a bulk heterojunction type in which a p-type semiconductor and an n-type semiconductor are mixed, and a p-type semiconductor and an n-type intermediate layer A structure having a layer (i layer) in which semiconductors are mixed can be given. In particular, when the p-type semiconductor is a high-molecular material, a bulk heterojunction type in which a p-type semiconductor and an n-type semiconductor are mixed is preferable. A structure having a layer (i layer) in which a n-type semiconductor and an n-type semiconductor are mixed is preferable.

The p-type semiconductor is not particularly limited, and examples thereof include a low molecular material and a high molecular material. Low molecular weight materials such as condensed aromatic hydrocarbons such as naphthacene, pentacene and pyrene; oligothiophenes containing 4 or more thiophene rings such as α-sexithiophene; thiophene ring, benzene ring, fluorene ring, naphthalene ring, anthracene A ring, a thiazole ring, a thiadiazole ring, a benzothiazole ring having a total of 4 or more linked; a phthalocyanine compound and a metal complex thereof, and a porphyrin compound such as tetrabenzoporphyrin and a macrocycle compound such as a metal complex thereof. A phthalocyanine compound and a metal complex thereof, or a porphyrin compound such as tetrabenzoporphyrin and a metal complex thereof are preferable.
Examples of the porphyrin compound and its metal complex (Q in the figure are Q), the phthalocyanine compound and its metal complex (Q is N) used as a p-type semiconductor material include compounds having the following structures.

Here, M represents a metal or two hydrogen atoms. As the metal, in addition to a divalent metal such as Cu, Zn, Pb, Mg, Co, Ni, a trivalent or higher metal having an axial ligand. For example, TiO, VO, SnCl2, AlCl, InCl, Si, and the like can also be mentioned.
Y ^{1 to} Y ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 24 carbon atoms. The alkyl group having 1 to 24 carbon atoms preferably represents an alkyl group having 1 to 12 carbon atoms.

  Among the phthalocyanine compounds and metal complexes thereof, 29H, 31H-phthalocyanine, copper phthalocyanine complex, zinc phthalocyanine complex, titanium phthalocyanine oxide complex, magnesium phthalocyanine complex, lead phthalocyanine complex, copper 4,4 ′, 4 ″, 4 '' '-Tetraaza-29H, 31H-phthalocyanine complex, more preferably 29H, 31H-phthalocyanine, copper phthalocyanine complex. In addition, the above kind of compound or a mixture of plural kinds of compounds may be used.

Among the porphyrin compounds and metal complexes thereof, 5,10,15,20-tetraphenyl-21H, 23H-porphine, 5,10,15,20-tetraphenyl-21H, 23H-porphine cobalt (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine copper (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20- Tetraphenyl-21H, 23H-porphine vanadium (IV) oxide, 5,10,15,20-tetra (4-pyridyl) -21H, 23H-porphine, preferably 5,10,15,20-tetraphenyl -21H, 23H-porphine. In addition, the above kind of compound or a mixture of plural kinds of compounds may be used.
In addition, the above kind of compound or a mixture of plural kinds of compounds may be used. Low molecular weight materials include film formation by vapor deposition or film formation by applying a semiconductor compound precursor and then converting it to a semiconductor.

The semiconductor compound precursor according to the present invention is converted into a semiconductor compound by changing the chemical structure of the semiconductor compound precursor by applying an external stimulus such as overheating or light irradiation to the semiconductor compound precursor. Is.
Further, the semiconductor compound precursor according to the present invention is preferably excellent in film formability. In particular, in order to be able to apply the coating method, the semiconductor compound precursor itself can be applied in a liquid state, or the semiconductor compound precursor can be applied as a solution with high solubility in some solvent. It is preferable. If the suitable range of solubility is raised, the solubility with respect to the solvent of a semiconductor compound precursor will be 0.1 weight% or more normally, Preferably it is 0.5 weight% or more, More preferably, it is 1 weight% or more.

  The type of the solvent is not particularly limited as long as it can uniformly dissolve or disperse the semiconductor precursor compound. For example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane, decane; toluene, xylene Aromatic hydrocarbons such as chlorobenzene and orthodichlorobenzene; lower alcohols such as methanol, ethanol and propanol; ketones such as acetone, methyl ethyl ketone, cyclopentanone and cyclohexanone; esters such as ethyl acetate, butyl acetate and methyl lactate Halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane, trichloroethylene; ethers such as ethyl ether, tetrahydrofuran, dioxane; dimethylformamide, dimethylacetate Amides such as amides. Among these, aromatic hydrocarbons such as toluene, xylene, chlorobenzene and orthodichlorobenzene, and halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane and trichloroethylene are preferable.

Furthermore, it is preferable that the semiconductor compound precursor according to the present invention can be easily converted into a semiconductor compound. In the step of converting a semiconductor compound precursor to a semiconductor compound, which will be described later, what kind of external stimulus is given to the semiconductor precursor is arbitrary, but usually heat treatment, light treatment, etc. are performed. Preferably, it is heat treatment. In this case, it is preferable that a part of the skeleton of the semiconductor compound precursor has a solvophilic group with respect to a predetermined solvent that can be eliminated by a reverse Diels-Alder reaction.

  Moreover, it is preferable that the semiconductor compound precursor which concerns on this invention is converted into a semiconductor compound with a high yield through a conversion process. Under the present circumstances, the yield of the semiconductor compound obtained by converting from a semiconductor compound precursor is arbitrary unless the performance of an organic photoelectric conversion element is impaired. If the suitable range of a yield is raised, the yield of the semiconductor compound obtained from a semiconductor compound precursor is so preferable that it is high, and is 90 mol% or more normally, Preferably it is 95 mol% or more, More preferably, it is 99 mol% or more.

The semiconductor compound precursor according to the present invention is not particularly limited as long as it has the above-described characteristics, but as a specific semiconductor compound precursor, a compound described in JP-A-2007-324587 can be used. Among them, preferred examples include compounds represented by the following formula (1).

In formula (1), at least one of X ¹ and X ² represents a group that forms a π-conjugated divalent aromatic ring, Z ¹ -Z ² is a group that can be removed by heat or light, The π-conjugated compound obtained by elimination of Z ¹ -Z ² represents a pigment molecule. Further, X ¹ and X ² which are not a group forming a π-conjugated divalent aromatic ring represent a substituted or unsubstituted ethenylene group.
In the compound represented by the formula (1), Z ¹ -Z ² is eliminated by heat or light as shown in the following chemical reaction formula to form a π-conjugated compound having high planarity. This produced π-conjugated compound is a semiconductor compound according to the present invention. In the present invention, the semiconductor compound preferably exhibits semiconductor characteristics.

  Examples of the compound represented by the formula (1) include the following. T-Bu represents a t-butyl group. M represents a divalent metal atom or an atomic group in which a trivalent or higher metal and another atom are bonded.

  For example, specific examples of converting the semiconductor compound precursor include the following.

  Examples of the polymer material include conjugated polymer semiconductors such as polythiophene, polyfluorene, polythienylene vinylene, polyacetylene, and polyaniline; and polymer semiconductors such as alkyl-substituted oligothiophene. These are semiconductors that are soluble in an organic solvent, and are preferable because a coating method can be used in the manufacturing process of an organic solar cell element. In addition, the above kind of compound or a mixture of plural kinds of compounds may be used.

It is desirable to use a porphyrin compound and / or a polymer semiconductor as the p-type semiconductor.
The n-type semiconductor according to the present invention is specifically an n-type semiconductor such as a fullerene compound, a quinolinol derivative metal complex typified by 8-hydroxyquinoline aluminum, naphthalene tetracarboxylic acid diimide, and perylene tetracarboxylic acid diimide. Fused ring tetracarboxylic acid diimides, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives, aldazine derivatives, bisstyryl Derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives, bipyridine derivatives, anthracene, pyrene, naphthacene, pentacene, etc. All fluorides case polycyclic aromatic, single-walled carbon nanotubes, polyquinoline, polypyridine, polyaniline, poly (benzo-bis-imidazo benzo phenanthroline), boron polymer, cyano-substituted polyphenylene vinylene, and the like. Among them, a fullerene compound is preferable. One or more of these may be included.

As the fullerene compound of the present invention, fullerene compounds represented by the general formulas (I), (II), (III) and (IV) are preferable.

In the formula, FLN represents fullerene which is a carbon cluster having a closed shell structure. The carbon number of fullerene is not limited as long as it is usually an even number of 60 to 1 3 0. The fullerene, for _{example, C 6 0, C 7 0} , C 7 6, C 7 8, C 8 2, C 8 4, C 9 0, C 9
_4, such as C _{9 6} and higher carbon cluster having a number of carbon than these. Among these, C ₆₀ or C ₇₀ is preferable. As fullerenes, carbon-carbon bonds on some fullerene rings may be broken. Some carbon atoms may be replaced with other atoms. Furthermore, a metal atom, a non-metal atom, or an atomic group composed of these may be included in the fullerene cage.

a, b, c and d are integers, and the sum of a, b, c and d is usually 1 to 5, preferably 1 to 3. The additional group in (I), (II), (III), (IV) is added to the same 5-membered ring or 6-membered ring in the fullerene skeleton. e is an integer of 1-8. e is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.
R ¹ in the general formula (I) has an optionally substituted alkyl group having 1 to 14 carbon atoms, an optionally substituted alkoxy group having 1 to 14 carbon atoms, and a substituent. An aromatic group that may be present. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group, particularly preferably a methyl group, It is an ethyl group. The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably a methoxy group or an ethoxy group. The aromatic group is an aromatic hydrocarbon group having 3 to 10 carbon atoms or an aromatic heterocyclic group, preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group, more preferably a phenyl group or a thienyl group. is there. The substituent which may be substituted on the alkyl group is a halogen atom or a silyl group. The halogen atom that may be substituted is preferably a fluorine atom. The silyl group that may be substituted is a diarylalkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group, or a trialkylsilyl group, preferably a dialkylarylsilyl group, more preferably a dimethylarylsilyl group. It is.

R ^{2 to} R ⁴ in the general formula (II) each represent an independent substituent, and have a hydrogen atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, and a substituent. May be an aromatic group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, or an n-hexyl group. It is a group. The fluorinated alkyl group is preferably a perfluorooctyl group, a perfluorohexyl group, or a perfluorobutyl group. The aromatic group is an aromatic hydrocarbon group having 3 to 10 carbon atoms or an aromatic heterocyclic group, preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group, more preferably a phenyl group or a thienyl group. is there. The substituent that the aromatic group may have is a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group or an alkoxy group, and an aromatic group having 3 to 10 carbon atoms, preferably a fluorine atom. Or it is a C1-C14 alkoxy group, More preferably, they are a methoxy group, n-butoxy group, and 2-ethylhexyloxy group. When the aromatic group has a substituent, the number is not limited, but is preferably 1 to 3, and more preferably 1. When the aromatic group has a plurality of substituents, the types of the substituents may be different, but are preferably the same.

R ^{5 to} R ⁹ in the general formula (III) are each independently a hydrogen atom, an alkyl group having 1 to 14 carbon atoms or an aromatic group which may have a substituent. The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-hexyl group, or an octyl group, and more preferably a methyl group. The aromatic group is an aromatic hydrocarbon group having 3 to 10 carbon atoms or an aromatic heterocyclic group, preferably a phenyl group or a pyridyl group, and more preferably a phenyl group. Although there is no limitation in particular as a substituent which an aromatic group may have, Preferably it is a fluorine atom, a C1-C14 alkyl group, a C1-C14 fluorinated alkyl group, and a C1-C14 alkoxy group. More preferably, it is a C1-C14 alkoxy group, More preferably, it is a methoxy group. When it has a substituent, there is no limitation in the number, However, Preferably it is 1-3, More preferably, it is 1. The types of substituents may be different but are preferably the same.

Ar ¹ in the general formula (III) is an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group having 3 to 10 carbon atoms, preferably a phenyl group, a naphthyl group, or a biphenyl group. , Thienyl group, furyl group, pyridyl group, pyrimidyl group, quinolyl group and quinoxalyl group, more preferably phenyl group, thienyl group and furyl group. The substituent that may be present is not limited, but is preferably a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group, an alkoxy group, an ester group, an alkylcarbonyl group, an arylcarbonyl group, Preferred are a fluorine atom, an alkoxy group, an ester group and an arylcarbonyl group, and more preferred are a methoxy group, a methyl ester group, an n-butyl ester group and a benzoyl group. When it has a substituent, although there is no limitation in the number, Preferably it is 1-3, More preferably, it is 1-2. When there are a plurality of substituents, the types may be different but are preferably the same.

R ^{10 to} R ¹³ in the general formula (III) are each independently a hydrogen atom, an oxygen atom, a sulfur atom, an alkyl group which may have a substituent, an amino group which may have a substituent, or An alkoxy group which may have a substituent. Bonded between R ¹⁰ or R ¹¹ and R ¹² or R ¹³ , or between R ¹⁰ or R ¹¹ and one of R ¹² or R ¹³ and the carbon atom forming the skeleton of (III). A ring may be formed. The structure in the case of forming a ring can be represented by, for example, the general formula (V) which is a bicyclo structure in which an aromatic group is condensed. F in the general formula (V) is the same as c, and X is an amino group, methoxy which may be substituted with an alkyl group having 1 to 6 carbon atoms such as an oxygen atom, a sulfur atom, a methyl group or an ethyl group. 1 or 6 carbon atoms which may be substituted with an alkoxyl group having 1 to 6 carbon atoms such as a group, a hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 3 to 10 carbon atoms or an aromatic heterocyclic group 2 is an arylene group such as an alkylene group or a phenylene group.

R ^{14 to} R ¹⁵ in the general formula (IV) are each independently a hydrogen atom, an alkoxycarbonyl group, an optionally substituted alkyl group having 1 to 14 carbon atoms, or a substituent. May be an aromatic group.
The alkoxy group in the alkoxycarbonyl group is a hydrocarbon group having 1 to 12 carbon atoms or a fluorinated alkyl group, more preferably a hydrocarbon group having 1 to 12 carbon atoms, more preferably a methyl group, an ethyl group, n -Propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group, octyl group, 2-propylpentyl group, 2-ethylhexyl group, 2-ethylhexyl group, cyclohexylmethyl group, benzyl group, more preferably Are a methyl group, an ethyl group, an isopropyl group, an n-butyl group, an isobutyl group, and an n-hexyl group.

The alkyl group is preferably a linear alkyl group having 1 to 8 carbon atoms, and more preferably an n-propyl group. There is no particular limitation on the substituent that the alkyl group may have, but an alkoxycarbonyl group is preferred. The alkoxy group of the alkoxycarbonyl group is a hydrocarbon group having 1 to 14 carbon atoms or a fluorinated alkyl group, preferably a hydrocarbon group having 1 to 14 carbon atoms, more preferably a methyl group, an ethyl group, n- Propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group, octyl group, 2-propylpentyl group,
2-ethylhexyl group, 2-ethylhexyl group, cyclohexylmethyl group and benzyl group, more preferably methyl group and n-butyl group.

  The aromatic group is an aromatic hydrocarbon group having 3 to 10 carbon atoms or an aromatic heterocyclic group, preferably a phenyl group, a biphenyl group, a thienyl group, a furyl group, or a pyridyl group, more preferably a phenyl group, Thienyl group. The substituent that the aromatic group may have is preferably an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms, and more preferably It is a C1-C14 alkoxy group, More preferably, they are a methoxy group and 2-ethylhexyloxy group. When it has a substituent, there is no limitation in the number, However, Preferably it is 1-3, More preferably, it is 1. The types of substituents may be different or the same, preferably the same.

Preferably, as the structure of the general formula (IV), R ¹⁴ and R ¹⁵ are both alkoxycarbonyl groups, R ¹⁴ and R ¹⁵ are both aromatic groups, R ¹⁴ is an aromatic group, and R ¹⁵ Is a 3- (alkoxycarbonyl) propyl group.
In addition, as a fullerene compound, the said 1 type compound or the mixture of multiple types of compound may be sufficient.

In order for the fullerene compound to be applicable to the coating method, the fullerene compound itself can be applied in a liquid state, or the semiconductor compound precursor can be applied as a solution with high solubility in some solvent. It is preferable. As a preferable range of solubility, the solubility in toluene at 25 ° C. is usually 0.1% by weight or more, preferably 0.4% by weight or more, more preferably 0.7% by weight or more. If the solubility is too low, the dispersion stability of the fullerene compound is lowered, and aggregation, sedimentation, separation, and the like are likely to occur.

  Although there is no restriction | limiting in particular as a preparation method of an organic active layer, The coating method is preferable. The coating method can be performed by any of the following methods. Examples include reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor method, impregnation / coating method, curtain coating method and the like.

  The thickness of the organic active layer is not particularly limited, but if it is less than 10 nm, there is a problem that uniformity is not sufficient and a short circuit is likely to occur. On the other hand, when the thickness of the organic active layer exceeds 1000 nm, the internal resistance increases, and the problem arises that the distance between the electrodes is increased and the charge diffusion is deteriorated, which is not preferable. Therefore, the thickness of the organic active layer is preferably 10 to 1000 nm, and more preferably 50 to 200 nm.

<Production method of photoelectric element>
[Overview]
The present invention relates to a method for producing a photoelectric conversion element comprising a substrate, at least a pair of electrodes formed on the substrate, a semiconductor layer formed between the electrodes, and an electron extraction layer containing a specific compound. A process for producing a photoelectric conversion element comprising a step of heating after all of a substrate of a conversion element, a pair of electrodes, a semiconductor layer, and an electron extraction layer are stacked.

Although there is no special restriction | limiting about the manufacturing method of a board | substrate, a pair of electrode, an organic active layer, and an electronic taking-out layer, The method as described in each said item can be used.
The step of heating the photoelectric conversion element in which the substrate, the pair of electrodes, the organic active layer, and the electron extraction layer are all laminated (sometimes referred to as an annealing treatment step) means that the photoelectric conversion element is usually 50 ° C. or higher, preferably It is preferable to heat in the temperature range of 80 ° C. or higher, usually 280 ° C. or lower, preferably 250 ° C. or lower. If the temperature of the annealing process is too low, the effect of improving the adhesion between the electron extraction layer and the electrode and / or the electron extraction layer and the semiconductor layer cannot be sufficiently obtained, and if the temperature of the annealing process is too high, There is a possibility that the compound of the organic active layer is thermally decomposed. In addition, about temperature operation, you may heat in steps within the said range.

  The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment is preferably terminated when the open circuit voltage, the short circuit current, and the fill factor, which are parameters of the solar cell performance, reach constant values. Further, it is preferable to carry out the annealing treatment in an inert gas atmosphere under normal pressure.

The annealing step improves the adhesion between the electron extraction layer and the electrode and / or the electron extraction layer and the organic active layer, thereby improving the thermal stability and durability of the photoelectric conversion element, as well as the organic active layer. The effect of promoting self-organization is obtained.
As a method for heating, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be put in a heating atmosphere such as an oven. Further, it may be a batch type or a continuous type.

<Solar cell module>
It is preferable that the photoelectric conversion element of this invention is used as a thin film solar cell as a solar cell element.
FIG. 2 is a cross-sectional view schematically showing the configuration of a thin film solar cell as one embodiment of the present invention. As shown in FIG. 2, the thin-film solar cell 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5,
A solar cell element 6, a sealing material 7, a getter material film 8, a gas barrier film 9, and a backsheet 10 are provided in this order, and a seal that seals the edge of the weatherproof protective film 1 and the backsheet 10. A material 11 is provided. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 is formed, and the solar cell element 6 generates power. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. .

[Weather-resistant protective film 1]
The weather-resistant protective film 1 is a film that protects the solar cell element 6 from weather changes.
Some components of the solar cell element 6 are deteriorated by temperature change, humidity change, natural light, erosion caused by wind and rain, and the like. Therefore, by covering the solar cell element 6 with the weather-resistant protective film 1, the solar cell element 6 and the like are protected from weather changes and the power generation capacity is kept high.

Since the weather-resistant protective film 1 is located on the outermost layer of the thin-film solar cell 14, it is suitable as a surface covering material for the thin-film solar cell 14 such as weather resistance, heat resistance, transparency, water repellency, stain resistance, and mechanical strength. It is preferable that it has a good performance and has the property of maintaining it for a long period of time in outdoor exposure.
Moreover, the weather-resistant protective film 1 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, more preferably 90% or more, and particularly preferably 95%.

  Furthermore, since the thin-film solar cell 14 is often heated by receiving light, it is preferable that the weather-resistant protective film 1 also has heat resistance. From this viewpoint, the melting point of the constituent material of the weather-resistant protective film 1 is usually 100 ° C. or higher, preferably 120 or higher, more preferably 130 or higher, and usually 350 or lower, preferably 320 or lower, more preferably 300 or lower. It is. By increasing the melting point, it is possible to reduce the possibility that the weather resistant protective film 1 is melted and deteriorated when the thin film solar cell 14 is used.

  The material which comprises the weather-resistant protective film 1 is arbitrary as long as it can protect the solar cell element 6 from a weather change. Examples of the material include polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene Examples thereof include polyester resins such as naphthalate, phenol resins, polyacrylic resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicone resins, and polycarbonate resins.

  Among them, fluorine resin is preferable, and specific examples thereof include polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoride. Propylene copolymer (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Can be mentioned.

In addition, the weather-resistant protective film 1 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the weather-resistant protective film 1 may be formed with the single layer film, the laminated | multilayer film provided with the film of 2 or more layers may be sufficient as it.
The thickness of the weather-resistant protective film 1 is not particularly specified, but is usually 10 μm or more, preferably 1
It is 5 μm or more, more preferably 20 μm or more, and is usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

Moreover, you may perform surface treatments, such as a corona treatment and a plasma treatment, for the weather-resistant protective film 1 in order to improve adhesiveness with another film.
The weatherproof protective film 1 is preferably provided on the outer side as much as possible in the thin-film solar cell 14. This is because more of the constituent members of the thin-film solar cell 14 can be protected.

[UV cut film 2]
The ultraviolet cut film 2 is a film that prevents the transmission of ultraviolet rays.
Some components of the thin film solar cell 14 are deteriorated by ultraviolet rays. Some of the gas barrier films 3 and 9 are deteriorated by ultraviolet rays depending on the type. Therefore, the ultraviolet cut film 2 is provided in the light receiving portion of the thin-film solar cell 14, and the ultraviolet cut film 2 covers the light receiving surface 6a of the solar cell element 6, so that the solar cell element 6 and, if necessary, the gas barrier films 3, 9 etc. Can be protected from ultraviolet rays and the power generation capacity can be kept high.

The degree of the ability to suppress the transmission of ultraviolet rays required for the ultraviolet cut film 2 is such that the transmittance of ultraviolet rays (for example, wavelength 300 nm) is preferably 50% or less, more preferably 30% or less, and particularly preferably. 10% or less.
Further, the ultraviolet cut film 2 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, the ultraviolet cut film 2 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the ultraviolet cut film 2 is usually 100 or more, preferably 120 or more, more preferably 130 or more, and usually 350 or less, preferably 320 or less, more preferably 300 or less. . If the melting point is too low, the ultraviolet cut film 2 may melt when the thin film solar cell 14 is used.

Moreover, the ultraviolet cut film 2 has a high softness | flexibility, its adhesiveness with an adjacent film is favorable, and what can cut water vapor | steam and oxygen is preferable.
The material which comprises the ultraviolet cut film 2 is arbitrary if the intensity | strength of an ultraviolet-ray can be weakened. Examples of the material include films formed by blending an ultraviolet absorber with an epoxy, acrylic, urethane, or ester resin. Further, a film in which a layer of an ultraviolet absorbent dispersed or dissolved in a resin (hereinafter referred to as “ultraviolet absorbing layer” as appropriate) is formed on a base film may be used.

  As the ultraviolet absorber, for example, a salicylic acid-based, benzophenone-based, benzotriazole-based, or cyanoacrylate-based one can be used. Of these, benzophenone and benzotriazole are preferable. Examples of this include various aromatic organic compounds such as benzophenone and benzotriazole. In addition, a ultraviolet absorber may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

As described above, a film in which an ultraviolet absorbing layer is formed on a base film can be used as the ultraviolet absorbing film. Such a film can be produced, for example, by applying a coating solution containing an ultraviolet absorber on a substrate film and drying it.
Although the material of a base film is not specifically limited, For example, polyester is mentioned at the point from which the balance of heat resistance and a softness | flexibility is obtained.

  Application | coating can be performed by arbitrary methods. Examples include reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating, air knife coating, wire barber coating, pipe doctor method, impregnation / coating method, curtain coating method and the like. In addition, these methods may be performed alone or in any combination of two or more.

  The solvent used for the coating solution is not particularly limited as long as it can uniformly dissolve or disperse the UV absorber. For example, liquid resin can be used as a solvent, and examples thereof include various synthetic resins such as polyester, acrylic, polyamide, polyurethane, polyolefin, polycarbonate, and polystyrene. It is done. Further, for example, natural polymers such as gelatin and cellulose derivatives; water, alcohol mixed solutions such as water and ethanol, and the like can also be used as the solvent. Further, an organic solvent may be used as the solvent. If an organic solvent is used, it becomes possible to dissolve or disperse the pigment and the resin, and to improve the coatability. In addition, 1 type may be used for a solvent and it may use 2 or more types together by arbitrary combinations and a ratio.

The coating solution may further contain a surfactant. Use of the surfactant improves the dispersibility of the ultraviolet absorbing dye in the resin. Thereby, in an ultraviolet absorption layer, generation | occurrence | production of the dent by adhesion of foreign matters etc. by a fine bubble, the repelling in a drying process, etc. are suppressed.
Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Among these, a silicon-based surfactant or a fluorine-based surfactant is preferable. In addition, 1 type may be used for surfactant and it may use 2 or more types together by arbitrary combinations and a ratio.

In addition, the drying after apply | coating a coating liquid to a base film can employ | adopt well-known drying methods, such as hot air drying and drying by an infrared heater, for example. Among these, hot air drying with a high drying speed is preferable.
Examples of specific products of the ultraviolet cut film 2 include Cut Ace (MKV Plastic Co., Ltd.).

The ultraviolet cut film 2 may be formed of one kind of material or may be formed of two or more kinds of materials. Further, the ultraviolet cut film 2 may be formed of a single layer film, but may be a laminated film including two or more layers.
The thickness of the ultraviolet cut film 2 is not particularly defined, but is usually 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase the absorption of ultraviolet rays, and decreasing the thickness tends to increase the transmittance of visible light.

Although the ultraviolet cut film 2 should just be provided in the position which covers at least one part of the light-receiving surface 6a of the solar cell element 6, Preferably it is provided in the position which covers all the light-receiving surfaces 6a of the solar cell element 6. FIG.
However, the ultraviolet cut film 2 may be provided at a position other than the position covering the light receiving surface 6 a of the solar cell element 6.
[Gas barrier film 3]
The gas barrier film 3 is a film that prevents permeation of water and oxygen.

The solar cell element 6 tends to be vulnerable to moisture and oxygen. In particular, transparent electrodes such as ZnO: Al, compound semiconductor solar cell elements, and organic solar cell elements may be deteriorated by moisture and oxygen. Therefore, by covering the solar cell element 6 with the gas barrier film 3, the solar cell element 6 can be protected from water and oxygen, and the power generation capacity can be kept high.
The degree of moisture resistance required for the gas barrier film 3 varies depending on the type of the solar cell element 6 and the like. For example, when the solar cell element 6 is a compound semiconductor solar cell element, the water vapor permeability per unit area (1 m ² ) per day is 1 × 10 ⁻¹ g / m ² / day or less. Is preferably 1 × 10 ⁻² g / m ² / day or less, more preferably 1 × 10 ⁻³ g / m ² / day or less, and further preferably 1 × 10 ⁻⁴ g / m ^2. / Day or less is particularly preferable, 1 × 10 ⁻⁵ g / m ² / day or less is particularly preferable, and 1 × 10 ⁻⁶ g / m ² / day or less is particularly preferable.

Moreover, when the solar cell element 6 is an organic solar cell element, it is preferable that the water vapor permeability per unit area (1 m ² ) per day is 1 × 10 ⁻¹ g / m ² / day or less. It is more preferably 1 × 10 ⁻² g / m ² / day or less, further preferably 1 × 10 ⁻³ g / m ² / day or less, and further preferably 1 × 10 ⁻⁴ g / m ² / day. Among them, the following is particularly preferable, and it is particularly preferably 1 × 10 ⁻⁵ g / m ² / day or less, and particularly preferably 1 × 10 ⁻⁶ g / m ² / day or less. The more water vapor has to pass through, the lower the degradation caused by the reaction of the solar cell element 6 and the transparent electrode such as ZnO: Al of the element 6 with moisture, thus increasing the power generation efficiency and extending the life.

The degree of oxygen permeability required for the gas barrier film 3 varies depending on the type of the solar cell element 6 and the like. For example, when the solar cell element 6 is a compound semiconductor solar cell element, the oxygen permeability per unit area (1 m ² ) per day is 1 × 10 ⁻¹ cc / m ² / day / atm or less. Preferably, it is 1 × 10 ⁻² cc / m ² / day / atm or less, more preferably 1 × 10 ⁻³ cc / m ² / day / atm or less, and further preferably 1 × 10 2. ⁻⁴ cc / m ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁵ cc / m ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁶ cc / m ² / day. / Atm or less is particularly preferable. For example, when the solar cell element 6 is an organic solar cell element, the oxygen permeability per unit area (1 m ² ) per day is 1 × 10 ⁻¹ cc / m ² / day / atm or less. Preferably, it is 1 × 10 ⁻² cc / m ² / day / atm or less, more preferably 1 × 10 ⁻³ cc / m ² / day / atm or less, and further preferably 1 × 10 2. ⁻⁴ cc / m ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁵ cc / m ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁶ cc / m ² / day. / Atm or less is particularly preferable. The deterioration due to oxidation of the solar cell element 6 and the transparent electrode such as ZnO: Al of the element 6 is suppressed as the oxygen does not permeate.

  Conventionally, it has been difficult to mount the gas barrier film 3 having such a high moisture-proof and oxygen-blocking capability, so that a solar cell including an excellent solar cell element such as a compound semiconductor solar cell element and an organic solar cell element is realized. Although it was difficult to carry out, implementation of the thin film solar cell 14 which utilized the outstanding properties, such as a compound semiconductor type solar cell element and an organic solar cell element, becomes easy by applying such a gas barrier film 3.

  Further, the gas barrier film 3 is preferably one that transmits visible light from the viewpoint of not preventing the light absorption of the solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. Preferably it is 90% or more, Especially preferably, it is 95% or more, Especially preferably, it is 97% or more. This is to convert more sunlight into electrical energy.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the gas barrier film 3 also has heat resistance. From this viewpoint, the melting point of the constituent material of the gas barrier film 3 is usually 100 or more, preferably 120 or more, more preferably 130 or more, and usually 350 or less, preferably 320 or less, more preferably 300 or less. By increasing the melting point, it is possible to reduce the possibility that the gas barrier film 3 is melted and deteriorated when the thin film solar cell 14 is used.

The specific configuration of the gas barrier film 3 is arbitrary as long as the solar cell element 6 can be protected from water. However, since the production cost increases as the amount of water vapor or oxygen that can permeate the gas barrier film 3 increases, it is preferable to use an appropriate film considering these points comprehensively.
Hereinafter, the configuration of the gas barrier film 3 will be described with examples.

Two examples of the configuration of the gas barrier film 3 are preferable.
The first example is a film in which an inorganic barrier layer is disposed on a plastic film substrate. In this case, the inorganic barrier layer may be formed only on one side of the plastic film substrate, or may be formed on both sides of the plastic film substrate. When forming on both surfaces, the number of inorganic barrier layers formed on both surfaces may be the same or different.

  The second example is a film in which a unit layer composed of two layers in which an inorganic barrier layer and a polymer layer are arranged adjacent to each other is formed on a plastic film substrate. At this time, a unit layer composed of two layers in which an inorganic barrier layer and a polymer layer are arranged adjacent to each other is regarded as one unit, and this unit layer is composed of one unit (one inorganic barrier layer and one polymer layer are combined into one unit). (Meaning of unit) may be formed, but two or more units may be formed. For example, 2 to 5 units may be laminated.

  The unit layer may be formed only on one side of the plastic film substrate, or may be formed on both sides of the plastic film substrate. When forming on both surfaces, the numbers of inorganic barrier layers and polymer layers formed on both surfaces may be the same or different. In addition, when forming a unit layer on a plastic film substrate, an inorganic barrier layer may be formed and then a polymer layer may be formed thereon, or after forming a polymer layer and forming an inorganic barrier layer. Also good.

(Plastic film substrate)
The plastic film substrate used for the gas barrier film 3 is not particularly limited as long as it is a film capable of holding the above-described inorganic barrier layer and polymer layer, and can be appropriately selected from the purpose of use of the gas barrier film 3 and the like.
Examples of the plastic film base material include polyester resin, polyarylate resin, polyethersulfone resin, fluorene ring-modified polycarbonate resin, alicyclic modified polycarbonate resin, and acryloyl compound. It is also preferable to use a condensation polymer containing spirobiindane or spirobichroman. Among the polyester resins, biaxially stretched polyethylene terephthalate (PET) and biaxially stretched polyethylene naphthalate (PEN) are preferably used as a plastic film substrate because they are excellent in thermal dimensional stability.

In addition, 1 type may be used for the material of a plastic film base material, and 2 or more types may be used together by arbitrary combinations and a ratio.
The thickness of the plastic film substrate is not particularly defined, but is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

  The plastic film substrate is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. Preferably it is 90% or more, Especially preferably, it is 95% or more, Especially preferably, it is 97% or more. This is to convert more sunlight into electrical energy.

  An anchor coat agent layer (anchor coat layer) may be formed on the plastic film substrate in order to improve adhesion to the inorganic barrier layer. Usually, the anchor coat layer is formed by applying an anchor coat agent. Examples of the anchor coating agent include polyester resins, urethane resins, acrylic resins, oxazoline group-containing resins, carbodiimide group-containing resins, epoxy group-containing resins, isocyanate-containing resins, and copolymers thereof. Among these, a combination of at least one of a polyester resin, a urethane resin, and an acrylic resin and at least one of an oxazoline group-containing resin, a carbodiimide group-containing resin, an epoxy group-containing resin, and an isocyanate group-containing resin is preferable. In addition, an anchor coat agent may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The thickness of the anchor coat layer is usually 0.005 μm or more, preferably 0.01 μm or more, and usually 5 μm or less, preferably 1 μm or less. If the thickness is less than or equal to the upper limit of this range, the slipperiness is good, and there is almost no peeling from the plastic film substrate due to the internal stress of the anchor coat layer itself. Moreover, if it is the thickness more than the lower limit of this range, a uniform thickness can be maintained and it is preferable.

In addition, in order to improve the applicability and adhesion of the anchor coating agent to the plastic film substrate, the plastic film substrate may be subjected to a surface treatment such as normal chemical treatment or electric discharge treatment before application of the anchor coating agent. Good.
(Inorganic barrier layer)
The inorganic barrier layer is usually a layer formed of a metal oxide, nitride or oxynitride. In addition, the metal oxide, nitride, and oxynitride which form an inorganic barrier layer may be 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Examples of the metal oxide include oxides such as Si, Al, Mg, In, Ni, Sn, Zn, Ti, Cu, Ce, and Ta, nitrides, and oxynitrides. Among these, in order to achieve both high barrier properties and high transparency, it is preferable to include aluminum oxide or silicon oxide, and it is particularly preferable to include silicon oxide from the viewpoint of moisture permeability and light transmittance.

The ratio of each metal atom to oxygen atom is also arbitrary, but in order to improve the transparency of the inorganic barrier layer and prevent coloring, the oxygen atom ratio should be extremely small from the stoichiometric ratio of the oxide. Is desirable. On the other hand, in order to improve the denseness of the inorganic barrier layer and increase the barrier property, it is desirable to reduce oxygen atoms. From this viewpoint, for example, when SiO _x is used as the metal oxide, the value of x is particularly preferably 1.5 to 1.8. For example, when AlO _x is used as the metal oxide, the value of x is particularly preferably 1.0 to 1.4.

Moreover, when an inorganic barrier layer is comprised from 2 or more types of metal oxides, it is desirable to contain aluminum oxide and silicon oxide as a metal oxide. Among them, when the inorganic barrier layer is made of aluminum oxide and silicon oxide, the ratio of aluminum to silicon in the inorganic barrier layer can be arbitrarily set, but the ratio of Si / Al is usually 1/9 or more, preferably 2/8 or more, and usually 9/1 or less, preferably 2/8 or less.

When the thickness of the inorganic barrier layer is increased, the barrier property tends to be increased. However, it is desirable to reduce the thickness in order to prevent cracking and prevent cracking when bent. Therefore, the appropriate thickness of the inorganic barrier layer is usually 5 nm or more, preferably 10 nm or more, and is usually 1000 nm or less, preferably 200 nm or less.
Although there is no restriction | limiting in the film-forming method of an inorganic barrier layer, Generally, it can carry out by sputtering method, a vacuum evaporation method, an ion plating method, plasma CVD method etc. For example, the sputtering method can be formed by a reactive sputtering method using plasma using one or more metal targets and oxygen gas as raw materials.

(Polymer layer)
Any polymer can be used for the polymer layer, and for example, a film that can be formed in a vacuum chamber can be used. In addition, the polymer which comprises a polymer layer may use 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.
A wide variety of compounds can be used as the compound that gives the polymer, and examples include the following (i) to (vii). In addition, 1 type may be used for a monomer and it may use 2 or more types together by arbitrary combinations and a ratio.

  (I) Examples include siloxanes such as hexamethyldisiloxane. An example of a method for forming a polymer layer in the case of using hexamethyldisiloxane is to introduce hexamethyldisiloxane as a vapor into a parallel plate type plasma apparatus using an RF electrode, to cause a polymerization reaction in the plasma, The polymer layer can be formed as a polysiloxane thin film by being deposited on a plastic film substrate.

  (Ii) Examples include paraxylylene such as diparaxylylene. An example of a method for forming a polymer layer in the case of using diparaxylylene is as follows. First, the vapor of diparaxylylene is heated at 650 to 700 in a high vacuum to generate thermal radicals. And the polymer layer can be formed by guiding the radical monomer vapor into the chamber and adsorbing it on the plastic film substrate, and at the same time proceeding radical polymerization reaction to deposit polyparaxylylene.

(Iii) For example, a monomer capable of alternately repeating addition polymerization of two kinds of monomers can be mentioned. The polymer thus obtained is a polyaddition polymer. Examples of the polyaddition polymer include polyurethane (diisocyanate / glycol), polyurea (diisocyanate / diamine), polythiourea (dithioisocyanate / diamine), polythioether urethane (bisethyleneurethane / dithiol), polyimine ( Bisepoxy / primary amine), polypeptide amide (bisazolactone / diamine), polyamide (diolefin / diamide) and the like.

(Iv) For example, an acrylate monomer can be mentioned. The acrylate monomer includes monofunctional, bifunctional, and polyfunctional acrylate monomers, and any of them may be used. However, in order to obtain an appropriate evaporation rate, degree of cure, cure rate, and the like, it is preferable to use a combination of two or more of the above acrylate monomers.
Examples of monofunctional acrylate monomers include aliphatic acrylate monomers, alicyclic acrylate monomers, ether acrylate monomers, cyclic ether acrylate monomers, aromatic acrylate monomers, hydroxyl group-containing acrylate monomers, carboxy group-containing acrylate monomers, and the like. There are, but any can be used.

  (V) Monomers capable of obtaining a photocationically cured polymer, such as epoxy and oxetane, are exemplified. As an epoxy-type monomer, an alicyclic epoxy-type monomer, a bifunctional monomer, a polyfunctional oligomer etc. are mentioned, for example. Examples of the oxetane monomer include monofunctional oxetane, bifunctional oxetane, and oxetane having a silsesquioxane structure.

(Vi) An example is vinyl acetate. When vinyl acetate is used as a monomer, polyvinyl alcohol is obtained by saponifying the polymer, and this polyvinyl alcohol can be used as a polymer.
(Vii) For example, acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid,
Examples thereof include unsaturated carboxylic acids such as itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride and itaconic anhydride. These constitute a copolymer with ethylene, and the copolymer can be used as a polymer. Furthermore, a mixture thereof, a mixture obtained by mixing glycidyl ether compounds, and a mixture with an epoxy compound can also be used as the polymer.

  There is no restriction | limiting in the polymerization method of a monomer when superposing | polymerizing the said monomer and producing | generating a polymer. However, the polymerization is usually carried out after a composition containing a monomer is applied or deposited to form a film. As an example of the polymerization method, when a thermal polymerization initiator is used, the polymerization is started by contact heating with a heater or the like; radiation heating with infrared rays, microwaves or the like; Moreover, when a photoinitiator is used, an active energy ray is irradiated and polymerization is started. Various light sources can be used when irradiating active energy rays, such as mercury arc lamps, xenon arc lamps, fluorescent lamps, carbon arc lamps, tungsten-halogen radiation lamps, and sunlight irradiation light. Can do. Further, electron beam irradiation or atmospheric pressure plasma treatment can also be performed.

Examples of the method for forming the polymer layer include a coating method and a vacuum film forming method.
When the polymer layer is formed by a coating method, for example, methods such as roll coating, gravure coating, knife coating, dip coating, curtain flow coating, spray coating, and bar coating can be used. Moreover, you may make it apply | coat the coating liquid for polymer layer formation in mist form. In this case, the average particle size of the droplets may be adjusted to an appropriate range. For example, when forming a coating liquid containing a polymerizable monomer in the form of a mist on a plastic film substrate, the droplets The average particle size of is 5 μm or less, preferably 1 μm or less.

On the other hand, when forming a polymer layer by a vacuum film-forming method, film-forming methods, such as vapor deposition and plasma CVD, are mentioned, for example.
The thickness of the polymer layer is not particularly limited, but is usually 10 nm or more, and is usually 5000 nm or less, preferably 2000 nm or less, more preferably 1000 nm or less. By increasing the thickness of the polymer layer, the uniformity of the thickness can be easily obtained, and structural defects of the inorganic barrier layer can be efficiently filled with the polymer layer, and the barrier property tends to be improved. In addition, by reducing the thickness of the polymer layer, the barrier property can be improved because the polymer layer itself is less likely to crack due to an external force such as bending.

Particularly suitable gas barrier film 3 includes, for example, a film obtained by vacuum-depositing SiO _x on a base film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).
In addition, the gas barrier film 3 may be formed with 1 type of material, and may be formed with 2 or more types of materials. The gas barrier film 3 may be formed of a single layer film, but may be a laminated film including two or more layers.

  The thickness of the gas barrier film 3 is not particularly defined, but is usually 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and is usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase gas barrier properties, and decreasing the thickness tends to increase flexibility and improve visible light transmittance.

  As long as the gas barrier film 3 covers the solar cell element 6 and can be protected from moisture and oxygen, the formation position is not limited. However, the front surface of the solar cell element 6 (surface on the light receiving surface side, lower surface in FIG. 2) and It is preferable to cover the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2). This is because the front and back surfaces of the thin film solar cell 14 are often formed in a larger area than the other surfaces. In this embodiment, the gas barrier film 3 covers the front surface of the solar cell element 6, and a gas barrier film 9 described later covers the back surface of the solar cell element 6. Then, the edges of the gas barrier films 3 and 9 are sealed with the sealing material 11, and the solar cell elements 6 are placed in the space surrounded by the gas barrier films 3 and 9 and the sealing material 11, so that the solar cell elements 6 It can be protected from oxygen. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. .

[Getter material film 4]
The getter material film 4 is a film that absorbs moisture and / or oxygen. Some components of the solar cell element 6 are deteriorated by moisture as described above, and some are deteriorated by oxygen. Therefore, by covering the solar cell element 6 with the getter material film 4, the solar cell element 6 and the like are protected from moisture and / or oxygen, and the power generation capacity is kept high.

  Here, unlike the gas barrier film 3 as described above, the getter material film 4 does not prevent moisture permeation but absorbs moisture. By using a film that absorbs moisture, when the solar cell element 6 is covered with the gas barrier film 3 or the like, the getter material film 4 absorbs moisture that slightly enters the space formed by the gas barrier films 3 and 9 and the sealing material 11. Can be captured and the influence of moisture on the solar cell element 6 can be eliminated.

The degree of water absorption capacity of the getter material film 4 is usually 0.1 mg / cm ² or more, preferably 0.5 mg / cm ² or more, more preferably 1 mg / cm ² or more. The higher this value, the higher the water absorption capacity, and the deterioration of the solar cell element 6 can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is usually 10 mg / cm < ² > or less.
Further, when the getter material film 4 absorbs oxygen, when the solar cell element 6 is covered with the gas barrier films 3, 9, etc., it slightly enters the space formed by the gas barrier films 3, 9 and the seal material 11. Oxygen is captured by the getter material film 4 and the influence of the oxygen on the solar cell element 6 can be eliminated.

  Furthermore, the getter material film 4 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. Preferably it is 90% or more, Especially preferably, it is 95% or more, Especially preferably, it is 97% or more. This is to convert more sunlight into electrical energy.

Furthermore, since the thin film solar cell 14 is often heated by receiving light, the getter material film 4 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the getter material film 4 is usually 100 or more, preferably 120 or more, more preferably 130 or more, and usually 350 or less, preferably 320 or less, more preferably 300 or less. . By increasing the melting point, it is possible to reduce the possibility that the getter material film 4 melts and deteriorates when the thin-film solar cell 14 is used.

  The material constituting the getter material film 4 is arbitrary as long as it can absorb moisture and / or oxygen. Examples of the material include alkali metal, alkaline earth metal, alkaline earth metal oxide, alkali metal or alkaline earth metal hydroxide, silica gel, zeolite compound, magnesium sulfate as a substance that absorbs moisture. And sulfates such as sodium sulfate and nickel sulfate, and organometallic compounds such as aluminum metal complexes and aluminum oxide octylates. Specifically, examples of the alkaline earth metal include Ca, Sr, and Ba. Examples of the alkaline earth metal oxide include CaO, SrO, and BaO. In addition, Zr-Al-BaO, an aluminum metal complex, etc. are also mentioned. Specific product names include, for example, OleDry (manufactured by Futaba Electronics).

Examples of the substance that absorbs oxygen include activated carbon, silica gel, activated alumina, molecular sieve, magnesium oxide, and iron oxide. In addition, Fe, Mn, Zn, and inorganic salts such as sulfates, chlorides, and nitrates of these metals are also included.
In addition, the getter material film 4 may be formed of one type of material or may be formed of two or more types of materials. The getter material film 4 may be formed of a single layer film, but may be a laminated film including two or more layers.

The thickness of the getter material film 4 is not particularly specified, but is usually 5 μm or more, preferably 10 μm or more, more preferably 15 μm or more, and usually 200 μm or less, preferably 180 μm or less, more preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.
If the getter material film 4 is in the space formed by the gas barrier films 3, 9 and the sealing material 11, the formation position is not limited. However, the front surface of the solar cell element 6 (surface on the light receiving surface side; lower in FIG. 2). Side surface) and the back surface (surface opposite to the light receiving surface; upper surface in FIG. 2) are preferably covered. This is because, in the thin film solar cell 14, the front and back surfaces are often formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, the getter material film 4 is preferably provided between the gas barrier film 3 and the solar cell element 6. In this embodiment, the getter material film 4 covers the front surface of the solar cell element 6, a getter material film 8 described later covers the back surface of the solar cell element 6, and the getter material films 4 and 8 are respectively the solar cell element 6 and the gas barrier film 3. , 9 are located between them. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. .

  The getter material film 4 can be formed by any method depending on the type of the water-absorbing agent or desiccant. For example, a method of attaching a film in which the water-absorbing agent or desiccant is dispersed with an adhesive, water-absorbing agent or desiccant A method of applying the solution by a spin coating method, an inkjet method, a dispenser method, or the like can be used. A film forming method such as a vacuum evaporation method or a sputtering method may be used.

Examples of the film for the water absorbing agent or the drying agent include polyethylene resins, polypropylene resins, cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymers (AS resins), and acrylonitrile-butadiene-styrene copolymers. (ABS resin), polyvinyl chloride resin, fluorine resin, poly (meth) acrylic resin, polycarbonate resin, and the like can be used. Among these, films of polyethylene resin, fluorine resin, cyclic polyolefin resin, and polycarbonate resin are preferable. In addition, the said resin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

[Sealing material 5]
The sealing material 5 is a film that reinforces the solar cell element 6. Since the solar cell element 6 is thin, the strength is usually weak, and thus the strength of the thin film solar cell tends to be weak. However, the strength can be maintained high by the sealing material 5.
Moreover, it is preferable that the sealing material 5 has high strength from the viewpoint of maintaining the strength of the thin-film solar cell 14.

The specific strength is related to the strength of the weatherproof protective film 1 other than the sealing material 5 and the strength of the back sheet 10 and is generally difficult to define, but the thin film solar cell 14 as a whole has good bending workability. However, it is desirable to have a strength that does not cause peeling of the bent portion.
In addition, the sealing material 5 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more, and particularly preferably 85% or more. Preferably it is 90% or more, Especially preferably, it is 95% or more, Especially preferably, it is 97% or more. This is to convert more sunlight into electrical energy.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the sealing material 5 also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material 5 is usually 100 or more, preferably 120 or more, more preferably 130 or more, and usually 350 or less, preferably 320 or less, more preferably 300 or less. . By increasing the melting point, it is possible to reduce the possibility that the sealing material 5 melts and deteriorates when the thin film solar cell 14 is used.

  The thickness of the sealing material 5 is not particularly defined, but is usually 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and usually 700 μm or less, preferably 600 μm or less, more preferably 500 μm or less. Increasing the thickness tends to increase the strength of the thin-film solar cell 14 as a whole, and decreasing the thickness tends to increase flexibility and improve visible light transmittance.

  As a material which comprises the sealing material 5, what used the ethylene-vinyl acetate copolymer (EVA) resin composition for the film (EVA film) etc. can be used, for example. In order to improve weather resistance, the EVA film is usually blended with a crosslinking agent to form a crosslinked structure. As the crosslinking agent, an organic peroxide that generates radicals at 100 ° C. or higher is generally used. Examples of such an organic peroxide include 2,5-dimethylhexane; 2,5-dihydroperoxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; Di-t-butyl peroxide or the like can be used. The compounding amount of these organic peroxides is usually 5 parts by weight or less, preferably 3 parts by weight or less, and usually 1 part by weight or more with respect to 100 parts by weight of the EVA resin. In addition, 1 type may be used for a crosslinking agent and it may use 2 or more types together by arbitrary combinations and a ratio.

This EVA resin composition may contain a silane coupling agent for the purpose of improving the adhesive strength. Examples of silane coupling agents used for this purpose include γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tris- (β-methoxyethoxy) silane; γ-methacryloxypropyltri Methoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane and the like can be mentioned. The compounding amount of these silane coupling agents is usually 5 parts by weight or less, preferably 2 parts by weight or less, and usually 0.1 parts by weight or more with respect to 100 parts by weight of the EVA resin.
In addition, 1 type may be used for a silane coupling agent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, in order to improve the gel fraction of the EVA resin and improve the durability, a crosslinking aid may be included in the EVA resin composition. Examples of the crosslinking aid provided for this purpose include monofunctional crosslinking aids such as trifunctional crosslinking aids such as triallyl isocyanurate and triallyl isocyanate. The amount of these crosslinking aids is usually 10 parts by weight or less, preferably 5 parts by weight or less, and usually 1 part by weight or more with respect to 100 parts by weight of the EVA resin. In addition, 1 type may be used for a crosslinking adjuvant, and 2 or more types may be used together by arbitrary combinations and a ratio.

Furthermore, for the purpose of improving the stability of the EVA resin, the EVA resin composition may contain, for example, hydroquinone; hydroquinone monomethyl ether; p-benzoquinone; methyl hydroquinone. These compounding quantities are normally 5 weight part or less with respect to 100 weight part of EVA resin.
However, since the EVA resin cross-linking process requires a relatively long time of about 1 to 2 hours, it may cause a reduction in the production rate and production efficiency of the thin-film solar cell 14. Further, when used for a long period of time, the decomposition gas (acetic acid gas) of the EVA resin composition or the vinyl acetate group of the EVA resin itself may adversely affect the solar cell element 6 and reduce the power generation efficiency. Therefore, as the sealing material 5, in addition to the EVA film, a copolymer film made of a propylene / ethylene / α-olefin copolymer can also be used. As this copolymer, the thermoplastic resin composition with which the following component 1 and the component 2 were mix | blended is mentioned, for example.

Component 1: The propylene-based polymer is usually 0 part by weight or more, preferably 10 parts by weight or more, and usually 70 parts by weight or less, preferably 50 parts by weight or less.
-Component 2: A soft propylene-type copolymer is 30 weight part or more, Preferably it is 50 weight part or more, and is 100 weight part or less normally, Preferably it is 90 weight part or less.
The total amount of component 1 and component 2 is 100 parts by weight. As described above, when component 1 and component 2 are in a preferred range, the moldability of the encapsulant 5 into a sheet is good, and the resulting encapsulant 5 has good heat resistance, transparency, and flexibility. Therefore, it is suitable for the thin film solar cell 14.

The thermoplastic resin composition in which the above component 1 and component 2 are blended has a melt flow rate (ASTM D 1238, 230 degrees, load 2.16 kg) of usually 0.0001 g / 10 min or more. It is 1000 g / 10 min or less, preferably 900 g / 10 min or less, more preferably 800 g / 10 min or less.
The melting point of the thermoplastic resin composition containing component 1 and component 2 is usually 100 or more, preferably 110 or more. Moreover, it is 140 or less normally, Preferably it is 135 or less.

In addition, the density of the thermoplastic resin composition in which component 1 and component 2 are blended and BR> wound is 0.98 g.
/ Cm ³ or less is preferable, 0.95 g / cm ³ or less is more preferable, and 0.94 g / cm ³ or less is more preferable.
In this sealing material 5, it is possible to mix | blend a coupling agent with the said component 1 and component 2 as an adhesion promoter with respect to a plastics. As the coupling agent, silane, titanate, and chromium coupling agents are preferably used, and a silane coupling agent (silane coupling agent) is particularly preferably used.

Known silane coupling agents can be used and are not particularly limited. For example, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxy-ethoxysilane), γ-glycidoxypropyl-tri Piltrie methoxysilane, γ-
Examples include aminopropyltriethoxysilane. In addition, 1 type may be used for a coupling agent and it may use 2 or more types together by arbitrary combinations and a ratio.

These are usually 0.1 parts by weight or more, usually 5 parts by weight or less, preferably 100 parts by weight of the silane coupling agent, based on 100 parts by weight of the thermoplastic resin composition (total amount of Component 1 and Component 2). It is desirable to contain 3 parts by weight or less.
The coupling agent may be grafted to the thermoplastic resin composition using an organic peroxide. In this case, it is desirable that 0.1 to 5 parts by weight of the coupling agent is included with respect to 100 parts by weight of the thermoplastic resin composition (total amount of component 1 and component 2). Even if a silane-grafted thermoplastic resin composition is used, the same or better adhesiveness as that of the silane coupling agent blend can be obtained for glass and plastic.

When the organic peroxide is used, the organic peroxide is usually 0.001 part by weight or more, preferably 0.01 part by weight with respect to 100 parts by weight of the thermoplastic resin composition (total amount of Component 1 and Component 2). Part or more, and usually 5 parts by weight or less, preferably 3 parts by weight or less.
Further, a copolymer made of an ethylene / α-olefin copolymer can be used as the sealing material 5. Examples of the copolymer include a laminate film having a hot tack property of 5 to 25 ° C., which is formed by laminating a resin composition for a sealing material comprising the following components A and B and a substrate.

Component A: ethylene resin.
Component B: a copolymer of ethylene and an α-olefin having the following properties (a) to (d).
(A) Density is 0.86-0.935 g / cm ³ .
(B) Melt flow rate (MFR) is 1 to 50 g / 10 min.

(C) There is one peak in the elution curve obtained by temperature rising elution fractionation (TREF); the peak temperature is 100 or less.
(D) The integrated elution amount by temperature rising elution fractionation (TREF) is 90% or more at 90 ° C.
The blending ratio (component A / component B) of component A and component B is usually 50/50 or more, preferably 55/45 or more, more preferably 60/40 or more, and usually 99 / 1 or less, preferably 90/10 or less, more preferably 85/15 or less. Increasing the amount of component B tends to increase transparency and heat sealability, and decreasing the amount of component B tends to increase the workability of the film.

  The melt flow rate (MFR) of the resin composition for a sealing material produced by blending component A and component B is usually 2 g / 10 minutes or more, preferably 3 g / 10 minutes or more, and usually 50 g / 10 minutes. Hereinafter, it is preferably 40 g / 10 min or less. In addition, the measurement and evaluation of MFR can be implemented by the method based on JISK7210 (190 degreeC, 2.16kg load).

The melting point of the encapsulant resin composition is preferably 50 or more, more preferably 55 or more, and is usually 300 or less, preferably 250 or less, and more preferably 200 or less. By increasing the melting point, the possibility of melting and deterioration during use of the thin-film solar cell 14 can be reduced.
The density of the resin composition for a sealing material is preferably 0.80 g / cm ³ or more, more preferably 0.85 g / cm ³ or more, and preferably 0.98 g / cm ³ or less, 0.95 g / cm ^3. The following is more preferable, and 0.94 g / cm ³ or less is more preferable. The measurement and evaluation of density can be performed by a method based on JIS K7112.

Further, in the encapsulant 5 using the ethylene / α-olefin copolymer, a coupling agent can be used as in the case of using the propylene / ethylene / α-olefin copolymer.
Since the sealing material 5 described above does not generate a decomposition gas derived from the material, the solar cell element 6 is not adversely affected, and has good heat resistance, mechanical strength, flexibility (solar cell sealing property), and transparency. Have sex. Further, since no material cross-linking step is required, the manufacturing time of the thin film solar cell 100 during sheet molding can be greatly reduced, and the thin film solar cell 14 after use can be easily recycled.

In addition, the sealing material 5 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the sealing material 5 may be formed with the single layer film, the laminated | multilayer film provided with the film of 2 or more layers may be sufficient as it.
The thickness of the sealing material 5 is usually 2 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 500 μm or less, preferably 300 μm or less, more preferably 100 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility and light transmittance.

Although there is no restriction | limiting in the position which provides the sealing material 5, Usually, it provides so that the solar cell element 6 may be inserted | pinched. This is for reliably protecting the solar cell element 6. In this embodiment, the sealing material 5 and the sealing material 7 are provided on the front surface and the back surface of the solar cell element 6, respectively.
[Solar cell element 6]
The solar cell element 6 is the same as the photoelectric conversion element of the other day.

-Connection between solar cell elements Only one solar cell element 6 may be provided for each thin film solar cell 14, but usually two or more solar cell elements 6 are provided. The specific number of solar cell elements 6 may be set arbitrarily. When a plurality of solar cell elements 6 are provided, the solar cell elements 6 are often arranged in an array.

When a plurality of solar cell elements 6 are provided, the solar cell elements 6 are usually electrically connected to each other, and electricity generated from the connected group of solar cell elements 6 is taken out from a terminal (not shown). At this time, the solar cell elements are usually connected in series in order to increase the voltage.
Thus, when connecting the solar cell elements 6, it is preferable that the distance between the solar cell elements 6 is small, and the clearance between the solar cell element 6 and the solar cell element 6 is preferably narrow. This is because the light receiving area of the solar cell element 6 is widened to increase the amount of received light, and the amount of power generated by the thin film solar cell 14 is increased.

[Encapsulant 7]
The sealing material 7 is a film similar to the sealing material 5 described above, and the same material as the sealing material 7 can be used in the same manner except that the arrangement position is different.
Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[Getter material film 8]
The getter material film 8 is the same film as the getter material film 4 described above, and the same material as the getter material film 4 can be used as necessary, except for the arrangement position.
Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used. It is also possible to use a film containing more water or oxygen absorbent than the getter material film 4. Examples of such absorbents include CaO, BaO, Zr-Al-BaO as moisture absorbents, and activated carbon, molecular sieves, etc. as oxygen absorbents.

[Gas barrier film 9]
The gas barrier film 9 is the same film as the gas barrier film 3 described above, and the same material as the gas barrier film 9 can be used as necessary except that the arrangement position is different.
Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

[Backsheet 10]
The back sheet 10 is the same film as the weather-resistant protective film 1 described above, and the same material as the weather-resistant protective film 1 can be used in the same manner except that the arrangement position is different. In addition, if the back sheet 10 is difficult to permeate water and oxygen, the back sheet 10 can also function as a gas barrier layer.

Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used. For this reason, it is particularly preferable to use the following (i) to (iv) as the backsheet 10.
(I) As the back sheet 10, various resin films or sheets excellent in strength and excellent in weather resistance, heat resistance, water resistance, and light resistance can be used. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate or polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyarylphthalate resins Sheet of various resins such as silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose resin, etc. It is possible to use. Among these resin sheets, it is preferable to use a fluorine resin, a cyclic polyolefin resin, a polycarbonate resin, a poly (meth) acrylic resin, a polyamide resin, or a polyester resin sheet. In addition, these may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

(Ii) As the back sheet 10, a metal thin film can also be used. For example, corrosion-resistant aluminum metal foil, stainless steel thin film, and the like can be mentioned. In addition, the said metal may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.
(Iii) As the back sheet 10, for example, a highly waterproof sheet in which a fluorine resin film is bonded to both surfaces of an aluminum foil may be used. Examples of the fluorine-based resin include ethylene monofluoride (trade name: Tedlar, manufactured by DuPont), polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and ethylene or propylene (ETFE), and vinylidene fluoride-based resin. (PVDF), vinyl fluoride resin (PVF) and the like. In addition, 1 type may be used for fluororesin and it may use 2 or more types together by arbitrary combinations and a ratio.

(Iv) As the back sheet 10, for example, an inorganic oxide vapor-deposited film is provided on one side or both sides of the base film, and further, on both sides of the base film provided with the inorganic oxide vapor-deposited film, You may use what laminated | stacked the heat resistant polypropylene resin film. Usually, when a polypropylene resin film is laminated on the base film, the lamination is performed by laminating with a laminating adhesive. By providing an inorganic oxide vapor-deposited film, it can be used as a back sheet 10 having excellent moisture resistance that prevents intrusion of moisture, oxygen and the like.

・ Base film
Basically, as the base film, various resin films having excellent close adhesion with an inorganic oxide vapor deposition film, etc., excellent strength, weather resistance, heat resistance, water resistance, and light resistance are used. Can be used. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate or polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyaryl phthalate resins Silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulosic resin, etc. It is possible to use. Among these, it is preferable to use a film of a fluorine resin, a cyclic polyolefin resin, a polycarbonate resin, a poly (meth) acrylic resin, a polyamide resin, or a polyester resin.

  Among the various resin films described above, for example, a film of a fluorine resin such as polytetrafluoroethylene (PTFE), vinylidene fluoride resin (PVDF), or vinyl fluoride resin (PVF) is used. More preferably it is used. Further, among the fluororesin films, in particular, a fluororesin film (PVF); a fluororesin film made of a copolymer of tetrafluoroethylene and ethylene or propylene (ETFE) is particularly preferable from the viewpoint of strength and the like. preferable. In addition, the said resin may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

Of the various resin films as described above, it is more preferable to use a film of a cyclic polyolefin resin such as cyclopentadiene and a derivative thereof, cyclohexadiene and a derivative thereof.
The film thickness of the base film is usually 12 μm or more, preferably 20 μm or more, and is usually 300 μm or less, preferably 200 μm or less.

・ Deposited film of inorganic oxide
As the inorganic oxide vapor-deposited film, basically any thin film on which a metal oxide is vapor-deposited can be used. For example, a deposited film of an oxide of silicon (Si) or aluminum (Al) can be used. At this time, for example, SiO _x (x = 1.0 to 2.0) can be used as silicon oxide, and for example, AlO _x (x = 0.5 to 1.5) can be used as aluminum oxide. .

In addition, the kind of metal and inorganic oxide to be used may be 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
The thickness of the inorganic oxide vapor-deposited film is usually 50 or more, preferably 100 or more, and usually 4000 or less, preferably 1000 or less.
As a method for forming the deposited film, a chemical vapor deposition method (chemical vapor deposition method, CVD method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method can be used. As a specific example, on one surface of the base film, a monomer gas for vapor deposition such as an organosilicon compound is used as a raw material, an inert gas such as argon gas or helium gas is used as a carrier gas, and oxygen is supplied. An oxygen oxide vapor or the like can be used as a gas, and a vapor deposition film of an inorganic oxide such as silicon oxide can be formed using a low temperature plasma chemical vapor deposition method using a low temperature plasma generator or the like.

-Polypropylene resin film As a polypropylene resin, the homopolymer of propylene; the copolymer of a propylene and another monomer (for example, alpha olefin etc.) can be used, for example. Moreover, an isotactic polymer can also be used as a polypropylene resin.
The melting point of the polypropylene resin is usually 164 to 170, the specific gravity is usually 0.90 to 0.91, and the molecular weight is usually 100,000 to 200,000.

Polypropylene resins are largely controlled by their crystallinity, but high isotactic polymers have excellent tensile strength and impact strength, good heat resistance and bending fatigue strength, and workability. Is very good.
-Adhesive When laminating a polypropylene resin film on a base film, an adhesive for laminating is usually used. Thereby, a base film and a polypropylene resin film are laminated | stacked via the adhesive bond layer for lamination.

  Examples of the adhesive constituting the adhesive layer for laminating include, for example, a polyvinyl acetate adhesive, a polyacrylate adhesive, a cyanoacrylate adhesive, an ethylene copolymer adhesive, a cellulose adhesive, and a polyester adhesive. Adhesives, polyamide adhesives, polyimide adhesives, amino resin adhesives, phenol resin adhesives, epoxy adhesives, polyurethane adhesives, reactive (meth) acrylic adhesives, silicone adhesives, etc. Is mentioned. In addition, 1 type may be used for an adhesive agent and it may use 2 or more types together by arbitrary combinations and a ratio.

The composition system of the adhesive may be any composition form such as an aqueous type, a solution type, an emulsion type, and a dispersion type. Further, the property may be any of film / sheet, powder, solid and the like. Furthermore, the bonding mechanism may be any form such as a chemical reaction type, a solvent volatilization type, a heat melting type, and a hot pressure type.
The adhesive can be applied by a coating method such as a roll coating method, a gravure roll coating method, a kiss coating method, or the like, or a printing method. As the amount of ^{coating, 0.1g / m 2 ~10g / m} 2 is desirable in the dry state.

[Sealant 11]
The sealing material 11 includes the weatherproof protective film 1, the ultraviolet cut film 2, the gas barrier film 3, the getter material film 4, the sealing material 5, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10. It is a member that seals the edge so that moisture and oxygen do not enter the space covered with these films.

The degree of moisture capacity required for the sealing member 11 is preferably water vapor transmission rate per day unit area (1 m ²⁾ is not more than ^{0.1g / m 2 / day, 0.05g} / m 2 / More preferably, it is not more than day. Conventionally, since it has been difficult to mount the sealing material 11 having such a high moisture-proof capability, it is possible to realize a solar cell including an excellent solar cell element such as a compound semiconductor solar cell element and an organic solar cell element. Although it was difficult, the implementation of the thin-film solar cell 14 utilizing the excellent properties of the compound semiconductor solar cell element and the organic solar cell element is facilitated by applying such a sealing material 11.

Furthermore, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the sealing material 11 also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material 11 is usually 100 or more, preferably 120 or more, more preferably 130 or more, and usually 250 ° C. or less, preferably 200 or less, more preferably 180 or less. .
If the melting point is too low, the sealing material 11 may melt when the thin film solar cell 14 is used.

Examples of the material constituting the sealing material 11 include polymers such as a fluorine resin, a silicone resin, and an acrylic resin.
In addition, the sealing material 11 may be formed with 1 type of material, and may be formed with 2 or more types of materials.
The sealing material 11 is provided at a position where at least the edges of the gas barrier films 3 and 9 can be sealed. Thereby, the space surrounded by at least the gas barrier films 3 and 9 and the sealing material 11 can be sealed, and moisture and oxygen can be prevented from entering the space.

Although there is no restriction | limiting in the method of forming this sealing material 11, For example, it can form by inject | pouring material between the weather-resistant protective film 1 and the back sheet | seat 10. FIG. Specific examples of the forming method include the following methods.
That is, for example, while the curing of the sealing material 5 proceeds, the semi-cured thin-film solar cell 14 is taken out from the laminating apparatus, and is the outer peripheral portion of the solar cell element 6, which is the weatherproof protective sheet 1 and the back sheet 10. A liquid polymer may be injected into a portion between the two and the polymer may be cured together with the sealing material 5. Further, after the sealing material 5 has been cured, it may be taken out from the laminating apparatus and cured alone. The temperature range for crosslinking and curing the polymer is usually 130 or more, preferably 140 or more, and usually 180 or less, preferably 170 or less.

[Dimensions]
The thin film solar cell 14 of the present embodiment is usually a thin film member. By forming the thin film solar cell 14 as a film-like member in this way, the thin film solar cell 14 can be easily installed in building materials, automobiles, interiors, and the like. The thin-film solar cell 14 is light and difficult to break, and thus a highly safe solar cell can be obtained and can be applied to a curved surface, so that it can be used for more applications. Since it is thin and light, it is preferable in terms of distribution such as transportation and storage. Furthermore, since it is in the form of a film, it can be manufactured in a roll-to-roll manner, and the cost can be greatly reduced.

Although there is no restriction | limiting in the specific dimension of the thin film solar cell 14, The thickness is 300 micrometers or more normally, Preferably it is 500 micrometers or more, More preferably, it is 700 micrometers or more, Moreover, it is 3000 micrometers or less normally, Preferably it is 2000 micrometers or less, More preferably. It is 1500 micrometers or less.
[Production method]
Although there is no restriction | limiting in the manufacturing method of the thin film solar cell 14 of this embodiment, For example, between the weather-resistant protective film 1 and the back sheet | seat 10, the 1 or 2 or more solar cell element 6 was connected in series or in parallel. The product can be manufactured by laminating with a general vacuum laminating apparatus together with the ultraviolet cut film 2, the gas barrier films 3, 9, the getter material films 4, 8 and the sealing materials 5, 7. At this time, the heating temperature is usually 130 or more, preferably 140 or more, and usually 180 or less, preferably 170 or less. The heating time is usually 10 minutes or longer, preferably 20 minutes or longer, usually 100 minutes or shorter, preferably 90 minutes or shorter. The pressure is usually 0.001 MPa or more, preferably 0.01 MPa or more, and usually 0.2 MPa or less, preferably 0.1 MPa or less. By setting the pressure within this range, sealing can be performed reliably, and the sealing materials 5 and 7 from the end can be prevented from protruding and film thickness reduction due to overpressure can be suppressed, and dimensional stability can be ensured.

[Usage]
There is no restriction | limiting in the use of the thin film solar cell 14 mentioned above, It is arbitrary. For example, as schematically shown in FIG. 3, a solar cell module 13 in which a thin film solar cell 14 is provided on a certain base material 12 is prepared and used at a place of use. As a specific example, when a building material plate is used as the base material 12, a thin film solar cell 14 is provided on the surface of the plate material to produce a solar cell panel as the solar cell module 13, and this solar cell panel is attached to the outer wall of the building. It can be installed and used.

  The substrate 12 is a support member that supports the solar cell element 6. Examples of the material for forming the substrate 12 include inorganic materials such as glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine. Organic materials such as resin films, vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene; paper materials such as paper and synthetic paper; metals such as stainless steel, titanium, and aluminum In addition, a composite material such as a material whose surface is coated or laminated in order to impart insulating properties may be used. In addition, 1 type may be used for the material of a base material, and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, carbon fiber may be included in these organic materials or paper materials to reinforce the mechanical strength.

Examples of fields to which the thin film solar cell of the present invention is applied include solar cells for building materials, solar cells for automobiles, solar cells for interiors, solar cells for railways, solar cells for ships, solar cells for airplanes, solar cells for spacecraft. It is suitable for use in batteries, solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like. Specific examples include the following.
1. Architectural use
1.1 Solar cell as a house roof material When a roof plate or the like is used as a base material, a thin film solar cell is provided on the surface of the plate material to produce a solar cell panel as a solar cell unit. Just install on the roof. Moreover, a roof tile can also be used directly as a base material. The solar cell of the present invention is suitable because it can be brought into close contact with the roof tiles by taking advantage of its flexibility.

1.2 Rooftop
It can also be installed on the roof of a building. A solar cell unit in which a thin film solar cell is provided on a base material can be prepared and installed on the roof of a building. At this time, it is desirable to use a waterproof sheet together with the base material to have a waterproof action. Furthermore, taking advantage of the property that the thin film solar cell of the present invention has flexibility, it can be brought into close contact with a roof that is not flat, for example, a folded roof. In this case, it is desirable to use a waterproof sheet in combination.

1.3 Toplight The thin-film solar cell of the present invention can also be used as an exterior at the entrance or at the atrium. Curves are often used for entrances and the like that have undergone some design processing, and in such a case, the flexibility of the thin film solar cell of the present invention is utilized. In addition, there is a case of see-through in an entrance or the like. In such a case, the green color of the organic solar cell is suitable because a design aesthetic can be obtained in an era when environmental measures are regarded as important.

1.4 Wall
When a building material plate is used as the base material, a thin film solar cell is provided on the surface of the plate material to produce a solar cell panel as a solar cell unit, and this solar cell panel may be installed on the outer wall of a building and used. . It can also be installed on curtain walls. In addition, it can be attached to a spandrel or a vertical.

In this case, the shape of the substrate is not limited, but a plate material is usually used. Moreover, what is necessary is just to set the material of a base material, a dimension, etc. arbitrarily according to the use environment. As an example of such a substrate, Alpolic (registered trademark; manufactured by Mitsubishi Plastics) and the like can be mentioned.
1.5 windows
It can also be used for see-through windows. The green color of the organic solar cell is preferable because a design aesthetic can be obtained in an era when environmental measures are important.

1.6 Other
It can also be used for eaves, louvers, handrails, etc. Even in such a case, the flexibility of the thin film solar cell of the present invention is suitable for these applications.
2. Interior
The thin film solar cell of the present invention can also be attached to a blind slat. Since the thin-film solar cell of the present invention is lightweight and rich in flexibility, such a use is possible. Further, the contents window can be used by utilizing the characteristic that the organic solar cell element is see-through.

3. Vegetable factory
Although the number of plant factories that use illumination light such as fluorescent lamps has increased, the current situation is that it is difficult to reduce cultivation costs due to the cost of electricity for lighting and replacement costs for light sources. Then, the thin film solar cell of this invention can be installed in a vegetable factory, and the illumination system combined with LED or the fluorescent lamp can be produced.

At this time, it is preferable to use an illumination system that combines an LED having a longer life than a fluorescent lamp and the solar cell of the present invention, because the cost required for illumination can be reduced by about 30% compared to the current situation.
Moreover, the solar cell of this invention can also be used for the roof and side wall of the reefer container (reefer container) which conveys vegetables etc. at fixed temperature.

4). Road materials and civil engineering
The thin film solar cell of the present invention can be used for an outer wall of a parking lot, a sound insulation wall of an expressway, an outer wall of a water purification plant, and the like.
5. Automobile
The thin film solar cell of the present invention can be used on the surfaces of automobile bonnets, roofs, trunk lids, doors, front fenders, rear fenders, pillars, bumpers, rearview mirrors and the like. The obtained electric power can be supplied to any of a traveling motor, a motor driving battery, an electrical component, and an electrical component battery. By providing the power generation status in the solar cell panel and the control means for selecting according to the power usage status in the motor for driving, the battery for driving the motor, the electrical equipment, and the battery for electrical equipment, the obtained power is It can be used properly and efficiently.

In the above case, the shape of the substrate 12 is not limited, but a plate material is usually used. Moreover, what is necessary is just to set the material of the base material 12, a dimension, etc. arbitrarily according to the use environment.
Examples of such a substrate 12 include Alpolic (registered trademark; manufactured by Mitsubishi Plastics).

Examples The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
<Synthesis Example 1>
Synthesis of POPy2

In a nitrogen atmosphere, 1-bromopyrene (Tokyo Kasei: 14 g, 50 mmol) is dissolved in dehydrated THF (Kanto Chemical: 200 mL), cooled to -78 ° C, and then n-BuLi (Kanto Chemical: 33 mL, 1.6 M) is slowly added dropwise. The mixture was stirred for 30 minutes while maintaining -78 ° C. Next, dichlorophenylphosphine (
(Tokyo Kasei: 4.3g, 9.0mmol) was added dropwise and stirred well, then warmed to room temperature and stirred for 1.5h. 10.7 g of the desired product was obtained by adding 30 mL of methanol (Pure Chemical) to the resulting reaction solution, filtering the obtained crude product, and recrystallizing with benzene. The compound obtained here was 350 mL of THF (Pure Chemical), 300 mL of CH2Cl2 (Kanto Chemical), Acetone (Kanto Chemical) 1
Dissolved in 00 mL, hydrogen peroxide solution (Wako Pure Chemical: 10 mL of 30% solution) was added, and the mixture was stirred at room temperature for 30 min. The reaction solution was added with 30 mL of water, concentrated to 600 mL, and filtered to obtain 7.5 g of the target product POPy2.

<Synthesis Example 2>
Synthesis of PSPy2

In a N 2 atmosphere, a THF solution of 1-bromopyrene (2.8 g, 10 mmol) was cooled to −78 ° C., and then a hexane solution of n-butyl lithium (6.8 mL, 1.6 M) was added dropwise. 3
After stirring for 0 min, dichlorophenylphosphine (880 mg, 5 mmol) was slowly added dropwise, and the mixture was warmed to room temperature and stirred for 2 hr. The resulting precipitate was filtered, washed with hexane, dissolved in dichloromethane, insolubles were removed by filtration, and concentrated. The obtained crude product was added to THF, S8 (1.5 g, 50 mmol) was added, and the mixture was refluxed for 2 hours. PSPy2 (1.1 g, 2 mmol) was obtained in 40% yield by column chromatography (dichloromethane / hexane (1/1) after concentration of the solvent. The obtained product was subjected to mass spectrometry. It was identified by the method.

<Synthesis Example 3>
Synthesis of BINAPO

BINAP (Wako Pure Chemical: 1.86 g, 3 mmol) in THF (80 mL) solution was added 30% hydrogen peroxide (Wako Pure Chemical: 3 mL) and stirred for 2.5 hours. 20 mL of water was added and THF was distilled off under reduced pressure. The crude product obtained was washed with methanol and filtered to obtain the target product BINAPO (1.78 g, 2.7 mmol) in a yield of 91%, and the obtained product was identified by mass spectrometry.
<Synthesis Example 4>
Synthesis of BINAPS

  Sulfur (660 mg, 20 mmol) was added to a solution of BINAP (Wako Pure Chemical: 1.86 g, 3 mmol) in THF (80 mL), and the mixture was refluxed for 3 hours. After concentration, the product was dissolved in methylene chloride solution, washed with aqueous ammonia chloride and saturated brine, dried over methylene chloride with Na2SO4, and concentrated by filtration. The obtained crude product was purified using column chromatography (developing solvent: dichloromethane) to obtain the target product BINAPS (1.9 g, 2.7 mmol) in a yield of 92%. The resulting product was identified by mass spectrometry.

<Synthesis Example 5>
Synthesis of fullerene compounds (C ₆₀ (CH ₂ SiMe ₂ Ph) [CH ₂ SiMe ₂ (o-An)])

The fullerene compound was synthesized as follows.
[Intermediate 1]
Chloromethyl (2-methoxyphenyl) dimethylsilane, (o-An) Me ₂ SiCH ₂ Cl

To a 500-mL three-necked eggplant flask, a 1.0 M THF solution (100 mL, 0.1 mol) of 2-methoxyphenylmagnesium bromide was placed in a nitrogen atmosphere and stirred at room temperature. Chloromethyldimethylchlorosilane (11.25 mL, 0.085 mol) was slowly added dropwise thereto. After stirring for 1 hour at room temperature, 4
Stir at 0 for 3 hours. It returned to room temperature and water was added slowly. The mixture was extracted with ethyl acetate, washed with brine, dried over sodium sulfate, filtered, and concentrated under reduced pressure. The obtained liquid was distilled under reduced pressure to obtain the desired product (chloromethyl (2-methoxyphenyl) dimethylsilane) as a colorless liquid in a yield of 52% (11.2 g, 0.0522 mol).

[Intermediate 2]
1- (Dimethylphenylsilylmethyl) -1,9-dihydro (C ₆₀ -I _h ) [5,6] fullerene, C ₆₀ (CH ₂ SiMe ₂ Ph) H

In a nitrogen atmosphere, N, N-dimethylformamide (6.45 mL, 83.3 mmol), fullerene C ₆₀ (2.00 g, 2.78 mmol) and 1,2-dichlorobenzene solution (500 mL) were mixed and degassed.
The pressure was restored with nitrogen. A THF solution of chloromethyl (2-methoxyphenyl) dimethylsilane PhMe ₂ SiCH ₂ MgCl (9.80 mL, 0.850 M, 8.33 mmol) obtained in the production of Intermediate 1 was added thereto at 25. After stirring for 10 minutes, degassed saturated aqueous ammonium chloride solution (1.0 mL) was added and stirred. The resulting solution was concentrated, dissolved in toluene (200 mL), passed through a silica gel filtration column, and concentrated. Methanol (about 100 to 200 mL) was added and reprecipitated to obtain a brown solid. The obtained solid was HPLC (Buckyprep column, eluent: toluene / 2-propanol =
7/3) 1- (Dimethylphenylsilylmethyl) -1,9-dihydro (C ₆₀ -Ih) [5.6] fullerene (1.99 g, 2.28 mmol, 82% isolated) yield, analytically pure).

Fullerene compounds (C ₆₀ (CH ₂ SiMe ₂ Ph) [CH ₂ SiMe ₂ (o-An)])

1- (Dimethylphenylsilylmethyl) -1,9-dihydro (C ₆₀ -Ih) [5.6] fullerene C ₆₀ (CH ₂ SiMe ₂ Ph) H (obtained in the production of intermediate 2 under a nitrogen atmosphere 1.02 g, 1.17 mmol) of the benzonitrile solution was degassed, and then a THF solution of potassium t-butoxy (1.41 mL, 1.0 M, 1.41 mmol) was added at 25 ° C. After stirring for 10 minutes, chloromethyl (2-methoxyphenyl) dimethylsilane (o-An) Me ₂ SiCH ₂ Cl (5.03 g, 23.4 mmol) obtained in the production of Intermediate 1 and potassium iodide were added, and 110 ° C. For 17 hours. To the obtained solution was added 1.0 mL of saturated aqueous ammonium chloride solution, and the mixture was concentrated. Toluene (100 mL) was added to the obtained crude product, and the mixture was concentrated by filtration, and then methanol (ca. 50 to 100 mL) was added to perform reprecipitation. The obtained crude product was subjected to silica gel column chromatography (eluent: CS ₂ / hexane = 1/1) purification, followed by HPLC fractionation (Buckyprep column, eluents: toluene / 2-propanol = 7/3) purification. By performing, the target product (0.810 g, 0.772 mmol, 66% isolated yield) was obtained.

<Example 1>
Coating conversion type organic thin film solar cell using POPy2 A poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) aqueous dispersion (H After applying a product name “CLEVIOS ^™ P VP AI4083” manufactured by Sea Starck Co., Ltd. by spin coating, the substrate was subjected to heat treatment in the air on a 120 hot plate for 10 minutes. The film thickness was about 30 nm.

  By putting a compound (compound A) tetrabenzoporphyrin represented by the following formula (A) into a metal boat, vacuum-depositing on the substrate, and then heat-treating the substrate at 180 for 20 minutes in a nitrogen atmosphere, A p-type semiconductor layer of about 25 nm was formed on the hole extraction layer.

  A solution prepared by dissolving 0.6% by weight of Compound B and 1.4% by weight of the fullerene compound obtained in Synthesis Example 5 in a 1: 1 mixed solvent (weight) of chloroform / monochlorobenzene was prepared, filtered, and filtered. The filtrate obtained under the atmosphere was spin-coated at 1500 rpm and heated at 180 for 20 minutes. Thus, a mixture layer containing tetrabenzoporphyrin (compound A) and a fullerene compound of about 100 nm was formed on the p-type semiconductor layer.

Next, a solution in which 1.2% by weight of a fullerene compound was dissolved in toluene was prepared and filtered, and the filtrate obtained in a nitrogen atmosphere was spin-coated at 3000 rpm and subjected to heat treatment at 180 for 5 minutes. This formed a fullerene compound layer of about 50 nm on the mixture layer.
Next, POPy2 obtained in Synthesis Example 1 is placed in a metal boat placed in a vacuum evaporation system.
It heated and vapor-deposited until it became a film thickness of 10 nm, and the electron taking-out layer was formed on the layer of a fullerene compound.

Furthermore, an aluminum electrode having a thickness of 80 nm was provided on the electron extraction layer by vacuum vapor deposition to produce a solar cell. A solar cell sealed using a glass plate as a sealing plate was irradiated with light of 100 mW / cm ^{2 with} a solar simulator (AM1.5G) from the ITO electrode side, and a source meter (Caysley, Model 2400) Then, the current-voltage characteristics between the ITO electrode and the aluminum electrode were measured (this value is the value before the heat treatment) and listed in Table 1. Then, this solar cell was heat-treated with a hot plate at 120 ° C. for 10 minutes, and the current-voltage characteristics between the ITO electrode and the aluminum electrode were measured (this value is the value after the heat treatment). Described.

<Example 2>
In Example 1, a solar cell was prepared in the same manner except that PSPy2 obtained in Synthesis Example 2 was used instead of POPy2 in the buffer layer, and the current between the ITO electrode and the aluminum electrode before and after the heat treatment was -Voltage characteristics were measured and listed in Table 1.
<Example 3>
In Example 1, BINAPO obtained in Synthesis Example 3 with a film thickness of 5 nm was used for the buffer layer instead of POPy2, and the heat treatment time was set to 15 minutes, and heating after spin coating of the fullerene compound solution A solar cell was prepared in the same manner except that the temperature was 120 ° C., and the current-voltage characteristics between the ITO electrode and the aluminum electrode before and after the heat treatment were measured, and are shown in Table 1.

<Example 4>
In Example 1, BINAPS obtained in Synthesis Example 4 having a film thickness of 6 nm was used instead of POPy2 for the buffer layer, the heat treatment time was set to 50 minutes, and the concentration of the fullerene compound solution was 1. A solar cell was produced in the same manner except that the heating temperature after spin coating of the fullerene compound solution was 120 ° C., and the current between the ITO electrode and the aluminum electrode before and after the heat treatment − The voltage characteristics were measured and listed in Table 1.

<Comparative Example 1>
In Example 1, it is the same except that 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP, manufactured by Dojindo Chemical Co., Ltd.) having a thickness of 6 nm is used for the electron extraction layer instead of POPy2. Thus, a solar cell was prepared, and the current-voltage characteristics between the ITO electrode and the aluminum electrode before and after the heat treatment were measured and listed in Table 1.

<Comparative example 2>
In Example 1, a solar cell was prepared in the same manner except that LiF (manufactured by Furuuchi Co., Ltd.) having a thickness of 0.8 nm was used instead of POPy2 for the electron extraction layer. The current-voltage characteristics between the aluminum electrodes were measured and listed in Table 1.

<Example 5>
Polymer type organic thin-film solar cell using PSPy2 Regioregular poly-3-hexylthiophene (P3HT, manufactured by Rieke Metals) having an electron-donating molecular structure and 1- (3-methoxycarbonyl) having an electron-accepting molecular structure Propyl-1-phenyl (6,6) -C61) (PCBM, manufactured by Frontier Carbon Co.) was dissolved in o-dichlorobenzene at a weight ratio of 1: 0.8 at a concentration of 2.1 wt%. The obtained solution was stirred and mixed with a stirrer at 40 ° C. in a nitrogen atmosphere for 4 hours. 0.45μm
Was filtered through a polytetrafluoroethylene (PTFE) filter to prepare an organic active layer coating solution.

A glass substrate on which an indium tin oxide (ITO) transparent conductive film with a thickness of 155 nm is deposited is cleaned in the order of ultrasonic cleaning with a surfactant, water with ultrapure water, and ultrasonic cleaning with ultrapure water, followed by nitrogen blowing. And dried by heating at 120 ° C. in the air for 5 minutes. Finally, ultraviolet ozone cleaning was performed.
On this transparent substrate, an aqueous dispersion of poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) filtered through a 0.45 μm polyvinylidene fluoride (PVDF) filter (manufactured by HC Starck Co., Ltd.) “CLEVIOS ^™ P VP AI4083”) was spin-coated and then heat-dried at 120 ° C. for 10 minutes in the air. Further, the substrate was heat-treated at 180 ° C. for 3 minutes in a nitrogen atmosphere. The film thickness was 60 nm.

  An organic active layer having a thickness of 200 nm was formed on the glass substrate by applying the organic active layer coating solution by spin coating under a nitrogen atmosphere. Heat treatment was performed at 150 in a nitrogen atmosphere for 10 minutes. Thereafter, PSPy2 (Synthesis Example 2) having a thickness of 6 nm as an electron extraction layer and aluminum having a thickness of 80 nm are sequentially formed by resistance heating vacuum deposition, and a 5 mm square bulk heterojunction organic thin film solar cell. Was made.

A solar cell sealed using a glass plate as a sealing plate was irradiated with light of 100 mW / cm ^{2 with} a solar simulator (AM1.5G) from the ITO electrode side, and a source meter (Caysley, Model 2400) Then, the current-voltage characteristics between the ITO electrode and the aluminum electrode were measured (this value is the value before the heat treatment) and listed in Table 2. Then, this solar cell was heat-treated with 120 hot plates for 10 minutes, and the current-voltage characteristics between the ITO electrode and the aluminum electrode were measured (this value is the value after the heat treatment). did.

<Example 6>
In Example 5, instead of PSPy2 for the electron extraction layer, BINAPO obtained in Synthesis Example 3 was used, except that the heat treatment was performed at 100 ° C. In the same manner, a solar cell was produced, and the heat treatment was performed. The current-voltage characteristics between the front and rear ITO electrodes and the aluminum electrode were measured and listed in Table 2.

<Example 7>
In Example 5, instead of PSPy2 for the electron extraction layer, BINAPS obtained in Synthesis Example 4 was used, except that the heat treatment was performed at 110 ° C. In the same manner, a solar cell was produced, and the heat treatment was performed. The current-voltage characteristics between the front and rear ITO electrodes and the aluminum electrode were measured and listed in Table 2.

<Comparative Example 3>
In Example 5, 2,9-dimethyl-4,7 was used instead of PSPy2 in the electron extraction layer.
A solar cell was prepared in the same manner except that diphenyl-1,10-phenanthroline (BCP, manufactured by Tokyo Chemical Industry Co., Ltd.) was used and the temperature of the heat treatment was 60 ° C., and the ITO electrode and aluminum before and after the heat treatment The current-voltage characteristics between the electrodes were measured and listed in Table 2.

<Comparative Example 4>
In Example 5, a solar cell was prepared in the same manner except that LiF (manufactured by Furuuchi Co., Ltd.) was used instead of PSPy2 for the electron extraction layer, and the temperature of the heat treatment was 100 ° C., and ITO before and after the heat treatment The current-voltage characteristics between the electrode and the aluminum electrode were measured and listed in Table 2.

  As mentioned above, the photoelectric conversion element produced by the manufacturing method including the process of heating after laminating | stacking all the board | substrates of this photoelectric conversion element, a pair of electrodes, a semiconductor layer, and the electron extraction layer containing a specific compound is a solar cell use. It is suitable as.

DESCRIPTION OF SYMBOLS 100 Substrate 101 Transparent electrode 102 Electron extraction layer 103 Organic active layer (p-type semiconductor, n-type semiconductor mixed layer)
104 Hole Extraction Layer 105 Counter Electrode 1 Weatherproof Protective Film
2 UV cut film
3,9 Gas barrier film
4,8 Getter material film
5,7 Sealing material
6 Solar cell elements
10 Back sheet
11 Sealing material
12 Base material
13 Solar cell module
14 Thin film solar cells

Claims (3)

Photoelectric conversion comprising a substrate, at least a pair of electrodes formed on the substrate, an organic active layer formed between the pair of electrodes, and an electron extraction layer containing a compound represented by the following general formula (I) a method of manufacturing a device, on the substrate, the pair of electrodes, a method for manufacturing a photoelectric conversion element characterized in that it comprises a step of heating after laminating the organic active layer and the electron extraction layer.
Wherein, R ¹ to R ² represent each independently may condensation which may have a substituent polycyclic aromatic group or an aromatic radical, n represents an integer of 1 or more. R ³ is an aromatic group. X is an oxygen atom or a sulfur atom.   The method for producing a photoelectric conversion element according to claim 1, wherein the organic active layer is formed by a coating method. Method of manufacturing a photoelectric conversion element according to claim 1 or 2 temperature steps are fifty to two hundred eighty ° C. to the heat.