JP2018166198A - Photoelectric conversion element and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element or solar cell module having high light resistance.SOLUTION: A photoelectric conversion element includes a pair of electrodes and an active layer between the pair of electrodes. The active layer includes a p type organic semiconductor compound, an n-type semiconductor compound and pigment. The surface energy γ(M1) of the pigment, the surface energy γ(M2) of the n-type semiconductor compound and the surface energy γ(M3) of the p type organic semiconductor compound satisfy the relationship of the following numerical expression (the numerical expression 1) or the following numerical expression (the numerical expression 2), and the ionization potential Ip (M1) of the pigment and the ionization potential Ip (M2) of the n-type semiconductor compound satisfy the relationship of the following numerical expression (the numerical expression 3). γ(M1)>γ(M2)>γ(M3) ...(the numerical expression 1), γ(M3)>γ(M2)>γ(M1) ...(the numerical expression 2) and Ip(M1)≥Ip(M2)-0.30 [eV] ... (the numerical expression 3)SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photoelectric conversion element and a solar cell module.

  In recent years, organic thin film solar cells (OPV) have been actively studied. The active layer of an organic thin-film solar cell is usually formed by containing a p-type organic semiconductor compound and an n-type semiconductor compound, and in particular, it is formed by mixing a p-type organic semiconductor compound and an n-type semiconductor compound. Organic thin-film solar cells using bulk heterojunction active layers are attracting particular attention.

  In order to increase the conversion efficiency of an organic thin film solar cell, for example, Non-Patent Document 1 absorbs light having a longer wavelength than p-type organic semiconductor compounds and n-type semiconductor compounds, and has a cascade structure in terms of energy levels. It has been proposed to add such a dye so that the dye exists at the interface between the p-type organic semiconductor compound and the n-type semiconductor compound. In Patent Document 1 and Non-Patent Document 2, conversion efficiency is improved by adding a dye having a surface energy between the surface energy of the p-type organic semiconductor compound and the surface energy of the n-type semiconductor compound to the active layer. Examples are shown.

JP 2014-154653 A

APPLIED MATERIALS AND INTERFACES, 2009, 1, 804-810 ADVANCED ENERGY MATERIALS, 2011, 1, 588-598

For practical use of organic thin-film solar cells, high light resistance with little light deterioration is required. However, according to the study by the present inventors, a dye is present at the interface between the p-type organic semiconductor compound and the n-type semiconductor compound as described in Patent Document 1, Non-Patent Document 1, and Non-Patent Document 2. However, it has been found that sufficient light resistance may not be obtained while the initial efficiency is improved.
This invention solves the said problem, and aims at providing the photoelectric conversion element or solar cell module provided with high light resistance.

  The present inventors diligently studied to solve the above-mentioned problems. As a result, they found that the above-mentioned problems can be solved by the fact that the active layer contains a specific dye, and the present invention has been achieved.

That is, the gist of the present invention is as follows.
[1] A photoelectric conversion element having a pair of electrodes and an active layer between the pair of electrodes, wherein the active layer contains a p-type organic semiconductor compound, an n-type semiconductor compound, and a dye. The surface energy γ (M1) of the dye, the surface energy γ (M2) of the n-type semiconductor compound, and the surface energy γ (M3) of the p-type organic semiconductor compound are represented by the following formula (Formula 1) or the following formula: The relationship of (Equation 2) is satisfied, and the ionization potential Ip (M1) of the dye and the ionization potential Ip (M2) of the n-type semiconductor compound satisfy the relationship of the following formula (Equation 3). Photoelectric conversion element.
γ (M1)> γ (M2)> γ (M3) (Equation 1)
γ (M3)> γ (M2)> γ (M1) (Equation 2)
Ip (M1) ≧ Ip (M2) −0.30 [eV] (Equation 3)
[2] The photoelectric conversion according to [1], wherein the difference between the surface energy γ (M1) of the dye and the surface energy γ (M2) of the n-type semiconductor compound is 10 mJ / cm ² or more. element.
[3] The photoelectric conversion element as described in [1] or [2], wherein the pigment is an azo dye.
[4] A solar cell module having the photoelectric conversion element according to any one of [1] to [3].

  According to the present invention, a photoelectric conversion element or a solar cell module having high light resistance can be provided.

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

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

The photoelectric conversion element according to the present invention has at least a pair of electrodes and an active layer between the pair of electrodes on the element substrate.
FIG. 1 shows an embodiment of a photoelectric conversion element according to the present invention. As shown in FIG. 1, one embodiment of a photoelectric conversion device according to the present invention includes a lower electrode 101, a buffer layer 102, an active layer 103, a buffer layer 104, and an upper electrode 105 on an element substrate 106. , Have a layered structure formed sequentially.

  In the present invention, the lower electrode means an electrode laminated on the element substrate 106 side, and the upper electrode means an electrode laminated above the lower electrode when the element substrate 106 is at the bottom. . In the present invention, the lower electrode 101 and the upper electrode 105 may be collectively referred to as a pair of electrodes. Of the pair of electrodes, one electrode is a cathode having a function of collecting electrons generated in the active layer 103, and the other electrode has a function of collecting holes generated in the active layer 103. It is an anode which has. That is, when the lower electrode 101 is a cathode, the upper electrode 105 may be an anode, and when the lower electrode 101 is an anode, the upper electrode 105 may be a cathode.

  Further, as described above, the photoelectric conversion element according to the embodiment of FIG. 1 has buffer layers between the lower electrode 101 and the active layer 103 and between the upper electrode 105 and the active layer 103, respectively. In the present invention, for convenience, the buffer layer 102 between the lower electrode 101 and the active layer 103 may be referred to as a lower buffer layer, and the buffer layer 104 between the upper electrode 105 and the active layer 103 is referred to as an upper buffer. Sometimes referred to as a layer.

  One of the lower buffer layer 102 and the upper buffer layer 104 is a hole extraction layer that improves the transport efficiency of holes generated in the active layer 103, and the other buffer layer is generated in the active layer 103. It is an electron extraction layer that improves electron transport efficiency. Therefore, when the lower electrode 101 is a cathode and the upper electrode is an anode, the lower buffer layer 102 is preferably an electron extraction layer and the upper buffer layer 104 is preferably a hole extraction layer. On the other hand, when the lower electrode 101 is an anode and the upper electrode is a cathode, the lower buffer layer 102 is preferably a hole extraction layer and the upper buffer layer 104 is preferably an electron extraction layer. In the present invention, it is not always necessary to have both the lower buffer layer 102 and the upper buffer layer 104, and only at least one buffer layer may be provided. Moreover, the photoelectric conversion element according to the present invention may optionally have another layer other than the above. Hereinafter, each component of the photoelectric conversion element will be described.

<1-1. Element Substrate 106>

  Each layer constituting the photoelectric conversion element 107 is usually formed on an element substrate 106 serving as a support. There is no particular limitation on the material of the element substrate 106. As a suitable example of the material of the element substrate 106, an inorganic material such as quartz, glass, sapphire, or titania, a resin material, or a metal foil such as stainless steel, titanium, or aluminum is coated or coated with a surface. A composite material such as a laminated one is mentioned. Especially, it is preferable that the element substrate 106 is formed of a resin material from the viewpoint of handleability and the degree of freedom of installation of the solar cell module.

Examples of the resin material include, but are not limited to, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluororesin film, vinyl chloride, or polyethylene. Examples of the polyolefin include cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, and epoxy resin.
Is mentioned.

  The film thickness of the element substrate 106 is not particularly limited, but is usually 5 μm or more, preferably 20 μm or more, and is usually 20 mm or less, preferably 10 mm or less. The film thickness of the element substrate is preferably 5 μm or more because the possibility that the strength of the photoelectric conversion element is insufficient is reduced.

  Note that in the solar cell, when the element substrate 106 side is a light receiving surface, the element substrate 106 preferably has a light-transmitting property. In the present invention, having translucency means that the visible light transmittance is 40% or more. Note that the visible light transmittance of the element substrate 106 is preferably 70% or more because more light can reach the active layer 103. The visible light transmittance of the element substrate 106 can be measured by a method defined in JIS R3106: 1998. On the other hand, in the solar cell, in the case where the upper electrode 105 side of the photoelectric conversion element 107 is a light receiving surface, the element substrate 106 may or may not have a light-transmitting property. However, when a solar cell is installed in a window or the like, a see-through solar cell is preferably used. In this case, the element substrate 106 preferably has a light-transmitting property regardless of the light receiving surface.

<1-2. Pair of electrodes (101, 105)>
As described above, the photoelectric conversion element according to the present invention has a pair of electrodes including the lower electrode 101 and the upper electrode 105.

  The material for forming the lower electrode 101 and the upper electrode 105 is not particularly limited, and nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO); gold, platinum, silver, copper, Examples thereof include metals such as iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, magnesium, and cobalt, or alloys thereof. Among the above, the anode is preferably formed using a material having a relatively large work function, and the cathode is preferably formed using a material having a relatively small work function. Note that in the case where the photoelectric conversion element includes the lower buffer layer 102 and / or the upper buffer layer 104, the lower electrode 101 and the upper electrode 105 may be formed using the same material by adjusting these buffer layer materials. it can.

  Each of the lower electrode 101 and the upper electrode 105 may have a single layer structure or a laminated structure.

  In addition, at least one of the pair of electrodes preferably has a light-transmitting property. For example, in the case of a sunlight receiving surface on the element substrate 106 side, the lower electrode 101 preferably has a light transmitting property, and the upper electrode 105 may have a light transmitting property. It does not have to have sex. Further, when the upper electrode 105 side is a sunlight receiving surface, the upper electrode 105 is preferably translucent, and the lower electrode 101 may be translucent. It does not have to be light. Note that in the case where the photoelectric conversion element is a see-through type, it is preferable that both the lower electrode 101 and the upper electrode 105 have translucency.

  In the case of using a light-transmitting electrode, the electrode may be formed using the above metal oxide. Moreover, the structure which laminated | stacked the layer containing a metal oxide and the thin metal layer may be sufficient.

  The film thickness of the lower electrode 101 and the upper electrode 105 is not particularly limited, but is usually 5 nm or more, preferably 10 nm or more, more preferably 20 nm or more, while usually 2 μm or less, preferably 1 μm or less, more preferably 500 nm or less.

  The sheet resistance of the lower electrode 101 and the upper electrode 105 is not particularly limited, but is usually 0.1Ω / □ or more, on the other hand, 1000Ω / □ or less, preferably 500Ω / □ or less, more preferably 100Ω / □ or less. .

  The formation method of the lower electrode 101 and the upper electrode 105 is not particularly limited, and can be formed by a known method in accordance with a material to be used. For example, a vacuum film forming method such as a vapor deposition method or a sputtering method; or a wet film forming method in which a coating solution containing nanoparticles or a precursor is applied to form a film.

<1-3. Active layer 103>
The active layer 103 is a layer that contains a p-type organic semiconductor compound and an n-type semiconductor compound and undergoes photoelectric conversion. That is, when the photoelectric conversion element 107 receives light, the light is absorbed by the active layer 103, charges are generated at the interface between the p-type organic semiconductor compound and the n-type semiconductor compound, and the generated charges are extracted from the anode and the cathode. . In the present invention, the active layer 103 is a bulk heterojunction active layer that is a layer (mixed layer) in which a p-type organic semiconductor compound and an n-type semiconductor compound are mixed, and further contains a dye. .

  The p-type organic semiconductor compound is not particularly limited, and examples thereof include a p-type low-molecular organic semiconductor compound, a p-type organic semiconductor oligomer, and a p-type organic semiconductor polymer.

The p-type low-molecular organic semiconductor compound is not particularly limited, but a porphyrin compound such as tetrabenzoporphyrin, tetrabenzocopper porphyrin, tetrabenzozinc porphyrin; phthalocyanine compound such as phthalocyanine, copper phthalocyanine, zinc phthalocyanine; naphthalocyanine compound; tetracene And pentacene polyacene.
The p-type organic semiconductor oligomer is not particularly limited, and examples thereof include oligothiophenes such as sexithiophene or derivatives containing these compounds as a skeleton.

  The p-type organic semiconductor polymer is not particularly limited, but includes polythiophene including poly (3-alkylthiophene), polyfluorene, polyphenylene vinylene, polytriallylamine, polyacetylene, polyaniline, polypyrrole, thiophene ring or thiophene condensed ring. Examples thereof include polymers. More specifically, the known p described in International Publication No. 2011/016430, International Publication No. 2013/180243, Japanese Unexamined Patent Publication No. 2012-191194, International Publication No. 2017/047808, etc. Type organic semiconductor polymer.

  The n-type semiconductor compound is not particularly limited. For example, a fullerene; a fullerene derivative; a quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum; a condensed ring such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide Tetracarboxylic acid diimides; perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzthiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazoles Derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquino Derivatives, bipyridine derivatives, borane derivatives; total fluorides of condensed polycyclic aromatic hydrocarbons such as anthracene, pyrene, naphthacene or pentacene; single-walled carbon nanotubes, n-type polymers (n-type polymer semiconductor materials), etc. .

  Among these n-type semiconductor compounds, n-type organic semiconductor compounds are preferable. Specifically, fullerene derivatives, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides, N-alkyl substituted perylene diimide derivatives or n-type polymer semiconductor materials More preferred are fullerene derivatives, N-alkyl substituted perylene diimide derivatives, N-alkyl substituted naphthalene tetracarboxylic acid diimides or n-type polymer semiconductor compounds, and fullerene derivatives are particularly preferred. These compounds are not particularly limited, but for example, those described in known literature such as International Publication No. 2011-016430 or Japanese Unexamined Patent Publication No. 2012-191194 can be used. In addition, a kind of compound may be used among the above, and a mixture of a plurality of kinds of compounds may be used.

  The ratio of the p-type organic semiconductor compound and the n-type semiconductor compound in the active layer 103 is not particularly limited, but the amount of the n-type semiconductor compound with respect to 100 parts by mass of the p-type organic semiconductor compound is 10 parts by mass or more. The amount is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, more preferably 500 parts by mass or less, and particularly preferably 300 parts by mass or less.

  As described above, the active layer 103 contains a specific dye in addition to the p-type organic semiconductor compound and the n-type semiconductor compound. In the present invention, a dye means an organic material that absorbs visible light and does not directly contribute to charge separation. The fact that it does not directly contribute to charge separation means that the contribution to power generation by excitons generated by absorption of the dye is substantially negligible. Compared to the case where the active layer does not contain the dye, the active layer It means that the increment of the integral value of the spectral sensitivity when containing 1% by mass of the dye with respect to the solid component composed of the p-type organic semiconductor compound and the n-type semiconductor compound is 5% or less. In brief, it can be evaluated by the change width of the short-circuit current density before and after the dye addition.

  Specifically, in the active layer 103, the surface energy γ (M1) of the dye, the surface energy γ (M2) of the n-type semiconductor compound, and the surface energy γ (M3) of the p-type organic semiconductor compound are expressed by the following formula (Equation 1). ) Or the following mathematical formula (Equation 2), and the ionization potential Ip (M1) of the pigment and the ionization potential Ip (M2) of the n-type semiconductor compound contain the pigment satisfying the relationship of the following mathematical formula (Equation 3).

γ (M1)> γ (M2)> γ (M3) (Equation 1)
γ (M3)> γ (M2)> γ (M1) (Equation 2)
Ip (M1) ≧ Ip (M2) −0.3 [eV] (Equation 3)

  When the active layer 103 contains the pigment | dye which satisfy | fills the said Numerical formula, it is thought that the photoelectric conversion element provided with high light resistance can be provided. The reason for this will be described below.

  Known Japanese Unexamined Patent Application Publication No. 2014-154653 or “ADVANCED ENERGY MATERIALS, 2011, 1, 588-598” describes examples of active layers containing dyes, It is described that the dye is preferably present at the interface between the p-type organic semiconductor compound and the n-type semiconductor compound. For example, according to the known ADVANCED ENERGY MATERIALS, 2011, 1, 588-598, in the active layer containing a p-type organic semiconductor compound, an n-type semiconductor compound, and a dye, the surface energy of the p-type organic semiconductor compound Describes that the dye is present in the domain of the n-type semiconductor if the surface energy of the dye is smaller than the surface energy of the n-type semiconductor compound. However, in the present invention, it is presumed that a large amount of dye is present in the n-type semiconductor domain by satisfying the above mathematical formula (Equation 1) or (Equation 2). That is, unlike the prior art, in the present invention, the dye is segregated in the domain of the n-type semiconductor compound, and the dye is segregated in the domain of the n-type semiconductor compound. I think that is preventing. The reason is not clear, but the following reasons are possible.

  When the organic thin film solar cell absorbs light, an electron trap is formed in the n-type semiconductor compound inside the active layer, so that the electron transport ability is lowered, and the internal electric field is screened by the accumulated carriers. As a result, it is considered that the charge extraction efficiency is deteriorated and the conversion efficiency of the organic thin film solar cell is gradually lowered. However, in the present invention, as described above, it is considered that the dye trapped in the n-type semiconductor domain absorbs visible light to fill the formed electron trap. Here, as a result of intensive studies by the present inventors, when the relationship between the ionization potential of the dye and the n-type semiconductor compound satisfies the above formula (Equation 3), the dye molecule is excited and the n-type semiconductor compound is converted into an n-type semiconductor compound. It is considered that the traps formed can be doped, or after doping, the electrons in the ground state of the n-type semiconductor can be received, and the electrons can be excited to the excited state of the n-type semiconductor in combination with the absorption of the dye itself. As a result, it is considered that a photoelectric conversion element having high light resistance can be provided.

In particular, in order to segregate the dye into the n-type semiconductor compound domain, the difference between the surface energy γ (M1) of the dye and the surface energy γ (M2) of the n-type semiconductor compound is 10 mJ / m ² or more. it is preferable, more preferably 15 mJ / m ² or more, more preferably 20 mJ / m ² or more, particularly preferably at 30 mJ / m ² or more, whereas the upper limit is not usually, 60 mJ / M ² or less.

Moreover, it is preferable to satisfy | fill the said numerical formula (Equation 1) especially among the said Numerical formula (Equation 1) and the said Numerical formula (Equation 2). In this case, the surface energy of the dye is preferably at 35 mJ / m ² or more, particularly preferably at 60 mJ / m ² or more, while, is usually, 100 mJ / m ² or less.

  In the case where the active layer 103 contains a plurality of p-type organic semiconductor compounds and / or n-type semiconductor compounds, in the above formula (Equation 1), γ (M2) is the n-type semiconductor compound in the active layer 103. Represents the surface energy of the n-type semiconductor compound having the largest surface energy, and γ (M3) is the surface energy of the p-type organic semiconductor compound having the largest surface energy among the p-type organic semiconductor compounds in the active layer 103. Means. On the other hand, in the above formula (Equation 2), when the active layer 103 contains a plurality of p-type organic semiconductor compounds and / or n-type semiconductor compounds, γ (M2) is the n-type semiconductor compound in the active layer 103. Represents the surface energy of the n-type semiconductor compound having the smallest surface energy, and γ (M3) represents the surface energy of the p-type organic semiconductor compound having the smallest surface energy among the p-type organic semiconductor compounds in the active layer 103. Shall mean.

  When the active layer 103 includes a plurality of n-type semiconductor compounds, the ionization potential Ip (M2) of the n-type semiconductor compound is referred to in the above formula (Formula 1) or (Formula 2) in the above formula (Formula 3). It means the ionization potential of an n-type semiconductor compound having a surface energy.

  Further, in order to enhance the above-described doping effect, it is more preferable that the following formula (Formula 4) is satisfied among the above formula (Formula 3), and it is particularly preferable that the following formula (Formula 5) is satisfied.

  Ip (M1) ≧ Ip (M2) −0.25 [eV] (Equation 4)

  Ip (M1) ≧ Ip (M2) −0.20 [eV] (Equation 5)

  Moreover, although there is no special restriction | limiting, it is preferable to satisfy | fill following numerical formula (Formula 6), it is still more preferable to satisfy the following Numerical formula (Formula 7), and it is especially preferable to satisfy the following numerical formula (Formula 8).

  Ip (M2) +0.9 [eV] ≧ Ip (M1) (Equation 6)

  Ip (M2) +0.7 [eV] ≧ Ip (M1) (Expression 7)

  Ip (M2) +0.5 [eV] ≧ Ip (M1) (Equation 8)

  In the present invention, the surface energy of each compound and dye can be calculated from the contact angle of ion-exchanged water on the compound and the dye thin film. Examples of the measurement method include a method of forming a thin film of the compound and the dye and measuring a contact angle of ion-exchanged water measured by a droplet method under a room temperature (25 ° C.) condition in the atmosphere. . For the measurement of the contact angle, for example, a fully automatic contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) can be used. The surface energy is calculated from the result of the measured contact angle. In addition, ion-exchange water can be produced using, for example, a pure water production apparatus (manufactured by ADVANTEC, GSH-500). The resistivity at a temperature of 25 ° C. of the ion exchange water is set to 17 MΩ / cm or more. The surface energy can be calculated with reference to a conventionally known method such as Journal of Colloid and Interface Science; 137; 1990; 304.

  In the present invention, the ionization potential (IP) of each compound and dye can be determined by quantum chemical calculation using a commercially available Gaussian 09 program. The ionization potential can be obtained by performing the energy calculation of the ground state by optimizing the structure with B3LYP / 6-31G (d, p).

  Moreover, since the pigment | dye exists in the active layer 103, what does not volatilize during the manufacturing process of a photoelectric conversion element is preferable. Therefore, the sublimation temperature of the dye is preferably 150 or more.

  As long as the above conditions are satisfied, there is no particular limitation, and specific examples of the pigment include dyes and pigments.

  The dye is not particularly limited. For example, azo dye, anthraquinone dye, phthalocyanine dye, quinoneimine dye, quinoline dye, nitro dye, carbonyl dye, methine dye, cyanine dye, triaryl Examples thereof include methane dyes, dipyrromethene dyes, and xanthene dyes.

  Examples of the azo dye include C.I. I. Acid Yellow 11, C.I. I. Acid Orange 7, C.I. I. Acid Red 37, C.I. I. Acid Red 180, C.I. I. Acid Blue 29, C.I. I. Direct Red 28, C.I. I. Direct Red 83, C.I. I. Direct Yellow 12, C.I. I. Direct Orange 26, C.I. I. Direct Green 28, C.I. I. Direct Green 59, C.I. I. Reactive Yellow 2, C.I. I. Reactive Red 17, C.I. I. Reactive Red 120, C.I. I. Reactive Black 5, C.I. I. Disperse Orange 5, C.I. I. Disperse thread 58, C.I. I. Disperse blue 165, C.I. I. Basic Blue 41, C.I. I. Basic Red 18, C.I. I. Molded Red 7, C.I. I. Moldant Yellow 5, C.I. I. Examples thereof include Moldant Black 7.

  Examples of anthraquinone dyes include C.I. I. Bat Blue 4, C.I. I. Acid Blue 25, C.I. I. Acid Blue 40, C.I. I. Acid Blue 80, C.I. I. Acid Green 25, C.I. I. Reactive Blue 19, C.I. I. Reactive Blue 49, C.I. I. Disperse thread 60, C.I. I. Disperse Blue 56, C.I. I. Disperse Blue 60 etc. are mentioned.

  Other examples of the phthalocyanine dye include C.I. I. Direct Blue 86, C.I. I. Direct Blue 199, C.I. I. Vat Blue 5, those described in JP-A No. 2002-14222, JP-A No. 2005-134759, JP-A No. 2010-191358 and JP-A No. 2011-148950 are examples of quinoneimine dyes such as C . I. Basic Blue 3, C.I. I. Basic Blue 9 and the like are quinoline dyes such as C.I. I. Solvent Yellow 33, C.I. I. Acid Yellow 3, C.I. I. Disperse Yellow 64 and the like are nitro dyes such as C.I. I. Acid Yellow 1, C.I. I. Acid Orange 3, C.I. I. Disperse Yellow 42 and the like.

Examples of triarylmethane dyes include C.I. I. Acid Blue 86, C.I. I. Acid Blue 88, C.I. I. Acid Blue 108, International Publication No. 2009/107734 Pamphlet, International Publication No. 2011/162217 Pamphlet, and the like.
Furthermore, examples of the cyanine dye include those described in International Publication No. 2011/162217 pamphlet, and preferred embodiments thereof are also the same.

  Examples of dipyrromethene dyes include, for example, JP-A-2008-292970, JP-A-2010-84009, JP-A-2010-84141, JP-A-2010-85454, JP-A-2011-158654, JP-A-2011-158654. Examples described in JP 2012-158739 A, JP 2012-224852 A, JP 2012-224849 A, JP 2012-224847 A, JP 2012-224846 A, and the like can be given.

  Examples of xanthene dyes include C.I. I. Acid Red 50, C.I. I. Acid Red 52, C.I. I. Acid Red 289, Japanese Patent No. 3387541, Japanese Patent Application Laid-Open No. 2010-32999, Japanese Patent No. 4492760, “Review Synthetic Dye” (Horiguchi Hiroshi, Sankyo Publishing, 1968), pages 326 to 348, etc. Is mentioned.

Although there is no special restriction | limiting as a pigment, A pigment of various colors, such as a blue pigment, a green pigment, a red pigment, a yellow pigment, a purple pigment, an orange pigment, a brown pigment, can be used. Further, the color tone may be adjusted by combining two or more pigments. In addition to the organic pigments such as azo, phthalocyanine, quinacridone, benzimidazolone, isoindolinone, dioxazine, indanthrene, and perylene as the structure of the pigment, various inorganic pigments are also used. Is possible. Although there is no special restriction | limiting as an inorganic pigment, For example, a metal nanoparticle or a metal oxide nanoparticle is mentioned. Gold, silver, aluminum, nickel, cobalt etc. are mentioned as a metal of these nanoparticles.

Hereinafter, specific examples of pigments that can be used in the present invention are shown by pigment numbers. Note that terms such as “CI Pigment Red 2” mentioned below mean a color index (CI).
Examples of red pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 37, 38, 41, 47, 48, 48: 1, 48: 2, 48: 3, 48: 4, 49, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53, 53: 1, 53: 2, 53: 3, 57, 57: 1, 57: 2, 58: 4, 60, 63, 63: 1, 63: 2, 64, 64: 1, 68, 69, 81, 81: 1, 81: 2, 81: 3, 81: 4, 83, 88, 90: 1, 101, 101: 1, 104, 108, 108: 1, 109, 112, 113, 114, 122, 123, 144, 146, 147, 149, 151, 166, 168, 169, 170, 172, 173, 174, 175, 176, 177, 178, 17 , 181, 184, 185, 187, 188, 190, 193, 194, 200, 202, 206, 207, 208, 209, 210, 214, 216, 220, 221, 224, 230, 231, 232, 233, 235 236, 237, 238, 239, 242, 243, 245, 247, 249, 250, 251, 253, 254, 255, 256, 257, 258, 259, 260, 262, 263, 264, 265, 266, 267 268, 269, 270, 271, 272, 273, 274, 275, 276. Of these, C.I. I. Pigment Red 48: 1, 122, 168, 177, 202, 206, 207, 209, 224, 242, 254, more preferably C.I. I. Pigment red 177, 209, 224, 254.

  Examples of blue pigments include C.I. I. Pigment Blue 1, 1: 2, 9, 14, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 19, 25, 27, 28, 29, 33, 35, 36, 56, 56: 1, 60, 61, 61: 1, 62, 63, 66, 67, 68, 71, 72, 73, 74, 75, 76, 78, 79. Of these, C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, more preferably C.I. I. Pigment blue 15: 6. Examples of green pigments include C.I. I. Pigment green 1, 2, 4, 7, 8, 10, 13, 14, 15, 17, 18, 19, 26, 36, 45, 48, 50, 51, 54, 55. Of these, C.I. I. Pigment Green 7, 36, 58.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 1: 1, 2, 3, 4, 5, 6, 9, 10, 12, 13, 14, 16, 17, 24, 31, 32, 34, 35, 35: 1, 36, 36: 1, 37, 37: 1, 40, 41, 42, 43, 48, 53, 55, 61, 62, 62: 1, 63, 65, 73, 74, 75, 81, 83, 87, 93, 94, 95, 97, 100, 101, 104, 105, 108, 109, 110, 111, 116, 117, 119, 120, 126, 127, 127: 1, 128, 129, 133, 134, 136, 138, 139, 142, 147, 148, 150, 151, 153, 154, 155, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 172, 17 174, 175, 176, 180, 181, 182, 183, 184, 185, 188, 189, 190, 191, 191: 1, 192, 193, 194, 195, 196, 197, 198, 199, 200, 202 , 203, 204, 205, 206, 207, 208. Of these, C.I. I. Pigment yellow 83, 117, 129, 138, 139, 150, 154, 155, 180, 185, more preferably C.I. I. Pigment yellow 83, 138, 139, 150, 180.

  Examples of orange pigments include C.I. I. Pigment Orange 1, 2, 5, 13, 16, 17, 19, 20, 21, 22, 23, 24, 34, 36, 38, 39, 43, 46, 48, 49, 61, 62, 64, 65, 67, 68, 69, 70, 71, 72, 73, 74, 75, 77, 78, 79. Of these, C.I. I. And CI pigment oranges 38 and 71.

  Examples of purple pigments include C.I. I. Pigment Violet 1, 1: 1, 2, 2: 2, 3, 3: 1, 3: 3, 5, 5: 1, 14, 15, 16, 19, 23, 25, 27, 29, 31, 32, 37, 39, 42, 44, 47, 49, 50. Of these, C.I. I. Pigment violet 19, 23, more preferably C.I. I. And CI Pigment Violet 23.

  Among these, preferred pigments include azo dyes, anthraquinone dyes, and triarylmethane dyes, and azo dyes are particularly preferred.

  The amount of the dye with respect to the p-type semiconductor compound and the n-type semiconductor compound in the active layer is not particularly limited, but is preferably 0.01% by mass or more in order to obtain an effect of improving light resistance by adding the dye, It is more preferably 0.1 or more, and particularly preferably 0.3 or more. On the other hand, in order to prevent the original charge transport performance of the n-type semiconductor from being hindered by the dye, it is 7% by mass or less. It is preferably 5% by mass or less, more preferably 3% by mass or less.

  Note that the active layer 103 may contain a plurality of pigments.

  The film thickness of the active layer 103 is not particularly limited, but is usually 50 nm or more, preferably 100 nm or more, more preferably 200 nm or more, in order to ensure the uniformity of the film and prevent a short circuit between the electrodes, In order to reduce the internal resistance and efficiently perform charge diffusion, the thickness is usually 1000 nm or less, preferably 500 nm or less, and more preferably 400 nm or less.

  The formation method of the active layer 103 is not particularly limited, and is a wet film formation method using a coating liquid for forming an active layer containing a p-type organic semiconductor compound, an n-type semiconductor compound, a dye, and a solvent. Can be formed. In addition, when a pigment | dye is insoluble in the solvent used for the coating liquid for active layer formation, it melt | dissolves beforehand in the suitable solvent which melt | dissolves a pigment | dye, and is added to the liquid containing a p-type semiconductor compound and an n-type semiconductor compound. A coating liquid for forming an active layer can be prepared.

  As a wet film forming method, there is no particular limitation, spin coating method, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method, Examples of the method include impregnation / coating and curtain coating.

  The solvent is not particularly limited, but for example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane, tetralin or decane; aroma such as toluene, xylene, mesitylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene Aromatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane, tetralin or decalin; lower alcohols such as methanol, ethanol or propanol; acetone, methyl ethyl ketone, cyclopentanone or Aliphatic ketones such as cyclohexanone; aromatic ketones such as acetophenone or propiophenone; esters such as ethyl acetate, butyl acetate or methyl lactate; Arm, methylene chloride, dichloroethane, halogenated hydrocarbons such as trichloroethane or trichlorethylene; ethers such as ethyl ether and tetrahydrofuran or dioxane; or an amide such as dimethylformamide or dimethylacetamide, and the like. In addition, a solvent may use 1 type of solvent independently, and may use arbitrary 2 or more types of solvents together by arbitrary ratios.

  The solvent for dissolving the dye is not particularly limited, but a solvent that appropriately dissolves the active layer material is preferable. Specific examples include alcohol-based solvents, and particularly ethanol.

  The ratio of the p-type organic semiconductor compound, the n-type semiconductor compound and the dye in the coating solution is not particularly limited, and may be appropriately adjusted in order to obtain a desired active layer.

  Further, the method for forming the active layer 103 is not limited to the above. For example, an upper buffer layer using a solvent that permeates the active layer on the active layer containing the p-type organic semiconductor compound and the n-type semiconductor compound. By using a coating solution and adding a dye to the upper buffer layer coating solution, the dye can be added into the active layer when the upper buffer layer is applied. Usually, since the p-type and n-type semiconductor compounds of the active layer are hydrophobic, the upper buffer layer coating solution often uses a hydrophilic solvent that does not dissolve the active layer. In this case, it is preferable that the solvent of the coating solution for forming the upper buffer layer contains a solvent that appropriately dissolves the n-type semiconductor compound that forms the active layer 103. Specifically, it is preferable to include a solvent in which the solubility of each n-type semiconductor compound at 25 ° C. is 0.01 mg / mL or more. Examples of such a solvent include organic solvents that are compatible with hydrophilic solvents, among which ethanol, isopropyl alcohol, butanol, propylene glycol monomethyl ether, methyl ethyl ketone, acetone, and the like. In this case, the dye concentration with respect to the solid component in the coating solution for the upper buffer layer is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 5% by mass or more. On the other hand, it is preferably 50% by mass or less, and particularly preferably 30% by mass or less. In the present invention, it is also possible to use a hydrophobic solvent for the upper buffer layer coating solution, and even in such a case, it is preferable to appropriately dissolve the n-type semiconductor compound.

<1-4. Buffer Layer (Lower Buffer Layer 102, Upper Buffer Layer 104)>
As described above, the photoelectric conversion element according to this embodiment includes the lower buffer layer 102 between the lower electrode 101 and the active layer 103, and the upper buffer layer 104 between the upper electrode 105 and the active layer 103. .

  The material of the electron extraction layer is not particularly limited as long as it is a material that improves the efficiency of extracting electrons from the active layer 103 to the cathode, and examples thereof include inorganic compounds and organic compounds.

  Examples of the inorganic compound include alkali metal salts such as Li, Na, K, and Cs; n-type semiconductor oxides such as titanium oxide (TiOx) and zinc oxide (ZnO). Among them, the alkali metal salt is preferably a fluoride salt such as LiF, NaF, KF or CsF, and the n-type semiconductor oxide is preferably zinc oxide (ZnO). Although the operation mechanism of such a material is unknown, it is conceivable to reduce the work function of the cathode when combined with a cathode made of Al or the like and increase the voltage applied to the solar cell element.

  Examples of organic compounds include phosphine compounds having a double bond between a phosphorus atom and a group 16 element such as triarylphosphine oxide compounds; substituents such as bathocuproin (BCP) or bathophenanthrene (Bphen) A phenanthrene compound in which the 1-position and the 10-position may be substituted with a heteroatom; a boron compound such as triarylboron; an organometallic such as (8-hydroxyquinolinato) aluminum (Alq3) Oxide; Compound having 1 or 2 ring structure which may have a substituent such as oxadiazole compound or benzimidazole compound; naphthalenetetracarboxylic anhydride (NTCDA) or perylenetetracarboxylic anhydride Such as (PTCDA), such as dicarboxylic anhydride Aromatic compounds having a slip dicarboxylic acid structure.

  The material for the hole extraction layer is not particularly limited as long as it is a material capable of improving the efficiency of extracting holes from the active layer 103 to the anode. Specifically, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like, a conductive polymer doped with sulfonic acid and / or iodine, a polythiophene derivative having a sulfonyl group as a substituent, or a conductive organic such as arylamine Examples thereof include compounds, copper oxide, nickel oxide, manganese oxide, molybdenum oxide, vanadium oxide, metal oxide such as tungsten oxide, Nafion, and a p-type semiconductor described later. Among them, a conductive polymer doped with sulfonic acid is preferable, and (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. It is. A thin film of metal such as gold, indium, silver or palladium can also be used. A thin film of metal or the like may be formed alone or in combination with the above organic material.

  The film thicknesses of the lower buffer layer 102 and the upper buffer layer 104 are each usually 0.1 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. If the thickness of each buffer layer is within the above range, charges can be easily taken out from the active layer 103, and the photoelectric conversion efficiency can be improved.

  There is no limitation on the method of forming the lower buffer layer 102 and the upper buffer layer 104. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. For example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as a spin coating method or an ink jet method.

  In addition, when forming a buffer layer by the apply | coating method, you may make a coating liquid contain a surfactant further. By using the surfactant, the occurrence of dents due to adhesion of fine bubbles or foreign matters and / or uneven coating in the drying process is suppressed. Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Of these, silicon-based surfactants, acetylenic diol-based surfactants, and fluorine-based surfactants are preferable. In addition, as surfactant, only 1 type may be used and 2 or more types may be used together by arbitrary combinations and a ratio.

<1-5. Manufacturing method of photoelectric conversion element>
The photoelectric conversion element 107 having the configuration shown in FIG. 1 is formed on the element substrate 106 on the element substrate 106 in accordance with the method described above for each layer, and the lower electrode 101, the lower buffer layer 102, the active layer 103, the upper buffer layer 104, and the upper electrode. It can be manufactured by sequentially stacking 105.

  After laminating the lower electrode 101 and the upper electrode 105, the photoelectric conversion element is usually in a temperature range of 50 ° C. or higher, preferably 80 ° C. or higher, usually 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 250 ° C. or lower. It is preferable to heat (this step is referred to as an annealing treatment step).

  Performing the annealing process at a temperature of 50 ° C. or higher improves adhesion between the layers of the photoelectric conversion element, for example, adhesion between the lower buffer layer 102 and the lower electrode 101 and / or the lower buffer layer 102 and the active layer 103. This is preferable because the effect of By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. In addition, the self-organization of the active layer can be promoted by the annealing process. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the possibility that the organic compound in the active layer 103 is thermally decomposed is reduced. In the annealing treatment step, stepwise heating may be performed within the above temperature range.

  The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment step 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 a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere.

  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.

  Each layer constituting the photoelectric conversion element according to the present invention is not particularly limited, and can be formed by a sheet-to-sheet (sheet-fed) method or a roll-to-roll method.

<2. Solar cell module>
The photoelectric conversion element according to the above-described embodiment is preferably used as a solar cell module. Note that the solar cell module is preferably sealed with a gas barrier layer or the like in order to prevent the photoelectric conversion element from being deteriorated by water or oxygen. Moreover, it is preferable to have a current collector for taking out the electricity generated by the photoelectric conversion element.

  FIG. 2 is a cross-sectional view schematically showing a configuration of a solar cell module as one embodiment of the present invention. As shown in FIG. 2, the solar cell module includes gas barrier layers 201 and 202, sealing layers 203 and 204, and a current collector 205 in addition to the element substrate 206 and the photoelectric conversion element 207.

  There are no particular restrictions on the materials and stacking methods of the gas barrier layers 201 and 202, the sealing layers 203 and 204, and the current collector 205 that constitute the solar cell module, and known techniques can be used. For example, the thing described in well-known literatures, such as international publication 2011/016430 or Japan Unexamined-Japanese-Patent No. 2012-191194, can be used. In addition, the structure of a solar cell module is not limited to the structure of FIG. 2, As long as it can generate electric power with a photoelectric conversion element, what kind of structure may be sufficient as it. In FIG. 2, the element substrate 206 side (gas barrier layer 201 side) is a sunlight incident surface, but the present invention is not limited to this, and the photoelectric conversion element 207 side (gas barrier layer 202 side) is sunlight. It may be a light receiving surface.

  There is no special restriction | limiting in the use of the solar cell module which concerns on this invention, It can use for arbitrary uses. Examples include solar cells for building materials, solar cells for vehicles, solar cells for spacecrafts, solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like.

  Especially, it is preferable to affix and use the solar cell module which concerns on this invention on adherends, such as partitions, such as glass, such as a window, a door, a wall surface, or a ceiling, such as a building and a vehicle.

  Hereinafter, embodiments of the present invention will be described by way of examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded. Items described in the examples were measured by the following methods.

(Measurement method of weight average molecular weight and number average molecular weight)
The weight average molecular weight (Mw) and number average molecular weight (Mn) in terms of polystyrene were determined by gel permeation chromatography (GPC). Molecular weight distribution (PDI) represents Mw / Mn.

Gel permeation chromatography (GPC) measurement was performed under the following conditions.
Column: Polymer Laboratories GPC column (PLgel MIXED-B 10 μm, inner diameter 7.5 mm, length 30 cm) connected in series Pump: LC-10AT (manufactured by Shimadzu Corporation) Oven: CTO-10A (Shimadzu Corporation) (Made by company)
Detector: differential refractive index detector (manufactured by Shimadzu Corporation, RID-10A) and UV-vis detector (manufactured by Shimadzu Corporation, SPD-10A)
Sample: 1 μL of 1 mg sample dissolved in chloroform (200 mg)
Mobile phase: Chloroform Flow rate: 1.0 mL / min
Analysis: LC-Solution (manufactured by Shimadzu Corporation)

(Evaluation of photoelectric conversion element)
A 4 mm square metal mask is attached to the photoelectric conversion element, a solar simulator with an air mass (AM) of 1.5 G and an irradiance of 100 mW / cm ² is used as an irradiation light source, and an ITO electrode is connected with a source meter (Keisley, Model 2400). The current-voltage characteristics with the silver electrode were measured. From this measurement result, open circuit voltage Voc (V), short circuit current density Jsc (mA / cm ² ), form factor FF, and photoelectric conversion efficiency PCE (%) were calculated.

Here, the open circuit voltage Voc is a voltage value when the current value = 0 (mA / cm @ 2), and the short circuit current density Jsc is a current density when the voltage value = 0 (V). The form factor FF is a factor representing the internal resistance, and is represented by the following expression when the maximum output is Pmax.
FF = Pmax / (Voc × Jsc)
Further, the photoelectric conversion efficiency PCE is given by the following equation when the incident energy is Pin.
PCE = (Pmax / Pin) × 100
= (Voc x Jsc x FF / Pin) x 100

(Measurement of surface energy of each compound)
A method for measuring dyes 1 to 8 and p-type surface energy to be described later is shown. For dyes 1, 2, 5, 6, 7, and 8, a 2% by weight aqueous solution was prepared. For dyes 3 and 4, a 2% by weight toluene solution was prepared, and a film was formed by spin coating at 1000 rpm for 120 seconds. A dye thin film was obtained. The surface energy of the obtained dye thin film was measured under the atmospheric temperature at room temperature (25 ° C.) by the method described above. The obtained results are shown in Table 1. Also, by the same method, a 2 mass% toluene solution of a mixture of a naphthobisthiadiazole unit, which is a p-type organic semiconductor polymer, which will be described later, and a copolymer containing PC61BM and PC71BM, which are n-type semiconductor compounds, is prepared. The results of measuring the surface energy are shown in Table 2.

(Measurement of ionization potential of each compound)
Regarding dyes 1 to 8 and an n-type semiconductor compound described later, the structure was optimized with B3LYP / 6-31G (d, p), the ground state energy was calculated, and obtained by quantum chemical calculation using a commercially available Gaussian 09 program. Table 1 shows the ionization potential values of the dyes 1 to 8. Table 2 shows the results of the ionization potential of PC61BM which is an n-type semiconductor compound and the ionization potential of PC71BM.

(Preparation of active layer coating solution P1)
As a p-type organic semiconductor polymer, a copolymer containing a naphthobisthiadiazole unit having a weight average molecular weight of 113,000 and a benzodithiophene unit, synthesized according to a method described in the known pamphlet of International Publication No. 2017/047808, and an n-type semiconductor compound PC61BM (phenyl C61 butyric acid methyl ester) and PC71BM (phenyl C71 butyric acid methyl ester) were mixed so that the mass ratio was 1: 1.8. The obtained mixture was dissolved in a solvent in a nitrogen atmosphere so as to be 45 mg with respect to 1 mL of the solvent to prepare an active layer coating solution P1. In addition, the solvent used the mixed solvent (volume ratio 9: 1) of toluene and tetralin.

(Preparation of active layer coating solution P2)
The solid content concentration of the dye 1 with respect to the solid content concentration of the active layer coating solution P1 is obtained by dissolving a solution Q1 in which the dye 1 represented by the following formula (1) is dissolved in ethanol so as to have a solid content concentration of 2% by mass. Was added to the above-described active layer coating solution P1 to prepare 0.32% by mass of active layer coating solution P2.

(Preparation of active layer coating solution P3)
The coating liquid P2 for the active layer except that the solution Q1 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 1 is 0.5% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P3 was prepared in the same manner as described above.

(Preparation of coating liquid P4 for active layer)
The coating liquid P2 for the active layer except that the solution Q1 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 1 is 1.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P4 was prepared in the same manner as described above.

(Preparation of active layer coating solution P5)
The coating liquid P2 for the active layer except that the solution Q1 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 1 is 3.0% by mass relative to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P5 was prepared in the same manner as described above.

(Preparation of coating liquid P6 for active layer)
The coating liquid P2 for the active layer except that the solution Q1 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 1 is 5.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P6 was prepared in the same manner as described above.

(Preparation of active layer coating solution P7)
The dye 2 was dissolved in ethanol so that the solid content concentration of the dye 2 represented by the following formula (2) was 2% by mass to obtain a solution Q2. This solution Q2 was added to the active layer coating solution P1 so that the solid content concentration of the dye 2 relative to the solid content concentration of the active layer coating solution P1 was 0.3% by mass to prepare an active layer coating solution P7. .

(Preparation of active layer coating solution P8)
The coating liquid P7 for the active layer except that the solution Q2 was added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 2 was 0.5% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P8 was prepared in the same manner as described above.

(Preparation of active layer coating solution P9)
The coating liquid P7 for the active layer except that the solution Q2 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 2 is 1.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P9 was prepared in the same manner as described above.

(Preparation of coating liquid P10 for active layer)
The coating liquid P7 for the active layer except that the solution Q2 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 2 is 3.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P10 was prepared in the same manner as described above.

(Preparation of active layer coating solution P11)
The coating liquid P7 for the active layer except that the solution Q2 is added to the coating liquid P1 for the active layer so that the solid component concentration of the dye 2 is 5.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. An active layer coating solution P11 was prepared in the same manner as described above.

(Preparation of active layer coating solution P12)
The dye 3 is added to the active layer coating liquid P1 so that the solid content concentration of the dye 3 represented by the following formula (3) is 1.0% by mass with respect to the solid content concentration of the active layer coating liquid P1. An active layer coating solution P12 was prepared.

(Preparation of active layer coating solution P13)
The dye 4 is added to the coating liquid P1 for the active layer so that the solid content concentration of the dye 4 represented by the following formula (4) is 1.0% by mass with respect to the solid content concentration of the coating liquid P1 for the active layer. Layer coating solution P14 was prepared.

(Preparation of upper buffer layer coating solution H2)
In the PEDOT: PSS aqueous dispersion, 50% by mass of ethanol, 20% by mass of isopropyl alcohol, and 10% by mass of propylene glycol monomethyl ether are added to the coating solution H1 for the upper buffer layer, which is 2% by mass of PEDOT: PSS dispersion. The pigment | dye 1 was added so that the density | concentration with respect to PEDOT: PSS which is a solid component might be 10.0 mass%, and the coating liquid H2 for upper buffer layers which is a coating liquid for positive hole taking layers was produced.

(Preparation of upper buffer layer coating solution H3)
The pigment | dye 2 was added to the coating liquid H1 for upper buffer layers so that the density | concentration with respect to PEDOT: PSS which is a solid component might be 10.0 mass%, and the coating liquid H3 for upper buffer layers was produced.

(Preparation of upper buffer layer coating solution H4)
Dye 5 represented by the following formula (5) is added to the upper buffer layer coating solution H1 so that the concentration with respect to the solid component PEDOT: PSS is 10.0% by mass, and the upper buffer layer coating solution H4 is added. Produced.

(Preparation of upper buffer layer coating solution H5)
Dye 6 represented by the following formula (6) is added to the upper buffer layer coating liquid H1 so that the concentration with respect to the solid component PEDOT: PSS is 10.0% by mass, and the upper buffer layer coating liquid H5 Was made.

(Preparation of upper buffer layer coating solution H6)
Dye 7 represented by the following formula (7) is added to the upper buffer layer coating solution H1 so that the concentration with respect to the solid component PEDOT: PSS is 10.0% by mass, and the upper buffer layer coating solution H6 Was made.

(Preparation of upper buffer layer coating solution H7)
Dye 8 represented by the following formula (8) is added to the upper buffer layer coating solution H1 so that the concentration with respect to the solid component PEDOT: PSS is 10.0% by mass, and the upper buffer layer coating solution H7 is added. Produced.

<Example 1: Production and evaluation of photoelectric conversion element>
A glass substrate (manufactured by Geomatic Co., Ltd.) patterned with an indium tin oxide (ITO) transparent conductive film is subjected to ultrasonic cleaning with acetone, followed by ultrasonic cleaning with isopropanol, followed by drying with nitrogen blowing and UV-ozone treatment. went.

  500 mg of zinc acrylate (manufactured by Wako Pure Chemical Industries) was dissolved in 7.77 g of ethanol (manufactured by Wako Pure Chemical Industries), and this solution was stirred for 1 hour. Thereafter, this solution was spin-coated on a glass substrate at a speed of 2000 rpm and heated at 150 ° C. for 5 minutes to form a zinc oxide-containing layer having a thickness of 50 nm as an electron extraction layer.

  The glass substrate on which the electron take-out layer is formed is brought into a glove box, heated at 150 ° C. for 3 minutes in a nitrogen atmosphere, and after cooling, the active layer coating solution P2 (0.06 mL) prepared as described above is set to a speed of 500 rpm. An active layer having a thickness of 350 nm was formed by spin coating. Thereafter, the substrate was heated at 140 degrees for 10 minutes.

  Further, the upper buffer layer coating solution H1 was spin-coated on the active layer at a speed of 1000 rpm, and then heated at 150 ° C. for 10 minutes to form a hole extraction layer as the upper buffer layer. The obtained hole extraction layer had a thickness of 300 nm.

  Next, an upper electrode is formed on the hole extraction layer by sequentially forming a 30 nm thick IZO film, an 8 nm silver film, and a 40 nm IZO film by vacuum sputtering, and a 5 mm square photoelectric conversion element is formed. Produced.

  Next, a UV curable resin was applied to the periphery of the photoelectric conversion element in nitrogen, a glass sealing plate was placed from the upper part, and the resin was UV cured to seal the photoelectric conversion element.

The photoelectric conversion efficiency (PCE) of the photoelectric conversion element obtained by the above method was measured. Moreover, in order to evaluate the light resistance of the photoelectric conversion element, as a light resistance test, exposure is performed with a solar simulator having an air mass (AM) of 1.5 G as an irradiation light source and an irradiance of 100 mW / cm ² , and conversion is performed as shown in the following formula. The time (T80) when the efficiency maintenance rate was 80% was calculated. The obtained results are shown in Table 1. In Table 1, the numerical value in the T80 (h) column represents the time when the conversion efficiency maintenance rate is 80%, but the T80 (h) column is ◯ for 500 hours exposure. This also means that the conversion efficiency maintenance rate is higher than 80%. In other words, a T80 (h) column with a circle indicates that the photoelectric conversion element has high light resistance with little decrease in initial conversion efficiency even after exposure for 500 hours.

(Conversion efficiency maintenance ratio) = ((Conversion efficiency after exposure) / (Initial conversion efficiency)) × 100

<Example 2: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P3 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 3: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P4 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1. The change rate of the short circuit current density when the active layer contains the dye 1 (1% by mass with respect to the solid component of the active layer) with respect to the short circuit current density when the active layer does not contain the dye is 2.6. %Met.

<Example 4: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was prepared in the same manner as in Example 1 except that the active layer coating solution P5 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 5: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating liquid P6 was used instead of the active layer coating liquid P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Comparative example 1: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P1 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 6: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P7 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 7: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P8 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 8: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P9 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1. The change rate of the short-circuit current density when the active layer contained the dye 2 (1 mass% with respect to the solid component of the active layer) relative to the short-circuit current density when the active layer did not contain the dye was 3.1. %Met.

<Example 9: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating liquid P10 was used instead of the active layer coating liquid P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Example 10: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P11 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1.

<Comparative example 2: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating solution P12 was used instead of the active layer coating solution P2, and the same evaluation was performed. The obtained results are shown in Table 1. The change rate of the short-circuit current density when the active layer contains the dye 3 (1% by mass with respect to the solid component of the active layer) with respect to the short-circuit current density when the active layer does not contain the dye is 3.8. %Met.

<Comparative Example 3: Production and Evaluation of Photoelectric Conversion Element>
A photoelectric conversion element was produced in the same manner as in Example 1 except that the active layer coating liquid P13 was used instead of the active layer coating liquid P2, and the same evaluation was performed. The obtained results are shown in Table 1. The change rate of the short-circuit current density when the active layer contained the dye 4 (1 mass% with respect to the solid component of the active layer) with respect to the short-circuit current density when the active layer did not contain the dye was 35.6. %Met.

<Example 11: Production and evaluation of photoelectric conversion element>
Except for using the active layer coating solution P1 instead of the active layer coating solution P2 and using the upper buffer layer coating solution H2 instead of the upper buffer layer coating solution H1, the same method as in Example 1 was used. A photoelectric conversion element was produced and evaluated in the same manner. In addition, it was confirmed that the active layer of the obtained photoelectric conversion element contains a pigment. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1.

<Example 12: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 11 except that the upper buffer layer coating solution H3 was used instead of the upper buffer layer coating solution H2, and the same evaluation was performed. It was confirmed that the active layer of the obtained photoelectric conversion element contained a dye. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1.

<Example 13: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 11 except that the upper buffer layer coating solution H4 was used instead of the upper buffer layer coating solution H2, and the same evaluation was performed. It was confirmed that the active layer of the obtained photoelectric conversion element contained a dye. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1. In addition, the change rate of the short circuit current density in case the active layer contains 1 mass% of pigment | dyes 5 with respect to a solid component with respect to the short circuit current density in case an active layer does not contain a pigment | dye was 5% or less.

<Comparative example 4: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 11 except that the upper buffer layer coating solution H5 was used instead of the upper buffer layer coating solution H2, and the same evaluation was performed. It was confirmed that the active layer of the obtained photoelectric conversion element contained a dye. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1. In addition, the change rate of the short circuit current density in case the active layer contains 1 mass% of pigment | dyes 6 with respect to a solid component with respect to the short circuit current density in case an active layer does not contain a pigment | dye was 5% or less.

<Comparative Example 5: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 11 except that the upper buffer layer coating solution H6 was used instead of the upper buffer layer coating solution H2, and the same evaluation was performed. It was confirmed that the active layer of the obtained photoelectric conversion element contained a dye. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1. In addition, the change rate of the short circuit current density when the active layer contains 1% by mass of the dye 7 with respect to the solid component was 5% or less with respect to the short circuit current density when the active layer did not contain the dye. .

<Comparative Example 6: Production and evaluation of photoelectric conversion element>
A photoelectric conversion element was produced in the same manner as in Example 11 except that the upper buffer layer coating solution H7 was used instead of the upper buffer layer coating solution H2, and the same evaluation was performed. It was confirmed that the active layer of the obtained photoelectric conversion element contained a dye. The reason for this is considered that the dye in the composition for forming the upper buffer layer penetrated into the active layer. The obtained results are shown in Table 1. In addition, the change rate of the short circuit current density in case the active layer contains 1 mass% of pigment | dyes 8 with respect to a solid component with respect to the short circuit current density in case an active layer does not contain a pigment | dye was 5% or less.

  As can be seen from the results in Table 1, with respect to the photoelectric conversion element obtained in Comparative Example 1 in which no dye was added in the active layer, Examples 1 to 10 in which the active layer contained a specific dye It turns out that the obtained photoelectric conversion element has high light resistance. In addition, as shown in Examples 11 to 13, when a photoelectric conversion element was produced using a coating solution for an upper buffer layer containing a specific dye, the dye penetrated into the active layer, and as a result, It turns out that the photoelectric conversion element which has high light resistance similarly to Examples 1-10 is obtained. The reason for this is considered that the dye segregates in the domain of the n-type semiconductor compound in the active layer and can appropriately compensate for the electron trap. On the other hand, regarding the photoelectric conversion elements obtained in Comparative Examples 2 and 3, a large amount of dye is present at the interface between the p-type organic semiconductor polymer and the n-type semiconductor compound, and the effects as in Examples 1 to 13 are obtained. It is thought that it was not obtained. Moreover, in the photoelectric conversion element obtained by Comparative Examples 4-6, although the pigment | dye has segregated to the n-type semiconductor domain, since the value of the ionization potential of this pigment | dye is too small, it is like Example 1-13. It is thought that the effect was not obtained.

101 Lower electrode 102 Lower buffer layer 103 Active layer 104 Upper buffer layer 105 Upper electrode 106, 206 Element substrate 107, 207 Photoelectric conversion element 201, 202 Gas barrier layer 203, 204 Sealing layer 205

Claims (4)

A photoelectric conversion element having a pair of electrodes and an active layer between the pair of electrodes,
The active layer contains a p-type organic semiconductor compound, an n-type semiconductor compound, and a dye,
The surface energy γ (M1) of the dye, the surface energy γ (M2) of the n-type semiconductor compound, and the surface energy γ (M3) of the p-type organic semiconductor compound are expressed by the following formula (Formula 1) or the following formula (Numerical formula). 2) and the ionization potential Ip (M1) of the dye and the ionization potential Ip (M2) of the n-type semiconductor compound satisfy the relationship of the following formula (Equation 3): element.
γ (M1)> γ (M2)> γ (M3) (Equation 1)
γ (M3)> γ (M2)> γ (M1) (Equation 2)
Ip (M1) ≧ Ip (M2) −0.30 [eV] (Equation 3) The photoelectric conversion element according to claim 1, wherein a difference between a surface energy γ (M1) of the dye and a surface energy γ (M2) of the n-type semiconductor compound is 10 mJ / cm ² or more.   The photoelectric conversion element according to claim 1, wherein the pigment is an azo dye.   The solar cell module which has a photoelectric conversion element of any one of Claims 1-3.

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