JP2013016671A - Transparent conductive film, method for producing the same, and organic thin-film solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent conductive film which is excellent in all of electrical conductivity, optical transparency, and smoothness, by an easy process.SOLUTION: A transparent conductive film 1 includes: an auxiliary electrode layer 11 provided with auxiliary metal wiring 21 having a plurality of openings 20, and a transparent resin 31 filling at least the openings 20; and a conductive resin layer 12 formed on the auxiliary electrode layer 11. The transparent resin 31 is obtained by polymerizing a monomer composition 30 having a low affinity to at least a surface of the auxiliary metal wiring 21.

Description

  The present invention relates to a transparent conductive film, a method for producing the same, and an organic thin film solar cell.

  In recent years, the demand for solar cells has increased, and organic electronics devices that can be expected to be lightweight (flexible) and cost-cutting have attracted attention. In particular, expectations for all-solid-state organic thin-film solar cells are increasing.

  The structure of an organic thin film solar cell (solar cell comprising an organic photoelectric conversion element) is a bulk heterostructure formed by mixing an electron donating material (donor) and an electron accepting material (acceptor) between two different electrodes (positive electrode and negative electrode). It is common to have a junction-type photoelectric conversion layer arranged, and it is easier to manufacture than conventional thin-film solar cells using amorphous silicon or the like, and solar cells of any area can be manufactured at low cost. There is an advantage that it can be obtained, and practical application is desired.

  In an organic electronic device such as an organic thin film solar cell, it is preferable from the viewpoint of power generation efficiency that the electrode on the light receiving side has high transparency. As the transparent electrode, a transparent conductive oxide (TCO) is usually used. In particular, indium tin oxide (equivalent to high visible light transmission and high electrical conductivity, and easy to process) ITO) is mainly used. However, the price of ITO materials has been rising in recent years, and high-quality ITO electrodes cannot be obtained unless they are formed by a physical vapor deposition method (PVD method) such as sputtering. . For this reason, there is a demand for an alternative electrode material.

  Moreover, when it is set as the thin film solar cell which has translucency, such as semi-transparency, both a positive electrode and a negative electrode require a light transmittance. Flexible thin-film solar cells using plastic film as a support, organic thin-film solar cells using an organic semiconductor containing a conductive polymer as a photoelectric conversion layer, and solar cells using a combination of both, have electrodes at low temperatures so that organic materials do not deteriorate. Although it is necessary to form it, when TCO such as ITO is formed at a low temperature, its crystallinity is deteriorated and the resistance of the electrode is increased.

In Patent Document 1 and Patent Document 2, after forming a mesh pattern metal electrode (mesh electrode) as a positive electrode auxiliary wiring on a support, a positive electrode (hole transport layer) made of TCO or a conductive polymer is formed, An organic thin film solar cell with reduced resistance on the positive electrode side is disclosed. However, since the portion where the positive electrode auxiliary wiring is formed is shielded from light, the effective area of the solar cell is reduced (the aperture ratio is reduced) and the conversion efficiency is deteriorated. Therefore, it is necessary to narrow the line width of the auxiliary wiring for positive electrode, while it is necessary to increase the film thickness so as not to lower the conductivity. However, since a step corresponding to the film thickness occurs at the end of the auxiliary wiring for positive electrode, the occurrence rate of short-circuit failure in which the positive electrode and the negative electrode contact and short-circuit increases. Patent Document 1 suggests that the thickness of the hole transport layer needs to be greater than or equal to the thickness of the mesh electrode. However, the increase in the thickness of the hole transport layer directly leads to an increase in cost, and the hole transport. The amount of incident light absorbed by the layer increases (transmittance decreases), leading to a further decrease in efficiency of the solar cell.
On the other hand, in Patent Document 2, when a mesh electrode having a sufficient thickness to ensure conductivity is formed so as to be embedded in a substrate (a step due to the mesh electrode is reduced), a negative electrode (counter electrode) The method which can suppress a short circuit with is effectively described.

  However, the production method described in Patent Document 2 increases the number of production steps and the process time, leading to an increase in cost. In particular, when the support is a plastic film, the support is etched or surface-polished. The support deteriorates and leads to an increase in surface irregularities, which in turn increases short circuit failures.

  Patent Document 3 discloses a conductive polymer after a transparent resin is embedded in a liquid discharge (inkjet) device only in an opening (translucent portion) of a mesh pattern metal wiring (described as a conductive metal pattern). An auxiliary electrode is disclosed in which a surface step is reduced by forming a film. However, this method greatly increases the process time including alignment.

  Furthermore, in Patent Document 3, an ultraviolet curable resin is formed on the entire surface of the support (transparent film substrate) on which the mesh pattern metal wiring is formed, and is exposed to ultraviolet light from the support (back surface) side and washed. A method of forming a transparent resin only at the metal wiring opening to eliminate the surface step is also disclosed.

US Patent Application Publication No. 2004/0187911 JP 2009-76668 A JP 2009-140750 A

  The method of eliminating the surface step by forming a transparent resin only in the metal wiring opening by forming a film of the ultraviolet curable resin described in Patent Document 3 and exposing it to ultraviolet light from the support (back surface) side and washing it. The cost can be suppressed by a relatively easy method.

  However, the cross section of the metal wiring is not an ideal rectangle and is actually a trapezoid (the cross section of the end is not a right angle but an acute angle), so according to this method, the UV curable resin formed on the slope of the end of the metal wiring Are not irradiated with ultraviolet light and are removed in the cleaning process. That is, there is a possibility that a groove in which the transparent resin is not formed is formed at the end portion of the metal wiring. When such an auxiliary electrode is used, it is considered that there is a possibility that a contact between the lower electrode and the upper electrode and a short circuit may occur due to a surface step due to the groove.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a transparent conductive film that can be produced by an easy process and has good conductivity, light transmission, and smoothness. To do. Another object of the present invention is to provide an organic thin-film solar cell in which occurrence of short-circuit failure is suppressed.

The transparent conductive film of the present invention is
An auxiliary electrode layer comprising an auxiliary metal wiring having a plurality of openings, and a transparent resin filled in the openings,
A conductive resin layer formed on the auxiliary electrode layer,
The transparent resin is obtained by polymerizing a monomer composition having a low affinity with at least the surface of the auxiliary metal wiring.

  Here, “low affinity” means that when the monomer composition is brought into contact with the surface, the surface does not get wet and the monomer composition is repelled from the surface. The monomer composition on the surface of the auxiliary metal wiring The contact angle with respect to is preferably 70 ° or more.

  The transparent conductive film of this invention WHEREIN: It is preferable that the difference of the water contact angle of the surface of the said auxiliary metal wiring and the water contact angle of the said transparent resin is 60 degrees or more.

  In the present invention, the “contact angle” is defined as the contact angle of the monomer composition or water with respect to the film formed on the surface of the auxiliary metal wiring or transparent resin on a flat substrate.

  The surface of the auxiliary metal wiring may be provided with a surface treatment agent that changes the water contact angle of the surface.

  In the transparent conductive film of the present invention, the transparent resin is preferably obtained by polymerizing a composition containing a polyfunctional (meth) acrylic monomer.

  In the present specification, the “polyfunctional (meth) acrylic monomer” means a monomer having two or more (meth) acrylic groups. “(Meth) acryl” means acrylic or methacrylic.

The method for producing the transparent conductive film of the present invention comprises:
On the support,
Forming an auxiliary metal wiring having a plurality of openings;
Filling the opening with the monomer composition by applying a monomer composition having a low affinity for at least the surface of the auxiliary metal wiring from the upper surface of the opening and the auxiliary metal wiring;
Sequentially performing the step of polymerizing the monomer composition to form an auxiliary electrode layer,
A conductive resin layer is formed on the auxiliary electrode layer.

The organic thin film solar cell of the present invention comprises a support, the transparent conductive film of the present invention,
A photoelectric conversion element formed by laminating a photoelectric conversion layer containing an organic material and an upper electrode in this order is provided.

  The transparent conductive film of the present invention includes an auxiliary metal wiring having a plurality of openings, and a transparent resin formed by polymerizing a monomer composition filled in the openings and having a low affinity with at least the surface of the auxiliary metal wiring. Auxiliary electrode is provided. Such a monomer composition forms an auxiliary metal wiring on a support, and then is applied from above the opening and the auxiliary metal wiring, so that the auxiliary metal wiring is well exposed and filled into the opening. Therefore, according to the present invention, a transparent flattening layer can be formed in the opening of the auxiliary metal wiring by a very easy process, that is, any of conductivity, light transmission, and smoothness can be formed. It is possible to provide a transparent conductive film having good quality by an easy process.

  Moreover, the aspect using the transparent resin formed by polymerizing a composition containing a polyfunctional (meth) acrylic monomer as the transparent resin is a heat treatment such as an annealing treatment in a subsequent process due to the good heat resistance and solvent resistance of the resin. In addition, the adverse effect on the smoothness caused by the material formed on the transparent resin can also be suppressed.

  As described above, since the transparent conductive film of the present invention has good conductivity, light transmittance, and smoothness, the photoelectric conversion element of the present invention having such a transparent conductive film as a positive electrode is The occurrence of short-circuit faults is suppressed.

The schematic sectional drawing which shows one Embodiment of the transparent conductive film of this invention. The schematic top view of the transparent conductive film shown in FIG. Schematic which shows the manufacturing process of the transparent conductive film of this invention. The schematic sectional drawing which shows one Embodiment of the organic thin-film solar cell of this invention.

<Transparent conductive film>
The configuration of the transparent conductive film of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing an embodiment of the transparent conductive film of the present invention, FIG. 2 is a schematic top view of the transparent conductive film shown in FIG. 1, and FIG. It is. In addition, in order to make it easy to visually recognize, the scale of each component in the drawing is appropriately different from the actual one (the same applies to the following drawings). In FIG. 2, the transparent resin and the conductive resin layer are omitted in order to make the configuration of the auxiliary metal wiring easily visible.

  As shown in FIGS. 1 and 2, the transparent conductive film 1 includes an auxiliary electrode 11 including an auxiliary metal wiring (metal mesh, conductive mesh) 21 and a transparent resin 31, and a conductive resin layer 12. Thus, the transparent resin 31 is located in the opening 20 of the auxiliary metal wiring 21 (the opening 20 is a region surrounded by the auxiliary metal wiring 21), and is provided so as to flatten the auxiliary metal wiring 21. That is, the transparent resin 31 is a planarization layer that fills the opening 20 of the auxiliary metal wiring 21 and reduces the level difference of the auxiliary metal wiring 21. Preferably, there is no level difference between the transparent resin 31 and the auxiliary metal wiring 21. It is the same.

  The transparent conductive film 1 has a surface resistance value of preferably 20 Ω / sq or less, more preferably 10 Ω / sq or less, and still more preferably 1 Ω / sq or less (measured according to JIS7194). Further, the average transmittance in the light wavelength range of 400 nm to 800 nm is 50% or more, preferably 60% or more, and more preferably 70% or more. Similar to the support, the light transmittance can be measured as the total light transmittance using an integrating sphere light transmittance measuring device. Further, molybdenum oxide may be used as part of the positive electrode.

  As shown in FIG. 3, the transparent conductive film 1 forms an auxiliary metal wiring 21 having a plurality of openings 20 on the support 10 (FIG. 3A), and the openings 20 and the auxiliary metal wiring 21 are formed. The monomer composition 30 is applied from the upper surface, and the opening 20 is filled with the monomer composition 30 (FIG. 3 (b)), and the monomer composition 30 is polymerized (FIG. 3 (c)). The auxiliary electrode layer 11 provided with the auxiliary metal wiring 21 and the transparent resin 31 is formed as a layer) (FIG. 3D), and the conductive resin layer 12 is further formed on the auxiliary electrode layer 11 to be manufactured. .

  In the transparent conductive film 1, the transparent resin 31 is obtained by polymerizing a monomer composition 30 having a low affinity with at least the surface of the auxiliary metal wiring 21. According to such a configuration, the monomer composition 30 applied on the auxiliary metal wiring 21 has a low affinity with the surface of the auxiliary metal wiring 21 when the monomer composition 30 shown in FIG. In addition, most of the coating liquid is applied to the opening 20 because it is easily repelled without wetting the surface. Therefore, the auxiliary electrode layer 11 obtained after the subsequent polymerization step does not require the step of removing the transparent resin 31 formed on the auxiliary metal wiring 21, and has a flatness where the surface of the auxiliary metal wiring 21 is well exposed. It will be good.

As described above, due to the low affinity between the monomer composition 30 and the surface of the auxiliary metal wiring 21, the amount of the monomer composition 30 remaining on the surface of the auxiliary metal wiring 21 before polymerization is small, but remains. The monomer composition 30 is also removed from the surface of the auxiliary metal wiring 21 having a low affinity at the time of volume shrinkage in the polymerization process. Moreover, even if it remains on the auxiliary metal wiring, the entire wiring is not covered, and as a result, electrical contact with the upper conductive polymer layer becomes possible. The transparent resin 31 that is a polymer of the monomer composition 30 having a low affinity with the surface of the auxiliary metal wiring 21 also has a low affinity with the surface of the auxiliary metal wiring 21. The monomer composition 30 is preferably applied in a slightly excessive amount in consideration of volume shrinkage.
Below, each structure of the transparent conductive film 1 is demonstrated.

<Support>
The support 10 is not particularly limited as long as it is a substrate or film having a smooth surface that can hold the auxiliary metal wiring 21 and the transparent resin 31, and can be appropriately selected according to the purpose. Usually, the support on which the transparent conductive film 1 is formed. Since 10 is used as it is for an organic thin film solar cell or the like, it is preferable to have transparency (transparency of light to be used). Examples include a plastic film and a thin glass plate. In addition, when forming the transparent conductive film 1 using the temporary support body 10, and peeling this temporary support body and arrange | positioning a solar cell on arbitrary transparent supports, the temporary support body 10 has transparency especially. It is not necessary, and a plastic film, a metal foil, a laminate in which plastic or metal is laminated on paper can be arbitrarily selected and used.

  Hereinafter, a plastic film substrate will be described as a representative example of the transparent support.

(Plastic film substrate)
There is no restriction | limiting in particular in a material, thickness, etc., a plastic film board | substrate can be suitably selected according to the objective. Specific examples of the plastic film material that can be used for the substrate include polyester resin, methacrylic resin, methacrylic acid-maleic acid copolymer, polystyrene resin, transparent fluororesin, polyimide resin, fluorinated polyimide resin, and polyamide resin. , Polyamideimide resin, polyetherimide resin, cellulose acylate resin, polyurethane resin, polyetheretherketone resin, polycarbonate resin, cycloaliphatic polyolefin resin, polyarylate resin, polyethersulfone resin, polysulfone resin, cycloolefin copolymer, Examples thereof include thermoplastic resins such as a fluorene ring-modified polycarbonate resin, an alicyclic ring-modified polycarbonate resin, a fluorene ring-modified polyester resin, and an acryloyl compound.

  A heat resistant resin having a high Tg is also preferably used as the plastic film substrate. Examples of the heat resistant resin include, for example, polyethylene naphthalate (PEN: 120 ° C.), polycarbonate (PC: 140 ° C.), alicyclic polyolefin (for example, Zeonore 1600: 160 ° C. manufactured by Nippon Zeon Co., Ltd.) PAr: 210 ° C), polyethersulfone (PES: 220 ° C), polysulfone (PSF: 190 ° C), cycloolefin copolymer (COC: compound of JP 2001-150584 A, 162 ° C), fluorene ring-modified polycarbonate (BCF) -PC: Compound disclosed in JP 2000-227603 A: 225 ° C., alicyclic modified polycarbonate (IP-PC: Compound disclosed in JP 2000-227603 A: 205 ° C.), acryloyl compound (JP 2002-80616 A) Compound: 300 ° C. or higher) Imide and the like (in parentheses indicate the Tg), they are suitable as substrates in the present invention.

  In the present invention, the plastic film is required to be transparent to light. More specifically, the light transmittance for light in the wavelength range of 400 nm to 800 nm is usually preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The light transmittance can be measured as the total light transmittance using an integrating sphere light transmittance measuring device. Although there is no restriction | limiting in particular regarding the thickness of a plastic film, Typically, they are 1 micrometer-800 micrometers, Preferably they are 10 micrometers-300 micrometers.

(Easily adhesive layer / undercoat layer)
The plastic film substrate may have an easy adhesion layer or an undercoat layer. The structure of the easy adhesion layer or the undercoat layer may be a single layer or a multilayer structure. The easy-adhesion layer must contain a binder polymer, but may appropriately contain a matting agent, a surfactant, an antistatic agent, fine particles for controlling the refractive index, and the like. There is no restriction | limiting in particular in the binder polymer which can be used for an easily bonding layer, It can select suitably from an acrylic resin, a polyurethane resin, a polyester resin, a rubber-type resin, etc., and can be used.

  The coating film thickness after drying the easy-adhesion layer or the undercoat layer is preferably in the range of 50 nm to 2 μm. In addition, when using a support body as a temporary support body, it is also possible to give an easily peelable process to the support surface.

  An acrylic resin is a polymer containing acrylic acid, methacrylic acid and derivatives thereof as components. Specifically, for example, acrylic acid, methacrylic acid, methyl methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylamide, acrylonitrile, hydroxyl acrylate, and the like as a main component and a monomer copolymerizable therewith (for example, styrene, A polymer obtained by copolymerizing divinylbenzene or the like is preferable.

  Polyurethane resin is a general term for polymers having a urethane bond in the main chain, and is usually obtained by reaction of polyisocyanate and polyol. Examples of the polyisocyanate include TDI (Tolylene Diisocyanate), MDI (Methyl Diphenylisocyanate), HDI (Hexylene diisocyanate), IPDI (Isophoron diisocyanate), and the like. And pentaerythritol. Furthermore, as the isocyanate of the present invention, a polymer obtained by subjecting a polyurethane polymer obtained by the reaction of polyisocyanate and polyol to chain extension treatment to increase the molecular weight can also be used.

  A polyester resin is a general term for polymers having an ester bond in the main chain, and is usually obtained by the reaction of a polycarboxylic acid and a polyol. Examples of the polycarboxylic acid include fumaric acid, itaconic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid. Examples of the polyol include those described above.

  The rubber-based resin refers to a diene-based synthetic rubber among the synthetic rubbers. Specific examples include polybutadiene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-divinylbenzene copolymer, butadiene-acrylonitrile copolymer, and polychloroprene.

<Auxiliary electrode layer>
<< Auxiliary metal wiring >>
Examples of the metal material constituting the auxiliary metal wiring 21 include gold, platinum, iron, copper, silver, aluminum, chromium, cobalt, and stainless steel. Preferable examples of the metal material include low resistance metals such as copper, silver, aluminum, and gold. Among them, silver or copper that is low in manufacturing cost and material cost and hardly oxidizes is preferably used.

  In the transparent conductive film 1, the affinity between the auxiliary metal wiring 21 and the monomer composition 30 or the transparent resin 31 needs to be low. Therefore, the material of the auxiliary metal wiring 21 may be appropriately selected in consideration of the affinity with the monomer composition 30 or the transparent resin 31 to be used. The criteria for determining affinity will be described later.

  Further, the auxiliary metal wiring 21 may be subjected to surface treatment for affinity control. Although it does not restrict | limit especially as a surface treatment method, The method of immersing in the liquid which can control the wettability of interfaces, such as a thiol fluoride, oxygen plasma treatment, UV ozone treatment, etc. are mentioned.

  In addition, when surface treatment is performed, it is preferable to remove the surface treatment agent before forming the conductive resin layer in the subsequent step. For example, the thiol fluoride surface treatment agent can be removed by immersing it in a mixed solution of sulfuric acid and hydrogen peroxide.

  The pattern shape of the auxiliary metal wiring 21 is not particularly limited, but a mesh shape (mesh pattern electrode) is preferable from the viewpoint of light transmittance and conductivity. There is no particular limitation on the mesh pattern, and a lattice shape such as a square, a rectangle, or a rhombus, a stripe shape (stripe shape), a honeycomb, or a combination of curves may be used.

  These mesh designs are adjusted so that the aperture ratio (light transmittance) and the surface resistance (electric conductivity) become desired values. When the auxiliary metal wiring 21 having such a mesh pattern is used, the mesh opening ratio is usually 70% or more, preferably 80% or more, and more preferably 85% or more.

  The surface resistance of the auxiliary metal wiring 21 is preferably 10Ω / □ or less, more preferably 3Ω / □ or less, and even more preferably 1Ω / □ or less. Since the light transmittance and the electrical conductivity are in a trade-off relationship, the larger the aperture ratio, the better. However, in practice, it becomes 95% or less.

  The thickness of the auxiliary metal wiring 21 is not particularly limited, but is usually about 0.02 μm to 20 μm.

  The line width in the mesh pattern of the auxiliary metal wiring 21 is in the range of 1 μm to 500 μm, preferably 1 μm to 100 μm, more preferably 3 μm to 20 μm, from the viewpoint of light transmittance and conductivity.

  A smaller pitch in the mesh pattern of the auxiliary metal wiring 21 (fine mesh) is advantageous in terms of the characteristics of the solar cell. However, if the pitch is small, the light transmittance decreases, so a compromise is chosen. Although a pitch changes according to the line | wire width of a metal fine wire, it is preferable that the pitch by planar view is 50 micrometers-2000 micrometers, 100 micrometers-1000 micrometers are more preferable, 150 micrometers-500 micrometers are more preferable.

From the viewpoint of the opening, the area of the opening 20 serving as a repeating unit of the auxiliary metal wiring 21 is preferably 1 × 10 ⁻⁹ m ² to 1 × 10 ⁻⁴ m ² , and 3 × 10 ⁻⁹ m ^2. It is more preferably ˜1 × 10 ⁻⁵ m ² , and further preferably 1 × 10 ⁻⁸ m ² to 1 × 10 ⁻⁶ m ² .

  There is no restriction | limiting in particular as a formation method of the auxiliary metal wiring 21, A well-known formation method can be used suitably. For example, a method in which a mesh pattern metal prepared in advance is bonded to the support surface, a method in which a conductive material is applied to the mesh pattern, a conductive film is formed on the entire surface using a PVD method such as vapor deposition or sputtering, and then the mesh pattern is etched. A method of forming a conductive film, a method of applying a conductive material of a mesh pattern by various printing methods such as screen printing, ink jet printing, etc., a metal mask of a mesh pattern directly on the substrate surface using a shadow mask by vapor deposition or sputtering And a method using a silver halide photosensitive material described in JP-A-2006-352073, JP-A-2009-231194, and the like (hereinafter sometimes referred to as silver salt method).

  When the auxiliary metal wiring 21 is formed as a mesh electrode, it is preferably formed by a silver salt method because the pitch is small. When the auxiliary metal wiring 21 is formed by the silver salt method, a step of providing a coating liquid for forming the auxiliary metal wiring on the support and performing pattern exposure on the coating film for forming the auxiliary metal wiring 21; The auxiliary metal wiring 21 having a desired pattern can be formed on the support by developing the pattern-exposed coating film and fixing the developed coating film.

  The auxiliary metal wiring 21 produced by the silver salt method is a layer of silver and a hydrophilic polymer. Examples of the hydrophilic polymer include water-soluble polymers such as gelatin, gelatin derivatives, casein, agar, sodium alginate, starch, and polyvinyl alcohol, and cellulose esters such as carboxymethyl cellulose and hydroxyethyl cellulose. In addition to silver and hydrophilic polymer, the layer contains substances derived from the coating, developing and fixing processes.

  A method of forming an auxiliary wiring by the silver salt method and then performing copper plating to obtain an auxiliary wiring with lower resistance is also preferably used.

<< Alignment mark >>
In the step of forming the auxiliary metal wiring 21, in order to improve the stacking accuracy of the functional films and film substrates to be stacked in the subsequent process and increase the integration density, the alignment mark 28 for position detection is formed simultaneously with the metal wiring. It is preferable to do. The alignment mark appropriately forms a pattern specified by the image recognition specifications of each functional film manufacturing device or printing device, but stripes, crosses, rectangles, circles, geometric patterns combining them, symbols, characters, etc. Preferably used.

<< Transparent resin (flattening layer) >>
The transparent resin 31 is obtained by polymerizing the monomer composition 30 having a low affinity with at least the surface of the auxiliary metal wiring 21. As described in the section “Means for Solving the Problems”, the affinity between the auxiliary metal wiring 21 and the transparent resin 31 is determined when the monomer composition 30 is brought into contact with (applied to) the surface of the auxiliary metal wiring 21. Furthermore, there is no particular limitation as long as the monomer composition 30 is low enough to be repelled from the surface without being wetted. As already described, if the monomer composition 30 has such properties, the transparent resin 31 that is a polymer can be a good planarization layer of the auxiliary metal wiring 21, but the surface of the auxiliary metal wiring 21 can be obtained. The contact angle with respect to the monomer composition 30 is preferably 70 ° or more.

  In selecting the material of the monomer composition 30, in addition to selecting a material having a good affinity and contact angle with the auxiliary metal wiring 21 as described above, the water contact angle on the surface of the auxiliary metal wiring 21 and the water of the transparent resin 31 are selected. You may select a thing with a large difference with a contact angle. In this case, the difference in water contact angle is preferably 60 ° or more.

  For example, the water contact angle of silver is about 20 °. Therefore, when a silver mesh is used as the auxiliary metal wiring 21, it is preferable to select the transparent resin 31 having a water contact angle of 80 ° or more.

  Further, the conductive resin layer 12 is formed on the surface of the transparent resin 31 in a later step. When the conductive resin layer 12 is formed, the smoothness of the surface of the auxiliary electrode 11 (transparent resin 31) serving as a base may be impaired depending on the formation method and the material of the conductive resin layer 12. For example, when the conductive resin layer 12 is formed by a coating method, if the resistance of the transparent resin 31 to the coating solution is low, the surface smoothness is reduced during film formation. In addition, when the conductive resin layer 12 is formed or when a heating step is required due to subsequent annealing treatment or the like, if the heat resistance of the transparent resin 31 is low, smoothness is impaired. Therefore, it is preferable that the transparent resin 31 is excellent in heat resistance and solvent resistance.

  Moreover, the polymerization method of the monomer composition 30 which is a raw material of the transparent resin 31 is not particularly limited, but photopolymerization using light or an electron beam is preferable. Therefore, it is preferable that the transparent resin 31 has good photopolymerizability, high transparency, and excellent heat resistance and solvent resistance.

  Examples of the transparent resin 31 include those obtained by polymerizing a composition containing a polyfunctional (meth) acrylic monomer. In the present specification, the “polyfunctional (meth) acrylic monomer” means a monomer having two or more (meth) acrylic groups. “(Meth) acryl” means acrylic or methacrylic.

  The monomer composition 30 preferably contains a suitable photopolymerization initiator depending on the type of monomer. What is necessary is just to select the wavelength of light and an electron beam suitably according to the kind of monomer and a polymerization initiator. In addition, a sensitizer may be added to the monomer composition 30 in relation to the irradiation light wavelength in the manufacturing process, and an additive for reducing the affinity with the surface of the auxiliary metal wiring 21 is appropriately included. May be.

  Since the polyfunctional (meth) acrylic monomer can form a crosslinked structure by polymerization, the transparent insulating layer 30 having excellent heat resistance and solvent resistance as compared with the case where the monofunctional (meth) acrylic monomer is used. Can be formed. Here, the solvent resistance means resistance to organic solvents and monomers.

Although it does not restrict | limit especially as a polyfunctional (meth) acryl monomer, From a viewpoint of solvent resistance and heat resistance, it may be a monomer which has 3 or more (henceforth trifunctional or more) (meth) acryl groups. preferable. Examples of the trifunctional (meth) acrylic monomer include the following trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETIA).
However, the water contact angle θc of these resins is relatively small, about 45 ° for TMPTA and about 40 ° for PETIA. For example, when a silver mesh is used as the auxiliary metal wiring 21, the transparent resin 31 has high affinity. It is not suitable as a monomer. Therefore, the transparent resin 31 becomes a very good planarization layer when the auxiliary metal wiring 21 having a surface with a sufficiently large water contact angle θc is used. For example, when a silver mesh is immersed in a surface treatment solution such as thiol fluoride, the water contact angle on the surface is about 120 °. When the surface-treated silver mesh is used as the auxiliary metal wiring 21, TMPTA or PETIA can be a good flattened layer (see Example 3 described later).

On the other hand, as described above, silver mesh is a preferable material for the auxiliary metal wiring 21. Examples of the polyfunctional (meth) acrylic monomer that can be used without subjecting the silver mesh to surface treatment include the following 1,6-hexanediol diacrylate (θc≈95 °) (bifunctional).

Polyethylene glycol diacrylate (A-600) (bifunctional) is also a polyfunctional (meth) acrylic monomer that has θc≈80 ° and can be used without subjecting the silver mesh to surface treatment. However, as in A-600, a resin obtained by polymerizing a polyfunctional (meth) acrylic monomer having a structure containing an oxygen atom in a portion (linking chain) that connects (meth) acrylic groups contains an oxygen atom. The shape retention is lower than that of a structure having no structure. Therefore, the polyfunctional (meth) acrylic monomer is preferably one having a structure that does not contain an oxygen atom in a portion (linking chain) that connects (meth) acrylic groups.

In addition to the above, examples of the bifunctional (meth) acrylic monomer include the following compounds.

  Moreover, the composition 30 containing a polyfunctional (meth) acrylic monomer may contain another vinyl monomer. The composition ratio of the polyfunctional (meth) acrylate monomer in the composition containing the polyfunctional (meth) acrylate monomer is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, Furthermore, it is more preferable that it is 70 mass%-100 mass%.

Examples of vinyl monomers include (meth) acrylate, (meth) acrylamide, styrene and the like, and monofunctional (meth) acrylic monomers are preferred. Below, the preferable specific example of a monofunctional (meth) acryl monomer is shown. The monomer composition 30 may be appropriately selected and prepared in consideration of the affinity with the surface of the auxiliary metal wiring 21.

  As described above, the embodiment using the transparent resin obtained by polymerizing the composition 30 containing the polyfunctional (meth) acrylic monomer as the transparent resin 31 is an annealing process in the subsequent process due to the good heat resistance and solvent resistance of the resin. The adverse effect on the smoothness due to the heat treatment such as the treatment and the substance formed on the transparent resin can also be suppressed.

  Before and at the time of forming the conductive resin layer 12 in a later process (during formation), the transparent resin 31 is raised from the auxiliary metal wiring 21 in the auxiliary electrode 11, or the auxiliary metal wiring 21 is formed by the transparent resin 31. If the opening is not filled, a step is formed in the unflattened portion. When this step is present, the conductive resin layer 12 at that portion becomes thin, and therefore, when used in an organic thin film solar cell or the like, a short circuit with the upper electrode is likely to occur at the corner of the step, which also adversely affects conversion efficiency. Effect.

  As described above, in the transparent conductive film 1, the flatness of the auxiliary electrode 11 can be improved, so that the uniformity of the film thickness of the conductive resin layer 12 is improved and a short circuit occurs in an element such as a solar cell. Can be difficult.

  It is preferable that the transparent resin 31 and the upper part of the auxiliary metal wiring 21 have no step and are flush with each other, but a step that can ensure the flatness of the conductive resin layer 12 formed thereon is allowed. The step between the transparent resin 31 and the upper part of the auxiliary metal wiring 21 is preferably 10 μm or less, more preferably 1 μm or less, and further preferably 0.2 μm or less.

<< Conductive Resin Layer 12 >>
The conductive resin layer 12 is selected from various conductive materials having optical transparency. Examples of the light-transmitting conductive material include a transparent conductive polymer, ITO (indium tin oxide), and the like, but a layer containing a conductive polymer as a main component is preferable because of excellent flexibility. Details of a conductive polymer layer suitable for the lower electrode are disclosed in Japanese Patent Application No. 2010-181078 (not disclosed at the time of this application).

Although the formation method in particular of the conductive resin layer 12 is not restrict | limited, For example, the water-system coating method etc. are employable.
As described above, the transparent conductive film 1 is configured.

  The transparent conductive film 1 is a transparent resin formed by polymerizing an auxiliary metal wiring 21 having a plurality of openings 20 and a monomer composition 30 filled in the openings 20 and having a low affinity with at least the surface of the auxiliary metal wiring 21. Auxiliary electrode 11 provided with 31 is provided. The monomer composition 30 is formed by forming the auxiliary metal wiring 21 on the support 10 and then applying the monomer composition 30 from above the opening 20 and the auxiliary metal wiring 21 so that the auxiliary metal wiring 21 is satisfactorily exposed. Part 20 is filled. Therefore, according to the present embodiment, the transparent planarization layer 31 can be formed in the opening 20 of the auxiliary metal wiring 21 by a very easy process, that is, conductivity, light transmission, and smoothness. The transparent conductive film 1 having good properties can be provided by an easy process.

  Moreover, the aspect using the transparent resin 31 which superposes | polymerizes the composition 30 containing a polyfunctional (meth) acryl monomer as the transparent resin 31 is an annealing process of a post process, etc. by the favorable heat resistance and solvent resistance of this resin. The adverse effects on the smoothness due to the heat treatment and the material deposited on the transparent resin 31 can also be suppressed.

<Organic thin film solar cell>
The transparent conductive film 1 can be suitably used as a transparent electrode such as an organic thin film solar cell. As one embodiment, the support 10, the transparent conductive film 1 (positive electrode), the photoelectric conversion layer 22 containing an organic material, and the upper electrode 24 (negative electrode) shown in FIG. 4 are laminated in this order. The aspect provided with the photoelectric conversion element which becomes. In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, and descriptions thereof are omitted unless particularly necessary.
Hereinafter, about the suitable aspect of the organic thin-film solar cell 2 provided with the transparent conductive film 1 as a positive electrode, structures other than the transparent conductive film 1 are described.

<Support>
The support is as described above, and is preferably a transparent film substrate.

<Photoelectric conversion layer>
After the photoelectric conversion layer 22 receives sunlight and generates excitons (electron-hole pairs), the excitons dissociate into electrons and holes, and electrons move to the negative electrode side and holes move to the positive electrode side. The photoelectric conversion process of being transported is selected from materials that are expressed with high efficiency. In the case of an organic thin film solar cell, a photoelectric conversion layer 22 including an electron donating region (donor) made of an organic material is formed, and from the viewpoint of conversion efficiency, a bulk heterojunction type photoelectric conversion layer (as appropriate, “to bulk”). "Terrorism layer") is preferably applied.

  The bulk hetero layer is an organic photoelectric conversion layer in which an electron donating material (donor) and an electron accepting material (acceptor) are mixed. The mixing ratio of the electron donating material and the electron accepting material is adjusted so that the conversion efficiency is the highest, but is usually selected from the range of 10:90 to 90:10 by mass ratio. As a method for forming such a mixed layer, for example, a co-evaporation method is used. Or it is also possible to produce by carrying out solvent application | coating using the solvent common to both organic materials.

The thickness of the bulk hetero layer is preferably 10 to 500 nm, particularly preferably 20 to 300 nm.

  An electron-donating material (also referred to as a donor or a hole-transporting material) is a π-electron conjugated compound having a maximum occupied orbital (HOMO) level of 4.5 to 6.0 eV. Conjugated polymers obtained by coupling arenes (for example, thiophene, carbazole, fluorene, silafluorene, thienopyrazine, thienobenzothiophene, dithienosilol, quinoxaline, benzothiadiazole, thienothiophene, etc.), phenylene vinylene polymers, porphyrins, phthalocyanines, etc. Is exemplified. In addition, the compound group described as Hole-Transporting Materials in Chemical Review Vol. 107, 953-1010 (2007) and the Porphyrin described in Journal of the American Chemical Society Vol. 131, page 16048 (2009) Derivatives are also applicable.

  Among these, a conjugated polymer obtained by coupling a structural unit selected from the group consisting of thiophene, carbazole, fluorene, silafluorene, thienopyrazine, thienobenzothiophene, dithienosilole, quinoxaline, benzothiadiazole, and thienothiophene is particularly preferable. Specific examples include poly-3-hexylthiophene (P3HT), poly-3-octylthiophene (P3OT), various polythiophene derivatives described in Journal of the American Chemical Society Vol. 130, p. 3020 (2008), and Advanced Materials. PCTBT described in Vol. 19, page 2295 (2007), Journal of the American Chemical Society vol. 130, PCDTQx, PCDTPP, PCDTPT, PCDTBX, PCDTPX, Nature Photonics vol. 3, described in page 732 (2008), PBDTTT-E, PBDTTTT-C, PBDTTTT-CF described in page 649 (2009), PTB7 described in Advanced Materials Vol. 22, E135-E138 (2010), and the like. It is done.

An electron-accepting material (also referred to as an acceptor or an electron-transporting material) is a π-electron conjugated compound having a lowest orbital (LUMO) level of 3.5 to 4.5 eV, specifically fullerene and Examples thereof include phenylene vinylene-based polymers, naphthalene tetracarboxylic imide derivatives, and perylene tetracarboxylic imide derivatives. Of these, fullerene derivatives are preferred. Specific examples of the fullerene derivative include C ₆₀ , phenyl-C ₆₁ -butyric acid methyl ester (fullerene derivatives referred to as PCBM, [60] PCBM, or PC ₆₁ BM in literatures), C ₇₀ , phenyl-C ₇₁ -butyric acid. Methyl esters (fullerene derivatives referred to as PCBM, [70] PCBM, or PC ₇₁ BM in many literatures) and fullerene derivatives described in Advanced Functional Materials, Vol. 19, pp. 779-788 (2009) And the fullerene derivative SIMEF described in Journal of the American Chemical Society, vol. 131, page 16048 (2009).

<Electron transport layer>
If necessary, an electron transport layer made of an electron transport material may be disposed between the photoelectric conversion layer (bulk hetero layer) 22 and the negative electrode. Examples of the electron transporting material that can be used for the electron transporting layer include the electron-accepting materials mentioned in the photoelectric conversion layer and Electron-Transporting and Hole-Blocking Materials in Chemical Review Vol. 107, pages 953 to 1010 (2007). Are described. Various metal oxides are also preferably used as materials for highly stable electron transport layers, such as lithium oxide, magnesium oxide, aluminum oxide, calcium oxide, titanium oxide, zinc oxide, strontium oxide, niobium oxide, ruthenium oxide, and indium oxide. Zinc oxide and barium oxide. Of these, relatively stable aluminum oxide, titanium oxide, and zinc oxide are more preferable. The film thickness of the electron transport layer is 0.1 to 500 nm, preferably 0.5 to 300 nm. The electron transport layer can be suitably formed by any of a wet film formation method by coating or the like, a dry film formation method by PVD method such as vapor deposition or sputtering, a transfer method, or a printing method.

<Upper electrode (negative electrode)>
The material constituting the upper electrode 24 can be appropriately selected from known electrode materials. When the upper electrode 24 functions as a negative electrode, metals such as magnesium, aluminum, calcium, titanium, chromium, manganese, iron, copper, zinc, strontium, silver, indium, tin, barium, bismuth, and alloys thereof are preferably used. It is done. When the upper electrode functions as a positive electrode, metals such as cobalt, nickel, copper, molybdenum, palladium, silver, tantalum, tungsten, platinum, and gold, alloys thereof, TCO, and conductive polymers are preferably used. These may be used alone, or two or more may be mixed or laminated.

  There is no restriction | limiting in particular about the formation method of the upper electrode 24, It can carry out according to a well-known method. For example, from the wet film forming method by coating or printing, the vacuum deposition method, the sputtering method, the PVD method such as the ion plating method, the dry film forming method by various chemical vapor deposition methods (CVD method), etc. It can be formed according to a method appropriately selected in consideration of suitability with the constituent material.

  When patterning the upper electrode 24, it may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or vacuum deposition or sputtering may be performed with a shadow mask overlapped. However, it may be performed by a lift-off method or a printing method.

  Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the upper electrode 24 and the semiconductor layer in a thickness of 0.1 to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, a PVD method such as a vacuum deposition method, a sputtering method, or an ion plating method.

  The thickness of the upper electrode 24 can be appropriately selected depending on the constituent material and cannot be generally defined. However, from the viewpoint of conductivity, it is usually about 0.01 μm to 10 μm, and 0.05 μm to 1 μm is preferable.

<Other semiconductor layers>
If necessary, it may have auxiliary layers such as a hole injection layer, a hole transport layer, an electron blocking layer, an electron injection layer, a hole blocking layer, and an exciton diffusion preventing layer. In this specification, a bulk hetero layer, a hole injection layer, a hole transport layer, an electron blocking layer, an electron injection layer, an electron transport layer, and a hole blocking formed between the transparent conductive film 1 and the upper electrode 24 are used. The term “semiconductor layer” is used as a general term for layers that transport electrons and holes, such as layers and exciton diffusion prevention layers.

  The organic thin film solar cell 2 may be annealed by various methods for the purpose of crystallization of the semiconductor layer and promotion of phase separation of the bulk hetero layer. Examples of the annealing method include a method of heating the substrate temperature during vapor deposition to 50 ° C. to 150 ° C. and a method of setting the drying temperature after coating to 50 ° C. to 150 ° C. Further, after the formation of the second electrode is completed, annealing may be performed by heating to 50 ° C. to 150 ° C.

<Protective layer>
The organic thin film solar cell 2 may be protected by a protective layer. Materials for the protective layer include metal oxides such as magnesium oxide, aluminum oxide, silicon oxide (SiO _x ), titanium oxide, germanium oxide, yttrium oxide, zirconium oxide, and hafnium, and metal nitride such as silicon nitride (SiN _x ). Metal nitride oxides (metal oxynitrides) such as silicon nitride oxide (SiO _x N _y ), metal fluorides such as lithium fluoride, magnesium fluoride, aluminum fluoride, calcium fluoride, diamond-like carbon (DLC) ), And the like. Examples of the organic material include polymers such as polyethylene, polypropylene, polyvinylidene fluoride, polyparaxylylene, and polyvinyl alcohol. Of these, metal oxides, nitrides, nitride oxides and DLC are preferred, and silicon, aluminum oxides, nitrides and nitride oxides are particularly preferred. The protective layer may be a single layer or a multilayer structure. The method for forming the protective layer is not particularly limited. For example, the vacuum deposition method, the sputtering method, the MBE (molecular beam epitaxy) method, the cluster ion beam method, the ion plating method, the plasma polymerization method, or the like, Various CVD methods including a layer deposition method (ALD method or ALE method), coating methods, printing methods, and transfer methods can be applied.

<Gas barrier layer>
A protective layer intended to prevent the penetration of active factors such as water molecules and oxygen molecules is also called a gas barrier layer, and the organic thin-film solar cell preferably has a gas barrier layer. The gas barrier layer is not particularly limited as long as it is a layer that blocks active factors such as water molecules and oxygen molecules, but the materials exemplified above as the protective layer are usually used. These may be pure substances, or may be a mixture of multiple compositions or a gradient composition. Of these, silicon, aluminum oxide, nitride, and nitride oxide are preferable.

  The gas barrier layer may be a single layer or a plurality of layers. An organic material layer and an inorganic material layer may be laminated, or a plurality of inorganic material layers and a plurality of organic material layers may be alternately laminated. Although there will be no restriction | limiting in particular if an organic material layer has smoothness, The layer etc. which consist of a polymer of (meth) acrylate are illustrated preferably. The above-mentioned protective layer material is preferable for the inorganic material layer, and silicon, aluminum oxide, nitride, and nitride oxide are particularly preferable.

  Although it does not specifically limit regarding the thickness of an inorganic material layer, It attaches to 1 layer, Usually, it is 5-500 nm, Preferably it is 10-200 nm. The inorganic material layer may have a laminated structure including a plurality of sublayers. In this case, each sublayer may have the same composition or a different composition. Further, as disclosed in US Patent Application Publication No. 2004/0046497, the interface with the organic material layer made of a polymer is not clear, and the layer may be a layer whose composition changes continuously in the film thickness direction. .

<Sealing film>
In the present invention, a gas barrier layer formed in advance on a plastic film substrate is expressed as a sealing film. A production method of bonding a sealing film with a known adhesive or sealant after forming a solar cell made of an organic photoelectric conversion element is preferably used because the number of production steps of the solar cell can be reduced. In particular, when the support 10 of the solar cell is made of a plastic film, active molecules such as water molecules and oxygen molecules penetrate from the back surface (surface not forming the lower electrode) side of the support. It is preferable to attach (laminate) the sealing film to the substrate.

<Functional layer>
A functional layer may be provided on the back side of the support 10 (the side on which the lower electrode is not formed). Examples thereof include a gas barrier layer, a matting agent layer, an antireflection layer, a hard coat layer, an antifogging layer, an antifouling layer, and an easy adhesion layer. In addition, the functional layer is described in detail in paragraphs [0036] to [0038] of JP-A-2006-289627, and the functional layer described herein may be provided according to the purpose.

  Although the thickness of the organic thin film solar cell 2 is not specifically limited, When setting it as the organic thin film solar cell which has a light transmittance, it is preferable that they are 50 micrometers-1 mm, and it is more preferable that they are 100 micrometers-500 micrometers.

  As described above, the transparent conductive film 1 has good conductivity, light transmittance, and smoothness. Therefore, the photoelectric conversion element of the present invention provided with the transparent conductive film 1 as a positive electrode is suppressed in occurrence of short circuit failure with the upper electrode 24 (negative electrode), and has excellent conversion efficiency.

  In addition, although the organic thin film solar cell 2 of the simplest structure was demonstrated above, the transparent conductive film 1 of various aspects, such as an organic thin film solar cell of what is called a tandem structure which laminated | stacked the several photoelectric converting layer, etc. It is applicable also to an organic thin film solar cell. In the case of a tandem type element, it may be a serial connection type or a parallel connection type.

  Examples and comparative examples according to the present invention will be described.

Example 1
<Formation of auxiliary metal wiring>
A polyethylene naphthalate (PEN) film (100 μm thick, 50 mm square) is prepared as a support, and on one surface, as auxiliary metal wiring, 0.01 mm width, 0.2 mm pitch, and 2 μm thick square lattice auxiliary silver wiring Formed.

  The method for forming the auxiliary silver wiring was as follows.

[Preparation of silver halide emulsion]
The following solution A was kept at 34 ° C. in the reaction vessel, and the hydrogen ion concentration pH was adjusted to 2 using nitric acid (concentration 6%) while stirring at high speed using the mixing and stirring apparatus described in JP-A-62-160128. .95. Subsequently, the following solution B and the following solution C were added at a constant flow rate over 8 minutes and 6 seconds using the double jet method. After completion of the addition, the pH was adjusted to 5.90 using sodium carbonate (concentration 5%), and then the following solution D and solution E were added.

(Solution A)
Alkali-treated inert gelatin (average molecular weight 100,000) 18.7g
Sodium chloride 0.31g
Solution I (below) 1.59 cm ³
Pure water 1,246cm ³

(Solution B)
169.9g of silver nitrate
Nitric acid (concentration 6%) 5.89 cm ³
The total amount was 317.1 cm ³ with pure water.

(Solution C)
Alkali-treated inert gelatin (average molecular weight 100,000) 5.66 g
Sodium chloride 58.8g
13.3 g of potassium bromide
Solution I (below) 0.85 cm ³
Solution II (below) 2.72 cm ³
The total amount was 317.1 cm ³ with pure water.

(Solution D)
2-Methyl-4hydroxy-1,3,3a, 7-tetraazaindene 0.56 g
Pure water 112.1cm ³

(Solution E)
Alkali-treated inert gelatin (average molecular weight 100,000) 3.96 g
Solution I (below) 0.40 cm ³
Pure water 128.5cm ³

<Solution I>
10% by mass methanol solution of polyisopropylene polyethylene oxydioxalate sodium salt

<Solution II>
10% by weight aqueous solution of rhodium hexachloride complex

  After completion of the above operation, desalting and washing with water using a flocculation method are performed at 40 ° C. according to a conventional method. To 90.90 to obtain a silver chlorobromide cubic grain emulsion finally containing 10 mol% of silver bromide and having an average grain size of 0.09 μm and a coefficient of variation of 10%.

(Solution F)
Alkali-treated inert gelatin (average molecular weight 100,000) 16.5g
Pure water 139.8cm ³

  The silver chlorobromide cubic grain emulsion was subjected to chemical sensitization at 40 ° C. for 80 minutes using 20 mg of sodium thiosulfate per mol of silver halide, and after completion of chemical sensitization, 4-hydroxy-6-methyl-1, 500 mg of 3,3a, 7-tetrazaindene (TAI) per 1 mol of silver halide and 150 mg of 1-phenyl-5-mercaptotetrazole per 1 mol of silver halide were added to obtain a silver halide emulsion. This silver halide emulsion had a volume ratio of silver halide grains to gelatin (silver halide grains / gelatin) of 0.625.

[Application]
Furthermore, tetrakis (vinylsulfonylmethyl) methane was added as a hardening agent at a ratio of 200 mg / g gelatin, and di (2-ethylhexyl) sodium sulfosuccinate was added as a coating aid (surfactant). The surface tension was adjusted.

The coating solution thus obtained was applied onto a PEN film substrate (support) with an undercoat layer so that the basis weight in terms of silver was 0.625 g · m ^−2, and then cured at 50 ° C. for 24 hours. Processing was carried out to obtain a photosensitive material.

[exposure]
The obtained photosensitive material was exposed to ultraviolet rays through a photomask having a mesh pattern (line width 0.01 mm, pitch 0.2 mm).

[Chemical development]
The exposed photosensitive material is subjected to development processing at 25 ° C. for 60 seconds using the following developer (DEV-1), and then subjected to fixing processing at 25 ° C. for 120 seconds using the following fixing solution (FIX-1). went.

(DEV-1)
Pure water 500cm ³
Metol 2g
80 g of anhydrous sodium sulfite
Hydroquinone 4g
4g borax
Sodium thiosulfate 10g
Potassium bromide 0.5g
Water was added to bring the total volume to 1000 cm ³ .

(FIX-1)
Pure water 750cm ³
Sodium thiosulfate 250g
Anhydrous sodium sulfite 15g
Glacial acetic acid 15cm ³
Potash alum 15g
Water was added to bring the total volume to 1000 cm ³ .

[Physical development]
Next, physical development was performed at 30 ° C. for 10 minutes using the following physical developer (PDEV-1), and then washed with tap water for 10 minutes.

(PDEV-1)
Pure water 900cm ³
Citric acid 10g
Trisodium citrate 1g
Ammonia water (28%) 1.5g
Hydroquinone 2.3g
Silver nitrate 0.23g
Water was added to bring the total volume to 1000 cm ³ .

[Electrolytic plating]
After the physical development treatment, electrolytic copper plating treatment was performed at 25 ° C. using the following electrolytic plating solution, followed by washing with water and drying treatment. In addition, the current control in electrolytic copper plating was performed over 3 minutes, 3 minutes for 1 minute and then 12 minutes for 1A. After the completion of the plating treatment, the plate was rinsed with tap water for 10 minutes to carry out a water washing treatment, and dried using a dry air (50 ° C.) until it was in a dry state.

(Electrolytic plating solution)
Copper sulfate (pentahydrate) 200g
50g of sulfuric acid
Sodium chloride 0.1g
Water was added to bring the total volume to 1000 cm ³ .

<Formation of transparent resin>
After forming the auxiliary silver wiring as described above, 2-acetoxy-1-methoxypropane of 1,6-hexanediol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) to which a photopolymerization initiator (Lamberti, Esacure KTO 46) is added. The (PGMEA) solution (monomer composition) was spin-coated to fill the openings of the auxiliary silver wiring. At this time, a slight coating liquid was attached to the upper surface of the auxiliary silver wiring.

  Next, the entire surface of the coating film was irradiated with ultraviolet rays (wavelength 365 nm) to polymerize the coating film to form a transparent resin (planarization layer), thereby forming an auxiliary electrode including auxiliary silver wiring and transparent resin. In the obtained auxiliary electrode, the upper surface of the auxiliary silver wiring was well exposed and the flatness was good.

  Thereafter, a polyethylene dioxythiophene-polystyrene sulfonic acid aqueous solution (PEDOT-PSS: HC Stark Clios, Clevios PH 500) (hereinafter referred to as “PEDOT-PSS aqueous solution”) added with dimethyl sulfoxide (DMSO) on the auxiliary electrode. I ”) and spin-coated at 100 ° C. for 20 minutes to form a conductive resin layer (film thickness 0.2 μm). This obtained the transparent conductive film formed on the PEN support body. When the surface conductivity of the obtained transparent conductive film was confirmed, good conductivity was confirmed.

  Next, a PEDOT-PSS aqueous solution having a different composition (manufactured by HC Stark Clevios, Clevios P VP.AI4083) (hereinafter abbreviated as “PEDOT-PSS aqueous solution II”) is spin-coated on the transparent conductive film. Heat treatment was performed at 100 ° C. for 20 minutes. This formed a positive hole transport layer (film thickness 0.04 micrometer).

A composition in which P3HT (manufactured by Merck, licicon SP001) as an electron donating material and PC ₆₁ BM (manufactured by Frontier Carbon, nanom spectra E100H) as an electron accepting material in chlorobenzene was dissolved in a dry nitrogen atmosphere on the hole transport layer. Was spin-coated and heat-treated at 110 ° C. for 20 minutes. Thereby, a bulk heterojunction photoelectric conversion layer (film thickness: 0.2 μm) was formed.

On the photoelectric conversion layer, lithium fluoride (film thickness: 1 nm) and aluminum (film thickness: 0.4 μm) were continuously vacuum deposited to form an upper electrode (negative electrode) to obtain an organic thin film solar cell. When forming the upper electrode, a shadow mask was used so that the element area was 1.1 cm ² .

About the organic thin-film solar cell obtained as mentioned above, simulated sunlight was irradiated from the back surface (surface which does not form a transparent conductive film) side of a PEN film support 80mW * cm- ² , and conversion efficiency was measured. Specifically, a current is applied to an organic thin film solar cell by applying a voltage from a source meter (Model 2400 manufactured by Keithley Instruments) while irradiating a light source in which an xenon lamp (Newport 96000) is combined with an air mass filter (Newport 84094). The value was measured. Conversion efficiency was calculated from the obtained current-voltage characteristics using Peccell IV Curve Analyzer (Pexcel Technologies ver. 2.1). The conversion efficiency obtained was 2.5%.

(Example 2)
A transparent conductive film and an organic thin film solar cell were produced in the same manner as in Example 1 except that polyethylene glycol diacrylate (A-600: manufactured by Shin-Nakamura Chemical Co., Ltd.) was used as the monomer. The surface conductivity of the obtained transparent conductive film was good, and the conversion efficiency of the solar cell was 1.6%.

(Example 3)
The same auxiliary silver wiring as in Example 1 was subjected to a surface treatment to change the surface wettability to make an auxiliary metal wiring, and trimethylolpropane triacrylate (TMPTA: manufactured by Kyoeisha Chemical Co., Ltd.) was used as a monomer. The transparent conductive film and the organic thin-film solar cell were produced in the same manner as in Example 1 after the film formation.

The surface treatment is performed by immersing the entire support in a 0.1 mM thiol fluoride solution (HS- (CH ₂ ) ₁₁ -O- (CF ₂ ) ₅ -CF ₃ : FO-001 series manufactured by Altec Co., Ltd.) for 1 hour. This was performed by washing with ethanol and drying at room temperature. Such a thiol fluoride solution is suitable as a surface treatment agent because it easily forms a self-assembled monolayer.

  After forming the auxiliary electrode, the support was immersed in 12 wt.% Sulfuric acid and 5 wt.% Hydrogen peroxide for 30 seconds to remove the surface treatment agent, and then a transparent conductive layer was formed. As a result, the surface conductivity of the obtained transparent conductive film was good, and the conversion efficiency of the solar cell was 2.7%.

(Comparative Example 1)
A transparent conductive film was produced in the same manner as in Example 1 except that TMPTA was used as the monomer. In this example, first, it was confirmed that almost the entire upper surface of the auxiliary silver wiring was wetted by the monomer composition when the monomer composition containing TMPTA was applied onto the auxiliary silver wiring. Moreover, surface conductivity was not confirmed also in the obtained transparent conductive film. When cross-sectional observation of the transparent conductive film was performed by SEM (scanning electron microscope), it was confirmed that TMPTA covered the entire surface of the upper surface of the auxiliary silver wiring.

(Comparative Example 2)
A transparent conductive film was produced in the same manner as in Example 1 except that pentaerythritol triacrylate (PETIA: manufactured by Daicel Cytec) was used as the monomer. Also in this example, as in Comparative Example 1, it was confirmed that almost the entire upper surface of the auxiliary silver wiring was wetted by the monomer composition when the monomer composition containing PETIA was applied onto the auxiliary silver wiring. Moreover, surface conductivity was not confirmed also in the obtained transparent conductive film. When a cross-sectional observation was performed in the same manner as in Comparative Example 1, it was confirmed that PETIA had covered the entire upper surface of the auxiliary silver wiring.

(Evaluation)
Table 1 shows combinations of materials, contact angle values, and evaluation results in Examples 1 to 3 and Comparative Examples 1 and 2. The contact angle in the table is the contact angle of water with respect to the film formed by depositing the surface of the auxiliary metal wiring or the constituent material of the transparent resin on a flat substrate. As shown in Table 1, the effectiveness of the present invention was confirmed.

DESCRIPTION OF SYMBOLS 1 Transparent conductive film 2 Organic thin film solar cell 10 Support body 11 Auxiliary electrode 12 Conductive resin layer 22 Photoelectric conversion layer 24 Upper electrode layer 31 Transparent resin (flattening layer)

Claims (10)

An auxiliary electrode layer comprising an auxiliary metal wiring having a plurality of openings, and at least a transparent resin filled in the openings;
A conductive resin layer formed on the auxiliary electrode layer,
The transparent conductive film, wherein the transparent resin is obtained by polymerizing a monomer composition having a low affinity with at least the surface of the auxiliary metal wiring.   The transparent conductive film according to claim 1, wherein a contact angle of the surface of the auxiliary metal wiring with respect to the composition is 70 ° or more.   The transparent conductive film according to claim 1, wherein a difference between a water contact angle on the surface of the auxiliary metal wiring and a water contact angle of the transparent resin is 60 ° or more.   The transparent conductive film according to claim 1, wherein the surface of the auxiliary metal wiring is hydrophilic and the transparent resin is hydrophobic.   The transparent conductive film according to claim 1, wherein a surface of the auxiliary metal wiring is hydrophobic and the transparent resin is hydrophilic.   The transparent conductive film according to claim 1, further comprising a surface treatment agent that changes a water contact angle of the surface on the surface of the auxiliary metal wiring.   The transparent conductive film according to claim 1, wherein the transparent resin is obtained by polymerizing a composition containing a polyfunctional (meth) acrylic monomer. A support, and the transparent conductive film according to any one of claims 1 to 7,
An organic thin-film solar cell comprising a photoelectric conversion element formed by laminating a photoelectric conversion layer containing an organic material and an upper electrode in this order. On the support,
Forming an auxiliary metal wiring having a plurality of openings;
Filling the opening with the monomer composition by applying a monomer composition having a low affinity for at least the surface of the auxiliary metal wiring from the upper surface of the opening and the auxiliary metal wiring;
Sequentially performing the step of polymerizing the monomer composition to form an auxiliary electrode layer,
A method for producing a transparent conductive film, comprising forming a conductive resin layer on the auxiliary electrode layer.   The method for producing a transparent conductive film according to claim 9, wherein a contact angle of the surface with respect to the monomer composition is 70 ° or more.