JP2019087675A - Electronic device and method of manufacturing the same, coating liquid for forming a semiconductor layer, and method of manufacturing the same - Google Patents

Abstract

To improve the durability of an electronic device.SOLUTION: A coating liquid including an organic semiconductor compound and a dopant for an organic semiconductor compound which is a hypervalent iodine compound is heated to 85°C or higher and/or the coating liquid is irradiated with ultraviolet light, and then the coating liquid is applied so as to form a semiconductor layer.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electronic device and a method of manufacturing the same, and a coating liquid for forming a semiconductor layer and a method of manufacturing the same.

  The performance of a semiconductor device having a semiconductor layer is greatly affected by the characteristics of the semiconductor layer. For this reason, the improvement of the semiconductor layer is a major target in the research for manufacturing high-performance semiconductor devices. For example, Non-Patent Document 1 describes that device reproducibility can be improved by producing a perovskite semiconductor layer obtained from methylamine iodide and tin iodide by the LT-VASP method. In Non-Patent Document 1, poly [bis (4-phenyl) (2,4) doped with 4-isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (TPFB) as a material of the hole transport layer , 6-trimethylphenyl) amine] (PTAA) is used.

T. Yokoyama et al. "Overcoming Short-Circuit in Lead-Free CH3NH3 SnI3 Perovskite Solar Cells via Kinetically Controlled Gas-Solid Reaction Film Fabrication Process", J. Phys. Chem. Lett. 2016, 7, 776.

  The present inventors have found that an electronic device provided with a semiconductor layer containing a doped semiconductor compound may have a decrease in photoelectric conversion efficiency over time. For example, when PTAA doped with TPFB as described in Non-Patent Document 1 is used for the buffer layer of the photoelectric conversion element, although the initial photoelectric conversion efficiency is high, the photoelectric conversion efficiency when stored under high temperature and high humidity Was found to decline rapidly. In order to put the photoelectric conversion element into practical use, it is required to enhance the durability of the photoelectric conversion efficiency and to make it difficult to reduce the photoelectric conversion efficiency.

  An object of the present invention is to improve the durability of an electronic device provided with a semiconductor layer.

  The inventors of the present invention have found that when doping a semiconductor compound, the durability of an electronic device using this semiconductor compound can be enhanced by treating under specific conditions, and based on this finding Completed the invention.

That is, the gist of the present invention resides in the following.
[1] A method of manufacturing an electronic device comprising a semiconductor layer, comprising: heating a coating solution containing an organic semiconductor compound and a dopant for the organic semiconductor compound which is a hypervalent iodine compound to 85 ° C. or higher Or the manufacturing method including the process of forming the said semiconductor layer by apply | coating this coating liquid after irradiating an ultraviolet-ray to this coating liquid.
[2] The method according to [1], wherein the dopant is an organic compound containing trivalent iodine.
[3] The method according to [1] or [2], wherein the dopant is a diaryliodonium salt.
[4] The process according to any one of [1] to [3], wherein the organic semiconductor compound is a triarylamine compound.
[5] The electronic device comprises a pair of electrodes composed of a lower electrode and an upper electrode, an active layer containing a perovskite compound between the pair of electrodes, and between the pair of electrodes and the active layer A manufacturing method according to [1], which is a photoelectric conversion element including a certain buffer layer, wherein the semiconductor layer is the buffer layer.
[6] The method according to [5], wherein the buffer layer is a hole extraction layer.
[7] The method according to [5] or [6], wherein the buffer layer is located between the upper electrode and the active layer.
[8] An electronic device manufactured by the manufacturing method according to any one of [1] to [7].
[9] A method for producing a coating solution for forming a semiconductor layer, comprising: heating a coating solution containing an organic semiconductor compound and a dopant for the organic semiconductor compound that is a hypervalent iodine compound to 85 ° C. or higher Or a step of irradiating the coating solution with ultraviolet light.
The coating liquid for semiconductor layer formation manufactured by the manufacturing method as described in [10] [9].
[11] It is an electronic device provided with a semiconductor layer, wherein the semiconductor layer contains an organic semiconductor compound doped with a dopant, and the amount of unreacted dopant contained in the semiconductor layer is reacted with the amount of unreacted dopant. An electronic device characterized in that it is 80 mass% or less of the dopant amount which is the sum of the dopant amount.
[12] A coating liquid for forming a semiconductor layer, wherein the coating liquid for forming a semiconductor layer contains an organic semiconductor compound doped with a dopant, and the amount of unreacted dopant contained in the coating liquid for forming a semiconductor layer is The coating liquid for forming a semiconductor layer, which is 80% by mass or less of the dopant amount which is the sum of the unreacted dopant amount and the reacted dopant amount.

  The durability of the electronic device provided with the semiconductor layer can be improved.

It is sectional drawing which represents typically the photoelectric conversion element as one Embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which represents typically the solar cell as one Embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which represents typically the solar cell module as one Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail. The description of the configuration requirements described below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to the contents unless it exceeds the gist.

  The present invention relates to a method of manufacturing an electronic device comprising a semiconductor layer. In the production method according to the present invention, a coating solution containing an organic semiconductor compound and a dopant for an organic semiconductor compound which is a hypervalent iodine compound is heated to 85 ° C. or higher and / or the coating solution is irradiated with ultraviolet light. Later, a step of forming a semiconductor layer by applying a coating solution is included. Below, the coating liquid for semiconductor layer formation used at the process of forming a semiconductor layer, its manufacturing method, and the electronic device manufactured by this manufacturing method are also explained.

[Organic semiconductor compound]
A semiconductor compound refers to the compound which can be used as a semiconductor material which shows a semiconductor characteristic. In the present specification, “semiconductor” is defined by the magnitude of carrier mobility in the solid state. Carrier mobility is an index indicating how fast (or many) the charge (electron or hole) can be moved, as is well known. Specifically, the “semiconductor” in the present specification preferably has a carrier mobility at room temperature of 1.0 × 10 ⁻⁶ cm ² / V · s or more, more preferably 1.0 × 10 ⁻⁵ cm ² / V · s or more More preferably, it is 5.0 × 10 ⁻⁵ cm ² / V · s or more, and particularly preferably 1.0 × 10 ⁻⁴ cm ² / V · s or more. Carrier mobility can be measured, for example, by measurement of IV characteristics of a field effect transistor, time-of-flight method, or the like.

  In the present embodiment, an organic semiconductor compound is used as the semiconductor compound, but the type is not particularly limited, and, for example, conventionally known ones can be used. Low molecular weight compounds and high molecular weight compounds are known as organic semiconductor compounds. The low molecular weight organic semiconductor compounds include polycyclic aromatic compounds, and specific examples thereof include acene compounds such as tetracene or pentacene, oligothiophene compounds, phthalocyanine compounds, perylene compounds, rubrene compounds, or triarene compounds. And arylamine compounds such as reelamine compounds. In addition, as the organic semiconductor compound of a polymer, a conjugated polymer such as polythiophene-based polymer, polyacetylene-based polymer, polyaniline-based polymer, polyphenylene-based polymer, polyphenylene vinylene-based polymer, polyfluorene-based polymer, or polypyrrole-based polymer, or triaryl Arylamine polymers such as amine polymers are included.

  The organic semiconductor compound is preferably an arylamine compound, more preferably a triarylamine compound. The arylamine compound is a compound having an arylamine structure (a bond of an aryl group and a nitrogen atom), and includes an arylamine polymer. An arylamine polymer is a polymer whose repeat unit contains an arylamine structure. In addition, a triarylamine compound is a compound having a triarylamine structure (a bond of three aryl groups to the same nitrogen atom), and includes a triarylamine polymer. A triarylamine polymer is a polymer whose repeat unit contains a triarylamine structure. Such arylamine compounds or triarylamine compounds are preferable in that they can be stably oxidized by the dopant and exhibit good semiconductor characteristics.

  Here, an aryl group (or an aromatic group) refers to an aromatic hydrocarbon group or an aromatic heterocyclic group, which has a single ring, a condensed ring, and a single ring or a fused ring. Including. The aromatic group is not particularly limited, but preferably has 30 or less carbon atoms, and more preferably 12 or less carbon atoms. A phenyl group, a naphthyl group, or a biphenyl group etc. are mentioned as a specific example of an aromatic hydrocarbon group. Specific examples of the aromatic heterocyclic group include thienyl group, furyl group, pyrrolyl group, pyridyl group, imidazolyl group and the like.

  The aromatic group may have further substituents. The substituent which the aromatic group may have is not particularly limited, and is, for example, a halogen atom, a hydroxyl group, a cyano group, an amino group, a carboxyl group, an ester group, an alkylcarbonyl group, an acetyl group, a sulfonyl group, a silyl group, Boryl group, nitrile group, alkyl group, alkenyl group, alkynyl group, alkoxy group, thio group, seleno group, aromatic hydrocarbon group, aromatic heterocyclic group and the like can be mentioned. As a substituent which an aryl group has, Preferably an amino group or a C1-C6 alkyl group is mentioned. Here, the amino group is preferably a dialkylamino group having 2 to 12 carbon atoms, an alkylarylamino group having 7 to 20 carbon atoms, or a diarylamino group having 12 to 30 carbon atoms.

Preferred examples of the organic semiconductor compound include compounds represented by the following formula (I) or (II).

In Formula (I) (II), Ar ¹ is a divalent aromatic group, and Ar ² is a direct bond or a divalent aromatic group. Ar ¹ and Ar ² may be the same or different. The divalent aromatic group is a substituent obtained by removing one hydrogen atom from the aromatic group described above. Ar ¹ and Ar ² each independently are preferably a divalent aromatic group having 2 to 20 carbon atoms, and more preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms (monocyclic, fused ring And those in which single rings or fused rings are linked). These divalent aromatic groups preferably have no further substituent or have an alkyl group having 1 to 6 carbon atoms.

In Formulas (I) and (II), Ar ^{3 to} Ar ⁵ are aromatic groups which may have a substituent. As the aromatic group, those described above can be used. Ar ^{3 to} Ar ⁵ may be the same or different aromatic groups. Ar ^{3 to} Ar ⁵ are each independently preferably an aromatic group having 2 to 20 carbon atoms, and more preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms (monocyclic or fused ring, And those in which single rings or fused rings are linked). These aromatic groups preferably have no further substituents or have the above mentioned amino groups or alkyl groups of 1 to 6 carbon atoms.

  The following compounds may be mentioned as specific examples of the organic semiconductor compound.

[Dopant]
In the present embodiment, a hypervalent iodine compound is used as a dopant. The hypervalent iodine compound acts as a dopant for the organic semiconductor compound. Hypervalent iodine compounds are known to exhibit electron acceptability (ie, function as an oxidizing agent). In addition, the electron accepting dopant can improve the conductivity or hole transporting ability of the semiconductor compound by depriving the semiconductor compound of electrons. Thus, the hypervalent iodine compound can improve the charge transport property of the semiconductor compound used for the electronic device.

  The hypervalent iodine compound is a compound containing hypervalent iodine, and is defined as a compound containing iodine having an oxidation number of +3 or more. For example, the dopant can be an iodine (III) compound or an iodine (V) compound. The iodine (V) compound containing pentavalent iodine may be, for example, a periodinane compound such as Dess-Martin periodinane. Further, as the iodine (III) compound containing trivalent iodine, a compound having a structure in which iodobenzene is oxidized, such as (diacetoxyiodo) benzene, or a diaryliodonium salt can be mentioned. It is preferable to use a diaryl iodonium salt in that it exhibits good electron acceptability and reverse reaction does not easily occur if the molecule is destroyed in the oxidation process.

The diaryl iodonium ^{salt, [Ar-I + -Ar]} X - is that the salt having a structure. Here, two Ars each represent an aryl group. The aryl group (aromatic group) is not particularly limited, and may be, for example, those already mentioned for the organic semiconductor compound. X < ^- > represents arbitrary anions. As X ⁻ , for example, a halide ion, a trifluoroacetate ion, a tetrafluoroborate ion, or a tetrakis (pentafluorophenyl) borate ion may be used. It is preferable that X ⁻ is an anion having a fluorine atom in that the solubility is high and the reaction for producing the coating liquid can proceed smoothly.

Preferred examples of the dopant include those represented by the general formula (III). In formula (III), X ^- represents an anion, specific examples are described above.

In Formula (III), R ¹ and R ² are each independently a monovalent organic group. Examples of monovalent organic groups include aliphatic or aromatic groups. As an example of an aliphatic group, a C1-C20 aliphatic hydrocarbon group or a C4-C20 aliphatic heterocyclic group is mentioned. For example, as the aliphatic group, an alkyl group containing a cycloalkyl group, an alkenyl group or an alkynyl group may be mentioned, and as a specific example, a methyl group, an ethyl group, a butyl group, a cyclohexyl group or a tetrahydrofuryl group may be mentioned. Be

  As an example of an aromatic group, a C6-C20 aromatic hydrocarbon group or a C2-C20 aromatic heterocyclic group is mentioned. For example, as an aromatic group, a phenyl group, a naphthyl group, a biphenyl group, a thienyl group, or a pyridyl group etc. are mentioned.

  In addition, said aliphatic group and aromatic group may have a substituent. There is no particular limitation on the substituent which may be possessed, but halogen atom, hydroxyl group, cyano group, amino group, carboxyl group, ester group, alkyl carbonyl group, acetyl group, sulfonyl group, silyl group, boryl group And nitrile group, alkyl group, alkenyl group, alkynyl group, alkoxy group, thio group, seleno group, aromatic hydrocarbon group, aromatic heterocyclic group and the like.

R ¹ and R ² are preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms, more preferably a phenyl group. Here, it is preferable that an aromatic hydrocarbon group does not have a substituent or has a C1-C6 alkyl group. R ¹ and R ² are particularly preferably a phenyl group having an alkyl group at the para position.

[Preparation of coating solution]
In the present embodiment, the coating solution containing the organic semiconductor compound and the dopant for the organic semiconductor compound which is a supervalent iodine compound is heated to 85 ° C. or higher and / or the coating solution is irradiated with ultraviolet light, and thus Preparation of the coating liquid for semiconductor layer formation is performed. For example, first, a solution containing an organic semiconductor compound and a dopant for an organic semiconductor compound which is a hypervalent iodine compound is prepared. Next, the prepared solution is heated to 85 ° C. or higher and / or the solution is irradiated with ultraviolet light. Thus, a coating solution for forming a semiconductor layer can be produced.

  First, a solution containing an organic semiconductor compound and a dopant is prepared. Specifically, the organic semiconductor compound and the dopant are dissolved in the solvent. However, these compounds do not need to be completely dissolved in the solvent, and the compounds may be dissolved in the solvent when heating or ultraviolet irradiation is performed.

  As the solvent, a solvent capable of dissolving the semiconductor compound and the dopant is used. Also, preferably, a solvent having a boiling point higher than that at the time of solution preparation is used. Examples of solvents include aliphatic hydrocarbons such as heptane, octane, isooctane, nonane or decane; and aromatic substances such as toluene, xylene, mesitylene, cumene, tetralin, cyclohexylbenzene, fluorobenzene, chlorobenzene, bromobenzene or orthodichlorobenzene Aliphatic hydrocarbons such as methylcyclohexane, cycloheptane, cyclooctane or decalin; aliphatic ketones such as cyclopentanone or cyclohexanone; aromatic ketones such as acetophenone or propiophenone; acetic acid Butyl, methyl lactate, methyl benzoate, ethyl benzoate, isopropyl benzoate, isobutyl benzoate or esters such as isoamyl benzoate; halogenated hydrocarbons such as trichloroethylene; or Cyclopentyl methyl ether, anisole, diphenyl ether, ethers such as dimethoxyethane or dioxane.

  Next, the prepared solution is heated to 85 ° C. or higher, the solution is irradiated with ultraviolet light, or both of them are performed. When heating is performed, the heating method is not particularly limited. For example, a heat source such as a hot plate may be used, or a heating atmosphere such as an oven may be used. Moreover, when irradiating an ultraviolet-ray, an irradiation method is not specifically limited, For example, it can carry out using an ultraviolet ray lamp. The solution can be stirred during heating or UV irradiation. In the present invention, ultraviolet light means light having a wavelength of 200 nm or more and less than 400 nm.

  According to the study of the inventor of the present invention, the durability of the electronic device having a semiconductor layer formed using the obtained coating solution for forming a semiconductor layer is obtained by heating to 85 ° C. or higher or by performing ultraviolet irradiation. improves. The reason for this is not clear, but the inventors believe that heating to 85 ° C. or higher or ultraviolet irradiation causes a chemical change in the organic semiconductor compound in the solution.

  Even when a coating liquid for forming a semiconductor layer is prepared by heating at 70 ° C. or less as in the prior art, it is known that an electronic device having a semiconductor layer formed using this coating liquid for forming a semiconductor layer functions. The However, the present inventors have found that the electronic device thus produced loses performance in a short time under a high temperature and high humidity environment. The inventors of the present invention have, for this reason, charge transfer from the semiconductor compound to the dopant even in the conventional method, so that although the semiconductor layer initially exhibits charge transport properties, the oxidation state of the semiconductor compound is unstable. It is estimated that the electric charge of the dopant is likely to return to the semiconductor compound again in a high temperature and high humidity environment. As a result, the conductivity of the semiconductor layer is lowered because the semiconductor layer is electrically neutral, and the performance of the electronic device is degraded.

  On the other hand, when the organic semiconductor compound is oxidized by the chemical reaction between the dopant and the organic semiconductor compound by heating to 85 ° C. or higher or by ultraviolet irradiation, the organic semiconductor compound becomes stable in the oxidized state. The present inventors estimate that the phenomenon in which the charge of the semiconductor layer returns to the dopant is less likely to occur. For example, when the reaction in which the dopant is broken at high temperature occurs and the organic semiconductor compound is oxidized as a result of the formation of the active oxidizing agent, it is considered that the reaction in which the organic semiconductor compound gains charge again does not progress easily.

  Especially in the solution state, the reaction is generally easy to proceed, so it is expected that the reaction between the dopant and the organic semiconductor compound smoothly proceeds by heating to 85 ° C. or higher or performing ultraviolet irradiation. On the other hand, it is expected that the reaction in the solid does not proceed smoothly even if the temperature is increased when the semiconductor layer is formed by applying the coating solution for forming a semiconductor layer and drying the semiconductor layer. In the present embodiment, the semiconductor layer is formed by coating at a low temperature at which damage to the electronic device does not occur, by heating to 85 ° C. or higher in the solution state or by performing ultraviolet irradiation. It is also considered that a semiconductor layer having a sufficiently high conductivity and a thermodynamically stable property is formed.

  In one embodiment, the amount of unreacted dopant contained in the coating solution for forming a semiconductor layer is 80% by mass or less of the amount of dopant. Here, the amount of dopant is the sum of the amount of unreacted dopant and the amount of reacted dopant. The unreacted dopant refers to a dopant which has not undergone a chemical reaction with the organic semiconductor compound and can return the charge it has because it is not broken back to the organic semiconductor compound. In addition, the reacted dopant refers to a decomposition product of a dopant which does not have the ability to charge the organic semiconductor compound again because it is broken through a chemical reaction with the organic semiconductor compound. In another embodiment, the amount of dopant refers to the amount of dopant used to prepare a coating solution for forming a semiconductor layer.

  As described above, if the chemical reaction between the organic semiconductor compound and the dopant proceeds to a certain extent, the phenomenon that the semiconductor layer loses charge transport properties hardly occurs, and the chemical reaction between the organic semiconductor compound and the dopant proceeds completely. It is considered that the semiconductor layer having higher durability can be obtained. From such a viewpoint, the amount of unreacted dopant contained in the coating solution for forming a semiconductor layer is preferably 60% by mass or less of the amount of dopant, more preferably 40% by mass or less, and 20% by mass or less More preferably, it is particularly preferred that it is substantially absent. The amount of unreacted dopant can be confirmed by chemical analysis, and can also be estimated by a quantitative method using an ultraviolet-visible absorption spectrum.

  The temperature of the solution during heating is preferably 90 ° C. or higher, more preferably 95 ° C. or higher, and still more preferably 100 ° C. or higher, from the viewpoint of sufficiently advancing the reaction. The above is more preferable, the temperature is preferably 135 ° C. or more, and particularly preferably 150 ° C. or more. On the other hand, in order to prevent the decomposition of the compound semiconductor, the temperature is preferably equal to or lower than the thermal decomposition temperature of the semiconductor compound. In the present invention, the thermal decomposition temperature means a temperature at which the mass is reduced by 5% as measured by TG-DTA.

  The heating time is preferably 10 minutes or more, more preferably 20 minutes or more, and still more preferably 30 minutes or more, from the viewpoint of sufficiently advancing the reaction. The upper limit of the time is not particularly limited, but may be, for example, 10 hours or less.

In the case of ultraviolet irradiation, the chemical reaction can be sufficiently advanced by irradiating the solution containing the organic semiconductor compound and the dopant with an amount of ultraviolet light of 0.1 J / cm ² or more. More preferably, it is 0.5 J / cm < ² > or more, More preferably, it is 1 J / cm < ² > or more. On the other hand, in order to prevent the decomposition of the semiconductor compound, the amount of ultraviolet light is preferably 1000 J / cm ² or less. More preferably 800 J / cm ² or less, more preferably 500 J / cm ² or less. There is no particular limitation on the ultraviolet light intensity, but for example, one having an intensity of 5 mW / cm ² or more at 365 nm can be used. There is no particular limitation on the ultraviolet light source, but a mercury lamp or a metal halide lamp can be used.

  Further, both heating to 85 ° C. or higher and ultraviolet irradiation may be performed on the coating solution for forming a semiconductor layer. For example, ultraviolet irradiation may be performed after the coating liquid for forming a semiconductor layer is heated to 85 ° C. or higher, or the coating liquid for forming a semiconductor layer may be heated to 85 ° C. or higher after ultraviolet irradiation. Further, ultraviolet irradiation may be performed simultaneously with heating the coating solution for forming a semiconductor layer to 85 ° C. or higher. As reaction conditions in these cases, the above-mentioned conditions can be appropriately adjusted and used so that the reaction between the dopant and the semiconductor compound can proceed smoothly.

  The concentrations of the organic semiconductor compound and the dopant in the coating solution are not particularly limited, and can be appropriately set according to the desired thickness of the semiconductor layer and the like. For example, the concentration of the organic semiconductor compound in the coating solution may be 1.0% by mass or more, or 10% by mass or less. In addition, the amount of the dopant in the coating solution may be 1.0% by mass or more and 20% by mass or less with respect to the amount of the organic semiconductor compound in the coating solution.

[Application of coating solution]
In the present embodiment, the semiconductor layer is formed by applying the coating solution prepared as described above. Although any method can be used as a coating method of a coating liquid, For example, a spin coat method, an inkjet method, a doctor blade method, a drop casting method, a reverse roll coat method, a gravure coat method, a kiss coat method, a roll brush method, A spray coating method, an air knife coating method, a wire bar bar coating method, a pipe doctor method, an impregnation / coating method or a curtain coating method may, for example, be mentioned.

  After applying the coating solution, heating and drying can be performed. The heating temperature at this time is not particularly limited, but is preferably 60 ° C. or more, more preferably 80 ° C. or more, from the viewpoint of sufficiently removing the solvent. On the other hand, in order to suppress damage to the electronic device, the heating temperature is preferably lower than the temperature at the time of preparation of the coating liquid. Specifically, the heating temperature is preferably less than 150 ° C., more preferably less than 135 ° C., still more preferably less than 115 ° C., more preferably less than 100 ° C., still more preferably less than 95 ° C., more preferably less than 90 ° C. Particularly preferably, it is less than 85 ° C. The heating time is also not particularly limited, but is preferably 1 minute or more, more preferably 3 minutes or more from the viewpoint of removing the solvent sufficiently, and from the viewpoint of improving production efficiency, preferably 10 hours or less More preferably, it is 1 hour or less. These heatings may be performed under normal pressure or under reduced pressure.

  The thickness of the semiconductor layer is not particularly limited, and can be appropriately selected according to the application of the semiconductor layer. As one example, the thickness of the semiconductor layer may be 0.5 nm or more and 500 nm or less.

[Electronic device]
The type of electronic device is not particularly limited. In the present specification, an electronic device is a device that has two or more electrodes, and controls the current or generated voltage flowing between the electrodes by electricity, light, magnetism, chemicals or the like, or between the electrodes It refers to a device that generates light, an electric field, a magnetic field, and the like by an applied voltage or current. Specific examples include an element that controls current or voltage by applying a voltage or current, an element that controls voltage or current by applying a magnetic field, or an element that controls a voltage or current by causing a chemical substance to act. Specific examples of control include rectification, switching, amplification, oscillation and the like.

  Examples of the electronic device include a resistor, a rectifier (diode), a switching element (transistor, thyristor), an amplifying element (transistor), a memory element, a chemical sensor, etc., or a semiconductor obtained by combining or integrating these elements. Device is mentioned. Further, a further example of the electronic device includes an optical element, and the optical element is a photodiode or a phototransistor which generates a photocurrent, an electroluminescent element which emits light by applying an electric field, or photoelectric conversion which generates an electromotive force by light. Elements or solar cells are included. As a more specific example of the semiconductor device, S.I. M. Mention may be made of those described in Sze, Physics of Semiconductor Devices, 2nd Edition (Wiley Interscience 1981).

  The electronic device according to the present embodiment includes the semiconductor layer, but the specific configuration thereof is not particularly limited. In one embodiment, the electronic device has a pair of electrodes and a semiconductor layer disposed between the pair of electrodes. A semiconductor layer is obtained by apply | coating the coating liquid for semiconductor layer formation which concerns on said this embodiment. The type of electrode is not particularly limited. Depending on the type of electronic device, the electrodes can be made using appropriate materials.

  Preferred examples of the electronic device include an electroluminescent element (LED), a photoelectric conversion element or a solar cell. For example, an electroluminescent device (LED) according to one embodiment includes an anode and a cathode which are a pair of electrodes, a light emitting layer disposed between the electrodes, and a semiconductor layer disposed between the light emitting layer and one of the electrodes. And can be provided. In one embodiment, the semiconductor layer obtained by applying the coating solution for forming a semiconductor layer according to the above-mentioned embodiment is provided as a hole transport layer between the light emitting layer and the anode.

  As described above, in the present embodiment, the electronic device is manufactured by the manufacturing method including the step of forming the semiconductor layer by applying the coating liquid prepared as described above. The method of manufacturing the electronic device according to the present embodiment is not particularly limited, and can be appropriately determined according to the configuration of the electronic device. For example, an electronic device can be manufactured by the process of forming a semiconductor layer by apply | coating a coating liquid on the base material in which the electrode was formed, and the process of forming an electrode on a semiconductor layer.

  After forming the semiconductor layer, the electronic device can be heated, for example, after each element constituting the electronic device is formed. This process may be referred to as an annealing process, and may improve the adhesion between the elements constituting the electronic device and may have the effect of improving the performance of the electronic device. The heating temperature at this time is not particularly limited, but is preferably 50 ° C. or more, more preferably 80 ° C. or more from the viewpoint of obtaining a sufficient adhesion improvement effect. Moreover, it is preferable to heat in a temperature range which is preferably 300 ° C. or less, more preferably 280 ° C. or less, more preferably 250 ° C. or less. On the other hand, in order to suppress damage to the electronic device, the heating temperature is preferably lower than the temperature at the time of preparation of the coating liquid. Specifically, the heating temperature is preferably less than 150 ° C., more preferably less than 135 ° C., still more preferably less than 115 ° C., more preferably less than 100 ° C., still more preferably less than 95 ° C., more preferably less than 90 ° C. Preferably it is less than 85 ° C. The heating time is also not particularly limited, but is preferably 1 minute or more, more preferably 3 minutes or more from the viewpoint of obtaining sufficient adhesion improvement effect, and preferably 180 minutes from the viewpoint of improving production efficiency. It is preferably at most 60 minutes, more preferably at most 60 minutes. These heatings may be performed under normal pressure or under reduced pressure.

  Hereinafter, the photoelectric conversion element provided with a semiconductor layer is demonstrated as a preferable example of an electronic device.

[Photoelectric conversion element]
The photoelectric conversion element according to the present embodiment includes a pair of electrodes including a lower electrode and an upper electrode, an active layer between the pair of electrodes, and a buffer layer between the pair of electrodes and the active layer. Prepare. In one embodiment, the buffer layer is a semiconductor layer obtained by applying the coating solution for forming a semiconductor layer according to the present embodiment.

  FIG. 1 is a cross-sectional view schematically showing an embodiment of a photoelectric conversion device according to the present invention. The photoelectric conversion element shown in FIG. 1 is a photoelectric conversion element used for a general thin film solar cell, but the photoelectric conversion element according to the present invention is not limited to that shown in FIG. The photoelectric conversion element 100 according to an embodiment of the present invention has a layer structure in which a base 108, a lower electrode 101, a buffer layer 102, an active layer 103, a buffer layer 105, and an upper electrode 107 are formed in this order. As shown in FIG. 3, in the case where the photoelectric conversion element 100 has a structure in which each layer is stacked on the base 108, the electrode closer to the base 108 is the lower electrode 101, and the electrode farther from the base 108 is the upper electrode 107. And can be called respectively. Note that it is not necessary to provide both the buffer layer 102 and the buffer layer 105.

  In addition, the photoelectric conversion element 100 may further include another layer. Other layers include a work function tuning layer for adjusting the work function of the lower electrode 101 or the upper electrode 107, an insulator layer, and the like.

  The semiconductor layer obtained by applying the coating solution for forming a semiconductor layer according to the present embodiment can exhibit good hole transport properties, and thus can be preferably used as a hole extraction layer. For example, in one embodiment, one of the lower electrode 101 and the upper electrode 107 is a cathode, and the other is an anode. In one embodiment, the lower electrode 101 is a cathode, in which case the buffer layer 102 is an electron extracting layer, the buffer layer 105 is a hole extracting layer, and the upper electrode 107 is an anode. In such a configuration, the buffer layer 105 (hole extraction layer) located between the upper electrode 107 and the active layer 103 can be obtained by applying the coating solution for forming a semiconductor layer according to the present embodiment described above. It may be a semiconductor layer. In one embodiment, the lower electrode 101 is an anode, in which case the buffer layer 102 is a hole extraction layer, the buffer layer 105 is an electron extraction layer, and the upper electrode 107 is a cathode. In such a configuration, the buffer layer 102 (hole extraction layer) may be a semiconductor layer obtained by applying the coating solution for forming a semiconductor layer according to the above-described embodiment.

  In addition, since the semiconductor layer obtained by applying the coating solution for forming a semiconductor layer according to the present embodiment can exhibit high durability, it is located between the upper electrode 107 and the active layer 103 and is not affected by the outside world. It can be preferably used as a susceptible buffer layer 105.

(1. Active layer 103)
The active layer 103 is a layer in which photoelectric conversion is performed. When the photoelectric conversion element 100 receives light, light is absorbed by the active layer 103 to generate carriers, and the generated carriers are extracted from the lower electrode 101 and the upper electrode 107.

  The type of the active layer 103 is not particularly limited, and conventionally known ones can be used. For example, the active layer 103 may be a heterojunction active layer including a layer containing a p-type semiconductor compound such as a porphyrin derivative and a layer containing a fullerene derivative n-type semiconductor compound. The active layer 103 may be a bulk hetero active layer having a layer (i layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed. The active layer 103 may be a layer containing a perovskite compound.

  Preferably, the active layer 103 is a layer containing a perovskite compound. A solar cell having such an active layer 103 is known as a perovskite solar cell. In a perovskite semiconductor, a perovskite compound having a perovskite structure forms a crystal. In such crystals, fast charge separation occurs and the distance of diffusion of holes and electrons is long, so efficient charge separation occurs. In addition, this invention is especially effective especially in manufacture of the photoelectric conversion element using the active layer containing a perovskite compound. The reason for this is that a perovskite compound is usually insoluble in the solvent used for the coating solution for forming a semiconductor layer, and a layer formed of the coating solution for forming a semiconductor layer contains a perovskite compound. Since it is insoluble in the solvent used to form W, the layer can be laminated by the coating process without deteriorating each layer.

The perovskite compound refers to a semiconductor compound having a perovskite structure. The perovskite compound is not particularly limited, but can be selected from, for example, those listed in Galasso et al. Structure and Properties of Inorganic Solids, Chapter 7-Perovskite type and related structures. For example, as the perovskite compound, one represented by the general formula AMX ₃ or one represented by the general formula A ₂ MX ₄ can be mentioned. Here, M indicates a divalent cation, A indicates a monovalent cation, and X indicates a monovalent anion. An appropriate perovskite compound can be selected according to the type of semiconductor device. As the perovskite compound, it is preferable to use a semiconductor compound having an energy band gap of 1.0 eV or more and 3.5 eV or less.

  The monovalent cation A is not particularly limited, but those described in the above-mentioned Galasso book can be used. More specific examples include cations containing elements of Groups 1 and 13 to 16 of the periodic table. Among these, cesium ion, rubidium ion, ammonium ion (including amidinium ion) which may have a substituent, phosphonium ion which may have a substituent, or even having a substituent Good amidinium ions are preferred. As an example of the ammonium ion which may have a substituent, a primary ammonium ion or a secondary ammonium ion can be mentioned. There is no particular limitation on the substituent. Specific examples of the ammonium ion which may have a substituent include an alkyl ammonium ion, an aryl ammonium ion, an amidinium ion, or a guanidinium ion. In particular, in order to avoid steric hindrance, monoalkylammonium ions having a three-dimensional crystal structure are preferable, and from the viewpoint of improving stability, it is preferable to use alkylammonium ions substituted with one or more fluorine groups. In addition, a combination of two or more types of cations can also be used as the cation A.

  Specific examples of the monovalent cation A include methyl ammonium ion, methyl ammonium monofluoride ion, methyl ammonium difluoride ion, methyl ammonium trifluoride ion, ethyl ammonium ion, isopropyl ammonium ion, n-propyl ammonium ion, isobutyl ammonium ion , N-butyl ammonium ion, t-butyl ammonium ion, dimethyl ammonium ion, diethyl ammonium ion, phenyl ammonium ion, benzyl ammonium ion, phenethyl ammonium ion, guanidinium ion, formamidinium ion, acetamidinium ion or imidazolium Ion etc. are mentioned.

The divalent cation M is not particularly limited, but is preferably a divalent metal cation or semimetal cation. Specific examples include cations of periodic table group 14 elements, and more specific examples include lead cations (Pb ²⁺ ), tin cations (Sn ²⁺ ), and germanium cations (Ge ²⁺ ). In addition, a combination of two or more types of cations can also be used as the cation M. From the viewpoint of obtaining a stable photoelectric conversion element, it is particularly preferable to use two or more kinds of cations including lead cations or lead cations.

  Examples of the monovalent anion X include halide ion, acetate ion, nitrate ion, sulfate ion, borate ion, acetylacetonate ion, carbonate ion, citrate ion, sulfur ion, tellurium ion, thiocyanate ion, titanate Ion, zirconate ion, 2,4-pentanedionato ion or silicofluorine ion may, for example, be mentioned. In order to adjust the band gap, X may be one type of anion or a combination of two or more types of anions. Among them, as X, it is preferable to use a halide ion or a combination of a halide ion and another anion. Examples of the halide ion X include chloride ion, bromide ion or iodide ion.

Preferred examples of the perovskite compound include organic-inorganic perovskite compounds, and in particular, halide organic-inorganic perovskite compounds. Specific examples of the perovskite compound are CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ SnI ₃ , CH ₃ NH ₃ SnBr ₃ , CH ₃ NH ₃ SnCl ₃ , CH ₃ NH ₃ PbI _(3-x) Cl _x , CH ₃ NH ₃ PbI _(3-x) Br _x , CH ₃ NH ₃ PbBr _(3-x) Cl _x , CH ₃ NH ₃ Pb _(1-y) Sn _y I ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Br ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y Cl ₃ , CH ₃ NH ₃ Pb _(1-y) Sn _y I _{(3- ) x)} Cl _x , CH ₃ NH ₃ Pb _(1-y) Sn _y I _(3-x) Br _x , and CH ₃ NH ₃ Pb _(1-y) Sn _y Br _(3-x) Cl _x , and above Those using _CH 3 _CFH 2 _NH in place of _{NH 3 3, CF 2 HNH 3} , CF 3 NH 3, NH 2 CH = NH 2 in the compounds, and the like. In addition, x is 0 or more and 3 or less, y shows any value of 0 or more and 1 or less.

  The active layer 103 may contain two or more types of perovskite compounds. For example, two or more types of perovskite compounds different in at least one of A, B, and X may be included in the active layer 103.

  The amount of the perovskite compound contained in the active layer 103 is preferably 50% by mass or more, more preferably 70% by mass or more, and more preferably 80% by mass or more, so as to obtain good semiconductor characteristics. . There is no particular upper limit.

  The thickness of the active layer 103 is not particularly limited. The thickness of the active layer 103 is preferably 5 nm or more, more preferably 10 nm or more, more preferably 50 nm or more, and particularly preferably 120 nm or more in that more light can be absorbed. On the other hand, the thickness of the active layer 103 is preferably 2000 nm or less, more preferably 1000 nm or less, in that the series resistance is reduced.

  The method for forming the active layer 103 is not particularly limited, and any method can be used. Specific examples include a coating method and a vapor deposition method (or a co-vapor deposition method). It is preferable to use a coating method in that the active layer 103 can be easily formed.

  As an example of a method for producing the active layer 103 containing a perovskite compound, for example, a method of forming a semiconductor layer by applying a coating liquid containing a perovskite compound or a precursor thereof can be mentioned. The perovskite compound precursor refers to a material that can be converted to a perovskite compound after the application liquid is applied. A specific example is a perovskite compound precursor which can be converted to a perovskite compound by heating. For example, by heating a film obtained by applying a coating solution, a perovskite compound precursor can be converted to a perovskite compound to form a semiconductor layer containing a perovskite compound. As a specific example of the perovskite compound precursor, a compound represented by the following formula (2) and / or a following formula (3), which can be converted to a perovskite compound represented by the following (1) by heating Compounds can be mentioned.

  One example is a method of preparing a coating solution containing a compound represented by the following formula (2), a compound represented by the following formula (3), and a solvent, and coating the coating solution. . Such a coating solution can be prepared by heating and stirring the compound in the solution. According to this method, the active layer 103 containing the compound represented by the following formula (1) can be produced.

AMX ₃ (1)
AX (2)
MX ₂ (3)
The definitions of A, M and X are as described above. Specific examples of AX include halogenated alkyl ammonium salts, and specific examples of MX ₂ include metal halides. AX and MX ₂ are precursors of velovskite semiconductor compound AMX ₃ .

  As another example, a coating liquid containing the compound represented by the above formula (2) and a solvent, and a coating liquid containing the compound represented by the above formula (3) and the solvent are prepared respectively. Coating methods. For example, first, a layer of the compound represented by Formula (3) is formed by applying a coating liquid containing the compound represented by Formula (3) and a solvent. The active layer 103 containing the compound represented by the following formula (1) can be produced by applying a coating solution containing the compound represented by the above formula (2) and a solvent thereon. . After each coating solution is applied, the layer can be dried or crystallization of the perovskite semiconductor compound can be promoted by heating. Heating can be performed, for example, at 60 ° C. or higher, or at 180 ° C. or lower.

  As a solvent, Brandrup, J. et al. It is preferable that the solubility parameter (SP value) described in J. et al., "Polymer Handbook, 4th Ed." Is 9 or more, and particularly preferably 10 or more. For example, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, pyridine, γ-butyrolactone and the like can be mentioned. A mixed solvent of two or more solvents may be used as the solvent. In addition, also when using a mixed solvent, it is preferable that the solubility parameter of at least 1 sort (s) of solvent is 10 or more.

(2. Buffer layer 102, 105)
The buffer layer can generally be classified into an electron extraction layer and a hole extraction layer. As described above, at least one of the buffer layers provided in the photoelectric conversion element 100 may be a semiconductor layer obtained by applying the coating liquid for forming a semiconductor layer according to the present embodiment. In addition, such a semiconductor layer is preferably used as a hole extraction layer. The buffer layer 102 may be a hole extraction layer, the buffer layer 105 may be an electron extraction layer, or the buffer layer 102 may be an electron extraction layer, and the buffer layer 105 may be a hole extraction layer. It is preferable that it is a buffer layer which apply | coats and forms the said coating liquid for semiconductor layer formation. The reason for this is that while the wettability tends to decrease with respect to the layer formed by using the coating solution for forming a semiconductor layer with the above-mentioned perovskite precursor solution, the composition for forming a semiconductor layer The wettability to the active layer containing the lobskite compound tends to be high. In addition, when the electrode 107 is formed by a sputtering process, the layer formed by the coating solution for forming a semiconductor layer tends to be difficult to oxidize, and therefore, it is difficult to receive oxidation damage due to the sputtering process. Each of the hole extraction layer and the electron extraction layer will be described below. Note that one buffer layer may be composed of a plurality of different films.

  There is no particular limitation on the material of the hole extraction layer, and it is not particularly limited as long as the material can improve the efficiency of extracting holes from the active layer 103 to the anode. As described above, it is preferable to use the semiconductor layer obtained by applying the coating liquid for forming a semiconductor layer according to the present embodiment as the hole extraction layer. As another example of the material of the hole extraction layer, inorganic compounds or organic compounds described in publicly known documents such as WO 2013/171517, WO 2013/180230 or JP 2012-191194 may be mentioned. Be

  For example, as the inorganic compound, metal oxides such as copper oxide, nickel oxide, manganese oxide, iron oxide, molybdenum oxide, vanadium oxide or tungsten oxide can be mentioned. In addition, as organic compounds, conductive polymers (for example, PEDOT: PSS or doped P3HT) in which sulfonic acid and iodine etc. are doped in polythiophene, polypyrrole, polyacetylene, triphenylenediamine or polyaniline etc., sulfonyl group is substituted Or a conductive organic compound such as arylamine, Nafion, or lithium-doped spiro-OMeTAD.

  The total thickness of the hole extraction layer is not particularly limited, but is preferably 0.5 nm or more. On the other hand, it is preferably 400 nm or less, more preferably 200 nm or less. When the film thickness of the hole extraction layer is 0.5 nm or more, the function as a buffer material is performed well, and when the film thickness of the hole extraction layer is 400 nm or less, holes are easily extracted. The photoelectric conversion efficiency can be improved.

  There is no limitation on the method of forming the hole extraction layer. In the case of using a compound having sublimation properties, it can be formed by a dry film forming method such as a vacuum evaporation method. Further, in the case of using a compound soluble in a solvent, it can be formed by a wet film forming method such as a spin coating method or an inkjet method.

  There is no particular limitation on the material of the electron extraction layer, and it is not particularly limited as long as it is a material that can improve the electron extraction efficiency from the active layer 103 to the cathode. Specifically, inorganic compounds, organic compounds, or organic inorganic perovskite compounds described in known documents such as WO 2013/171517, WO 2013/180230 or JP 2012-191194 may be mentioned.

  For example, as the inorganic compound, salts of alkali metals such as lithium, sodium, potassium or cesium, metal oxides such as zinc oxide, titanium oxide, aluminum oxide, indium oxide, or tin oxide can be mentioned. As organic compounds, vasocuproin (BCP), bathophenanthrene (Bphen), (8-hydroxyquinolinato) aluminum (Alq3), boron compounds, oxadiazole compounds, benzimidazole compounds, naphthalenetetracarboxylic acid anhydride (NTCDA), And phosphine compounds having a double bond with a periodic table group 16 element such as perylene tetracarboxylic acid anhydride (PTCDA), a fullerene compound, or a phosphine oxide compound or a phosphine sulfide compound.

  There is no particular limitation on the method of forming the electron extraction layer. In the case of using a sublimable compound as a material, it can be formed by a dry film forming method such as a vacuum evaporation method. In addition, when a compound soluble in a solvent is used as a material, it can be formed by a wet film formation method such as a spin coating method or an inkjet method.

  The total thickness of the electron extraction layer is not particularly limited, but is preferably 0.5 nm or more, more preferably 1 nm or more, more preferably 5 nm or more, and particularly preferably 10 nm or more. On the other hand, it is preferably 1 μm or less, more preferably 700 nm or less, more preferably 400 nm or less, and particularly preferably 200 nm or less. When the film thickness of the electron extraction layer 105 is in the above range, uniform coating becomes easy, and an electron extraction function can be exhibited well.

(3. Electrodes 101 and 107)
The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, as a pair of electrodes, it is preferable to use an anode suitable for collecting holes and a cathode suitable for collecting electrons. Any one of the pair of electrodes may be translucent, and both of them may be translucent. Being translucent means that sunlight transmits 40% or more. In addition, it is preferable that the sunlight transmittance of the transparent electrode is 70% or more, in order to transmit more light through the transparent electrode and reach the active layer 103. The transmittance of light can be measured with a spectrophotometer (for example, U-4100 manufactured by Hitachi High-Tech Co., Ltd.).

  There is no particular limitation on the components of the anode and the cathode and the method of manufacturing the same, and known techniques can be used. For example, the members described in the known documents such as WO 2013/171517, WO 2013/180230 or JP 2012-191194 can be used as well as methods for producing the members.

(4. Base material 108)
The photoelectric conversion element 100 usually has a base material 108 as a support. However, the photoelectric conversion element according to the present invention may not have the base material 108. The material of the base material 108 is not particularly limited as long as the effects of the present invention are not significantly impaired. For example, known materials such as WO 2013/171517, WO 2013/180230 or JP 2012-191194 A The materials described in can be used.

(5. Manufacturing method of photoelectric conversion element)
The photoelectric conversion element 100 can be manufactured by forming each layer constituting the photoelectric conversion element 100 according to the method described above. In addition, in order to improve the durability, the photoelectric conversion element 100 may be further sealed. For example, the photoelectric conversion element 100 can be sealed by further stacking a sealing plate over the upper electrode 107 and fixing the substrate 108 and the sealing plate with an adhesive.

  There is no particular limitation on the method of forming each layer constituting the photoelectric conversion element 100, and it can be formed by a sheet-to-sheet (many-leaf) method or a roll-to-roll method. The roll-to-roll method is a method in which a flexible base material wound in a roll is drawn out and processed while being intermittently or continuously conveyed while being taken up by a take-up roll. is there. The roll-to-roll method is suitable for mass production as compared to the sheet-to-sheet method because it is possible to collectively process long substrates of the km order. On the other hand, when each layer is to be formed by the roll-to-roll method, the film may be scratched or partially peeled off due to the contact between the film formation surface and the roll due to its structure.

  The size of the roll that can be used in the roll-to-roll system is not particularly limited as long as it can be handled by a roll-to-roll system manufacturing apparatus, but the upper limit of the outer diameter is preferably 5 m or less, more preferably 3 m or less, more preferably It is less than 1 m. On the other hand, the lower limit is preferably 10 cm or more, more preferably 20 cm or more, and more preferably 30 cm or more. The upper limit of the outer diameter of the roll core is preferably 4 m or less, more preferably 3 m or less, and more preferably 0.5 m or less. On the other hand, the lower limit is preferably 1 cm or more, more preferably 3 cm or more, more preferably 5 cm or more, still more preferably 10 cm or more, particularly preferably 20 cm or more. It is preferable that the diameter is not more than the above upper limit in view of high handleability of the roll, and it is preferable in being not less than the lower limit in that the layer formed in each step is less likely to be broken by bending stress. . The lower limit of the width of the roll is preferably 5 cm or more, more preferably 10 cm or more, and more preferably 20 cm or more. On the other hand, the upper limit is preferably 5 m or less, more preferably 3 m or less, more preferably 2 m or less. It is preferable that the width is not more than the upper limit in view of high handleability of the roll, and it is preferable that the width is not less than the lower limit because the degree of freedom of the size of the photoelectric conversion element 100 is increased.

  In addition, after the upper electrode 107 is stacked, the above-described annealing process can be performed on the photoelectric conversion element 100. By performing the annealing treatment step at a temperature of 50 ° C. or higher, the effect of improving the adhesion between the layers of the photoelectric conversion element 100 is obtained, which is preferable. By improving the adhesion between the layers, the thermal stability, durability, and the like of the photoelectric conversion element can be improved. In the annealing process step, stepwise heating using different temperatures may be performed.

  The annealing process 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 fixed values. The annealing treatment step is preferably carried out under normal pressure and in an inert gas atmosphere also in order to prevent thermal oxidation of the constituent materials. As a heating method, the photoelectric conversion element may be placed on a heat source such as a hot plate, or the photoelectric conversion element may be placed in a heating atmosphere such as an oven. The heating may be performed batchwise or continuously.

(6. Photoelectric conversion characteristics)
The photoelectric conversion characteristic of the photoelectric conversion element 100 can be obtained as follows. The photoelectric conversion element 100 is irradiated with light of an AM 1.5 G condition with an irradiation intensity of 100 mW / cm ² by a solar simulator to measure current-voltage characteristics. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be determined.

  The photoelectric conversion efficiency of the photoelectric conversion element 100 is not particularly limited, but is preferably 1% or more, more preferably 1.5% or more, and more preferably 2% or more. On the other hand, the upper limit is not particularly limited, and the higher the better. The fill factor of the photoelectric conversion element 100 is not particularly limited, but is preferably 0.6 or more, more preferably 0.7 or more, and more preferably 0.9 or more. On the other hand, the upper limit is not particularly limited, and the higher the better.

The photoelectric conversion element according to the present embodiment has a feature of high durability. In one embodiment, the maintenance rate of the photoelectric conversion efficiency after being placed in a test environment at a temperature of 60 ° C. and a humidity of 90% for one day is 60% or more, preferably 80% or more, and more preferably 90%. Or more, and particularly preferably 95% or more. For example, the maintenance rate can be determined based on the initial photoelectric conversion efficiency immediately after producing the photoelectric conversion element and the photoelectric conversion efficiency after placing the photoelectric conversion element in a test environment. In addition, the maintenance rate can be measured after sealing the photoelectric conversion element as described above. Here, the maintenance rate can be calculated as follows based on the photoelectric conversion efficiency before and after being placed in the test environment.
Maintenance rate (%) = ((photoelectric conversion efficiency after being put in the test environment) / (photoelectric conversion efficiency before being put in the test environment)) × 100

  In one embodiment, the maintenance rate of the photoelectric conversion efficiency after being placed in a test environment at a temperature of 60 ° C. and a humidity of 90% for 96 hours is 40% or more, preferably 60% or more, and more preferably It is 80% or more, more preferably 90% or more, and particularly preferably 95% or more.

(7. Solar cell)
The photoelectric conversion element 100 according to the present embodiment is preferably used as a solar cell, particularly as a solar cell element of a thin film solar cell. FIG. 2 is a cross-sectional view schematically showing the structure of a solar cell according to an embodiment of the present invention, and FIG. 2 shows a thin film solar cell which is a solar cell according to an embodiment of the present invention. As shown in FIG. 2, the thin film solar cell 14 according to the present embodiment includes the weather resistant protective film 1, the ultraviolet ray cut film 2, the gas barrier film 3, the getter material film 4, the sealing material 5, and the solar cell The element 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. The thin film solar cell 14 according to the present embodiment includes the photoelectric conversion element according to the present embodiment as the solar cell element 6. Then, light is irradiated from the side (lower side in FIG. 2) on which the weather resistant protective film 1 is formed, and the solar cell element 6 generates power. In addition, the thin film solar cell 14 does not need to have all these structural members, and can select a required structural member arbitrarily.

  There is no particular limitation on these components constituting the thin film solar cell and the method of manufacturing the same, and known techniques can be used. For example, the techniques described in known documents such as WO 2013/171517, WO 2013/180230 or JP 2012-191194 can be used.

  There is no limitation on the application of the solar cell according to the present invention, in particular the thin film solar cell 14 described above, and it can be used for any application. For example, a solar cell according to one embodiment includes a solar cell for building materials, a solar cell for automobiles, a solar cell for interiors, a solar cell for railways, a solar cell for ships, a solar cell for airplanes, a solar cell for space vehicles, a solar for home appliances It can be used as a battery, a solar cell for mobile phones, or a solar cell for toys.

  The solar cell according to the present invention, in particular, the thin film solar cell 14 described above may be used as it is or may be used as a component of a solar cell module. For example, as shown in FIG. 5, a solar cell module 13 including the solar cell according to the present embodiment, in particular, the thin film solar cell 14 described above on the substrate 12 is manufactured, and the solar cell module 13 is installed at a use place Can be used. A well-known technique can be used as the base material 12, For example, as a material of the base material 12, the material as described in the international publication 2013/171517, the international publication 2013/180230 or Unexamined-Japanese-Patent No. 2012-191194 etc. Can be used. For example, when using the board | plate material for building materials as the base material 12, the solar cell panel for the outer wall of a building can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of this board | plate material.

  Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to the following examples unless the gist is exceeded.

[Preparation of coating solution]
(Preparation of Coating Solution for Electronic Extraction Layer)
A tin oxide aqueous dispersion of 7.5% was prepared by adding ultrapure water to a 15% aqueous dispersion of tin (IV) oxide (manufactured by Alfa Aesar).

(Preparation of coating solution for active layer)
Lead iodide (II) was weighed into vials and introduced into a glove box. N, N-dimethylformamide as a solvent was added so that the concentration of lead (II) iodide was 1.3 mol / L, and then heating and stirring were performed at 100 ° C. for 1 hour to prepare Coating Solution 1 for Active Layer. .

  Next, in a separate vial, formamidine hydroiodide (FAI), methylamine hydrobromide (MABr), and methylamine hydrochloride (MACl) in a mass ratio of 10: 1: 1 We weighed it to become and introduced it to the glove box. By adding isopropyl alcohol as a solvent there, the coating liquid 2 for active layers whose total concentration of FAI, MAbr, and MACl is 0.49 mol / L was prepared.

(Preparation of Coating Solution 1 for Hole Extraction Layer)
32 mg of poly [bis (4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA, manufactured by Sigma Aldrich) and 3.6 mg of 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluoro) Phenyl) borate (TPFB, manufactured by TCI) was weighed into a vial and introduced into a glove box. Thereto was added 1.6 mL of chlorobenzene as a solvent. Next, the obtained mixed solution was heated and stirred at 100 ° C. for 1 hour to prepare Coating Solution 1 for Hole Extraction Layer.

(Preparation of Coating Solution 2 for Hole Extraction Layer)
For a hole extraction layer except that 64 mg of PTAA and 3.6 mg of TPFB were weighed in a vial, and orthodichlorobenzene was used as a solvent, and the obtained mixture was heated and stirred at 150 ° C. for 1 hour instead of 100 ° C. Coating solution 2 for the hole extraction layer was prepared by the same method as coating solution 1.

(Preparation of Coating Solution 3 for Hole Extraction Layer)
Coating solution 3 for a hole extraction layer was prepared by the same method as Coating Solution 1 for a hole extraction layer except that the obtained mixed solution was heated and stirred at 70 ° C. for 1 hour instead of 100 ° C.

(Preparation of Coating Solution 4 for Hole Extraction Layer)
A LiTFSI solution was prepared by weighing 170 mg of lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) into a vial in a glove box and adding 1 mL of acetonitrile.

  Next, 15 mg of PTAA was weighed into another vial in a glove box, and 1 mL of toluene was added thereto as a solvent. The hole extraction layer coating solution 4 was prepared by adding 15 microliters of said LiTFSI solutions and 7.5 microliters of 4-tert- butylpyridines to the obtained solution, and stirring at room temperature for 1 hour.

[Example 1: Production of photoelectric conversion element 1]
Ultrasonic cleaning using ultrapure water, drying by nitrogen blow, and UV-ozone treatment were performed on a glass substrate (made by Geomatec Co., Ltd.) provided with a patterned indium tin oxide (ITO) transparent conductive film.

  Next, the coating solution for an electron extracting layer prepared as described above was spin coated on the above substrate at a speed of 2000 rpm at room temperature to form an electron extracting layer with a thickness of about 35 nm. The substrate was then heated on a hot plate at 150 ° C. for 10 minutes.

  Next, the substrate was introduced into a glove box, and 150 μL of Active Layer Coating Solution 1 heated to 100 ° C. was dropped on the electron extraction layer, and spin-coated at a speed of 2000 rpm. Next, the substrate was heat annealed on a hot plate at 100 ° C. for 10 minutes to form a lead iodide layer. Next, after the substrate returns to room temperature, an active layer coating solution 2 (120 μL) is spin coated on a lead iodide layer at a speed of 2000 rpm and heated at 150 ° C. for 20 minutes to form an organic / inorganic perovskite active layer. A thickness of 650 nm was formed.

  Next, after the substrate returns to room temperature, a hole extracting layer coating solution 1 (200 μL) is spin-coated on the active layer at a speed of 1500 rpm and further heated on a hot plate at 90 ° C. for 5 minutes to obtain positive A hole extraction layer (170 nm) was formed.

  Next, an electrode was formed on the hole extraction layer by depositing a silver film having a thickness of about 100 nm using a patterning mask by a resistance heating vacuum evaporation method. Thus, a 50 × 50 mm square photoelectric conversion element 1 was produced. Furthermore, the photoelectric conversion element 1 was sealed by bonding together the glass in which the center part was dug down, and the glass substrate of the photoelectric conversion element 1 with a sealing material (photocuring resin).

Example 2 Production of Photoelectric Conversion Element 2
The photoelectric conversion was carried out using the same method as in Example 1, except that the hole extraction layer coating solution 2 was spin coated on the active layer at a speed of 1000 rpm instead of spin coating the hole extraction layer coating solution 1. The conversion element 2 was produced.

Comparative Example 1: Production of Photoelectric Conversion Element 3
The photoelectric conversion device 3 is manufactured using the same method as in Example 1, except that the coating liquid 3 for hole extraction layer is spin-coated on the active layer instead of spin coating the coating liquid 1 for hole extraction layer. Made.

Reference Example 1: Production of Photoelectric Conversion Element 4
A photoelectric conversion was carried out using the same method as in Example 1, except that the hole extracting layer coating solution 4 was spin coated on the active layer at a speed of 3000 rpm instead of spin coating the hole extracting layer coating solution 1. The conversion element 4 was produced.

[Evaluation of photoelectric conversion element]
A 4 mm square metal mask is attached to each of the photoelectric conversion elements 1 to 4 obtained in Examples 1 and 2 and Comparative Example 1 and Reference Example 1, and the current-voltage characteristics between the ITO electrode and the silver electrode are measured. did. For measurement, a source meter (Keithley, model 2400) was used, and a solar simulator with an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm ² was used as an irradiation light source. From this measurement result, the initial conversion efficiency PCE (%) was calculated for the photoelectric conversion element not included in the durability tester. Next, each of the photoelectric conversion elements 1 to 4 was put into a high temperature high humidity durability tester at a temperature of 60 ° C. and a humidity of 90% and taken out after 1 day, and current-voltage characteristics were measured. Next, each of the photoelectric conversion elements 1 to 4 was put into a high temperature and high humidity durability tester and taken out after a long time, and the current-voltage characteristics were measured (the time taken into the durability tester is shown 1). The conversion efficiency PCE at each time point calculated based on each measurement result is shown in Table 1. In Table 1, the retention rate indicates the ratio of PCE after the durability test to the initial PCE.

  As shown in Table 1, the initial conversion efficiency was not significantly different between Examples 1 and 2 and Comparative Example 1 and Reference Example 1. On the other hand, looking at the results of the durability test, the conversion efficiency was significantly reduced in Comparative Example 1 and Reference Example 1, but in Examples 1 and 2, conversion equivalent to the initial conversion efficiency even after the durability test Efficiency was maintained. From the above results, it can be seen that the photoelectric conversion elements according to Examples 1 and 2 in which the coating solution was prepared under the conditions of 100 ° C. or 150 ° C. have high durability. Thus, it is understood that although the materials used to form the buffer layer are the same in Comparative Example 1 and Examples 1 and 2, there is a difference in the structure. The reason is not necessarily determined at present, but the inventors of the present application prepared the coating solution for the hole extraction layer at a high temperature, and the oxidation of the organic semiconductor compound (PTAA in this example) proceeded smoothly. I guess that is the reason for high durability.

  In addition, the present inventors measured the absorbance spectrum of the coating liquid for hole extraction layer according to Example 2 in order to support the above estimation. When a mixed solution containing PTAA and TPFB was heated and stirred at 150 ° C. for 10 minutes, and the absorbance spectrum was measured, a clear absorption peak was observed at 521 nm. Since PTAA does not have this absorption peak, this 521 nm absorption peak is considered to be characteristic of oxidized PTAA. In addition, the size of the absorption peak hardly increased even after heating and stirring for 1.5 hours. Thus, in the coating solution for the hole extraction layer according to Example 2, it is considered that the oxidation reaction by TPFB has almost completely advanced. On the other hand, when a mixed solution containing PTAA and TPFB was heated and stirred for 10 minutes using a lower temperature, the absorption peak at 521 nm showed a tendency to hardly increase.

  From these results, when the temperature is low, the inventors of the present invention tend to hardly advance the oxidation reaction of the organic semiconductor compound, and while the oxidation state of the organic semiconductor compound is unstable, the conductivity tends to be lost. By preparing a coating solution for forming a semiconductor layer under conditions of 85 ° C. or higher, the oxidation reaction of the organic semiconductor compound proceeds to a certain extent, and thus a stable oxidized organic semiconductor compound is obtained, which is a semiconductor layer or an electronic device. It is speculated that it has led to high durability.

DESCRIPTION OF SYMBOLS 1 Weather resistance protective film 2 UV cut film 3, 9 Gas barrier film 4, 8 Getter material film 5, 7 Sealing material 6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell module 14 Thin film solar cell 100 Photoelectric conversion element 101 Lower part Electrode 102 Buffer layer 103 Active layer 105 Buffer layer 107 Upper electrode 108 Base material

Claims (12)

A method of manufacturing an electronic device comprising a semiconductor layer, the method comprising:
A coating solution containing an organic semiconductor compound and a dopant for the organic semiconductor compound which is a hypervalent iodine compound is heated to 85 ° C. or higher and / or the coating solution is irradiated with ultraviolet light, and then the coating solution is applied. Manufacturing the semiconductor layer by carrying out.   The method according to claim 1, wherein the dopant is an organic compound containing trivalent iodine.   The method according to claim 1, wherein the dopant is a diaryl iodonium salt.   The method according to any one of claims 1 to 3, wherein the organic semiconductor compound is a triarylamine compound. The electronic device comprises a pair of electrodes comprising a lower electrode and an upper electrode, an active layer containing a perovskite compound between the pair of electrodes, a buffer layer between the pair of electrodes and the active layer And a photoelectric conversion element comprising
The method according to claim 1, wherein the semiconductor layer is the buffer layer.   6. The method of claim 5, wherein the buffer layer is a hole extraction layer.   The method according to claim 5 or 6, wherein the buffer layer is located between the upper electrode and the active layer.   An electronic device manufactured by the manufacturing method according to any one of claims 1 to 7. A method for producing a coating solution for forming a semiconductor layer, comprising
A step of heating a coating solution containing an organic semiconductor compound and a dopant for the organic semiconductor compound which is a hypervalent iodine compound to 85 ° C. or higher and / or irradiating the coating solution with ultraviolet light How to make it.   The coating liquid for semiconductor layer formation manufactured by the manufacturing method of Claim 9. An electronic device comprising a semiconductor layer,
The semiconductor layer comprises an organic semiconductor compound doped with a dopant,
The electronic device, wherein the amount of unreacted dopant contained in the semiconductor layer is 80% by mass or less of the amount of dopant which is the sum of the amount of unreacted dopant and the amount of reacted dopant. A coating solution for forming a semiconductor layer, which is
The coating solution for forming a semiconductor layer contains an organic semiconductor compound doped with a dopant,
The amount of unreacted dopant contained in the coating solution for forming a semiconductor layer is 80% by mass or less of the amount of dopant which is the sum of the amount of unreacted dopant and the amount of reacted dopant. Coating solution.

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