JP2012199541A - Organic thin-film solar cell element, solar cell, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic thin-film solar cell element which has higher conversion efficiency.SOLUTION: An organic thin-film solar cell element 100 includes at least an active layer 140 and a pair of electrodes 120 and 160. The active layer contains an additive, a p-type semiconductor compound, and an n-type semiconductor compound. The additive contains a dibenzopyrromethene boron chelate compound represented by general formula (A1).

Description

  The present invention relates to an organic thin film solar cell element, a solar cell, and a solar cell module.

  Conventionally, in a wet dye-sensitized solar cell, a technique that utilizes a dye that absorbs light having a longer wavelength is known. For example, Patent Document 1 proposes a technique of applying a benzopyromethene dye as a dye in a dye-sensitized solar cell.

JP 2010-184880 A

  However, in order to make the solar cell lower in cost and higher in performance, development of a solar cell that is easier to handle and has as high a conversion efficiency as possible is required.

  An object of this invention is to provide the organic thin-film solar cell element with higher conversion efficiency.

  As a result of intensive studies, the present inventors can effectively solve the above problem by adding a dibenzopyromethene boron chelate compound to the active layer of the organic thin film solar cell in addition to the p-type semiconductor and the n-type semiconductor. And found the present invention. That is, the gist of the present invention is as follows.

（式中、Ｒ^１〜Ｒ^１７はそれぞれ独立に１価の原子又は原子団を示す。） [1] An organic thin film solar cell element including at least an active layer and a pair of electrodes,
The active layer contains an additive, a p-type semiconductor compound and an n-type semiconductor compound;
The said additive contains the dibenzopyromethene boron chelate compound represented by the following general formula (A1), The organic thin-film solar cell element characterized by the above-mentioned.

(In formula, R < ¹ > -R < ¹⁷ > shows a monovalent atom or atomic group each independently.)

[2] A solar cell comprising the organic thin-film solar cell element according to [1].

[3] A solar cell module comprising the solar cell according to [2].

  ADVANTAGE OF THE INVENTION According to this invention, an organic thin film solar cell element with higher conversion efficiency can be provided.

It is sectional drawing which shows typically the structure of the photoelectric conversion element as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell as one Embodiment of this invention. It is sectional drawing which shows typically the structure of the solar cell module as one Embodiment of this invention. It is a graph which shows the external quantum yield with respect to the light of each wavelength of the solar cell element which concerns on each Example. It is an ultraviolet-visible absorption spectrum of the active layer of each Example.

  Examples of the present invention will be described in detail below. Examples described below are merely examples (representative examples) of the examples of the present invention, and the present invention is not limited to the following examples.

  The organic thin-film solar cell element according to the present invention includes at least an active layer and a pair of electrodes, and the active layer contains an additive, a p-type semiconductor compound, and an n-type semiconductor compound. Contains the dibenzopyromethene boron chelate compound described. Below, the organic thin-film solar cell element which concerns on one Embodiment of this invention is demonstrated. In the following description, a p-type semiconductor compound is a material of a p-type semiconductor, and an n-type semiconductor compound is a material of an n-type semiconductor.

  In an organic thin film solar electronic device, electrons and holes generated by photoexcitation in a p-type semiconductor are usually transported through the p-type semiconductor and the n-type semiconductor, thereby generating electricity. When a dibenzopyromethene boron chelate compound is present in the active layer as in the organic thin film solar cell element according to this embodiment, electrons and holes generated by photoexcitation in the dibenzopyromethene boron chelate compound also contribute to the generation of electricity. It is thought to do. For this reason, according to the organic thin-film solar cell element which concerns on this embodiment, it is thought that bigger photoelectric conversion efficiency is implement | achieved.

[1. Dibenzopyromethene boron chelate compound according to this embodiment]
First, the dibenzopyromethene boron chelate compound contained in the active layer of the organic thin-film solar cell element according to this embodiment will be described. The dibenzopyromethene boron chelate compound according to this embodiment is represented by the following general formula (A1).

In the formula (A1), the substituents R ^{1 to} R ¹⁷ each independently represent a monovalent atom or atomic group. Specific examples of R ^{1 to} R ¹⁷ include a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, an amino group, a carboxy group, a sulfone group, an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 2 to 20 carbon atoms. An alkenyl group, an alkynyl group having 2 to 20 carbon atoms, a halogenoalkyl group having 1 to 20 carbon atoms, an aralkyl group having 2 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, a heteroaryl group having 1 to 30 carbon atoms, An alkoxyalkyl group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxyalkoxy group having 2 to 20 carbon atoms, an aryloxy group having 1 to 30 carbon atoms, a dialkylaminoalkoxy group having 1 to 20 carbon atoms, C1-C20 alkylthioalkoxy group, C1-C20 alkylthio group, C1-C30 arylthio group, C1-C20 monoalkyl amine Group, C1-C20 dialkylamino group, C2-C20 alkylcarbonylamino group, C2-C30 arylcarbonylamino group, C1-C20 acyl group, C2-C20 Alkoxycarbonyl group, aryloxycarbonyl group having 2 to 30 carbon atoms, alkenyloxycarbonyl group having 3 to 20 carbon atoms, aralkyloxycarbonyl group having 3 to 30 carbon atoms, alkoxycarbonylalkoxycarbonyl group having 4 to 30 carbon atoms, carbon C 4-30 alkylcarbonylalkoxycarbonyl group, C 2-20 alkylaminocarbonyl group, C 3-30 dialkylaminocarbonyl group, C 2-30 arylaminocarbonyl group, C 2-20 carbon atom Mono (hydroxyalkyl) aminocarbonyl group, dicarboxylic acid having 3 to 30 carbon atoms Hydroxyalkyl) aminocarbonyl group, mono (alkoxyalkyl) aminocarbonyl group having 3 to 20 carbon atoms, di (alkoxyalkyl) aminocarbonyl group having 5 to 30 carbon atoms, and the like.

  Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

  Examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t-butyl group, and n-pentyl. Group, iso-pentyl group, 2-methylbutyl group, 1-methylbutyl group, neo-pentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, cyclopentyl group, n-hexyl group, 4-methylpentyl Group, 3-methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl Group, 1,2-dimethylbutyl group, 1,1-dimethylbutyl group, 3-ethylbutyl group, 2-ethylbutyl group, 1-ethylbutyl group, 1,2,2-triethyl Butyl group, 1,1,2-triethylbutyl group, 1-ethyl-2-methylpropyl group, cyclohexyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5 -Methylhexyl group, 2,4-dimethylpentyl group, n-octyl group, 2-ethylhexyl group, 2,5-dimethylhexyl group, 2,5,5-triethylpentyl group, 2,4-dimethylhexyl group, 2 , 2,4-trimethylpentyl group, n-nonyl group, 3,5,5-trimethylhexyl group, n-decyl group, 4-ethyloctyl group, 4-ethyl-4,5-dimethylhexyl group, n-undecyl Group, n-dodecyl group, 1,3,5,7-tetramethyloctyl group, 4-butyloctyl group, 6,6-diethyloctyl group, n-tridecyl group, 6-methyl 4-butyloctyl group, 6,6-diethyloctyl group, n-tetradecyl group, n-pentadecyl group, 3,5-dimethylheptyl group, 2,6-dimethylheptyl group, 2,4-dimethylheptyl group, 2, C1-C20 linear, branched or cyclic alkyl such as 2,5,5-tetramethylhexyl group, 1-cyclopentyl-2,2-dimethylpropyl group, 1-cyclohexyl-2,2-dimethylpropyl group Groups.

  Examples of the alkenyl group having 2 to 20 carbon atoms include vinyl group, propenyl group, 1-butenyl group, iso-butenyl group, 1-pentenyl group, 2-pentenyl group, 2-methyl-1-butenyl group, 3-methyl- Examples include 1-butenyl group, 2-methyl-2-butenyl group, 2,2-dicyanovinyl group, 2-cyano-2-methylcarboxyl vinyl group, 2-cyano-2-methylsulfonvinyl group, and the like.

  Examples of the alkynyl group having 2 to 20 carbon atoms include an ethynyl group, a 1-propynyl group, and a 1-butynyl group.

  Examples of the halogenoalkyl group having 1 to 20 carbon atoms include a chloromethyl group, a dichloromethyl group, a fluoromethyl group, a trifluoromethyl group, a pentafluoroethyl group, and a nonafluorobutyl group.

  Examples of the aralkyl group having 2 to 30 carbon atoms include benzyl group, nitrobenzyl group, cyanobenzyl group, hydroxybenzyl group, methylbenzyl group, trimethylbenzyl group, dichlorobenzyl group, methoxybenzyl group, ethoxybenzyl group, trifluoromethylbenzyl. Group, naphthylmethyl group, nitronaphthylmethyl group, cyanonaphthylmethyl group, hydroxynaphthylmethyl group, methylnaphthylmethyl group, trifluoromethylnaphthylmethyl group, tetrazolylmethyl group and the like.

  Examples of the aryl group having 6 to 30 carbon atoms include phenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, methylphenyl group, dimethylphenyl group, trimethylphenyl group, cyclohexylphenyl group, diisopropylphenyl group, dichlorophenyl group, and methoxy. Examples include phenyl group, ethoxyphenyl group, trifluoromethylphenyl group, N, N-dimethylaminophenyl group, naphthyl group, nitronaphthyl group, cyanonaphthyl group, hydroxynaphthyl group, methylnaphthyl group, trifluoromethylnaphthyl group and the like. .

  Examples of the heteroaryl group having 1 to 30 carbon atoms include pyrrolyl, thienyl, furanyl, oxazolyl, isoxazolyl, oxadiazolyl, imidazolyl, benzoxazolyl, benzothiazolyl, benzoimidazolyl, and benzoxazolyl Benzothiazolyl group, benzimidazolyl group, benzofuranyl group, indolyl group, tetrazolyl group, and the like.

  Examples of the alkoxyalkyl group having 2 to 20 carbon atoms include a methoxyethyl group, an ethoxyethyl group, an iso-propyloxyethyl group, a 3-methoxypropyl group, and a 2-methoxybutyl group.

  Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, iso-butoxy group, sec-butoxy group, t-butoxy group, and n-pentoxy group. Group, iso-pentoxy group, neo-pentoxy group, n-hexyloxy group, n-dodecyloxy group, and the like.

  Examples of the alkoxyalkoxy group having 2 to 20 carbon atoms include a methoxyethoxy group, an ethoxyethoxy group, a 3-methoxypropyloxy group, and a 3- (iso-propyloxy) propyloxy group.

  Examples of the aryloxy group having 1 to 30 carbon atoms include phenoxy group, 2-methylphenoxy group, 4-methylphenoxy group, 4-t-butylphenoxy group, 2-methoxyphenoxy group, 4-iso-propylphenoxy group, etc. Is mentioned.

  Examples of the dialkylaminoalkoxy group having 1 to 20 carbon atoms include 2-dimethylaminoethoxy group, 2- (2-dimethylaminoethoxy) ethoxy group, 4-dimethylaminobutoxy group, 1-dimethylaminopropan-2-yloxy group, 3-dimethylaminopropoxy group, 2-dimethylamino-2-methylpropoxy group, 2-diethylaminoethoxy group, 2- (2-diethylaminoethoxy) ethoxy group, 3-diethylaminopropoxy group, 1-diethylaminopropoxy group, 2-diethyl Examples include linear or branched dialkylaminoalkoxy groups such as -iso-propylaminoethoxy group and 2-di-n-butylaminoethoxy group.

  Examples of the alkylthioalkoxy group having 1 to 20 carbon atoms include 2-methylthioethoxy group, 2-ethylthioethoxy group, 2-n-propylthioethoxy group, 2-iso-propylthioethoxy group, 2-n-butylthioethoxy group. Group, 2-iso-butylthioethoxy group, and the like.

  Examples of the alkylthio group having 1 to 20 carbon atoms include methylthio group, ethylthio group, n-propylthio group, iso-propylthio group, n-butylthio group, iso-butylthio group, sec-butylthio group, t-butylthio group, and n-pentylthio group. Group, iso-pentylthio group, 2-methylbutylthio group, 1-methylbutylthio group, neo-pentylthio group, 1,2-dimethylpropylthio group, 1,1-dimethylpropylthio group, and the like.

  Examples of the arylthio group having 1 to 30 carbon atoms include a phenylthio group, a 4-methylphenylthio group, a 2-methoxyphenylthio group, and a 4-t-butylphenylthio group.

  Examples of the monoalkylamino group having 1 to 20 carbon atoms include a methylamino group, an ethylamino group, and a t-butylamino group.

  Examples of the dialkylamino group having 1 to 20 carbon atoms include a dimethylamino group, a diethylamino group, and a methylethylamino group.

  Examples of the alkylcarbonylamino group having 2 to 20 carbon atoms include an acetylamino group, an ethylcarbonylamino group, and a butylcarbonylamino group.

  Examples of the arylcarbonylamino group having 2 to 30 carbon atoms include a phenylcarbonylamino group, a 4-ethylphenylcarbonylamino group, and a 3-butylphenylcarbonylamino group.

  Examples of the acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, ethylcarbonyl group, n-propylcarbonyl group, iso-propylcarbonyl group, n-butylcarbonyl group, n-pentylcarbonyl group, and iso-pentylcarbonyl group. , Neo-pentylcarbonyl group, 2-methylbutylcarbonyl group, nitrobenzylcarbonyl group, and the like.

  Examples of the alkoxycarbonyl group having 2 to 20 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropyloxycarbonyl group, and a 2,4-dimethylbutyloxycarbonyl group.

  Examples of the aryloxycarbonyl group having 2 to 30 carbon atoms include phenoxycarbonyl group, 2-methylphenoxycarbonyl group, 4-methoxyphenylcarbonyl group, 4-t-butylphenoxycarbonyl group, and the like.

  Examples of the alkenyloxycarbonyl group having 3 to 20 carbon atoms include allyloxycarbonyl group and 2-butenoxycarbonyl group.

  Examples of the aralkyloxycarbonyl group having 3 to 30 carbon atoms include benzyloxycarbonyl group and phenethyloxycarbonyl group.

  Examples of the alkoxycarbonylalkoxycarbonyl group having 4 to 30 carbon atoms include a methoxycarbonylmethoxycarbonyl group, an ethoxycarbonylmethoxycarbonyl group, an n-propoxycarbonylmethoxycarbonyl group, and an isopropoxycarbonylmethoxycarbonyl group.

  Examples of the alkylcarbonylalkoxycarbonyl group having 4 to 30 carbon atoms include a methylcarbonylmethoxycarbonyl group and an ethylcarbonylmethoxycarbonyl group.

  Examples of the alkylaminocarbonyl group having 2 to 20 carbon atoms include a methylaminocarbonyl group, an ethylaminocarbonyl group, an n-propylaminocarbonyl group, an n-butylaminocarbonyl group, and an n-hexylaminocarbonyl group.

  Examples of the dialkylaminocarbonyl group having 3 to 30 carbon atoms include dimethylaminocarbonyl group, diethylaminocarbonyl group, di-n-propylaminocarbonyl group, di-n-butylaminocarbonyl group, and N-methyl-N-cyclohexylaminocarbonyl group. , Etc.

  Examples of the arylaminocarbonyl group having 2 to 30 carbon atoms include a phenylaminocarbonyl group, a 4-methylphenylaminocarbonyl group, a 2-methoxyphenylaminocarbonyl group, and a 4-n-propylphenylaminocarbonyl group.

  Examples of the mono (hydroxyalkyl) aminocarbonyl group having 2 to 20 carbon atoms include a hydroxyethylaminocarbonyl group, a 2-hydroxypropylaminocarbonyl group, and a 3-hydroxypropylaminocarbonyl group.

  Examples of the di (hydroxyalkyl) aminocarbonyl group having 3 to 30 carbon atoms include di (hydroxyethyl) aminocarbonyl group, di (2-hydroxypropyl) aminocarbonyl group, di (3-hydroxypropyl) aminocarbonyl group, and the like. Can be mentioned.

  Examples of the mono (alkoxyalkyl) aminocarbonyl group having 3 to 20 carbon atoms include a methoxymethylaminocarbonyl group, a methoxyethylaminocarbonyl group, an ethoxymethylaminocarbonyl group, an ethoxyethylaminocarbonyl group, and a propoxyethylaminocarbonyl group. It is done.

  Examples of the di (alkoxyalkyl) aminocarbonyl group having 5 to 30 carbon atoms include di (methoxyethyl) aminocarbonyl group, di (ethoxymethyl) aminocarbonyl group, di (ethoxyethyl) aminocarbonyl group, and di (propoxyethyl) amino. A carbonyl group, and the like.

Preferred examples of the substituents R ^{1 to} R ¹⁷ include a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydroxy group, an amino group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, carbon Examples thereof include an alkylthio group having 1 to 12 carbon atoms, a dialkylamino group having 1 to 12 carbon atoms, an alkylcarbonylamino group having 2 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, and a heteroaryl group having 4 to 30 carbon atoms. .

  These substituents may have further substituents. Examples of further substituents include those described above. Examples of the substituent having a further substituent are preferably a halogenoalkyl group having 1 to 12 carbon atoms and a halogenoaryl group having 6 to 20 carbon atoms.

From the viewpoint of ease of synthesis, the substituents R ¹ , R ⁴ , R ⁶ , R ⁹ , R ¹⁰ , R ¹³ , R ¹⁴ , and R ¹⁷ may be hydrogen atoms.

In the formula (A1), the substituents R ^{1 to} R ¹⁷ may be bonded to each other to form a ring. For example, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁴ and R ⁵ , R ⁵ and R ⁶ , R ⁷ and R ⁸ , R ⁸ and R ⁹ , R ⁹ and R ¹⁰ , At least one of R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹⁴ and R ¹⁵ , R ¹⁵ and R ¹⁶ , R ¹⁶ and R ¹⁷ , and R ¹⁷ and R ¹ is They may be bonded together to form a ring structure. Any cyclic structure formed by bonding substituents to each other may be used, for example, an aliphatic ring or an aromatic ring.

In particular, one of the substituents R ¹ and R ² , R ² and R ³ , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹⁴ and R ¹⁵ , and R ¹⁵ and R ¹⁶ A compound in which two or more are bonded to each other to form a cyclic structure is preferable from the viewpoint of production cost because synthesis is easy.

An example of the cyclic structure includes a case where the substituents R ² and R ³ are —CH═CH—CH═CH—. That ring formed with the substituent R ² and R ³ may form an aromatic ring engages ring condensed to the substituents R ² and R ³ are attached. Here, the ring formed by the substituents R ² and R ³ may have a further substituent. Examples of further substituents include those described above. An example of a further substituent is preferably a halogen atom. Further, a further ring structure may be condensed with respect to the ring formed by the substituents R ² and R ³ . The same applies to the substituents R ¹ and R ² , R ⁷ and R ⁸ , R ¹¹ and R ¹² , R ¹² and R ¹³ , R ¹⁴ and R ¹⁵ , and R ¹⁵ and R ¹⁶ .

  In order for the dibenzopyromethene boron chelate compound according to this embodiment to sufficiently exhibit the effect of increasing the conversion efficiency, the dibenzopyromethene boron chelate compound according to this embodiment is a p-type semiconductor compound or an n-type semiconductor compound in the active layer. It is advantageous to be in the vicinity of. From this viewpoint, as described later, it is preferable that the solubility of the dibenzopyromethene boron chelate compound according to the present embodiment is higher.

On the other hand, it is also preferable that the dibenzopyromethene boron chelate compound according to the present embodiment has a stronger interaction with the p-type semiconductor compound or the n-type semiconductor compound contained in the active layer. From this viewpoint, another preferable example of the substituents R ^{1 to} R ¹⁷ includes a case where the substituents R ^{1 to} R ¹⁷ have a structure similar to the p-type semiconductor compound or the n-type semiconductor compound included in the active layer. That is, the dibenzopyromethene boron chelate compound according to the present embodiment preferably includes a part of the structure of the p-type semiconductor compound or the n-type semiconductor compound included in the active layer in a part of its structure. It is also preferable that the dibenzopyromethene boron chelate compound according to the present embodiment includes a part of the structure similar to the structure of the p-type semiconductor compound or the n-type semiconductor compound included in the active layer. When the dibenzopyromethene boron chelate compound according to this embodiment has a structure that matches or is similar to the p-type semiconductor compound or the n-type semiconductor compound contained in the active layer, the dibenzopyromethene boron chelate compound according to this embodiment; It is expected that the interaction with the p-type semiconductor compound or the n-type semiconductor compound becomes strong. For this reason, the dibenzopyromethene boron chelate compound according to this embodiment is likely to be present at the interface between the p-type semiconductor and the n-type semiconductor, and the dibenzopyromethene boron chelate compound according to this embodiment acts to increase the conversion efficiency. It is thought that it will be possible to fully demonstrate.

  Specific examples include a case where the dibenzopyromethene boron chelate compound and the p-type semiconductor compound or the n-type semiconductor compound have a heterocyclic ring such as a thiophene ring. It is also preferable that an aliphatic chain having 4 or more carbon atoms is bonded to the heterocyclic ring.

  As another specific example, when the p-type semiconductor compound is a polymer organic semiconductor compound, the dibenzopyromethene boron chelate compound according to the present embodiment preferably has a monomer of the p-type semiconductor compound as a substituent. Here, the substituents of the dibenzopyromethene boron chelate compound according to the present embodiment and the monomer do not need to be completely identical in structure. For example, the carbon skeletons may be identical or similar. In the present specification, the carbon skeleton is similar to one or more carbon atoms, preferably 6 or less carbon atoms, preferably 3 or less carbon atoms, particularly preferably 1 or less carbon atoms are added or removed. This means that the other carbon skeleton can be obtained by changing the kind of bond. Here, the type of bond means a single bond, a double bond, and a triple bond.

  As another specific example, when the p-type semiconductor compound is a polymer organic semiconductor compound, both the dibenzopyromethene boron chelate compound according to the present embodiment and the monomer of the p-type semiconductor compound have a hydrophobic group. It is preferable to have. In this case, it is expected that a hydrophobic interaction acts between the p-type semiconductor compound and the dibenzopyromethene boron chelate compound according to this embodiment. The hydrophobic group is preferably an aliphatic carbon chain having 4 to 20 carbon atoms. The aliphatic carbon chain having 4 to 20 carbon atoms usually has no substituent, but may have a substituent. As an example of the substituent which may be contained, a halogen atom such as a fluorine atom is preferable.

  When the p-type semiconductor compound is a low-molecular organic semiconductor compound, the dibenzopyromethene boron chelate compound according to this embodiment may have a p-type semiconductor compound as a substituent. As in the case where the p-type semiconductor compound is a polymer organic semiconductor compound, the substituents of the dibenzopyromethene boron chelate compound according to this embodiment and the p-type semiconductor compound need to be completely identical in structure. For example, the carbon skeletons may be identical or similar.

  As a further specific example, when a p-type semiconductor compound is obtained by a conversion reaction from a precursor described later, both the precursor and the dibenzopyromethene boron chelate compound according to this embodiment may have a hydrophobic group. preferable. The above-mentioned thing can be used as a hydrophobic group. As will be described later, the precursor often has a crosslinked structure, and this crosslinked structure often contains an aliphatic chain having 4 or more carbon atoms. That is, as described later, when a film is formed using a coating solution containing a precursor, an n-type semiconductor compound, and the dibenzopyromethene boron chelate compound according to this embodiment, the precursor and the dibenzo according to this embodiment are formed in the film. It is expected that the pyromethene boron chelate compound is located in the vicinity. Since the precursor is converted into the p-type semiconductor compound by the conversion reaction, it is considered that the dibenzopyromethene boron chelate compound located in the vicinity of the p-type semiconductor compound can sufficiently exhibit the effect of increasing the conversion efficiency.

  Furthermore, the dibenzopyromethene boron chelate compound according to this embodiment may have an n-type semiconductor compound as a substituent. Moreover, it is also preferable that both the dibenzopyromethene boron chelate compound according to the present embodiment and the n-type semiconductor compound have a hydrophobic group. The above-mentioned thing can be used as a hydrophobic group. In addition, since the fullerene structure is considered to be a hydrophobic structure, it is also preferable that the n-type semiconductor compound is a fullerene.

  Specific examples of the dibenzopyromethene boron chelate compound represented by formula (A1) include compounds 1-1 to 1-68 having the following substituents.

  Among these, dibenzopyromethene boron chelate compounds 1-47 to 1-68 are preferable.

<1.1 Characteristics of dibenzopyromethene boron chelate compound according to this embodiment>
The dibenzopyromethene boron chelate compound according to the present embodiment has an absorption maximum wavelength of 650 nm or more in ultraviolet-visible spectroscopic analysis in tetrahydrofuran from the viewpoint that the conversion efficiency can be improved when absorbing long-wavelength light better. Preferably, it is 700 nm or more, more preferably 720 nm or more. Further, the molar extinction coefficient at the absorption maximum wavelength is preferably 7 × 10 ⁴ or more, and more preferably 1 × 10 ⁵ or more.

  As described above, the dibenzopyromethene boron chelate compound according to this embodiment is used in the active layer of the organic thin film solar cell element. The dibenzopyromethene boron chelate compound according to the present embodiment preferably absorbs light having a wavelength different from that of the p-type semiconductor compound and the n-type semiconductor compound contained in the active layer, from the viewpoint of improving the photoelectric conversion efficiency. In particular, since it is preferable in terms of improving photoelectric conversion efficiency that light of a long wavelength can be absorbed, the dibenzopyromethene boron chelate compound according to the present embodiment has a light absorption coefficient of, for example, 700 nm and a p-type semiconductor compound and n It is preferably larger than the type semiconductor compound. From the same viewpoint, the absorption maximum wavelength of the dibenzopyromethene boron chelate compound according to this embodiment is preferably longer than the absorption maximum wavelength of the p-type semiconductor compound (or n-type semiconductor compound).

  Further, from the same viewpoint, the absorption maximum wavelength of the dibenzopyromethene boron chelate compound according to the present embodiment is more preferably longer than the absorption edge of the absorption spectrum of the p-type semiconductor compound (or n-type semiconductor compound). . The absorption edge of the absorption spectrum of a general p-type semiconductor used in an organic thin film solar cell is in the vicinity of 600 nm to 750 nm. Therefore, the absorption maximum wavelength of the dibenzopyromethene boron chelate compound according to this embodiment is preferably 650 nm or more, more preferably 700 nm or more, and particularly preferably 750 nm or more.

  Furthermore, the organic thin-film solar cell 100 according to the present embodiment can exhibit higher conversion efficiency for light having a wavelength that can be normally absorbed by the p-type semiconductor compound. The reason for this is that when the dibenzopyromethene boron chelate compound according to this embodiment is present between the p-type semiconductor and the n-type semiconductor, electrons and holes generated by excitation are transferred to the p-type semiconductor and the n-type semiconductor. It can be considered that it can be transported smoothly.

<1.2 Synthesis Method of Dibenzopyromethene Boron Chelate Compound According to this Embodiment>
The dibenzopyromethene boron chelate compound represented by the general formula (A1) according to this embodiment is not particularly limited, but can be synthesized according to, for example, JP-A 2010-184880.

[2. Organic thin-film solar cell element according to this embodiment]
The organic thin-film solar cell element according to this embodiment includes at least an active layer between a pair of electrodes. Below, the organic thin-film solar cell element which concerns on this embodiment is demonstrated. In the present embodiment, the active layer includes a dibenzopyromethene boron chelate compound, a p-type semiconductor compound, and an n-type semiconductor compound according to the present embodiment.

  FIG. 1 shows an organic thin film solar cell element 100 according to this embodiment. FIG. 1 shows an organic thin film solar cell element used in a general organic thin film solar cell, but the organic thin film solar cell element according to this embodiment is not limited to the structure of FIG. The organic thin film solar cell element 100 in FIG. 1 includes electrodes 120 and 160 and an active layer 140. Furthermore, as shown in FIG. 1, the organic thin-film solar cell element according to this embodiment may include at least one of a substrate 110 and buffer layers 130 and 150. In FIG. 1, the electrode 120 is an electrode that collects holes (hereinafter also referred to as an anode), and the electrode 160 is an electrode that collects electrons (hereinafter also referred to as a cathode). is there. Of course, in other embodiments, the anode 120 and the cathode 160 may be reversed, and in this case, the buffer layer 130 and the buffer layer 150 may be reversed. Hereinafter, each of these parts will be described.

<2.1 Active layer (140)>
As described above, the active layer 140 of the organic thin-film solar cell element 100 according to this embodiment includes the dibenzopyromethene boron chelate compound, the p-type semiconductor compound, and the n-type semiconductor compound according to this embodiment. When the organic thin-film solar cell element 100 receives light, the light is absorbed by the active layer 140, electricity is generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound, and the generated electricity is extracted from the electrodes 120 and 160. Hereinafter, the p-type semiconductor compound and the n-type semiconductor compound will be described in detail. In the present embodiment, the active layer 140 may include a plurality of types of p-type semiconductor compounds. Similarly, in the present embodiment, the active layer 140 may include a plurality of types of n-type semiconductor compounds.

  The layer structure of the active layer 140 includes a thin film stacked type in which a p-type semiconductor compound and an n-type semiconductor compound are stacked, a bulk heterojunction type in which a p-type semiconductor compound and an n-type semiconductor compound are mixed, a p-type semiconductor compound layer, and an n-type semiconductor. Examples include a structure in which a layer (i layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed exists between the compound layer and the like. In the case of the thin film stack type, the dibenzopyromethene boron chelate compound according to this embodiment can be included in at least one of the p-type semiconductor compound layer and the n-type semiconductor compound layer. Moreover, the dibenzopyromethene boron chelate compound which concerns on this embodiment may be contained in the interface of a p-type semiconductor compound layer and an n-type semiconductor compound layer.

  In the case of the bulk heterojunction type, the dibenzopyromethene boron chelate compound according to this embodiment may be contained in the mixed layer of the p-type semiconductor compound and the n-type semiconductor compound. In the case of a structure having a layer (i layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed in a thin film laminated type intermediate layer, if the i-layer contains the dibenzopyromethene boron chelate compound according to this embodiment Good.

  From the viewpoint of enlarging a region that generates a photocurrent in the active layer 140, when the p-type semiconductor compound is a polymer organic semiconductor compound described later, the active layer 140 particularly preferably has a bulk heterojunction structure. In the case where the p-type semiconductor compound is a low-molecular organic semiconductor compound described later, a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed between the p-type semiconductor compound layer and the n-type semiconductor compound layer (i It is particularly preferable that the active layer 140 has a structure in which a layer is present.

  The thickness of the active layer 140 is not particularly limited, but is usually 10 nm or more, preferably 50 nm or more, and is usually 1000 nm or less, preferably 500 nm or less, more preferably 200 nm or less. It is preferable for the thickness of the active layer to be 10 nm or more because uniformity is maintained and short-circuiting is less likely to occur. Further, it is preferable that the thickness of the active layer is 1000 nm or less because the internal resistance is reduced and the distance between the electrodes is not increased, and the charge diffusion is improved.

  The amount of the dibenzopyromethene boron chelate compound according to the present embodiment contained in the active layer 140 is 0.1% by weight or more based on the p-type semiconductor material from the viewpoint of increasing the conversion efficiency increase effect. It is preferably 1% by weight or more. Similarly, it is preferably 0.1% by weight or more, more preferably 1% by weight or more with respect to the n-type semiconductor material. Further, from the viewpoint of not preventing the generated electrons and holes from being transported, the amount of the dibenzopyromethene boron chelate compound according to the present embodiment is preferably 50% by weight or less based on the p-type semiconductor material, and 20% by weight. More preferably, it is% or less. Similarly, it is preferably 50% by weight or less, more preferably 20% by weight or less, based on the n-type semiconductor material.

<2.1.1 p-type semiconductor compound>
There is no limitation in particular in the p-type semiconductor compound which the active layer 140 of the organic thin-film solar cell element concerning this embodiment contains. As examples of the p-type semiconductor compound, a low molecular organic semiconductor compound and a high molecular organic semiconductor compound will be described below.

(Low molecular organic semiconductor compounds)
The molecular weight of the low molecular weight organic semiconductor compound according to this embodiment is not particularly limited both at the upper limit and the lower limit, but is usually 5000 or less, preferably 2000 or less, and is usually 100 or more, preferably 200 or more.

  In addition, the low molecular organic semiconductor compound according to this embodiment preferably has crystallinity. Since the p-type semiconductor compound having crystallinity has a strong intermolecular interaction, holes (holes) generated at the interface of the mixture layer of the p-type semiconductor compound and the n-type semiconductor compound in the active layer 140 can be efficiently used as the electrode (anode) 160. This is because it is expected that it can be transported to.

In the present specification, the fact that a compound has crystallinity means that the compound takes a three-dimensional periodic array structure with uniform orientation. Examples of the method for measuring crystallinity include X-ray diffraction (XRD) or field effect mobility measurement. From the viewpoint of good crystallinity, the low molecular organic semiconductor compound according to the present embodiment has a hole mobility of 1.0 × 10 ⁽⁻⁵⁾ cm ² / (Vs) or more in the field effect mobility measurement. It is preferably 1.0 × 10 ⁽⁻⁴⁾ cm ² / (Vs) or more. On the other hand, the low molecular organic semiconductor compound according to the present embodiment preferably has a hole mobility of 1.0 × 10 ⁴ cm ² / (Vs) or less, and 1.0 × 10 ³ cm ² / (Vs). Or less, more preferably 1.0 × 10 ² cm ² / (Vs) or less.

  There is no restriction | limiting in particular in the low molecular organic-semiconductor compound which concerns on this embodiment. Examples of the low molecular weight organic semiconductor compound according to the present embodiment include condensed aromatic hydrocarbons such as naphthacene, pentacene or pyrene; oligothiophenes containing 4 or more thiophene rings such as α-sexithiophene; thiophene ring, benzene A ring, a fluorene ring, a naphthalene ring, an anthracene ring, a thiazole ring, a thiadiazole ring, and a benzothiazole ring, and a total of four or more linked; phthalocyanine compounds and metal complexes thereof, tetrabenzoporphyrins, etc. And macrocyclic compounds such as porphyrin compounds and metal complexes thereof. Preferable examples of the low molecular weight organic semiconductor compound according to this embodiment are a phthalocyanine compound and a metal complex thereof, and a porphyrin compound and a metal complex thereof.

  As the porphyrin compound and its metal complex (Q in the figure is CH) used as the p-type semiconductor compound, and the phthalocyanine compound and its metal complex (Q in the figure is N), for example, compounds having the following structures are used: Can be mentioned.

In the above formula, M represents a metal or two hydrogen atoms. Examples of the metal M include divalent metals such as Cu, Zn, Pb, Mg, Co, or Ni. Other examples of the metal M include a trivalent or higher metal having an axial ligand such as TiO, VO, SnCl ₂ , AlCl, InCl, or Si.

In the above formula, Y ^{1 to} Y ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 24 carbon atoms. The alkyl group having 1 to 24 carbon atoms is a saturated or unsaturated chain hydrocarbon group having 1 to 24 carbon atoms, or a saturated or unsaturated cyclic hydrocarbon having 3 to 24 carbon atoms. Among these, a saturated or unsaturated chain hydrocarbon group having 1 to 12 carbon atoms or a saturated or unsaturated cyclic hydrocarbon group having 3 to 12 carbon atoms is preferable.

  Among the phthalocyanine compounds and metal complexes thereof, 29H, 31H-phthalocyanine, copper phthalocyanine complex, zinc phthalocyanine complex, titanium phthalocyanine oxide complex, magnesium phthalocyanine complex, lead phthalocyanine complex, or copper 4,4 ′, 4 ″, 4 ′ ″-tetraaza-29H, 31H-phthalocyanine complex. More preferably, it is 29H, 31H-phthalocyanine or a copper phthalocyanine complex.

  Among the porphyrin compounds and metal complexes thereof, 5,10,15,20-tetraphenyl-21H, 23H-porphine, 5,10,15,20-tetraphenyl-21H, 23H-porphine cobalt (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine copper (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20- Tetraphenyl-21H, 23H-porphine nickel (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine vanadium (IV) oxide, 5,10,15,20-tetra (4-pyridyl)- 21H, 23H-porphine, 29H, 31H-tetrabenzo [b, g, l, q] porphine, 2 H, 31H-tetrabenzo [b, g, l, q] porphine cobalt (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine copper (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine zinc (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine nickel (II) or 29H, 31H-tetrabenzo [b, g, l, q] porphine vanadium (IV) oxide And preferably 5,10,15,20-tetraphenyl-21H, 23H-porphine or 29H, 31H-tetrabenzo [b, g, l, q] porphine.

  The active layer 140 according to this embodiment may include one type of p-type semiconductor compound or may include a plurality of types of p-type semiconductor compounds.

(Low molecular organic semiconductor compound precursor)
The low molecular organic semiconductor compound according to this embodiment is preferably obtained by a conversion reaction from the precursor according to this embodiment. The precursor is a substance that changes its chemical structure and is converted into a low molecular organic semiconductor compound by applying an external stimulus such as heating or light irradiation. Since a low molecular organic semiconductor compound often has low solubility in a solvent, it is often difficult to form a film of the low molecular organic semiconductor compound by a coating method. On the other hand, a film of a low molecular organic semiconductor compound can be produced by forming a film of a precursor by a coating method and converting the precursor into a low molecular organic semiconductor compound. Here, a precursor of a p-type semiconductor compound will be described, but an n-type semiconductor compound can be similarly obtained by a conversion reaction from the precursor.

  The precursor according to the present embodiment is preferably excellent in film formability. In particular, in order to be able to apply the coating method, it is preferable that the precursor itself is liquid or the precursor is highly soluble in any solvent. From the viewpoint of facilitating film formation by a coating method, the solubility of the precursor according to this embodiment in a solvent is usually 0.1% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more. It is. On the other hand, the upper limit is not particularly limited, but is usually 50% by weight or less, preferably 40% by weight or less.

  The type of solvent is not particularly limited as long as the precursor can be uniformly dissolved or dispersed. Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane and decane; aromatic hydrocarbons such as toluene, xylene, cyclohexylbenzene, chlorobenzene and orthodichlorobenzene; methanol, ethanol or propanol Lower alcohols such as acetone; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; esters such as ethyl acetate, butyl acetate or methyl lactate; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene; Examples include ethers such as ethyl ether, tetrahydrofuran and dioxane; amides such as dimethylformamide and dimethylacetamide.

  Among the solvents, aromatic hydrocarbons such as toluene, xylene, cyclohexylbenzene, chlorobenzene, or orthodichlorobenzene; ketones such as acetone, methyl ethyl ketone, cyclopentanone, or cyclohexanone; chloroform, methylene chloride, dichloroethane, trichloroethane, or trichloroethylene Halogen ethers such as ethyl ether, ethers such as tetrahydrofuran, dioxane and the like. More preferably, non-halogen aromatic hydrocarbons such as toluene, xylene or cyclohexylbenzene; non-halogen ketones such as cyclopentanone or cyclohexanone; non-halogen aliphatic ethers such as tetrahydrofuran or 1,4-dioxane is there. Particularly preferred are non-halogen aromatic hydrocarbons such as toluene, xylene or cyclohexylbenzene. In addition, a solvent may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, it is preferable that the precursor according to the present embodiment can be easily converted to the low molecular organic semiconductor compound according to the present embodiment. It is arbitrary what kind of external stimulus is given to the precursor in the step of converting the precursor to the low-molecular organic semiconductor compound. Examples of external stimuli include heat treatment and light treatment, and heat treatment is preferred. For example, it is preferable that the precursor has a structure that can be eliminated by a reverse Diels-Alder reaction at a part of its skeleton. From the viewpoint of improving the solubility in a solvent, the detachable structure is more preferably a solvophilic group in a predetermined solvent.

  Moreover, it is preferable that the precursor which concerns on this embodiment is converted into the low molecular organic-semiconductor compound which concerns on this embodiment with a high yield. The yield is arbitrary, but is usually 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more from the viewpoint of not impairing the performance of the organic thin film solar cell element.

  As the precursor according to the present embodiment, for example, compounds described in JP-A-2007-324587 can be used. Preferable examples of the precursor according to this embodiment include a compound represented by the following chemical formula (B1).

In the formula (B1), at least one of X ¹ and X ² represents a group forming a π-conjugated divalent aromatic ring. Z ¹ -Z ² is a group removable by heat or light. In Formula (B1), when Z ¹ -Z ² is eliminated, a π-conjugated compound that is a low-molecular organic semiconductor compound according to this embodiment is obtained. Further, X ¹ and X ² which are not a group that forms a π-conjugated divalent aromatic ring represent a substituted or unsubstituted ethenylene group.

As shown in the following formula, the compound represented by the formula (B1) is converted into a π-conjugated compound (B2) having high planarity by elimination of Z ¹ -Z ² by heat or light. This π-conjugated compound (B2) is the low molecular organic semiconductor compound according to this embodiment.

  Examples of the compound represented by the formula (B1) include the following. T-Bu represents a t-butyl group. M represents a divalent metal atom or an atomic group in which a trivalent or higher metal and another atom are bonded.

  Specific examples of the conversion from the precursor according to this embodiment to the low-molecular organic semiconductor compound according to this embodiment include the following.

  The precursor represented by the formula (B1) may have a structure in which a positional isomer exists. In this case, a mixture of a plurality of regioisomers may be used to make the active layer. A mixture of multiple positional isomers is often more soluble in a solvent than a single isomer. That is, a mixture of a plurality of positional isomers can be easily formed by coating. It is considered that the mixture of positional isomers is more difficult to arrange regularly, so that the solubility is improved. When a mixture of a plurality of isomers is used for preparing an active layer, the solubility of the mixture in a solvent is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more. Although there is no restriction | limiting in an upper limit, Usually, it is 50 weight% or less, More preferably, it is 40 weight% or less.

(High molecular organic semiconductor compounds)
There is no limitation in particular as a high molecular organic-semiconductor compound which concerns on this embodiment. Examples of the polymer organic semiconductor compound include conjugated polymer semiconductors such as polythiophene, polyfluorene, polyphenylene vinylene, polythienylene vinylene, polyacetylene, and polyaniline; polymer semiconductors such as oligothiophene having a substituent such as an alkyl group, and the like. Can be mentioned. Moreover, the semiconductor polymer which copolymerized 2 or more types of monomer units is also mentioned. The conjugated polymers, ^{e.g., Handbook of Conducting Polymers, 3 rd} Ed. (2 volumes in total), 2007. Materials Science and Engineering, 2001, 32, 1-40. Pure Appl. Chem. 2002, 74, 2031-3044. Handbook of THIOPHENE-BASED MATERIALS (2 volumes in total), 2009. Polymers and derivatives thereof described in known literature such as the above can be used. Further, as the conjugated polymer, a polymer that can be synthesized by a combination of monomers described in these known documents may be used. Polymer or monomer substituents can be selected to control solubility, crystallinity, film-forming properties, HOMO level, LUMO level, and the like.

  From the viewpoint that a film can be formed by a coating method, the polymer organic semiconductor compound according to this embodiment is preferably soluble in an organic solvent. The active layer 140 may contain one type of polymer organic semiconductor compound according to this embodiment, or may contain a mixture of two or more types of polymer organic semiconductor compounds according to this embodiment. Good. The polymer organic semiconductor compound according to this embodiment may have some self-organized structure in a film-formed state, or may be in an amorphous state.

  Specific examples of the polymer organic semiconductor compound include the following, but are not limited thereto.

  Among the examples given above, it is desirable to use at least one of a porphyrin compound and a polymer organic semiconductor compound as the p-type semiconductor compound according to this embodiment.

<2.1.2 n-type semiconductor compound>
There is no particular limitation on the n-type semiconductor compound according to this embodiment. Examples of n-type semiconductor compounds according to this embodiment include fullerene compounds, quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, condensed ring tetracarboxylic acid diimides such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide. Perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazole derivatives, triazole derivatives , Aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives, bipyridy Derivatives, borane derivatives, anthracene, pyrene, total fluoride condensed polycyclic aromatic hydrocarbons such as naphthacene or pentacene, and single-walled carbon nanotubes, and the like. The active layer 140 according to the present embodiment may include one type of n-type semiconductor compound according to the present embodiment, or may include a mixture of two or more types of n-type semiconductor compounds according to the present embodiment. May be.

  A preferred example of the n-type semiconductor compound according to this embodiment is a fullerene compound. The fullerene compound according to this embodiment preferably has a partial structure represented by the formula (n1), (n2), (n3) or (n4).

In the above formula, FLN represents fullerene, which is a carbon cluster having a closed shell structure. The carbon number of fullerene is not particularly limited as long as it is usually an even number of 60 to 130. Examples of fullerenes include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ and higher carbon clusters having more carbon than these. . Among these, _C60 or _C70 is preferable. Some carbon-carbon bonds on the fullerene ring may be broken. Further, some carbon atoms constituting the fullerene ring may be replaced with other atoms. Furthermore, a metal atom, a non-metal atom, or an atomic group composed of these may be included in the fullerene (in the fullerene cage).

In the formulas (n1) to (n4), a, b, c, and d are integers. The sum of a, b, c and d is usually 1 or more. The total of a, b, c and d is usually 5 or less, preferably 3 or less. The partial structures represented by (n1) to (n4) are added to the same 5-membered ring or 6-membered ring in the fullerene skeleton. That is, when the fullerene has a partial structure of the formula (n1), -R ¹⁸ and-(CH ₂ ) _L with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. And are added respectively. When the fullerene has a partial structure of the formula (n2), -C (R ²² ) (R ²³ ) -N with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton (R ²⁴ ) —C (R ²⁵ ) (R ²⁶ ) — is added to form a 5-membered ring. If the fullerene having a partial structure of formula (n3), for the same 5-membered ring or 6-membered two adjacent carbon atoms on the ring in the fullerene ^{skeleton, -C (R 27) (R} 28) -Ar ^1- C (R ²⁹ ) (R ³⁰ ) — is added to form a 6-membered ring. When the fullerene has a partial structure of the formula (n4), -C (R ³¹ ) (R ³² )-is the same for two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. In addition, a three-membered ring is formed. Here, L is an integer of 1-8. L is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.

R ¹⁸ in formula (n1) has an optionally substituted alkyl group having 1 to 14 carbon atoms, an optionally substituted alkoxy group having 1 to 14 carbon atoms, or a substituent. An aromatic group that may be used. As an alkyl group, a C1-C10 alkyl group is preferable, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, or an isobutyl group is more preferable, and a methyl group or an ethyl group is still more preferable. As an alkoxy group, a C1-C10 alkoxy group is preferable, a C1-C6 alkoxy group is more preferable, and a methoxy group or an ethoxy group is especially preferable. As an aromatic group, a C6-C20 aromatic hydrocarbon group or a C2-C20 aromatic heterocyclic group is preferable, a phenyl group, a thienyl group, a furyl group, or a pyridyl group is more preferable, a phenyl group or More preferred is a thienyl group. The substituent that the alkyl group, alkoxy group and aromatic group may have may be, for example, a halogen atom or a silyl group. As the halogen atom, a fluorine atom is preferable. The silyl group is preferably a diarylalkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group or a trialkylsilyl group, more preferably a dialkylarylsilyl group, and even more preferably a dimethylarylsilyl group.

R ^{19 to} R ²¹ in formula (n1) are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 14 carbon atoms, or an optionally substituted aromatic group. Represents. As an alkyl group, a C1-C10 alkyl group is preferable and a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, or n-hexyl group is preferable. The substituent that the alkyl group may have is preferably a halogen atom. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group. The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group or a pyridyl group, and a phenyl group or a thienyl group. Groups are more preferred. Examples of the substituent that the aromatic group may have include a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, or 3 carbon atoms. Is preferably a fluorine atom or an alkoxy group having 1 to 14 carbon atoms, more preferably a methoxy group, an n-butoxy group or a 2-ethylhexyloxy group. When the aromatic group has a substituent, the number is not limited, but is preferably 1 or more and 3 or less, and more preferably 1. When the aromatic group has a plurality of substituents, the types of the substituents may be different, but are preferably the same.

R ^{22 to} R ²⁶ in formula (n2) are each independently a hydrogen atom, an optionally substituted alkyl group having 1 to 14 carbon atoms, or an optionally substituted aromatic group. It is. The alkyl group is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group or octyl group, and more preferably a methyl group. As an aromatic group, a C6-C20 aromatic hydrocarbon group or a C2-C20 aromatic heterocyclic group is preferable, a phenyl group or a pyridyl group is more preferable, and a phenyl group is further more preferable.

  The substituent that the alkyl group may have is preferably a halogen atom. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group. The substituent that the aromatic group may have is not particularly limited, but is preferably a fluorine atom, an alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms. The alkyl group may be substituted with a fluorine atom. More preferably, it is a C1-C14 alkoxy group, More preferably, it is a methoxy group. When it has a substituent, there is no limitation in the number, However, Preferably it is 1-3, More preferably, it is 1. The types of substituents may be different, but are preferably the same.

Ar ¹ in formula (n3) is an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, preferably a phenyl group or naphthyl. Group, biphenyl group, thienyl group, furyl group, pyridyl group, pyrimidyl group, quinolyl group or quinoxalyl group, more preferably phenyl group, thienyl group or furyl group. There is no limitation on the substituent that the aromatic hydrocarbon group and the aromatic heterocyclic group may have, but it is substituted with a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, a silyl group, a boryl group, or an alkyl group. Amino group, alkyl group having 1 to 14 carbon atoms, alkoxy group having 1 to 14 carbon atoms, alkylcarbonyl group having 1 to 14 carbon atoms, alkylthio group having 1 to 14 carbon atoms, alkenyl group having 1 to 14 carbon atoms , An alkynyl group having 1 to 14 carbon atoms, an ester group, an arylcarbonyl group, an arylthio group, an aryloxy group, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or a heterocyclic group having 2 to 20 carbon atoms. An atom, an alkyl group having 1 to 14 carbon atoms, an alkoxy group having 1 to 14 carbon atoms, an ester group, an alkylcarbonyl group having 1 to 14 carbon atoms, or an arylcarbonyl group is more preferable. . The alkyl group having 1 to 14 carbon atoms may be substituted with fluorine. As the alkyl group having 1 to 14 carbon atoms, a methyl group, an ethyl group or a propyl group is preferable. As a C1-C14 alkoxy group, a methoxy group, an ethoxy group, or a propoxyl group is preferable. As the alkylcarbonyl group having 1 to 14 carbon atoms, an acetyl group is preferable. As the ester group, a methyl ester group or an n-butyl ester group is preferable. As the arylcarbonyl group, a benzoyl group is preferable. When it has a substituent, although there is no limitation in the number, 1-4 are preferable and 1-3 are more preferable. When there are a plurality of substituents, the types may be different, but are preferably the same.

R ^{27 to} R ³⁰ in formula (n3) are each independently a hydrogen atom, an alkyl group that may have a substituent, an amino group that may have a substituent, or an alkoxy that may have a substituent. Represents an alkylthio group which may have a group or a substituent. R ²⁷ or R ²⁸ may form a ring with R ²⁹ or R ³⁰ . In the case of forming a ring, the formula (n3) can be represented by the formula (n5).

Formula (n5) represents a bicyclo structure in which an aromatic group is condensed. F in formula (n5) has the same value as c in formula (n3). In formula (n5), X represents an oxygen atom, a sulfur atom, an amino group that may be substituted, an alkylene group that may be substituted, or an arylene group that may be substituted. As an alkylene group, a C1-C2 thing is preferable. As the arylene group, those having 5 to 12 carbon atoms are preferable, and for example, a phenylene group is preferable. The amino group may be substituted with an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group. The alkylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an aromatic group having 2 to 20 carbon atoms. It may be substituted with a heterocyclic group. The arylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an aromatic group having 2 to 20 carbon atoms. It may be substituted with a heterocyclic group. In the formula (n5), the bridgehead carbon atom to which X is bonded may have a substituent. As an example of this substituent, the same thing as R < ²⁷ > -R < ³⁰ > is mentioned.

R ^{31 to} R ³² in formula (n4) may each independently have a hydrogen atom, an alkoxycarbonyl group, an optionally substituted alkyl group having 1 to 14 carbon atoms, or a substituent. Represents a good aromatic group. The alkoxy group in the alkoxycarbonyl group is preferably an alkoxy group having 1 to 12 carbon atoms or a fluorinated alkoxy group having 1 to 12 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, a methoxy group, an ethoxy group, n -Propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group are more preferable, methoxy group, An ethoxy group, isopropoxy group, n-butoxy group, isobutoxy group or n-hexoxy group is particularly preferred. As the alkyl group, a linear alkyl group having 1 to 8 carbon atoms is preferable, and an n-propyl group is more preferable. The substituent that the alkyl group may have is not particularly limited, but is preferably an alkoxycarbonyl group. The alkoxy group of the alkoxycarbonyl group is preferably an alkoxy group having 1 to 14 carbon atoms or a fluorinated alkoxy group, more preferably an alkoxy group having 1 to 14 carbon atoms, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group. Group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group, more preferably methoxy group or n-butoxy group. preferable. As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, and a phenyl group, a biphenyl group, a thienyl group, a furyl group, or a pyridyl group is preferable. A group or a thienyl group is more preferred. The substituent that the aromatic group may have is preferably an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms, 14 alkoxy groups are more preferable, and a methoxy group or 2-ethylhexyloxy group is particularly preferable. When it has a substituent, the number is not limited, but it is preferably 1 or more and 3 or less, more preferably 1. The types of substituents may be different or the same, preferably the same.

As the structure of the formula (n4), R ³¹ and R ³² are both alkoxycarbonyl groups, R ³¹ and R ³² are both aromatic groups, or R ³¹ is an aromatic group and R ³² is 3 A-(alkoxycarbonyl) propyl group is preferred.

  From the viewpoint of producing the active layer 140 by a coating method, it is preferable that the fullerene compound can be applied in a liquid state or is highly soluble in some solvent. For example, the fullerene compound has a solubility in toluene at 25 ° C. of preferably 0.1% by weight or more, more preferably 0.4% by weight or more, and preferably 0.7% by weight or more. More preferred. It is preferable that the solubility of the fullerene compound is 0.1% by weight or more because the dispersion stability of the fullerene compound is increased, and aggregation, sedimentation, separation, and the like in the fullerene compound solution are less likely to occur.

<2.1.3 Formation Method of Active Layer>
There is no restriction | limiting in particular in the formation method of the active layer 140. FIG. However, from the viewpoint of ease of formation, the active layer 140 is preferably formed by a wet coating method such as a spin coating method, an ink jet method, a doctor blade method, or a drop casting method.

  When the above-described thin film stacked active layer is manufactured, for example, a layer containing a dibenzopyromethene boron chelate compound and a p-type semiconductor compound according to this embodiment and a layer containing an n-type semiconductor compound may be stacked. Further, a layer containing a dibenzopyromethene boron chelate compound and an n-type semiconductor compound according to this embodiment and a layer containing a p-type semiconductor compound may be stacked.

  When producing the above-described bulk heterojunction type active layer, for example, a coating solution containing a dibenzopyromethene boron chelate compound, a p-type semiconductor compound, and an n-type semiconductor compound according to this embodiment is prepared, and this coating solution is applied. Thus, an active layer can be produced. However, a co-evaporation method can also be used.

  When an active layer having a structure having the above-described i layer is manufactured, a p-type semiconductor compound layer, an i layer, and an n-type semiconductor compound layer may be stacked in this order (or in the reverse order). In this case, the p-type semiconductor compound layer and the n-type semiconductor compound layer can be produced by any method including a vapor deposition method and a coating method. The method for forming the i layer is also arbitrary. For example, a coating solution containing a dibenzopyromethene boron chelate compound, a p-type semiconductor compound, and an n-type semiconductor compound according to the present embodiment is prepared, and this coating solution is applied. It is preferable to prepare by. However, a co-evaporation method can also be used.

  Furthermore, when a p-type semiconductor compound is produced by converting a precursor as described above, a layer including the precursor may be formed, and then the precursor may be converted into a p-type semiconductor compound. As a specific example, a coating solution containing a dibenzopyromethene boron chelate compound, a precursor, and an n-type semiconductor compound according to this embodiment is prepared. An active layer can be produced by converting the precursor into an n-type semiconductor compound after applying this coating solution.

  A coating solution containing a dibenzopyromethene boron chelate compound, a p-type semiconductor compound, and an n-type semiconductor compound according to this embodiment will be described in detail. The type of the solvent contained in the coating solution is not particularly limited as long as each compound can be uniformly dissolved. Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane and decane; aromatic hydrocarbons such as toluene, xylene, chlorobenzene and orthodichlorobenzene; lower levels such as methanol, ethanol and propanol Alcohols; ketones such as acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone; esters such as ethyl acetate, butyl acetate, and methyl lactate; halogen hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane, and trichloroethylene; ethyl ether; Examples include ethers such as tetrahydrofuran and dioxane; amides such as dimethylformamide and dimethylacetamide. This coating solution may contain only one type of solvent, or may contain two or more types of solvents.

  The amount of the dibenzopyromethene boron chelate compound contained in the coating liquid (ink) containing the dibenzopyromethene boron chelate compound, the p-type semiconductor compound (or precursor), and the n-type semiconductor compound according to this embodiment is based on the entire ink. On the other hand, it is usually 0.001% by weight or more, preferably 0.01% by weight or more. On the other hand, the amount of the dibenzopyromethene boron chelate compound is usually 0.6% by weight or less, preferably 0.24% by weight or less based on the whole ink. When the amount of the dibenzopyromethene boron chelate compound is within this range, the conversion efficiency of the organic thin-film solar cell element 100 according to this embodiment can be improved.

  Moreover, it is preferable that the solubility of the dibenzopyromethene boron chelate compound which concerns on this embodiment is easily soluble like a p-type semiconductor compound (or precursor) and an n-type semiconductor compound. When the solubility of the dibenzopyromethene boron chelate compound according to the present embodiment is low, the dibenzopyromethene boron chelate compound according to the present embodiment becomes a p-type semiconductor compound (or precursor) and an n-type semiconductor compound during coating film formation. It is conceivable to crystallize earlier. In this case, since the dibenzopyromethene boron chelate compound aggregates, the possibility that the dibenzopyromethene boron chelate compound exists in the vicinity of the p-type semiconductor compound (or precursor) and the n-type semiconductor compound is considered to be low. It is done. From this viewpoint, the solubility of the dibenzopyromethene boron chelate compound according to this embodiment in the solvent contained in the coating solution is preferably 0.005% by weight or more, and more preferably 0.05% by weight or more. preferable. In particular, the solubility of the dibenzopyromethene boron chelate compound according to this embodiment in chlorobenzene is preferably 0.01% by weight or more, and more preferably 0.1% by weight or more.

  As described above, the organic thin film solar cell element according to this embodiment is applied by applying an ink (active layer coating solution) containing a dibenzopyromethene boron chelate compound, a p-type semiconductor compound, and an n-type semiconductor compound, that is, by a coating method. 100 active layers 140 can be formed.

<2.2 Electrodes (120, 160)>
The electrodes 120 and 160 according to the present embodiment have a function of collecting holes or electrons generated when the active layer 140 absorbs light. Therefore, one electrode 120 is preferably an electrode suitable for collecting holes, and the other electrode 160 is preferably an electrode suitable for collecting electrons.

  At least one of the pair of electrodes 120 and 160 is preferably translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Moreover, it is preferable that the translucent electrode transmits 70% or more of sunlight in order to allow light to reach the active layer 140 through the transparent electrode. The light transmittance can be measured with a normal spectrophotometer, and can be an average transmittance for visible light (400 nm to 760 nm), for example.

  Specific examples of the materials for the electrodes 120 and 160 will be given below. But at least one of the electrode 120 and the electrode 160 may be comprised with the some material, for example, may be comprised by the laminated structure of two or more layers. In addition, characteristics (electric characteristics, wetting characteristics, etc.) may be improved by performing a surface treatment on the materials listed below.

<2.2.1 Electrode (Anode) 120 Suitable for Collecting Holes>
An electrode (anode) suitable for collecting holes is generally an electrode made of a conductive material having a work function higher than that of the cathode. Such an anode 120 can smoothly extract holes generated in the active layer 140.

  Examples of materials for the anode 120 include conductive metal oxides such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide, and zinc oxide. A metal such as gold, platinum, silver, chromium, cobalt, or an alloy thereof. These materials are preferred because they have a high work function. These substances are preferable because a conductive polymer material represented by PEDOT / PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid can be laminated. For example, a buffer layer 130 made of such a conductive polymer can be provided between the anode 120 and the active layer 140. When conductive polymers are laminated in this way, the conductive polymer material has a high work function. Therefore, instead of the material having a high work function as described above, a metal suitable for a cathode such as aluminum or magnesium. Can also be widely used.

  In addition, the conductive polymer material itself can be used as the material of the anode 120. Examples of the conductive polymer material include the above-described PEDOT / PSS, materials obtained by doping polypyrrole, polyaniline, and the like with iodine or the like.

  When the anode 120 is a transparent electrode, it is preferable to use a light-transmitting conductive metal oxide such as ITO, zinc oxide, or tin oxide as the material of the anode 120, and it is particularly preferable to use ITO. .

  The thickness of the anode 120 is not particularly limited, but is 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm. If the film thickness of the anode 120 is too thin, the sheet resistance increases, and if it is too thick, the light transmittance decreases. When the anode 120 is a transparent electrode, it is preferable to select a film thickness so that both high light transmittance and low sheet resistance can be obtained. The sheet resistance 120 of the anode is not particularly limited, but is usually 1Ω / □ or more, and 1000Ω / □ or less, preferably 500Ω / □ or less, more preferably 100Ω / □ or less. From the viewpoint of extracting a larger current, the sheet resistance is preferably small.

  A method for forming the anode 120 includes a vacuum film formation method such as vapor deposition and sputtering, and a method for forming a film by applying an ink containing nanoparticles and a precursor. Here, the precursor is a compound that is converted into a material suitable for the anode 120 by performing a conversion treatment after coating.

<2.2.2 Electrode (Cathode) 160 Suitable for Electron Collection>
An electrode (cathode) suitable for collecting electrons is generally an electrode made of a conductive material having a work function higher than that of an anode. Such a cathode 160 can smoothly extract electrons generated in the active layer 140.

  Examples of the material of the cathode 160 include metals such as platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, and magnesium, and alloys thereof; Inorganic salts such as lithium fluoride and cesium fluoride; metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. Since these materials have a low work function, they are preferable as materials for the cathode 160.

  In addition, as with the anode 120, the buffer layer 150 can be provided between the cathode 160 and the active layer 140 for the cathode 160. For example, when an n-type semiconductor such as titania having conductivity is used as the buffer layer 130, a material having a high work function can be used as the material of the cathode 160. From the viewpoint of electrode protection, the cathode 160 is preferably made of a metal such as platinum, gold, silver, copper, iron, tin, aluminum, calcium and indium, or an alloy using these metals.

  The film thickness of the cathode 160 is not particularly limited, but is 10 nm or more and 10 μm or less, preferably 20 nm or more and 1 μm or less, and more preferably 50 nm or more and 500 nm or less. If the film thickness of the cathode 160 is too thin, the sheet resistance increases, and if it is too thick, the light transmittance decreases. When the cathode 160 is a transparent electrode, it is preferable to select a film thickness so that both high light transmittance and low sheet resistance can be obtained. The sheet resistance of the cathode 160 is not particularly limited, but is 1000Ω / □ or less, preferably 500Ω / □ or less, and more preferably 100Ω / □ or less. Although there is no restriction on the lower limit, it is usually 1Ω / □ or more. From the viewpoint of extracting a larger current, the sheet resistance is preferably small.

  As a method for forming the cathode 160, there are a vacuum film formation method such as vapor deposition and sputtering, and a method in which an ink containing nanoparticles and a precursor is applied to form a film.

<2.3 Buffer layer (130, 150)>
The organic thin film solar cell element 100 according to the present embodiment may further include one or more buffer layers in addition to the pair of electrodes 120 and 160 and the active layer 140 disposed therebetween. The buffer layer can be classified into a hole extraction layer 130 and an electron extraction layer 150. Usually, the hole extraction layer 130 is disposed between the active layer 140 and the anode 120, and the electron extraction layer 150 is disposed between the active layer 140 and the cathode 160.

<2.3.1 Hole Extraction Layer (130)>
The material of the hole extraction layer 130 is not particularly limited as long as it can improve the efficiency of extracting holes from the active layer 140 to the anode 120. Specific examples include conductive polymers obtained by doping polythiophene, polypyrrole, polyacetylene, triphenylenediamine polypyrrole, polyaniline, and the like with a doping material such as at least one of sulfonic acid and iodine. Among them, a conductive polymer doped with sulfonic acid is preferable, and PEDOT / PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable.

  A thin film of metal such as gold, indium, silver, or palladium can also be used as the hole extraction layer 130. A thin film such as a metal may be used alone as the hole extraction layer 130. In addition, a thin film such as a metal and the above conductive polymer can be used in combination as the hole extraction layer 130.

  The thickness of the hole extraction layer is not particularly limited, but is usually 10 nm or more, preferably 30 nm or more, and usually 200 nm or less. If it is too thin, the uniformity is not sufficient and a short circuit tends to occur, and if it is too thick, the resistance value tends to increase and it becomes difficult to extract holes.

<2.3.2 Electron extraction layer (150)>
The material of the electron extraction layer 150 is not particularly limited as long as it can improve the efficiency of extracting electrons from the active layer 140 to the cathode 160. The electron extraction layer material is roughly divided into an inorganic compound and an organic compound. As the electron extraction layer, only one of these materials or both materials may be used. For example, a stacked body of an inorganic compound layer and an organic compound layer may be used as the electron extraction layer 150.

  As the inorganic compound material used for the electron extraction layer, alkali metal salts such as lithium, sodium, potassium, and cesium, and metal oxides such as titanium oxide (TiOx) and zinc oxide (ZnO) are desirable. As the alkali metal salt, a fluoride salt such as lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride and the like is desirable. One reason why such a material is desirable is that when combined with a cathode such as aluminum, the work function of the cathode is reduced and the voltage applied to the inside of the solar cell element is increased.

  When an alkali metal salt is used as a material for the electron extraction layer 150, the electron extraction layer 150 can be formed using a vacuum film formation method such as vacuum deposition or sputtering. In particular, it is desirable to form the electron extraction layer 150 by vacuum deposition using resistance heating. By using vacuum deposition, damage to other layers such as the active layer 140 can be reduced. The film thickness in this case is usually 0.1 nm or more, while it is usually 50 nm or less, preferably 20 nm or less. If the electron extraction layer 150 is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer 150 tends to deteriorate the characteristics of the device by acting as a series resistance component.

  When titanium oxide TiOx is used as a material for the electron extraction layer 150, the electron extraction layer 150 can be formed using a vacuum film formation method such as sputtering. However, it is more desirable to form a film using a coating method. For example, Adv. Mater. 18, 572 (2006), an electron extraction layer 150 made of titanium oxide can be formed. The film thickness is usually 0.1 nm or more, preferably 0.5 nm or more, more preferably 1 nm or more, and usually 1 μm or less, preferably 100 nm or less, more preferably 50 nm or less. If the electron extraction layer 150 is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer 150 tends to deteriorate the characteristics of the device by acting as a series resistance component.

  When zinc oxide ZnO is used as the material of the electron extraction layer 150, a vacuum film formation method such as a sputtering method can be used, but it is desirable to form the electron extraction layer 150 using a coating method. For example, Sol-Gel Science, C.I. J. et al. Brinker, G.M. W. According to the sol-gel method described by Scherer, Academic Press (1990), the electron extraction layer 150 made of zinc oxide can be formed. The film thickness is usually 0.1 nm or more, preferably 2 nm or more, more preferably 5 nm or more, and usually 1 μm or less, preferably 100 nm or less, more preferably 50 nm or less. If the electron extraction layer 150 is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer 150 tends to deteriorate the characteristics of the device by acting as a series resistance component.

Examples of the organic compound material used as the electron extraction layer 150 include bathocuproin (BCP), bathophenanthrene (Bphen), (8-hydroxyquinolinato) aluminum (Alq ₃ ), boron compound, oxadiazole compound, and benzimidazole compound. , Naphthalenetetracarboxylic anhydride (NTCDA), perylenetetracarboxylic anhydride (PTCDA), phosphine oxide compounds, phosphine sulfide compounds, and the like. Moreover, you may dope metals, such as an alkali metal or alkaline-earth metal, with respect to the above organic compound materials.

  Although there is no limitation in particular as a glass transition temperature of the organic compound used for the electron extraction layer 150, 50 degreeC or more is preferable, More preferably, it is 80 degreeC or more. The upper limit is not particularly limited, but the glass transition temperature by DSC method may not be observed below 300 ° C. If the glass transition temperature is too low, the compound tends to change in structure against external stresses such as applied electric field, flowing current, stress due to bending or temperature changes. Therefore, the durability of the organic thin film solar cell element 100 may be reduced. In addition, when the glass transition temperature is too low, crystallization of the compound thin film tends to proceed. That is, the compound may change between an amorphous state and a crystalline state in the operating temperature range of the organic thin film solar cell element 100. In this case, since the stability as the electron extraction layer 150 is lost, the durability of the organic thin-film solar cell element 100 may be reduced.

  When an organic compound is used as the electron extraction layer 150, the thickness of the electron extraction layer 150 is usually 0.5 nm or more, more preferably 1 nm or more, and usually 1 μm or less, more preferably 100 nm or less. If the electron extraction layer 150 is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer 150 tends to deteriorate the characteristics of the device by acting as a series resistance component.

  When the electron extraction layer 150 is formed using a plurality of materials, the total thickness of the electron extraction layer 150 is usually 0.1 nm or more, more preferably 0.2 nm, and usually 100 nm or less, more preferably 60 nm or less. It is. If the electron extraction layer 150 is too thin, the effect of improving the electron extraction efficiency is not sufficient, and if it is too thick, the electron extraction layer 150 tends to deteriorate the characteristics of the device by acting as a series resistance component.

<2.3.3 Method of Forming Buffer Layer>
There is no restriction | limiting in the formation method of the buffer layers 130 and 150. Although several methods for forming a film have been described above, in general, when a material having sublimation properties is used, a vacuum film forming method such as a vacuum evaporation method can be used. In addition, when a material soluble in a solvent is used, a wet coating method such as spin coating or ink jet can be used.

<2.4 Substrate (110)>
The organic thin-film solar cell element 100 according to this embodiment has a substrate 110 that is normally a support. That is, the electrodes 120 and 160, the active layer 140, and the buffer layers 130 and 150 are formed on the substrate 100. The material of the substrate 110 (substrate material) is arbitrary as long as the effects of the present embodiment are not significantly impaired. Preferable examples of the substrate material include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine Resin films, polyolefins such as vinyl chloride and polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene, epoxy resin and other organic materials; paper, synthetic paper and other paper materials; stainless steel, Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as titanium or aluminum to impart insulation. Examples of the glass include soda glass, blue plate glass, and alkali-free glass. As for the glass material, alkali-free glass is preferred because it is better that there are fewer ions eluted from the glass.

  There is no restriction | limiting in the shape of a board | substrate, For example, shapes, such as a board, a film, a sheet | seat, can be used. There is no limitation on the thickness of the substrate. However, it is preferably 5 μm or more, especially 20 μm or more, and usually 20 mm or less, especially 10 mm or less. If the substrate is too thin, the strength of the organic thin film solar cell element may be insufficient, and if the substrate is too thick, the cost may be increased or the weight may be increased. In the case where the substrate is glass, if it is too thin, the mechanical strength is reduced and the substrate is liable to break. Therefore, the thickness is preferably 0.01 mm or more, more preferably 0.1 mm or more. Moreover, since a weight will become heavy when too thick, 10 mm or less is preferable and 5 mm or less is more preferable.

<2.5 Manufacturing Method of Organic Thin Film Solar Cell Element 100>
The organic thin film solar cell element 100 according to this embodiment can be formed by sequentially forming the electrode 120, the active layer 140, and the electrode 160 on the substrate 110 by the method as described above. In the case of providing the buffer layers 130 and 150, the electrode 120, the buffer layer 130, the active layer 140, the buffer layer 150, and the electrode 160 may be sequentially formed on the substrate 110.

  Furthermore, it is preferable to perform a heat treatment (annealing treatment) on a stacked body obtained by sequentially forming at least the electrode 120, the active layer 140, and the electrode 160 on the substrate 110. By performing the annealing treatment, the thermal stability and durability of the organic thin film solar cell element 100 may be improved. One reason for this is considered to be that the adhesion between the layers can be improved by the annealing treatment. The heating temperature is usually 200 ° C. or lower, preferably 180 ° C. or lower, more preferably 150 ° C. or lower. Moreover, heating temperature is 50 degreeC or more normally, Preferably it is 80 degreeC or more. If the temperature is too low, the adhesion may not be sufficiently improved. If the temperature is too high, for example, the compound contained in the active layer 140 may be thermally decomposed. Note that the annealing treatment may include heating at a plurality of temperatures.

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

[3. Thin-film solar cell according to the present invention]
The organic thin film solar cell element according to this embodiment is preferably used as a solar cell element. In particular, the organic thin film solar cell element according to this embodiment is preferably used as a solar cell element in a solar cell (or a solar cell module). Furthermore, the organic thin film solar cell element according to this embodiment is preferably used as a solar cell element in a thin film solar cell. The solar cell including the organic thin-film solar cell element according to the present embodiment can be produced using any method. For example, according to a well-known technique, a solar cell can be produced by covering the surface of the organic thin-film solar cell element according to this embodiment with an appropriate protective material.

  Below, an example of the suitable embodiment is explained about a solar cell containing an organic thin film solar cell element concerning this embodiment. FIG. 2 is a cross-sectional view schematically showing a configuration of a thin film solar cell as one embodiment according to the present invention. The thin film solar cell shown in FIG. 2 is only an example of the solar cell according to the present invention. It will be apparent to those skilled in the art that the solar cell according to the present invention can have a different configuration than that shown in FIG. For example, some of the components shown in FIG. 2 may not be present, or may be replaced with another element having the same kind of function. Further components may also be added to the solar cell shown in FIG.

  As shown in FIG. 2, the thin film solar cell 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and a solar cell element. 6, a sealing material 7, a getter material film 8, a gas barrier film 9, and a back sheet 10 are provided in this order. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 is formed, and the solar cell element 6 generates power. In addition, when using the sheet | seat with high waterproofness, such as a sheet | seat which adhere | attached the fluorine resin film on both surfaces of the aluminum foil as the back sheet | seat 10 mentioned later, at least one of the getter material film 8 and the gas barrier film 9 does not need to be used depending on a use. Good.

<3.1 Weatherproof Protective Film (1)>
The weather-resistant protective film 1 is a film that protects the solar cell element 6 from weather changes. Some components of the solar cell element 6 are deteriorated by temperature change, humidity change, natural light, erosion caused by wind and rain, and the like. Therefore, by covering the solar cell element 6 with the weather-resistant protective film 1, the solar cell element 6 and the like are protected from weather changes and the power generation capacity is kept high.

  Since the weather-resistant protective film 1 is located on the outermost layer of the thin-film solar cell 14, it is suitable as a surface covering material for the thin-film solar cell 14 such as weather resistance, heat resistance, transparency, water repellency, stain resistance and mechanical strength. It is preferable that it has a good performance and has the property of maintaining it for a long period of time in outdoor exposure.

  Moreover, the weather-resistant protective film 1 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, more preferably 90% or more, and particularly preferably 95%. The power generation efficiency of the thin-film solar cell 14 can be increased by increasing the light transmittance.

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

  The material which comprises the weather-resistant protective film 1 is arbitrary as long as it can protect the solar cell element 6 from a weather change. Examples of the material include polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene naphthalate. Polyester resins such as, phenol resins, polyacrylic resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicon resins, and polycarbonate resins. Of these, fluorine resins are preferred, and specific examples thereof include polytetrafluoroethylene (PTFE), 4-fluorinated ethylene-perchloroalkoxy copolymer (PFA), 4-fluorinated ethylene-6-fluoropropylene copolymer. Examples include coalesce (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF).

  In addition, the weather-resistant protective film 1 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the weather-resistant protective film 1 may be formed with the single layer film, the laminated | multilayer film provided with the film of two or more layers may be sufficient as it.

  Although the thickness of the weather-resistant protective film 1 is not particularly defined, it is usually preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. Further, it is usually preferably 200 μm or less, more preferably 180 μm or less, and further preferably 150 μm or less. The mechanical strength tends to increase by increasing the thickness to 10 μm or more, and the flexibility tends to increase by decreasing the thickness to 200 μm or less.

  Moreover, you may perform surface treatment, such as a corona treatment and a plasma treatment, for the weather-resistant protective film 1 in order to improve adhesiveness with another film.

  The weatherproof protective film 1 is preferably provided on the outer side as much as possible in the thin-film solar cell 14. This is because more of the constituent members of the thin-film solar cell 14 can be protected.

<3.2 UV cut film (2)>
The ultraviolet cut film 2 is a film that prevents the transmission of ultraviolet rays. Some components of the thin film solar cell 14 are deteriorated by ultraviolet rays. Some of the gas barrier films 3 and 9 are deteriorated by ultraviolet rays depending on the type. Therefore, the ultraviolet cut film 2 is provided on the light receiving portion of the thin-film solar cell 14 and the light receiving surface of the solar cell element 6 is covered with the ultraviolet cut film 2 so that the solar cell element 6 and, if necessary, the gas barrier films 3 and 9 are provided. It is protected from ultraviolet rays and can maintain high power generation capacity.

  The degree of the ability to suppress the transmission of ultraviolet rays required for the ultraviolet cut film 2 is such that the transmittance of ultraviolet rays (for example, wavelength 300 nm) is preferably 50% or less, more preferably 30% or less, and more preferably 10% or less. Is particularly preferred. Deterioration of the thin film solar cell 14 can be prevented by suppressing transmission of ultraviolet rays.

  Further, the ultraviolet cut film 2 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. Due to the high transmittance, more sunlight can be converted into electricity.

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, the ultraviolet cut film 2 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the ultraviolet cut film 2 is usually preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and further preferably 130 ° C. or higher. Moreover, 350 degrees C or less is preferable normally, 320 degrees C or less is more preferable, and 300 degrees C or less is especially preferable. By setting the melting point to 100 ° C. or higher, the ultraviolet cut film 2 can be prevented from melting when the thin film solar cell 14 is used.

  Moreover, the ultraviolet cut film 2 has a high softness | flexibility, its adhesiveness with an adjacent film is favorable, and what can cut water vapor | steam and oxygen is preferable. The material which comprises the ultraviolet cut film 2 is arbitrary if the intensity | strength of an ultraviolet-ray can be weakened. Examples of the material include a film formed by blending an ultraviolet absorber with an epoxy resin, an acrylic resin, a urethane resin, or an ester resin.

  Alternatively, a film in which a layer of an ultraviolet absorbent dispersed or dissolved in a resin (hereinafter referred to as “ultraviolet absorbing layer” as appropriate) is formed on a base film may be used. As the ultraviolet absorber, for example, salicylic acid series, benzophenone series, benzotriazole series and cyanoacrylate series can be used. Of these, benzophenone and benzotriazole are preferred. Examples of this include various aromatic organic compounds such as benzophenone and benzotriazole. In addition, a ultraviolet absorber may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

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

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

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

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

  In addition, the drying after apply | coating a coating liquid to a base film can employ | adopt well-known drying methods, such as drying by a hot air drying and an infrared heater, for example. Among these, hot air drying with a high drying speed is preferable. Examples of specific products of the ultraviolet cut film 2 include Cut Ace (MKV Plastic Co., Ltd.). In addition, the ultraviolet cut film 2 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Further, the ultraviolet cut film 2 may be formed of a single layer film, but may be a laminated film including two or more layers.

  The thickness of the ultraviolet cut film 2 is not particularly limited, but is usually preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. Further, it is usually preferably 200 μm or less, more preferably 180 μm or less, and further preferably 150 μm or less. As the thickness is increased to 5 μm or more, the absorption of ultraviolet rays is increased and the mechanical strength is increased. As the thickness is decreased to 200 μm or less, the visible light transmittance is increased and the flexibility is increased.

  Although the ultraviolet cut film 2 should just be provided in the position which covers at least one part of the light-receiving surface of the solar cell element 6, Preferably it is provided in the position which covers all the light-receiving surfaces of the solar cell element 6. FIG. However, the ultraviolet cut film 2 may be provided at a position other than the position covering the light receiving surface of the solar cell element 6.

<3.3 Gas barrier film (3)>
The gas barrier film 3 is a film that prevents permeation of water and oxygen. The solar cell element 6 tends to be vulnerable to moisture and oxygen. In particular, a transparent electrode such as ZnO: Al and an active layer of the solar cell element may be deteriorated by moisture and oxygen. Therefore, by covering the solar cell element 6 with the gas barrier film 3, the solar cell element 6 can be protected from water and oxygen, and the power generation capacity can be kept high.

The degree of moisture resistance required for the gas barrier film 3 is preferably such that, for example, the water vapor transmission rate per unit area (1 m ² ) per day is 1 × 10 ⁻¹ g / m ² / day or less. X10 ⁻² g / m ² / day or less is more preferable, 1 × 10 ⁻³ g / m ² / day or less is more preferable, and 1 × 10 ⁻⁴ g / m ² / day or less. Among them, it is particularly preferable, and it is particularly preferably 1 × 10 ⁻⁵ g / m ² / day or less, and particularly preferably 1 × 10 ⁻⁶ g / m ² / day or less. The more water vapor has to penetrate, the more the degradation of the solar cell element 6 due to the reaction with moisture, particularly the degradation of the active layer and the electrode, is suppressed, so that the power generation efficiency is increased and the life is extended.

The degree of oxygen permeability required for the gas barrier film 3 is, for example, that the oxygen permeability per unit area (1 m ² ) per day is 1 × 10 ⁻¹ cc / m ² / day / atm or less. Preferably, it is 1 × 10 ⁻² cc / m ² / day / atm or less, more preferably 1 × 10 ⁻³ cc / m ² / day / atm or less, and further preferably 1 × 10 ⁻⁴ cc. / M ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁵ cc / m ² / day / atm or less is particularly preferable, and 1 × 10 ⁻⁶ cc / m ² / day / atm or less. It is particularly preferred that The more oxygen has to permeate, the more the degradation of the solar cell element 6 due to the reaction with oxygen, particularly the degradation of the active layer and the electrode, is suppressed, so that the power generation efficiency is increased and the life is extended.

  Conventionally, since it was difficult to mount the gas barrier film 3 having such a high moisture-proof and oxygen-blocking capability, it was difficult to realize a solar cell including an excellent solar cell element such as an organic solar cell element. However, by applying such a gas barrier film 3, it becomes easy to realize the thin film solar cell 14 utilizing the excellent properties of the organic solar cell element.

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

  Furthermore, since the thin film solar cell 14 is often heated by receiving light, it is preferable that the gas barrier film 3 also has heat resistance. From this viewpoint, the melting point of the constituent material of the gas barrier film 3 is usually preferably 100 ° C. or higher, more preferably 120 ° C. or higher, and further preferably 130 ° C. or higher. Moreover, 350 degrees C or less is preferable normally, 320 degrees C or less is more preferable, and 300 degrees C or less is further more preferable. By setting the melting point to 100 ° C. or higher, the possibility that the gas barrier film 3 is melted and deteriorated when the thin film solar cell 14 is used can be reduced.

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

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

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

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

(Plastic film substrate)
The plastic film substrate used for the gas barrier film 3 is not particularly limited as long as it is a film that can hold the above-described inorganic barrier layer and polymer layer, and can be appropriately selected depending on the purpose of use of the gas barrier film 3.

  Examples of plastic film base materials include polyester resins, polyarylate resins, polyethersulfone resins, fluorene ring-modified polycarbonate resins, alicyclic modified polycarbonate resins, and acryloyl compounds. It is also preferable to use a condensation polymer containing spirobiindane and spirobichroman. Among the polyester resins, biaxially stretched polyethylene terephthalate (PET) and biaxially stretched polyethylene naphthalate (PEN) are preferably used as a plastic film substrate because they are excellent in thermal dimensional stability. In addition, 1 type may be used for the material of a plastic film base material, and 2 or more types may be used together by arbitrary combinations and a ratio.

  The thickness of the plastic film substrate is not particularly defined, but is usually preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. Further, it is usually preferably 200 μm or less, more preferably 180 μm or less, and further preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

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

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

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

  In addition, in order to improve the applicability and adhesion of the anchor coating agent to the plastic film substrate, the plastic film substrate may be subjected to a surface treatment such as normal chemical treatment or electric discharge treatment before application of the anchor coating agent. Good.

(Inorganic barrier layer)
The inorganic barrier layer is usually a layer formed of a metal oxide, nitride or oxynitride. In addition, the metal oxide, nitride, and oxynitride which form an inorganic barrier layer may be 1 type, and may use 2 or more types together by arbitrary combinations and a ratio. Examples of the metal oxide include oxides such as Si, Al, Mg, In, Ni, Sn, Zn, Ti, Cu, Ce, and Ta, nitrides, and oxynitrides. Among these, in order to achieve both high barrier properties and high transparency, it is preferable to include aluminum oxide or silicon oxide, and it is particularly preferable to include silicon oxide from the viewpoint of moisture permeability and light transmittance.

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

  Moreover, when comprising an inorganic barrier layer from 2 or more types of metal oxides, it is preferable that an aluminum oxide and a silicon oxide are included as a metal oxide. In particular, when the inorganic barrier layer is made of aluminum oxide and silicon oxide, the ratio of aluminum to silicon in the inorganic barrier layer can be arbitrarily set. However, in order to achieve both high barrier properties and high transparency, the Si / Al ratio is usually preferably 1/9 or more, and more preferably 2/8 or more. Moreover, usually 9/1 or less is preferable and 8/2 or less is more preferable.

  When the thickness of the inorganic barrier layer is increased, the barrier property tends to be increased. However, in order to prevent cracking and prevent cracking when bent, it is preferable to reduce the thickness. Therefore, the appropriate thickness of the inorganic barrier layer is usually preferably 5 nm or more, and more preferably 10 nm or more. Moreover, 1000 nm or less is preferable normally and 200 nm or less is more preferable.

  Although there is no restriction | limiting in the film-forming method of an inorganic barrier layer, Generally, it can carry out by sputtering method, a vacuum evaporation method, an ion plating method, plasma CVD method, etc. For example, the sputtering method can be formed by reactive sputtering using plasma using one or more metal targets and oxygen gas as raw materials.

(Polymer layer)
Any polymer can be used for the polymer layer, and for example, a film that can be formed in a vacuum chamber can be used. In addition, the polymer which comprises a polymer layer may use 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  A wide variety of compounds can be used to form the polymer layer. Here, as an example, a case where a polymer layer is formed using the following monomers (i) to (vii) will be described. In addition, 1 type may be used for a monomer and it may use 2 or more types together by arbitrary combinations and a ratio.

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

  (Ii) Examples include paraxylylene such as diparaxylylene. As an example of a method for forming a polymer layer in the case of using diparaxylylene, first, the vapor of diparaxylylene is heated at 650 ° C. to 700 ° C. in a high vacuum to generate thermal radicals. Then, the radical monomer vapor is introduced into the chamber and adsorbed to the plastic film substrate, and at the same time, the radical polymerization reaction proceeds to deposit polyparaxylylene to form a polymer layer.

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

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

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

  (Vi) An example is vinyl acetate. When vinyl acetate is used as a monomer, polyvinyl alcohol is obtained by saponifying the polymer, and this polyvinyl alcohol can be used as a polymer.

  (Vii) Examples thereof include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, ethacrylic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monoethyl maleate, maleic anhydride and itaconic anhydride. These constitute a copolymer with ethylene, and the copolymer can be used as a polymer. Furthermore, a mixture thereof, a mixture obtained by mixing a glycidyl ether compound, and a mixture with an epoxy compound can also be used as the polymer.

  There is no restriction | limiting in the polymerization method of a monomer when superposing | polymerizing the said monomer and producing | generating a polymer. However, the polymerization is usually carried out after a composition containing a monomer is applied or vapor deposited to form a film. As an example of the polymerization method, when a thermal polymerization initiator is used, polymerization is started by contact heating with a heater or the like; radiation heating with infrared rays or microwaves; Moreover, when a photoinitiator is used, an active energy ray is irradiated and polymerization is started.

  Various light sources can be used when irradiating active energy rays, such as mercury arc lamps, xenon arc lamps, fluorescent lamps, carbon arc lamps, tungsten-halogen radiation lamps, and irradiation light from sunlight. Can do. Further, electron beam irradiation or atmospheric pressure plasma treatment can also be performed.

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

  Although there is no limitation in particular about the thickness of a polymer layer, 10 nm or more is preferable normally. Moreover, 5000 nm or less is preferable normally, 2000 nm or less is more preferable, and 1000 nm or less is especially preferable. By setting the thickness of the polymer layer to 10 nm or more, the uniformity of the thickness can be easily obtained, and structural defects of the inorganic barrier layer can be efficiently filled with the polymer layer, and the barrier property tends to be improved. Moreover, since the polymer layer itself becomes difficult to generate | occur | produce a crack by external force, such as bending, by making the thickness of a polymer layer 5000 nm or less, barrier property can improve.

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

  The thickness of the gas barrier film 3 is not particularly defined, but is usually preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. Further, it is usually preferably 200 μm or less, more preferably 180 μm or less, and further preferably 150 μm or less. When the thickness is 5 μm or more, gas barrier properties tend to be increased, and when the thickness is 200 μm or less, flexibility is increased and visible light transmittance tends to be improved.

  As long as the gas barrier film 3 covers the solar cell element 6 and can be protected from moisture and oxygen, the formation position is not limited. However, the front surface of the solar cell element 6 (surface on the light receiving surface side, lower surface in FIG. 2) and It is preferable to cover the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2). This is because the front and back surfaces of the thin film solar cell 14 are often formed in a larger area than the other surfaces. In this embodiment, the gas barrier film 3 covers the front surface of the solar cell element 6, and a gas barrier film 9 described later covers the back surface of the solar cell element 6.

  In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, at least one of the getter material film 8 and the gas barrier film 9 is used depending on the application. It does not have to be.

<3.4 Getter material film (4)>
The getter material film 4 is a film that absorbs at least one of moisture and oxygen. Some components of the solar cell element 6 are deteriorated by moisture as described above, and some are deteriorated by oxygen. Therefore, by covering the solar cell element 6 with the getter material film 4, the solar cell element 6 and the like are protected from at least one of moisture and oxygen, and the power generation capacity is kept high.

  Here, unlike the gas barrier film 3 as described above, the getter material film 4 does not prevent moisture permeation but absorbs moisture. By using a film that absorbs moisture, when the solar cell element 6 is covered with the gas barrier film 3 or the like, the getter material film 4 captures moisture that slightly enters the space sandwiched between the gas barrier films 3 and 9, and the moisture. The influence on the solar cell element 6 due to can be eliminated.

The degree of water absorption capacity of the getter material film 4 is preferably usually 0.1 mg / cm ² or more, 0.5 mg / cm ² or more, more preferably, 1 mg / cm ² or more is more preferable. The higher this value, the higher the water absorption capacity, and the deterioration of the solar cell element 6 can be suppressed. Moreover, although there is no restriction | limiting in an upper limit, it is usually 10 mg / cm < ² > or less.

  Further, when the solar cell element 6 is covered with the gas barrier films 3 and 9 by absorbing the oxygen by the getter material film 4, the getter material film absorbs oxygen that slightly enters the space between the gas barrier films 3 and 9. 4 captures and the influence of oxygen on the solar cell element 6 can be eliminated.

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

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

  The material constituting the getter material film 4 is arbitrary as long as it can absorb at least one of moisture and oxygen. As the material, for example, as a substance that absorbs moisture, alkali metal, alkaline earth metal, oxide of alkaline earth metal, hydroxide of alkali metal and alkaline earth metal, silica gel, zeolite compound, magnesium sulfate And sulfates such as sodium sulfate and nickel sulfate, and organometallic compounds such as aluminum metal complexes and aluminum oxide octylates.

  Specifically, examples of the alkaline earth metal include Ca, Sr, and Ba. Examples of the alkaline earth metal oxide include CaO, SrO, and BaO. Other examples include Zr—Al—BaO and aluminum metal complexes. Specific product names include, for example, OleDry (Futaba Electronics Co., Ltd.).

  Examples of the substance that absorbs oxygen include activated carbon, silica gel, activated alumina, molecular sieve, magnesium oxide, and iron oxide. In addition, Fe, Mn and Zn and inorganic salts such as sulfates, chlorides and nitrates of these metals are also included.

  In addition, the getter material film 4 may be formed of one type of material or may be formed of two or more types of materials. The getter material film 4 may be formed of a single layer film, but may be a laminated film including two or more layers.

  Although the thickness of the getter material film 4 is not particularly defined, it is usually preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. Further, it is usually preferably 200 μm or less, more preferably 180 μm or less, and further preferably 150 μm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

  The formation position of the getter material film 4 is not limited as long as it is within the space between the gas barrier films 3 and 9, but the front surface of the solar cell element 6 (surface on the light receiving surface side, lower surface in FIG. 2) and It is preferable to cover the back surface (the surface opposite to the light receiving surface; the upper surface in FIG. 2). This is because, in the thin film solar cell 14, the front and back surfaces are often formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, the getter material film 4 is preferably provided between the gas barrier film 3 and the solar cell element 6. In this embodiment, the getter material film 4 covers the front surface of the solar cell element 6, a getter material film 8 described later covers the back surface of the solar cell element 6, and the getter material films 4 and 8 are respectively the solar cell element 6 and the gas barrier film 3. , 9 are located between them.

  In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, at least one of the getter material film 8 and the gas barrier film 9 is used depending on the application. It does not have to be.

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

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

<3.5 Encapsulant (5)>
The sealing material 5 is a film that reinforces the solar cell element 6. Since the solar cell element 6 is thin, the strength is usually weak, and thus the strength of the thin film solar cell tends to be weak. However, the strength can be maintained high by the sealing material 5. Moreover, it is preferable that the sealing material 5 has high strength from the viewpoint of maintaining strength of the thin-film solar cell 14. The specific strength is related to the strength of the weatherproof protective film 1 or the backsheet 10 other than the sealing material 5 and is generally difficult to define, but the thin film solar cell 14 as a whole has good bending workability. In addition, it is preferable to have a strength that does not cause peeling of the bent portion.

  In addition, the sealing material 5 is preferably one that transmits visible light from the viewpoint of not preventing the solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually preferably 60% or more, more preferably 70% or more, further preferably 75% or more, particularly preferably 80% or more, and particularly preferably 85% or more. Preferably, 90% or more is particularly preferable, 95% or more is particularly preferable, and 97% or more is most preferable. This is to convert more sunlight into electrical energy.

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

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

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

  This EVA resin composition may contain a silane coupling agent for the purpose of improving the adhesive strength. Examples of silane coupling agents used for this purpose include γ-chloropropyltrimethoxysilane; vinyltrichlorosilane; vinyltriethoxysilane; vinyl-tris- (β-methoxyethoxy) silane; γ-methacryloxypropyltri Examples include methoxysilane; β- (3,4-ethoxycyclohexyl) ethyltrimethoxysilane and the like. In order to obtain more suitable weather resistance, transparency, adhesive strength, and strength for use as the sealing material 5, the blending amount of these silane coupling agents is usually 5 weights with respect to 100 parts by weight of the EVA resin. Part by weight or less, more preferably 2 parts by weight or less, and usually 0.1 part by weight or more is preferred. In addition, 1 type may be used for a silane coupling agent and it may use 2 or more types together by arbitrary combinations and a ratio.

  Furthermore, in order to improve the gel fraction of the EVA resin and improve the durability, a crosslinking aid may be included in the EVA resin composition. Examples of the crosslinking aid provided for this purpose include trifunctional crosslinking aids such as triallyl isocyanurate and monofunctional crosslinking aids such as allyl isocyanate.

  In order to obtain more suitable durability, weather resistance, transparency, and strength for use as the sealing material 5, the amount of these crosslinking aids is usually 10 parts by weight with respect to 100 parts by weight of the EVA resin. The following is preferable, and 5 parts by weight or less is more preferable. Moreover, usually 1 weight part or more is preferable. In addition, 1 type may be used for a crosslinking adjuvant, and 2 or more types may be used together by arbitrary combinations and a ratio.

  Furthermore, for the purpose of improving the stability of the EVA resin, the EVA resin composition may contain, for example, hydroquinone; hydroquinone monomethyl ether; p-benzoquinone; methylhydroquinone. In order to obtain more suitable stability, weather resistance, transparency, and strength for use as the sealing material 5, these blending amounts are usually preferably 5 parts by weight or less with respect to 100 parts by weight of the EVA resin.

  However, since the EVA resin cross-linking process requires a relatively long time of about 1 to 2 hours, it may cause a reduction in the production rate and production efficiency of the thin-film solar cell 14. In addition, when used for a long time, the decomposition gas (acetic acid gas) of the EVA resin composition or the vinyl acetate group of the EVA resin itself may adversely affect the solar cell element 6 and reduce the power generation efficiency. Therefore, as the sealing material 5, in addition to the EVA film, a copolymer film made of a propylene / ethylene / α-olefin copolymer can also be used. As this copolymer, the thermoplastic resin composition with which the following component 1 and the component 2 were mix | blended is mentioned, for example.

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

  The thermoplastic resin composition containing component 1 and component 2 described above preferably has a melt flow rate (ASTM D 1238, 230 degrees, load 2.16 g) of usually 0.0001 g / 10 min or more. Moreover, 1000 g / 10min or less is preferable normally, 900 g / 10 min or less is more preferable, and 800 g / 10 min or less is further more preferable. When the melt flow rate is in this range, molding into a sheet becomes easier.

  The melting point of the thermoplastic resin composition containing Component 1 and Component 2 is usually preferably 100 ° C. or higher, more preferably 110 ° C. or higher. Moreover, 140 degrees C or less is preferable normally, and 135 degrees C or less is more preferable. When the melting point is within this range, molding into a sheet becomes easier.

Density of The thermoplastic resin composition components 1 and 2 is blended is preferably from 0.98 g / cm ³ or less, more preferably 0.95 g / cm ³ or less, more preferably 0.94 g / cm ³ or less . When the density is in this range, the physical properties of the sealing material 5 including, for example, mechanical strength can be made more suitable.

  In this sealing material 5, it is possible to mix | blend a coupling agent with the said component 1 and component 2 as an adhesion promoter with respect to a plastics. As the coupling agent, silane-based, titanate-based and chromium-based coupling agents are preferably used, and silane-based coupling agents (silane coupling agents) are particularly preferably used.

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

  Further, the content of the silane coupling agent with respect to 100 parts by weight of the thermoplastic resin composition (total amount of component 1 and component 2) is usually preferably 0.1 parts by weight or more, and usually preferably 5 parts by weight or less. It is more preferable to contain 3 parts by weight or less. By setting the content within this range, it is possible to obtain more suitable weather resistance, transparency, adhesive strength, and strength for use as the sealing material 5.

  The coupling agent may be grafted to the thermoplastic resin composition using an organic peroxide. In this case, it is preferable that 0.1-5 weight part of said coupling agents are included with respect to 100 weight part of thermoplastic resin compositions (total amount of component 1 and component 2). Even if a silane-grafted thermoplastic resin composition is used, the same or better adhesiveness as that of the silane coupling agent blend can be obtained for glass and plastic.

  When the organic peroxide is used, the organic peroxide is usually preferably 0.001 part by weight or more with respect to 100 parts by weight of the thermoplastic resin composition (the total amount of Component 1 and Component 2), and 0.01% by weight. Part or more is more preferable. Moreover, 5 weight part or less is preferable normally, and 3 weight part or less is more preferable. By setting the content within this range, it is possible to obtain more suitable weather resistance, transparency, adhesive strength, and strength for use as the sealing material 5.

Further, a copolymer made of an ethylene / α-olefin copolymer can be used as the sealing material 5. As this copolymer, a laminate film having a hot tack property of 5 to 25 ° C., which is formed by laminating a resin composition for a sealing material comprising the following components A and B and a substrate, is exemplified.
Component A: ethylene resin.
Component B: a copolymer of ethylene and an α-olefin having the following properties (a) to (d).
(A) Density is 0.86-0.935 g / cm ³ .
(B) Melt flow rate (MFR) is 1 to 50 g / 10 min.
(C) There is one peak in the elution curve obtained by temperature rising elution fractionation (TREF); the peak temperature is 100 ° C. or lower.
(D) The integrated elution amount by temperature rising elution fractionation (TREF) is 90% or more at 90 ° C.

  The blending ratio of component A and component B (component A / component B) is generally preferably 50/50 or more, more preferably 55/45 or more, and still more preferably 60/40 or more in terms of weight ratio. Moreover, 99/1 or less is preferable normally, 90/10 or less is more preferable, and 85/15 or less is further more preferable. Increasing the amount of component B tends to increase transparency and heat sealability, and decreasing the amount of component B tends to increase the workability of the film.

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

  The melting point of the encapsulant resin composition is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, usually 300 ° C. or lower, more preferably 250 ° C. or lower, and further preferably 200 ° C. or lower. By increasing the melting point, the possibility of melting and deterioration during use of the thin-film solar cell 14 can be reduced.

The density of the resin composition for a sealing material is preferably 0.80 g / cm ³ or more, more preferably 0.85 g / cm ³ or more, and preferably 0.98 g / cm ³ or less, 0.95 g / cm ^3. The following is more preferable, and 0.94 g / cm ³ or less is more preferable. When the density is within this range, for example, the physical properties of the sealing material 5 including heat resistance and mechanical strength can be made more suitable. The measurement and evaluation of density can be performed by a method based on JIS K7112.

  Further, in the encapsulant 5 using the ethylene / α-olefin copolymer, a coupling agent can be used as in the case of using the propylene / ethylene / α-olefin copolymer.

  Since the sealing material 5 described above does not generate a decomposition gas derived from the material, there is no adverse effect on the solar cell element 6, and good heat resistance, mechanical strength, flexibility (solar cell sealing property) and transparency. Have sex. In addition, since a material cross-linking step is not required, the manufacturing time of the sheet solar cell 100 and the thin film solar cell 100 can be greatly reduced, and the thin film solar cell 14 after use can be easily recycled.

  In addition, the sealing material 5 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the sealing material 5 may be formed with the single layer film, the laminated | multilayer film provided with the film of 2 or more layers may be sufficient as it.

  The thickness of the sealing material 5 is usually preferably 2 μm or more, more preferably 5 μm or more, and further preferably 10 μm or more. Moreover, 500 micrometers or less are preferable normally, 300 micrometers or less are more preferable, and 100 micrometers or less are further more preferable. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility and light transmittance.

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

<3.6 Solar Cell Element (6)>
As the solar cell element 6, the organic thin film solar cell element according to the present invention can be used.

(Connection between solar cell elements)
Although only one solar cell element 6 may be provided for each thin film solar cell 14, usually two or more solar cell elements 6 are provided. The specific number of solar cell elements 6 can be arbitrarily set. When a plurality of solar cell elements 6 are provided, the solar cell elements 6 are often provided in an array. In the case of using a plurality of solar cell elements, the organic thin film solar cell element according to the present invention and any other organic thin film solar cell element can be used in combination.

  When a plurality of solar cell elements 6 are provided, normally, the solar cell elements 6 are electrically connected to each other, and electricity generated from the connected group of solar cell elements 6 is taken out from a terminal (not shown). Yes. At this time, the solar cell elements are normally connected in series in order to increase the voltage. But the connection method of a solar cell element is arbitrary and may be connected in parallel.

  Thus, when connecting the solar cell elements 6, it is preferable that the distance between the solar cell elements 6 is small, and the clearance between the solar cell element 6 and the solar cell element 6 is preferably narrow. This is because the light receiving area of the solar cell element 6 is widened to increase the amount of received light, and the amount of power generated by the thin film solar cell 14 is increased.

<3.7 Sealing material (7)>
The sealing material 7 is a film similar to the sealing material 5 described above, and the same material as the sealing material 5 can be used in the same manner except that the arrangement position is different. Further, the constituent members that are not on the light receiving surface side of the solar cell element 6 do not necessarily need to transmit visible light. Therefore, in the thin film solar cell 14 shown in FIG. 2, a material that does not transmit visible light can be used as the sealing material 7.

<3.8 Getter Material Film (8)>
The getter material film 8 is the same film as the getter material film 4 described above, and the same material as the getter material film 4 can be used as necessary, except for the arrangement position. Further, the constituent members that are not on the light receiving surface side of the solar cell element 6 do not necessarily need to transmit visible light. Therefore, in the thin film solar cell 14 shown in FIG. 2, a material that does not transmit visible light can be used as the getter material film 8. Further, as the getter material film 8, it is possible to use a film containing a larger amount of moisture absorbent or oxygen absorbent than the getter material film 4. Examples of such an absorbent include CaO, BaO, and Zr—Al—BaO as moisture absorbents. Examples of the oxygen absorbent include activated carbon and molecular sieve.

<3.9 Gas barrier film (9)>
The gas barrier film 9 is the same film as the gas barrier film 3 described above, and the same material as the gas barrier film 3 can be used as necessary, except for the arrangement position. Further, the constituent members that are not on the light receiving surface side of the solar cell element 6 do not necessarily need to transmit visible light. Therefore, in the thin film solar cell 14 shown in FIG. 2, the gas barrier film 9 may be made of a material that does not transmit visible light.

<3.10 Back sheet (10)>
The back sheet 10 is the same film as the weather-resistant protective film 1 described above, and the same material as the weather-resistant protective film 1 can be used in the same manner except that the arrangement position is different. In addition, if the back sheet 10 is difficult to permeate water and oxygen, the back sheet 10 can also function as a gas barrier layer.

  Further, the constituent members that are not on the light receiving surface side of the solar cell element 6 do not necessarily need to transmit visible light. Therefore, in the thin film solar cell 14 shown in FIG. 2, a material that does not transmit visible light can be used as the back sheet 10. For example, it is particularly preferable to use the following (i) to (iv) as the backsheet 10.

  (I) As the back sheet 10, various resin films or sheets excellent in strength and excellent in weather resistance, heat resistance, water resistance, and light resistance can be used. For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyarylphthalate resins Silicone resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyurethane resin, acetal resin, cellulose resin, and other resin resins. It is possible to use the door.

  Among these resin sheets, it is preferable to use sheets of fluorine resin, cyclic polyolefin resin, polycarbonate resin, poly (meth) acrylic resin, polyamide resin, and polyester resin. In addition, these may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  (Ii) As the back sheet 10, a metal thin film can also be used. For example, an aluminum metal foil or a stainless thin film subjected to a corrosion prevention treatment can be used. In addition, as a material of a metal thin film, only 1 type of metal may be used and 2 or more types of metals may be used together by arbitrary combinations and ratios.

  (Iii) As the back sheet 10, for example, a highly waterproof sheet in which a fluorine resin film is bonded to both surfaces of an aluminum foil may be used. Examples of the fluororesin include, for example, ethylene monofluoride (trade name: Tedlar, manufactured by DuPont), polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and ethylene (ETFE), and tetrafluoroethylene and propylene. Examples thereof include a copolymer, a vinylidene fluoride resin (PVDF), and a vinyl fluoride resin (PVF). In addition, 1 type of fluororesin may be used for the backsheet 10, and 2 or more types of fluororesins may be used together in arbitrary combinations and ratios.

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

(Base film)
Basically, as the base film, various resin films that are excellent in tight adhesion with inorganic oxide vapor deposition film, etc., excellent in strength, weather resistance, heat resistance, water resistance and light resistance are used. Can be used.

  For example, polyethylene resin, polypropylene resin, cyclic polyolefin resin, polystyrene resin, acrylonitrile-styrene copolymer (AS resin), acrylonitrile-butadiene-styrene copolymer (ABS resin), polyvinyl chloride resin, fluorine Resins, poly (meth) acrylic resins, polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylons, polyimide resins, polyamideimide resins, polyarylphthalate resins , Silicone resins, polysulfone resins, polyphenylene sulfide resins, polyethersulfone resins, polyurethane resins, acetal resins, cellulose resins, and other various resin films. It is possible to use the beam. Among these, it is preferable to use a film of a fluorine resin, a cyclic polyolefin resin, a polycarbonate resin, a poly (meth) acrylic resin, a polyamide resin, or a polyester resin.

  Among the various resin films as described above, for example, fluorine resin films such as polytetrafluoroethylene (PTFE), vinylidene fluoride resin (PVDF), and vinyl fluoride resin (PVF) are used. It is more preferable. Further, among these fluororesin films, in particular, a fluororesin film containing polyvinyl fluoride resin (PVF), a copolymer of tetrafluoroethylene and ethylene (ETFE), or a copolymer of tetrafluoroethylene and propylene. Is particularly preferable from the viewpoint of strength and the like. In addition, 1 type of components may be used for a base film, and 2 or more types may be used together by arbitrary combinations and a ratio. Of the various resin films as described above, it is more preferable to use a film of a cyclic polyolefin resin such as cyclopentadiene and a derivative thereof, cyclohexadiene and a derivative thereof.

  As a film thickness of a base film, 12 micrometers or more are preferable normally, 20 micrometers or more are more preferable, and 300 micrometers or less are preferable normally, and 200 micrometers or less are more preferable. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

(Deposited film of inorganic oxide)
Any inorganic oxide can be used as long as it is a thin film on which a metal oxide is deposited. For example, a deposited film of an oxide of silicon (Si) or aluminum (Al) can be used. At this time, for example, SiO _x (x = 1.0 to 2.0) can be used as silicon oxide, and for example, AlO _x (x = 0.5 to 1.5) can be used as aluminum oxide. . In addition, one type of inorganic oxide may be vapor-deposited on the vapor deposition film, or two or more types may be used in any combination and ratio.

  The thickness of the deposited inorganic oxide film is usually preferably 50 mm or more, more preferably 100 mm or more. Also, it is usually preferably 4000 mm or less, more preferably 1000 mm or less. Increasing the thickness tends to increase mechanical strength, and decreasing the thickness tends to increase flexibility.

  As a method for forming the deposited film, a chemical vapor deposition method (chemical vapor deposition method, CVD method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method can be used. Specifically, for example, a monomer gas for vapor deposition such as an organosilicon compound is used as a raw material, an inert gas such as argon gas and helium gas is used as a carrier gas, and an oxygen gas is used as an oxygen supply gas. By using a low temperature plasma chemical vapor deposition method using a plasma generator or the like, a vapor deposition film of an inorganic oxide such as silicon oxide can be formed on one surface of the base film.

(Polypropylene resin film)
As the polypropylene resin, for example, a homopolymer of propylene or a copolymer of propylene and another monomer (for example, an α-olefin) can be used. Moreover, an isotactic polymer can also be used as a polypropylene resin. In order to obtain weather resistance and strength more suitable for use as the back sheet 10, the melting point of the polypropylene resin is usually preferably 164 ° C to 170 ° C, the specific gravity is usually preferably 0.90 to 0.91, and the molecular weight is usually 100,000 to 200,000 are preferable. Polypropylene resins are largely controlled by their crystallinity, but high isotactic polymers have excellent tensile strength and impact strength, good heat resistance and bending fatigue strength, and workability. Is very good.

(adhesive)
When a polypropylene resin film is laminated on the base film, a laminating adhesive is usually used. Thereby, a base film and a polypropylene resin film are laminated | stacked via the adhesive bond layer for lamination.

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

  The composition system of the adhesive may be any of an aqueous type, a solution type, an emulsion type, and a dispersion type. Further, the shape may be any form such as a film / sheet, a powder, and a solid. Further, the bonding mechanism may be any form of a chemical reaction type, a solvent volatilization type, a heat melting type, and a hot pressure type.

For example, the adhesive can be coated on the film using any method such as a roll coating method, a gravure roll coating method, a coating method such as a kiss coating method and others, and a printing method. To obtain the strength and adhesion that is more suitable for use as the backsheet 10, the coating amount of the adhesive is preferably a 0.1g ^{/ m 2} ~10g ^/ m 2 in a dry state.

<3.11 Dimensions of Thin Film Solar Cell>
The thin film solar cell 14 of the present embodiment is usually a thin film member. Thus, by forming the thin film solar cell 14 as a film-like member, the thin film solar cell 14 can be easily installed in building materials, automobiles, interiors, and the like. The thin film solar cell 14 is light and difficult to break, and thus a highly safe solar cell can be obtained. Moreover, since the thin film solar cell 14 can also be installed on a curved surface, it can be used for more applications. Since the thin film solar cell 14 of this embodiment is thin and light, it is preferable also in terms of distribution such as transportation and storage. Furthermore, since it is in the form of a film, it can be manufactured in a roll-to-roll manner, and the cost can be greatly reduced.

  Although there is no restriction | limiting in the specific dimension of the thin film solar cell 14, From the viewpoint of increasing mechanical strength, the thickness is usually preferably 300 μm or more, more preferably 500 μm or more, and further preferably 700 μm or more. From the viewpoint of increasing flexibility, it is usually preferably 3000 μm or less, more preferably 2000 μm or less, and even more preferably 1500 μm or less.

<3.12 Manufacturing Method of Thin Film Solar Cell>
There is no restriction | limiting in the manufacturing method of the thin film solar cell 14 of this embodiment. As an example, one or two or more solar cell elements 6 connected in series or in parallel between the weather resistant protective film 1 and the back sheet 10 are the ultraviolet cut film 2, the gas barrier films 3, 9, and the getter material. It can manufacture by laminating with the film 4 and 8 and the sealing materials 5 and 7 with a general vacuum laminating apparatus.

  At this time, from the viewpoint of increasing the adhesion by making the laminate sufficient, the heating temperature is usually preferably 130 ° C. or higher, and more preferably 140 ° C. or higher. Moreover, from a viewpoint of preventing deterioration of each part of the thin film solar cell 14 including the solar cell element 6, it is usually preferably 180 ° C. or lower, and more preferably 170 ° C. or lower. Further, from the viewpoint of increasing the adhesiveness with a sufficient laminate, the heating time is usually preferably 10 minutes or more, and more preferably 20 minutes or more. Moreover, from a viewpoint of preventing deterioration of each part of the thin film solar cell 14 including the solar cell element 6, the heating time is usually preferably 100 minutes or less, and more preferably 90 minutes or less. The pressure is usually preferably 0.001 MPa or more, and more preferably 0.01 MPa or more. Moreover, 0.2 MPa or less is preferable normally and 0.1 MPa or less is more preferable. Sealing can be reliably performed by setting the pressure within this range. Moreover, the sealing materials 5 and 7 can be prevented from protruding from the end portions, and the film thickness reduction due to over-pressurization can be suppressed, and dimensional stability can be ensured.

<3.13 Applications of thin film solar cells>
There is no restriction | limiting in the use of the thin film solar cell 14 mentioned above, It can use for arbitrary uses. For example, as schematically shown in FIG. 3, a solar cell module 13 including a thin film solar cell 14 may be prepared and used at a place of use. Here, the thin film solar cell 14 may be disposed on some base material 12. As a specific example, when a building material plate is used as the base material 12, a solar cell panel can be produced as the solar cell module 13 by providing the thin film solar cell 14 on the surface of the plate material. This solar cell panel can be installed on the outer wall of a building. But the solar cell module in this embodiment does not need to be provided with the base material 12. FIG. The sheet-like thin film solar cell 14 itself can also be used as a solar cell module.

  The substrate 12 is a support member that supports the solar cell element 6. Examples of the material for forming the substrate 12 include inorganic materials such as glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine. Organic materials such as resin, vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate and polynorbornene; paper materials such as paper and synthetic paper; metals such as stainless steel, titanium and aluminum And composite materials such as those coated or laminated on the surface in order to impart insulating properties.

  In addition, as a base material 12, 1 type of materials may be used and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, carbon fiber may be included in these organic materials or paper materials to reinforce the mechanical strength. The substrate may have any shape, may be a rigid body, or may have flexibility such as a sheet.

  Examples of fields to which the thin film solar cell according to the present embodiment is applied include solar cells for building materials, solar cells for automobiles, solar cells for interiors, solar cells for railways, solar cells for ships, solar cells for airplanes, and space vehicles. Examples include solar cells, solar cells for home appliances, solar cells for mobile phones, and solar cells for toys. Specific examples include the following.

(I. Architectural use)
(I-1 House roofing material)
When using a roof plate or the like as a base material, a thin film solar cell is provided on the surface of the plate material to produce a solar cell panel that is a solar cell module, and the solar cell panel may be installed on the roof of the house. . Moreover, a roof tile can also be used directly as a base material. The solar cell according to the present embodiment is preferable because it can be brought into close contact with the curve of the roof tile by taking advantage of the property that it has flexibility.

(I-2 Rooftop)
Thin film solar cells can also be installed on the roof of the building. A solar cell module in which a thin film solar cell is provided on a substrate can be prepared and installed on the roof of a building. At this time, it is preferable to use a waterproof sheet together with the base material to impart waterproofness. Furthermore, taking advantage of the property that the thin film solar cell according to the present embodiment has flexibility, it can be brought into close contact with a non-planar roof, for example, a folded roof. Also in this case, it is preferable to use a waterproof sheet in combination.

(I-3 Top Light)
The thin film solar cell according to the present embodiment can also be used as an exterior at the entrance or a blow-off portion. In many cases, a curved line is used for an entrance or the like that has undergone some design processing. In such a case, the flexibility of the thin film solar cell according to the present embodiment is utilized. In addition, a see-through member may be used for an entrance or the like. In such a case, in an era when environmental measures are regarded as important, particularly when the organic solar cell has a greenish hue, a design aesthetic appearance can be obtained, which is preferable.

(I-4 wall)
When a building material plate is used as a base material, a thin-film solar cell is provided on the surface of the plate material to produce a solar cell panel as a solar cell module, and this solar cell panel may be installed on the outer wall of a building and used. . It can also be installed on curtain walls. In addition, it can be attached to a spandrel or a vertical. In this case, the shape of the substrate is not limited, but a plate material is usually used. Moreover, what is necessary is just to set the material of a base material, a dimension, etc. arbitrarily according to the use environment. As an example of such a substrate, Alpolic (registered trademark; manufactured by Mitsubishi Plastics) and the like can be mentioned.

(I-5 window)
The thin film solar cell according to this embodiment can also be used for a see-through window. In an era when environmental measures are regarded as important, particularly when the organic solar cell has a greenish tint, it is preferable because a beautiful design can be obtained.

(I-6 other)
The thin film solar cell according to the present embodiment can be used for eaves, louvers, handrails and the like as an exterior of a building. Even in such a case, the flexibility of the thin film solar cell according to the present embodiment is suitable for these applications.

(II interior)
The thin film solar cell according to the present embodiment can be attached to a blind slat. Since the thin film solar cell according to the present embodiment is lightweight and rich in flexibility, it can be used in such applications. Moreover, because of the property that the organic solar cell element is see-through, the thin-film solar cell according to this embodiment can also be used as an interior window.

(III Vegetable Factory)
The number of plant factories that use illumination light such as fluorescent lamps is increasing, but the current situation is that it is difficult to reduce cultivation costs due to the cost of lighting and replacement of light sources. Then, the thin film solar cell which concerns on this embodiment can be installed in a vegetable factory, and the illumination system combined with LED or the fluorescent lamp can be constructed | assembled. At this time, it is preferable to use an illumination system that combines the LED having a longer life than the fluorescent lamp and the solar cell according to the present embodiment, because the cost required for illumination can be reduced by about 30% compared to the current situation. Moreover, the solar cell according to the present embodiment can be used for the roof and side walls of a reefer container that transports vegetables and the like at a constant temperature.

(IV Road materials and civil engineering)
The thin film solar cell according to the present embodiment can be used for an outer wall of a parking lot, a sound insulation wall of a highway, an outer wall of a water purification plant, and the like.

(V car)
The thin film solar cell according to this embodiment can be used on the surfaces of automobile bonnets, roofs, trunk lids, doors, front fenders, rear fenders, pillars, bumpers, rearview mirrors, and the like. The obtained electric power can be supplied to any of a traveling motor, a motor driving battery, an electrical component, and an electrical component battery. Considering the power generation status in the solar cell panel and the power usage status in the motor for driving, the motor drive battery, the electrical equipment and the electrical equipment battery, the power supply source is a thin film solar cell, or other battery or power generation Control means for selecting whether to use the machine or both of them may be further installed. Thus, the obtained electric power can be used appropriately and efficiently.

  When the thin film solar cell according to the present embodiment is used in an automobile, the shape of the substrate 12 is not limited, but a plate material is usually used. Moreover, what is necessary is just to set the material of the base material 12, a dimension, etc. arbitrarily according to the use environment. Examples of such a substrate 12 include Alpolic (registered trademark; manufactured by Mitsubishi Plastics).

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[Synthesis Example 1: Synthesis of dibenzopyromethene boron chelate compound]
Compound C1, which is a dibenzopyromethene boron chelate compound (boron chelate [5- [3-hexylthiophen-2-yl] -1-[[5- [3-hexylthiophen-2-yl] -3- (2- Hydroxyphenyl) -2H-isoindol-1-yl] methylene] -3- (2-hydroxyphenyl) -1H-isoindole]) and compound C2 (boron chelate [5- [5-hexylthiophen-2-yl]) -1-[[5- [5-Hexylthiophen-2-yl] -3- (2-hydroxyphenyl) -2H-isoindol-1-yl] methylene] -3- (2-hydroxyphenyl) -1H- A synthesis example of (isoindole) will be described. First, an outline of the synthesis route of Compound C1 and Compound C2 is shown, and then each step is described in detail.

<Synthesis of Compound D3>

  Under a nitrogen atmosphere, Compound D1 (14.1352 g, 65.73 mmol) and Compound D2 (9.80 g, 58.97 mmol) were dissolved in absolute ethanol (65 ml). Then, it heated at 85 degreeC and stirred for 4 days. After confirming the completion of the reaction by thin layer chromatography (normal phase silica gel, ethyl acetate: n-hexane = 1: 1), the mixture was air-cooled and filtered using a Kiriyama funnel. The obtained solid was dissolved in chloroform (1000 mL) and filtered again using a Kiriyama funnel. The filtrate was distilled off under reduced pressure to obtain a white solid (Compound D3) (yield 7.8838 g, yield 62%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＣＤＣｌ_３） δ （ｐｐｍ）： ２．３３ （３Ｈ， ｓ， ＣＨ_３）， ４．０８ （３Ｈ， ｓ， ＯＭｅ）， ６．９５ （１Ｈ， ｄｄ， Ｊ ＝ ２．０７， ８．５２ Ｈｚ， Ｈ_ｂ）， ７．０２ （１Ｈ， ｄ， Ｊ ＝ ７．９９ Ｈｚ， Ｈ_ｇ）， ７．１４ （１Ｈ， ａｐｐ． ｔ， Ｊ ＝ ７．５７ Ｈｚ， Ｈ_ｅ）， ７．１９ （１Ｈ， ｄ， Ｊ ＝ １．９７ Ｈｚ， Ｈ_ｃ）， ７．２６ （１Ｈ， ｄ， Ｊ ＝ ８．５３ Ｈｚ， Ｈ_ａ）， ７．５１ （１Ｈ， ｄｄｄ， Ｊ ＝ １．８３， ８．３４， ７．３２ Ｈｚ， Ｈ_ｆ）， ８．３２ （１Ｈ， ｄｄ， Ｊ ＝ １．８１， ７．８３ Ｈｚ， Ｈ_ｄ）， １０．９９ （１Ｈ， ｓ， ＮＨ）， １３．１２ （１Ｈ， ｓ， ＯＨ）．
Ｅｘａｃｔ ｍａｓｓ： ３６２．０３
ＦＡＢ ＭＳ： ３６３ ［Ｍ＋Ｈ］^＋ Compound D3: (Z) -N ′-(1- (4-bromo-2-hydroxyphenyl) ethylidene) -2-methoxybenzohydrazine

¹ H NMR (270 MHz, CDCl ₃ ) δ (ppm): 2.33 (3H, s, CH ₃ ), 4.08 (3H, s, OMe), 6.95 (1H, dd, J = 2. 07, 8.52 Hz, H _b ), 7.02 (1H, d, J = 7.99 Hz, H _g ), 7.14 (1H, app. T, J = 7.57 Hz, H _e ) 7.19 (1H, d, J = 1.97 Hz, H _c ), 7.26 (1H, d, J = 8.53 Hz, H _a ), 7.51 (1H, ddd, J = 1) .83, 8.34, 7.32 Hz, H _f ), 8.32 (1H, dd, J = 1.81, 7.83 Hz, H _d ), 10.99 (1H, s, NH), 13.12 (1H, s, OH).
Exact mass: 362.03
FAB MS: 363 [M + H] ⁺

<Synthesis of Compound D4>

  Compound D3 (7.77751 g, 21.4 mmol) was dissolved in tetrahydrofuran (390 ml) and stirring was started. Subsequently, the solution was ice-cooled, lead tetraacetate (11.386 g, 25.68 mmol) was added little by little, the temperature was returned to room temperature, and stirring was continued for 7 hours. After confirming the completion of the reaction by thin layer chromatography (normal phase silica gel, ethyl acetate: n-hexane = 1: 1), filtration was performed using a Kiriyama funnel, and the obtained filtrate was distilled off under reduced pressure. Thereafter, the mixture was freeze-dried to obtain a pale yellow solid (Compound D4) (yield 7.3170 g, yield 99%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＣＤＣｌ_３） δ （ｐｐｍ）： ２．４６ （３Ｈ， ｓ， ＣＨ_３）， ３．６２ （３Ｈ， ｓ， ＯＭｅ）， ６．９３ （１Ｈ， ｄ， Ｊ ＝ ８．３２ Ｈｚ， Ｈ_ｇ）， ７．０５ （１Ｈ， ｔｄ， Ｊ ＝ ０．８９， ７．５３ Ｈｚ， Ｈ_ｅ）， ７．４６ （１Ｈ， ｄ， Ｊ ＝ １．８１ Ｈｚ， Ｈ_ｃ）， ７．５０８ （１Ｈ， ｄｄｄ， Ｊ ＝ １．７９， ７．３５， ８．３９ Ｈｚ， Ｈ_ｆ）， ７．５７ （１Ｈ， ｄ， Ｊ ＝ ８．２１ Ｈｚ， Ｈ_ａ）， ７．６４ （１Ｈ， ｄｄ， Ｊ ＝ １．９０， ８．２５ Ｈｚ， Ｈ_ｄ）， ７．７６ （１Ｈ， ｄｄ， Ｊ ＝ １．８０， ７．７４ Ｈｚ， Ｈ_ｂ）．
Ｅｘａｃｔ Ｍａｓｓ： ３３２．００
ＦＡＢ ＭＳ： ３３３ ［Ｍ＋Ｈ］^＋ Compound D4: 1- (4-bromo-2- (2-methoxybenzoyl) phenyl) ethanone

¹ H NMR (270 MHz, CDCl ₃ ) δ (ppm): 2.46 (3H, s, CH ₃ ), 3.62 (3H, s, OMe), 6.93 (1H, d, J = 8. _{32 Hz, H g), 7.05} (1H, td, J = 0.89, 7.53 Hz, H e), 7.46 (1H, d, J = 1.81 Hz, H c), 7 .508 (1H, ddd, J = 1.79, 7.35, 8.39 Hz, H _f ), 7.57 (1H, d, J = 8.21 Hz, H _a ), 7.64 (1H , Dd, J = 1.90, 8.25 Hz, H _d ), 7.76 (1H, dd, J = 1.80, 7.74 Hz, H _b ).
Exact Mass: 332.00
FAB MS: 333 [M + H] ⁺

<Synthesis of Compound D5>

  Compound D4 (7.237 g, 21.7 mmol) was dissolved in methanol (230 ml), acetic acid (130 ml) was added and stirred, and aqueous ammonia (100 ml) was added little by little while cooling with ice. After returning to room temperature, the mixture was heated to 40 ° C. and stirred for 5 days. After confirming the completion of the reaction by thin layer chromatography (normal phase silica gel, chloroform: n-hexane = 2: 1), the reaction solution was air-cooled, and a saturated aqueous sodium hydrogen carbonate solution (150 ml) was added until the pH became around 7. The purple solid obtained by filtering using a Kiriyama funnel was sufficiently dried, and then a liquid separation operation was performed using chloroform (300 ml) and saturated saline (300 ml). After drying the organic phase with sodium sulfate, the solvent was distilled off under reduced pressure. Thereafter, purification was performed by column chromatography (normal phase silica gel, chloroform: n-hexane = 2: 1) to obtain a purple solid (compound D5) (yield 2.905 g, yield 44%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＤＭＳＯ−ｄ_６） δ （ｐｐｍ）： ３．７５ （６Ｈ， ｓ， ＯＭｅ）， ７．１８ （２Ｈ， ｔｄ， Ｊ ＝ ０．６８， ７．４７ Ｈｚ， Ｈ_ｆ）， ７．２５ （２Ｈ， ｄ， Ｊ ＝ ７．９９ Ｈｚ， Ｈ_ｈ）， ７．４６−７．５２ （２Ｈ， ｍ， Ｈ_ｇ）， ７．５４ （２Ｈ， ｄｄ， Ｊ ＝ １．６４， ８．５５ Ｈｚ， Ｈ_ｃ）， ７．９０ （２Ｈ， ｄｄ， Ｊ ＝ １．５９， ７．６４ Ｈｚ， Ｈ_ｅ）， ７．９６ （２Ｈ， ｄ， Ｊ ＝ １．４０ Ｈｚ， Ｈ_ｄ）， ８．１４ （２Ｈ， ｄ， Ｊ ＝ ８．５６ Ｈｚ， Ｈ_ｂ）， ８．１９ （１Ｈ， ｓ， Ｈ_ａ）．
Ｅｘａｃｔ ｍａｓｓ： ６１２．００
ＦＡＢ ＭＳ： ６１２ ［Ｍ］^＋ Compound D5: (Z) -5-bromo-1-((5-bromo-3- (2-methoxyphenyl) -2H-isoindol-1-yl) methylene) -3- (2-methoxyphenyl) -1H -Isoindole

¹ H NMR (270 MHz, DMSO-d ₆ ) δ (ppm): 3.75 (6H, s, OMe), 7.18 (2H, td, J = 0.68, 7.47 Hz, H _f ) 7.25 (2H, d, J = 7.99 Hz, H _h ), 7.46-7.52 (2H, m, H _g ), 7.54 (2H, dd, J = 1.64) _{8.55 Hz, H c), 7.90} (2H, dd, J = 1.59, 7.64 Hz, H e), 7.96 (2H, d, J = 1.40 Hz, H d) 8.14 (2H, d, J = 8.56 Hz, H _b ), 8.19 (1H, s, H _a ).
Exact mass: 612.00
FAB MS: 612 [M] ⁺

<Synthesis of Compound D6>

  Compound D5 (2.148 g, 3.5 mmol) was dissolved in anhydrous toluene (130 ml) and triethylamine (1.33 ml, 9.6 mmol) was added. After heating to 80 ° C. and adding boron trifluoride diethyl ether complex (3.5 ml, 27.7 mmol), the mixture was heated to 100 ° C. and stirred for 12 hours. After confirming the completion of the reaction by thin layer chromatography (normal phase silica gel, chloroform: n-hexane = 1: 1), the mixture was air-cooled and water (30 ml) was added while further cooling with ice. The compound was extracted with ethyl acetate (200 ml), the organic layer was dried over sodium sulfate, and the solvent was distilled off under reduced pressure. Reprecipitation was performed using chloroform (50 mL) and n-hexane (100 mL), and the obtained solid was purified by column chromatography (normal phase silica gel, chloroform: n-hexane = 1: 1). Furthermore, the obtained solid was dissolved in toluene at 100 ° C., air-cooled and recrystallized, and the resulting solid was washed with n-hexane to obtain an amber solid (compound D6) (yield 1.84). g, yield 79%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＤＭＳＯ−ｄ_６） δ （ｐｐｍ）： ３．６８ （３Ｈ， ｓ， ＯＭｅ）， ３．７３ （３Ｈ， ｓ， ＯＭｅ）， ７．０１， （１Ｈ， ｔ， Ｊ ＝ ７．９３ Ｈｚ， Ｈ_ｆ）， ７．０７ （１Ｈ， ｔ， Ｊ ＝ ７．７５ Ｈｚ， Ｈ_ｆ）， ７．１８ （１Ｈ， ｄ， Ｊ ＝ ８．７５ Ｈｚ， Ｈ_ｈ）， ７．２１ （１Ｈ， ｄ， Ｊ ＝ ８．７８ Ｈｚ， Ｈ_ｈ）， ７．３６−７．４５ （２Ｈ， ｍ， Ｈ_ｅ）， ７．４２ （２Ｈ， ｄ， Ｊ ＝ ０．８１ Ｈｚ， Ｈ_ｄ）， ７．５１ （２Ｈ， ａｐｐ． ｔ， Ｊ ＝ ７．８６ Ｈｚ Ｈ_ｇ）， ７．６９ （２Ｈ， ｄｄ， Ｊ ＝ １．４４， ８．６５ Ｈｚ， Ｈ_ｃ）， ８．１１ （２Ｈ， ｄ， Ｊ ＝ ８．４８ Ｈｚ， Ｈ_ｂ）， ８．７６ （１Ｈ， ｓ， Ｈ_ａ）．
Ｅｘａｃｔ ｍａｓｓ： ６６０．００
ＦＡＢ ＭＳ： ６６０ ［Ｍ］^＋ Compound D6: Difluoro [5-bromo-1-[[5-bromo-3- (2-methoxyphenyl) -2H-isoindol-1-yl] methylene] -3- (2-methoxyphenyl) -1H-iso Indian rate ^-N 1, ^{N 2]} boron

¹ H NMR (270 MHz, DMSO-d ₆ ) δ (ppm): 3.68 (3H, s, OMe), 3.73 (3H, s, OMe), 7.01, (1H, t, J = 7.93 Hz, H _f ), 7.07 (1H, t, J = 7.75 Hz, H _f ), 7.18 (1H, d, J = 8.75 Hz, H _h ), 7.21 (1H, d, J = 8.78 Hz, H h), 7.36-7.45 (2H, m, H e), 7.42 (2H, d, J = 0.81 Hz, H d) , 7.51 (2H, app. t , J = 7.86 Hz H g), 7.69 (2H, dd, J = 1.44, 8.65 Hz, H c), 8.11 (2H, d, J = 8.48 Hz, H _b ), 8.76 (1H, s, H _a ).
Exact mass: 660.00
FAB MS: 660 [M] ⁺

<Synthesis of Compound D8>

  First, tetrahydrofuran and water were bubbled with nitrogen for 60 minutes, and a 2M potassium carbonate aqueous solution was prepared using this water. Under a nitrogen atmosphere, Compound D6 (500 mg, 0.755 mmol) and Compound D7 (423 mg, 1.510 mmol) were dissolved in tetrahydrofuran (25 ml), and an aqueous potassium carbonate solution (2 M) prepared as described above was used. , 7.5 ml). The reaction solution was frozen and degassed twice, and tetrakis (triphenylphosphine) palladium (0) (174.5 mg, 0.151 mmol) was added and the atmosphere was replaced with nitrogen while the solution was frozen. After returning to room temperature, the mixture was heated to 70 ° C. to reflux and stirred for 16 hours. After confirming the completion of the reaction by thin layer chromatography (normal phase silica gel, chloroform: n-hexane = 3: 1), air-cooled, ethyl acetate (50 ml) and water (1 ml) were added, and THF was distilled off under reduced pressure. did. The compound was extracted with ethyl acetate (200 ml), the organic layer was dried over sodium sulfate, and the solvent was distilled off under reduced pressure. Purification by column chromatography (normal phase silica gel, chloroform: n-hexane = 3: 1) gave a dark blue solid (compound D8) (yield 420 mg, 83%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＤＭＳＯ−ｄ_６） δ （ｐｐｍ）： ０．７６−０．８１ （６Ｈ， ｍ， Ｈ_ｐ）， １．１３−１．２３ （１２Ｈ， ｍ， Ｈ_ｍ， Ｈ_ｎ， Ｈ_ｏ）， １．４３−１．５５ （４Ｈ， ｍ， Ｈ_ｌ）， ２．５９ （４Ｈ， ｔ， Ｊ ＝ ７．３３ Ｈｚ， Ｈ_ｋ）， ３．６８ （３Ｈ， ｓ， ＯＭｅ）， ３．７４ （３Ｈ， ｓ， ＯＭｅ）， ６．９９−７．２３ （６Ｈ， ｍ， Ｈ_ｄ， Ｈ_ｆ， Ｈ_ｈ）， ７．０４ （２Ｈ， ｄ， Ｊ ＝ ５．１０ Ｈｚ， Ｈ_ｉ）， ７．４０−７．５１ （４Ｈ， ｍ， Ｈ_ｅ， Ｈ_ｇ）， ７．４７ （２Ｈ， ｄ， Ｊ ＝ ５．０８ Ｈｚ， Ｈ_ｊ）， ７．６１ （２Ｈ， ｄ， Ｊ ＝ ９．１８ Ｈｚ， Ｈ_ｃ）， ８．２２ （２Ｈ， ｄ， Ｊ ＝ ８．２９ Ｈｚ， Ｈ_ｂ）， ８．７３ （１Ｈ， ｓ， Ｈ_ａ）．
Ｅｘａｃｔ ｍａｓｓ： ８３６．３５
ＦＡＢ ＭＳ： ８３６ ［Ｍ］^＋ Compound D8: Difluoro [5- [3-hexylthiophen-2-yl] -1-[[5- [3-hexylthiophen-2-yl] -3- (2-methoxyphenyl) -2H-isoindole-1 -Yl] methylene] -3- (2-methoxyphenyl) -1H-isoindolate-N ¹ , N ² ] boron

¹ H NMR (270 MHz, DMSO-d ₆ ) δ (ppm): 0.76-0.81 (6H, m, H _p ), 1.13-1.23 (12H, m, H _m , H _{n , H o), 1.43-1.55 (4H} , m, H l), 2.59 (4H, t, J = 7.33 Hz, H k), 3.68 (3H, s, OMe) , 3.74 (3H, s, OMe ), 6.99-7.23 (6H, m, H d, H f, H h), 7.04 (2H, d, J = 5.10 Hz, H _{i), 7.40-7.51 (4H, m} , H e, H g), 7.47 (2H, d, J = 5.08 Hz, H j), 7.61 (2H, d, J = 9.18 Hz, H _c ), 8.22 (2H, d, J = 8.29 Hz, H _b ), 8.73 (1H, s, H _a ).
Exact mass: 836.35
FAB MS: 836 [M] ⁺

<Synthesis of Compound C1>

  Under a nitrogen atmosphere, Compound D8 (500 mg, 0.60 mmol) was dissolved in anhydrous dichloromethane (36 mL) and cooled to 0 ° C. with ice. Thereafter, a solution of boron tribromide in dichloromethane (1 M, 3.0 mL) was added, and the mixture was stirred for 12 hours while returning to room temperature. After completion of the reaction, the mixture was cooled with ice and a saturated aqueous sodium hydrogen carbonate solution was added. The reaction product was extracted with dichloromethane (250 ml) and dried over magnesium sulfate, and then the solvent was distilled off under reduced pressure. Purification was performed by column chromatography (normal phase silica gel, chloroform: n-hexane = 2: 3) to obtain a green solid (compound C1) (yield 242 mg, yield 53%).

^１Ｈ ＮＭＲ （２７０ ＭＨｚ， ＤＭＳＯ−ｄ_６） δ （ｐｐｍ）： ０．７４−０．７９ （６Ｈ， ｍ， Ｈ_ｐ）， １．１９−１．３０ （１２Ｈ， ｍ， Ｈ_ｍ， Ｈ_ｎ， Ｈ_ｏ）， １．６４ （４Ｈ， ｑｕｉｎｔ， Ｊ ＝ ６．９８ Ｈｚ， Ｈ_ｌ）， ２．７１ （４Ｈ， ｔ， Ｊ ＝ ７．７５ Ｈｚ， Ｈ_ｋ）， ６．９５ （２Ｈ， ｄ， Ｊ ＝ ８．１８ Ｈｚ， Ｈ_ｈ）， ７．１３ （２Ｈ， ｄ， Ｊ ＝ ５．１６ Ｈｚ， Ｈ_ｉ）， ７．２１ （２Ｈ， ｔ， Ｊ ＝ ７．５６ Ｈｚ， Ｈ_ｆ）， ７．４６ （２Ｈ， ｔ， Ｊ ＝ ７．７６ Ｈｚ， Ｈ_ｇ）， ７．５６ （２Ｈ， ｄ， Ｊ ＝ ５．１０ Ｈｚ， Ｈ_ｊ）， ７．７１ （２Ｈ， ｄ， Ｊ ＝ ８．５６ Ｈｚ， Ｈ_ｃ）， ８．３１ （２Ｈ， ｄ， Ｊ ＝ ８．４５ Ｈｚ， Ｈ_ｂ）， ８．３８ （２Ｈ， ｓ， Ｈ_ｄ）， ８．４６ （２Ｈ， ｄ， Ｊ ＝ ７．８０ Ｈｚ， Ｈ_ｅ）， ８．６４ （１Ｈ， ｓ， Ｈ_ａ）．
Ｅｘａｃｔ Ｍａｓｓ： ７６８．３０
ＦＡＢ ＭＳ： ７６８ ［Ｍ］^＋
元素分析： Ｃａｌｃ． Ｆｏｒ Ｃ_４９Ｈ_４５ＢＮ_２Ｏ_２Ｓ_２： Ｃ， ７６．５５； Ｈ， ５．９； Ｎ， ３．６４； Ｓ， ８．３４； Ｂ， １．４１， Ｆｏｕｎｄ： Ｃ， ７６．５０； Ｈ， ５．９９； Ｎ， ３．５２； Ｓ， ８．２； Ｂ， １．４． Compound C1: Boron chelate [5- [3-hexylthiophen-2-yl] -1-[[5- [3-hexylthiophen-2-yl] -3- (2-hydroxyphenyl) -2H-isoindole- 1-yl] methylene] -3- (2-hydroxyphenyl) -1H-isoindole]

¹ H NMR (270 MHz, DMSO-d ₆ ) δ (ppm): 0.74-0.79 (6H, m, H _p ), 1.19-1.30 (12H, m, H _m , H _{n , H o), 1.64 (4H} , quint, J = 6.98 Hz, H l), 2.71 (4H, t, J = 7.75 Hz, H k), 6.95 (2H, d _{, J = 8.18 Hz, H h} ), 7.13 (2H, d, J = 5.16 Hz, H i), 7.21 (2H, t, J = 7.56 Hz, H f), 7.46 (2H, t, J = 7.76 Hz, H _g ), 7.56 (2H, d, J = 5.10 Hz, H _j ), 7.71 (2H, d, J = 8. _{56 Hz, H c), 8.31} (2H, d, J = 8.45 Hz, H b), 8.38 (2H, s _{H d), 8.46 (2H,} d, J = 7.80 Hz, H e), 8.64 (1H, s, H a).
Exact Mass: 768.30
FAB MS: 768 [M] ⁺
Elemental analysis: Calc. For C ₄₉ H ₄₅ BN ₂ O ₂ S ₂ : C, 76.55; H, 5.9; N, 3.64; S, 8.34; B, 1.41, Found: C, 76.50; H, 5.9; N, 3.52; S, 8.2; B, 1.4.

<Synthesis of Compound D11>

  First, anhydrous toluene was bubbled with nitrogen for 60 minutes. Under a nitrogen atmosphere, Compound D6 (410.2 mg, 0.62 mmol) and Compound D10 (621.0 mg, 1.36 mmol) were dissolved in this anhydrous toluene (50 mL), and freeze degassing was performed twice. It was. Thereafter, the mixture was frozen again, and tetrakis (triphenylphosphine) palladium (0) (36.2 mg, 0.031 mmol) was added to replace the nitrogen. After returning to room temperature, the mixture was heated to 90 ° C. and stirred for 31 hours. After completion of the reaction, the reaction mixture was air-cooled and the solvent was distilled off under reduced pressure. Purification by column chromatography (normal phase silica gel, chloroform: n-hexane = 3: 1) gave a green solid (Compound D11) (Yield 241.7 mg, Yield 47%).

^１Ｈ ＮＭＲ （５００ ＭＨｚ， ＤＭＳＯ−ｄ_６） δ （ｐｐｍ）： ０．８４−０．８７ （６Ｈ， ｍ， Ｈ_ｐ）， １．２４−１．３４ （１２Ｈ， ｍ， Ｈ_ｍ， Ｈ_ｎ， Ｈ_ｏ）， １．６１ （４Ｈ， ｑｕｉｎｔ， Ｊ ＝ ７．３５ Ｈｚ， Ｈ_ｌ）， ２．７７ （４Ｈ， ｔ， Ｊ ＝ ７．４７ Ｈｚ， Ｈ_ｋ）， ３．６９ （３Ｈ， ｓ， ＯＭｅ）， ３．７５ （３Ｈ， ｓ， ＯＭｅ）， ６．８３ （２Ｈ， ｄ， Ｊ ＝ ３．４５ Ｈｚ， Ｈ_ｊ）， ７．０４ （１Ｈ， ｔ， Ｊ ＝ ７．３７ Ｈｚ， Ｈ_ｆ）， ７．１０ （１Ｈ， ｔ， Ｊ ＝ ７．４０ Ｈｚ， Ｈ_ｆ）， ７．２１ （１Ｈ， ｄ， Ｊ ＝ ８．３０ Ｈｚ， Ｈ_ｈ）， ７．２５ （１Ｈ， ｄ， Ｊ ＝ ８．４５ Ｈｚ， Ｈ_ｈ）， ７．３３ （２Ｈ， ｓ， Ｈ_ｄ）， ７．３５ （２Ｈ， ｄ， Ｊ ＝ ３．４５ Ｈｚ， Ｈ_ｉ）， ７．４２ （１Ｈ， ｄ， Ｊ ＝ ７．６５ Ｈｚ， Ｈ_ｅ）， ７．４９ （１Ｈ， ｄ， Ｊ ＝ ７．５５ Ｈｚ， Ｈ_ｅ）， ７．５２ （２Ｈ， ｔ， Ｊ ＝ ８．００ Ｈｚ， Ｈ_ｇ）， ７．８５ （２Ｈ， ｄｄ， Ｊ ＝ １．５０， ８．６０ Ｈｚ， Ｈ_ｃ）， ８．１７ （２Ｈ， ｄｄ， Ｊ ＝ ２．３８， ８．５２ Ｈｚ， Ｈ_ｂ）， ８．６７ （１Ｈ， ｓ， Ｈ_ａ）．
Ｅｘａｃｔ Ｍａｓｓ： ８３６．３５
ＦＡＢ ＭＳ： ８３６ ［Ｍ］^＋ Compound D11: Difluoro [5- [5-hexylthiophen-2-yl] -1-[[5- [5-hexylthiophen-2-yl] -3- (2-methoxyphenyl) -2H-isoindole-1 -Yl] methylene] -3- (2-methoxyphenyl) -1H-isoindolate-N ¹ , N ² ] boron

¹ H NMR (500 MHz, DMSO-d ₆ ) δ (ppm): 0.84-0.87 (6H, m, H _p ), 1.24-1.34 (12H, m, H _m , H _{n , H o), 1.61 (4H} , quint, J = 7.35 Hz, H l), 2.77 (4H, t, J = 7.47 Hz, H k), 3.69 (3H, s , OMe), 3.75 (3H, s, OMe), 6.83 (2H, d, J = 3.45 Hz, H _j ), 7.04 (1H, t, J = 7.37 Hz, H _{f), 7.10 (1H, t} , J = 7.40 Hz, H f), 7.21 (1H, d, J = 8.30 Hz, H h), 7.25 (1H, d, J _{= 8.45 Hz, H h),} 7.33 (2H, s, H d), 7.35 (2H, d, J = _{.45 Hz, H i), 7.42} (1H, d, J = 7.65 Hz, H e), 7.49 (1H, d, J = 7.55 Hz, H e), 7.52 ( 2H, t, J = 8.00 Hz, H _g ), 7.85 (2H, dd, J = 1.50, 8.60 Hz, H _c ), 8.17 (2H, dd, J = 2. 38, 8.52 Hz, H _b ), 8.67 (1H, s, H _a ).
Exact Mass: 836.35
FAB MS: 836 [M] ⁺

<Synthesis of Compound C2>

  Under a nitrogen atmosphere, Compound D11 (223.0 mg, 0.27 mmol) was dissolved in anhydrous dichloromethane (25 mL) and cooled to 0 ° C. with ice. Boron tribromide in dichloromethane (1 M, 1.1 mL) was added thereto, and the mixture was stirred for 18 hours while gradually returning to room temperature. After completion of the reaction, a saturated aqueous sodium hydrogen carbonate solution was added, and the reaction product was extracted with chloroform (150 mL). The organic layer was dried over sodium sulfate, the solvent was distilled off under reduced pressure, and purification was performed by column chromatography (normal phase silica gel, chloroform: n-hexane = 2: 1) to obtain a green solid (compound C2). (Yield 182.3 mg, 89% yield).

^１Ｈ ＮＭＲ （５００ ＭＨｚ， ＣＤＣｌ_３） δ （ｐｐｍ）： ０．９１−０．９４ （６Ｈ， ｍ， Ｈ_ｐ）， １．３４−１．３７ （８Ｈ， ｍ， Ｈ_ｎ， Ｈ_ｏ）， １．４４ （４Ｈ， ｑｕｉｎｔ， Ｊ ＝ ７．２１ Ｈｚ， Ｈ_ｍ）， １．７５ （４Ｈ， ｑｕｉｎｔ， Ｊ ＝ ７．５７ Ｈｚ， Ｈ_ｌ）， ２．８６ （４Ｈ， ｔ， Ｊ ＝ ７．６０ Ｈｚ， Ｈ_ｋ）， ６．７８ （２Ｈ， ｄ， Ｊ ＝ ３．４５ Ｈｚ， Ｈ_ｊ）， ７．０２ （２Ｈ， ｄｄ， Ｊ ＝ ０．７８， ８．１３ Ｈｚ， Ｈ_ｈ）， ７．２０ （２Ｈ， ｄ， Ｊ ＝ ３．５０ Ｈｚ， Ｈ_ｉ）， ７．２３ （２Ｈ， ａｐｐ． ｔ， Ｊ ＝ ７．５８ Ｈｚ， Ｈ_ｆ）， ７．４２ （２Ｈ， ａｐｐ． ｔ， Ｊ ＝ ７．７４ Ｈ_ｇ）， ７．５８ （１Ｈ， ｓ， Ｈ_ａ）， ７．６７ （２Ｈ， ｄｄ， Ｊ ＝ １．３０， ８．４５ Ｈｚ， Ｈ_ｃ）， ７．８１ （２Ｈ， ｄ， Ｊ ＝ ８．４０ Ｈｚ， Ｈ_ｂ）， ８．２５ （２Ｈ， ｄｄ， Ｊ ＝ １．３８， ７．９２ Ｈｚ， Ｈ_ｅ）， ８．２７ （２Ｈ， ｓ， Ｈ_ｄ）．
Ｅｘａｃｔ Ｍａｓｓ： ７６８．３０
ＦＡＢ ＭＳ： ７６８ ［Ｍ^＋］
元素分析： Ｃａｌｃ． Ｆｏｒ Ｃ_４９Ｈ_４５ＢＮ_２Ｏ_２Ｓ_２・０．４Ｈ_２Ｏ・０．１Ｃ_６Ｈ_１４ ： Ｃ， ７５．９； Ｈ， ６．０６； Ｎ， ３．５７，Ｆｏｕｎｄ： Ｃ， ７５．９０； Ｈ， ６．００； Ｎ， ３．５７． 推定分子量 Ｍｏｌ． Ｗｔ．： ７８４．８４ Compound C2: Boron chelate [5- [5-hexylthiophen-2-yl] -1-[[5- [5-hexylthiophen-2-yl] -3- (2-hydroxyphenyl) -2H-isoindole- 1-yl] methylene] -3- (2-hydroxyphenyl) -1H-isoindole

¹ H NMR (500 MHz, CDCl ₃ ) δ (ppm): 0.91-0.94 (6H, m, H _p ), 1.34-1.37 (8H, m, H _n , H _o ), 1.44 (4H, quint, J = 7.21 Hz, H _m ), 1.75 (4H, quint, J = 7.57 Hz, H ₁ ), 2.86 (4H, t, J = 7. 60 Hz, H _k ), 6.78 (2H, d, J = 3.45 Hz, H _j ), 7.02 (2H, dd, J = 0.78, 8.13 Hz, H _h ), 7 20 (2H, d, J = 3.50 Hz, H _i ), 7.23 (2H, app. T, J = 7.58 Hz, H _f ), 7.42 (2H, app. T, J = 7.74 H _g ), 7.58 (1H, s, H _a ), 7.67 (2H, dd, J = 1.30, 8.45 Hz, H _c ), 7.81 (2H, d, J = 8.40 Hz, H _b ), 8.25 (2H, dd, J = 1.38, 7. _{92 Hz, H e), 8.27} (2H, s, H d).
Exact Mass: 768.30
FAB MS: 768 [M ⁺ ]
Elemental analysis: Calc. _{For C 49 H 45 BN 2 O} 2 S 2 · 0.4H 2 O · 0.1C 6 H 14: C, 75.9; H, 6.06; N, 3.57, Found: C, 75.90 H, 6.00; N, 3.57. Estimated molecular weight Mol. Wt. : 784.84

上記反応式に従い、国際公開第２００８／０１８９３１号に記載の方法に準じてＣ７０（Ｉｎｄ）_２の合成を行った。反応生成物に対してＧＰＣ精製（溶媒：クロロホルム）を行うことにより、インデンのビス付加体であるＣ_７０（Ｉｎｄ）_２（化合物Ｅ１）の異性体混合物を得た。なお、得られた混合物を質量分析（ＡＰＣＩ法、ｎｅｇａｔｉｖｅ）すると、化合物Ｅ１の質量と一致するｍ／ｚ：１０７２［Ｍ］⁻が検出された。 [Synthesis Example 2: Synthesis of Fullerene Compound E1 (C ₇₀ (Ind) ₂ )]

According to the above reaction formula, C70 (Ind) ₂ was synthesized according to the method described in International Publication No. 2008/018931. By performing GPC purification (solvent: chloroform) on the reaction product, an isomer mixture of C ₇₀ (Ind) ₂ (compound E1) which is a bis-adduct of indene was obtained. In addition, when the obtained mixture was subjected to mass spectrometry (APCI method, negative), m / z: 1072 [M] ⁻ corresponding to the mass of the compound E1 was detected.

上記反応式に従い、特開２０１１−２２２９５７号公報に記載の方法に準じて、フラーレン化合物体Ｅ２の合成を行った。得られた反応液をシリカゲルろ過カラム（溶媒：トルエン）に通した後で濃縮し、シリカゲルカラムクロマトグラフィー精製（溶媒：トルエン）及びＧＰＣ精製（クロロホルム）を行うことにより、フラーレン化合物Ｅ２を得た。 [Synthesis Example 3: Synthesis of Fullerene Compound E2]
<Synthesis of Compound D22>

According to the above reaction formula, fullerene compound E2 was synthesized according to the method described in JP2011-222957A. The obtained reaction solution was passed through a silica gel filtration column (solvent: toluene) and then concentrated, and silica gel column chromatography purification (solvent: toluene) and GPC purification (chloroform) were performed to obtain fullerene compound E2.

[Synthesis Example 4: Synthesis of bicycloporphyrin compound]

In a 500 mL four-necked flask equipped with a condenser under a nitrogen atmosphere, ethyl 4,7-dihydro-8,8-dimethyl-4,7-ethano-2H-isoindole-1-carboxylate (compound D21, 5.00 g, 20.4 mmol) and sodium hydroxide (6.25 g, 150 mmol) previously ground in a mortar were dissolved in ethylene glycol (150 mL), the solvent was degassed, and the inside of the container was purged with nitrogen. The reaction vessel was shielded from light, stirred at 170 ° C. for 60 minutes, and cooled to room temperature. The reaction solution was put into ice water (300 mL), the product was extracted with chloroform, and anhydrous sodium sulfate was added to the organic layer and dried. After filtering the powder, the filtrate was concentrated under reduced pressure. The obtained oil was purified by sublimation to obtain Compound D22 (2.54 g, 14.7 mmol, 72%). It was confirmed by ¹ H NMR that the obtained compound was compound D22. The result of ¹ H NMR is shown below.

Compound D22: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 7.46 (brs, 1H), 6.54 (m, 1H), 6.48 (m, 1H), 6.47 (m, 1H) , 6.41 (m, 1H), 3.70 (m, 1H), 3.22 (d, 1H, J = 5.9 Hz), 1.41 (dd, 1H, J = 11.5, 2 .7 Hz), 1.24 (dd, 1H, J = 11.5, 2.7 Hz), 1.04 (s, 3H), 0.72 (s, 3H).

<Synthesis of Bicycloporphyrin Compound Isomeric Mixture (CP-1)>

Compound D22 (3.81 g, 22 mmol) was dissolved in chloroform (containing amylene, 400 mL), and paraformaldehyde (850 mg) was added thereto under a nitrogen atmosphere, and then p-toluenesulfonic acid monohydrate (200 mg) was added. Add and stir at room temperature for 5 hours. Subsequently, p-chloranil (2.17 g) was added and further stirred for 5 hours. The reaction solution was poured into water, the organic layer was separated, washed with saturated sodium bicarbonate solution, water, and brine, and dried over anhydrous sodium sulfate. After filtering the powder, the filtrate was concentrated under reduced pressure, and the residue was first purified by alumina column chromatography (solvent: chloroform) and then purified by silica gel chromatography (solvent: ethyl acetate / chloroform) to obtain bicycloporphyrin. A regioisomer mixture (2.44 g, 3.30 mmol) of compound (CP-1) was obtained (yield 60%). It was confirmed by ¹ H NMR, LC analysis, and MS analysis that the obtained compound was an isomer mixture of the target bicycloporphyrin compound. Various analysis results are shown below.

Compound CP-1: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 10.26-10.33 (m, 4H), 7.11-7.26 (m, 8H), 5.63 (m, 4H) ), 5.12-5.16 (m, 4H), 2.06-2.11 (m, 4H), 1.75-1.88 (m, 4H), 1.55-1.56 (m , 12H), 0.59-0.80 (m, 12H), -4.63 (brs, 2H).
The LC analysis results are shown in Table 1.
By mass spectrometry (FAB-MS method), m / z: 736 [M ⁺ ] corresponding to the mass of the target product was detected.

<Synthesis of Bicycloporphyrin Compound (CP-2)>

  Tetrakis (bicyclo [2.2.2] octadiene) porphyrin (compound CP-2) was synthesized according to the method described in paragraphs [0060] to [0066] of JP-A-2003-304014.

Compound CP-2: ¹ H NMR (400 MHz, CDCl ₃ ) δ: 10.40 (m, 4H), 7.20 (m, 8H), 5.81 (m, 8H), 2.24 (m, 8H), -4.80 (brs, 2H).
The LC analysis results are shown in Table 1.
By mass spectrometry (FAB-MS method), m / z: 623 [M ⁺ +1] consistent with the mass of the target product was detected.

[Synthesis Example 5: Synthesis of CF ₃ -POPy ₂ ]

  In a nitrogen atmosphere, 1-bromopyrene (Compound D23, manufactured by Tokyo Chemical Industry Co., Ltd., 5.6 g, 20 mmol) was dissolved in dehydrated tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., 100 mL), cooled to −78 ° C. Kanto Chemical Co., Ltd., 1.6M, 13 mL) was slowly added dropwise and stirred for 45 minutes while maintaining -78 ° C. Subsequently, triphenyl phosphite (manufactured by Wako Pure Chemical Industries, Ltd., 3.1 g, 10 mmol) was added dropwise, and after sufficient stirring, the reaction solution was warmed to room temperature, further stirred for 1.5 hours, and again -78. Cooled to ° C. On the other hand, 4-trifluoromethyl bromobenzene (Compound D24, manufactured by Tokyo Chemical Industry Co., Ltd., 4.4 g, 20 mmol) was dissolved in dehydrated tetrahydrofuran (50 mL) in another reaction vessel, and in a nitrogen atmosphere at −78 ° C., n-Butyllithium (manufactured by Kanto Chemical Co., Ltd., 1.6 M, 13 mL) was added and stirred for 30 minutes, and then the resulting solution was added dropwise to the first vessel, allowed to warm to room temperature, and stirred for 1 hour. . Water (20 mL) was added to the resulting reaction solution, tetrahydrofuran was distilled off under reduced pressure, and the product was extracted with methylene chloride. The organic layer was dried by adding magnesium sulfate, concentrated by filtration, and purified by column chromatography (developing solvent: hexane) to obtain Compound D25 (2.9 g, yield 50%). The compound was identified using NMR.

Compound D25 (2.9 g) was dissolved in acetone (manufactured by Kanto Chemical Co., Inc., 150 mL), hydrogen peroxide solution (manufactured by Wako Pure Chemical Industries, 30% aqueous solution, 2 mL) was added, and the mixture was stirred at room temperature. Water (20 mL) was added to the reaction solution, and the mixture was concentrated and washed with acetonitrile to obtain the desired product CF ₃ -POPy ₂ (2.4 g, yield 80%). The resulting product was confirmed by NMR.

[Example 1: Preparation and evaluation of organic thin-film solar cell element]
[Example 1-1: Organic thin film solar cell element using compound C1 as additive]

<Preparation of hole extraction layer>
A poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) aqueous dispersion (manufactured by H.C. Starck, Inc., trade name “CLEVIOUS ^™ PVP” as a hole extraction layer on a glass substrate on which an ITO electrode is patterned. AI4083 ") was applied by spin coating, and the substrate was heated on a hot plate at 120 ° C for 10 minutes in the air. The film thickness of the hole extraction layer was about 30 nm.

<Production of active layer>
0.7 mL of chlorobenzene, compound C1 (0.8 mg), poly (3-hexylthiophene) (P3HT: poly (3-hexylthiophene)) (11.3 mg) as a p-type semiconductor compound, and fullerene as an n-type semiconductor compound Compound E1 (10.7 mg) was added, heated and stirred at 80 ° C. for 1 hour, and filtered through a 0.45 μm filter to prepare an active layer coating solution. The substrate on which the hole extraction layer was formed was heat-treated at 185 ° C. for 3 minutes in a nitrogen atmosphere. On the substrate after the heat treatment, the active layer coating solution was applied by spin coating at 800 rpm. After confirming that the substrate surface was dried, the substrate coated with the active layer coating solution was heat-treated at 150 ° C. for 20 minutes in a nitrogen atmosphere.

<Preparation of electron extraction layer>
As an electron extraction layer, calcium was deposited on the active layer using a vacuum deposition apparatus. The layer thickness of the electron extraction layer was 10 nm.

<Production of cathode>
As a cathode, aluminum was vapor-deposited on the electron extraction layer using a vacuum vapor deposition apparatus. The cathode layer thickness was 80 nm. As described above, the organic thin-film solar cell element of Example 1 was produced.

<Evaluation of organic thin film solar cell element>
The obtained organic thin-film solar cell element was irradiated with light having an intensity of 100 mW / cm ^{2 with} a solar simulator (AM1.5G) from the ITO electrode side, and a source meter (type 2400, manufactured by Keithley) The current-voltage characteristic between the aluminum electrode was measured. Table 2 shows the measurement results of the open circuit voltage Voc [V], the short circuit current density Jsc [mA / cm ² ], the form factor FF, and the photoelectric conversion efficiency PCE [%]. Moreover, the external quantum yield (EQE) with respect to each wavelength of irradiation light is shown in FIG.

Here, the open circuit voltage Voc is the voltage value (V) when the current value = 0 (mA / cm ² ), and the short circuit current density Jsc is the current density (mA / mA when the voltage value = 0 (V). cm ² ). The form factor (FF) is a factor representing the internal resistance, and is represented by the following expression when the maximum output point 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 = Voc × Jsc × FF / Pin
For measurement of external quantum yield (EQE) for each wavelength of irradiation light, a PEC-S20 type action spectrum measuring device manufactured by Pexel Technologies, Inc. was used.

[Example 1-2: Organic thin film solar cell element using compound C2 as additive]
An organic thin-film solar cell element was produced in the same manner as in Example 1 except that Compound C2 was used instead of Compound C1 when the active layer coating solution was produced. About the produced organic thin-film solar cell element, the open circuit voltage Voc [V], the short circuit current density Jsc [mA / cm ² ], the shape factor FF, and the photoelectric conversion efficiency PCE [%] were measured in the same manner as in Example 1. The measurement results are shown in Table 2. Moreover, the external quantum yield (EQE) with respect to each wavelength of irradiation light is shown in FIG.

[Comparative Example 1-3: Organic thin-film solar cell element using no additive]
An organic thin film solar cell element was produced in the same manner as in Example 1 except that the compound C1 was not added when producing the active layer coating solution. About the produced organic thin-film solar cell element, the open circuit voltage Voc [V], the short circuit current density Jsc [mA / cm ² ], the shape factor FF, and the photoelectric conversion efficiency PCE [%] were measured in the same manner as in Example 1. The measurement results are shown in Table 2. Moreover, the external quantum yield (EQE) with respect to each wavelength of irradiation light is shown in FIG.

  As shown in Table 2, an organic thin film solar cell element (Example 1-1) containing dibenzopyromethene boron chelate compound C1 in the active layer and an organic thin film solar cell element containing dibenzopyromethene boron chelate compound C2 in the active layer (Example 1-2) improves the short circuit current, the form factor, and the photoelectric conversion efficiency as compared with an organic thin film solar cell element (Comparative Example 1-3) that does not contain a dibenzopyromethene boron chelate compound in the active layer. I understand that.

  Moreover, as shown in FIG. 4, in Example 1-1 and Example 1-2, the external quantum yield with respect to incident light of 680 nm to 800 nm is improved as compared with Comparative Example 1-3. That is, the conversion efficiency for light having a long wavelength is improved by including the dibenzopyromethene boron chelate compounds C1 and C2 in the active layer. This suggests that the energy obtained by absorbing light by the dibenzopyromethene boron chelate compounds C1 and C2 is extracted as an electric current.

  Furthermore, as shown in FIG. 4, in Example 1-1 and Example 1-2, the external quantum yield with respect to incident light of 480 nm to 620 nm is also improved as compared with Comparative Example 1-3. In this wavelength region, the p-type semiconductor compound (P3HT) also absorbs light, but P3HT and dibenzopyromethene boron chelate compounds C1 and C2 are more active layers than Comparative Example 1-3 including P3HT in the active layer. Examples 1-1 and 1-2 included in the above have higher conversion efficiency. This suggests that the energy obtained by the light absorption of the dibenzopyromethene boron chelate compound is extracted more smoothly as an electric current.

[Example 2: UV-visible absorption spectrum measurement]
An active layer is formed on the ITO electrode by applying the active layer coating solution used in Example 1-1, Example 1-2, or Comparative Example 1-3 on the glass substrate on which the ITO electrode is patterned. did. FIG. 5 shows an ultraviolet-visible absorption spectrum obtained by transmitting ultraviolet-visible light to the obtained active layer. In FIG. 5, the vertical axis represents the absorbance.

  FIG. 5 shows that the active layer of Example 1-1 and the active layer of Example 1-2 absorb light with a wavelength of 700 nm to 800 nm better than the active layer of Comparative Example 1-3. . This light absorption is considered to be derived from the dibenzopyromethene boron chelate compounds C1 and C2.

[Example 3: Production and evaluation of organic thin-film solar cell element (2)]
[Example 3-1: Organic thin-film solar cell element using compound C1 as additive]
<Preparation of hole extraction layer>
A poly (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) aqueous dispersion (manufactured by H.C. Starck, Inc., trade name “CLEVIOUS ^™ PVP” as a hole extraction layer on a glass substrate on which an ITO electrode is patterned. AI4083 ") was applied by spin coating, and then the substrate was subjected to heat treatment on the hot plate at 120 ° C for 10 minutes in the air. The film thickness was about 30 nm.

<Production of active layer>
Subsequently, an active layer was formed on the hole extraction layer. In this embodiment, the active layer includes a p-type semiconductor layer and a mixed layer (i layer).

  First, a p-type semiconductor layer was formed on the hole extraction layer. The substrate on which the hole extraction layer was formed in a nitrogen atmosphere was heat-treated at 180 ° C. for 3 minutes. Thereafter, a toluene solution containing 0.6% by weight of the bicycloporphyrin compound CP-1 synthesized in Synthesis Example 4 was prepared, and filtered with a 0.2 μm filter to prepare a coating solution 1. On the substrate after the heat treatment, the coating liquid 1 was applied by spin coating at 1500 rpm in a nitrogen atmosphere. After confirming that the substrate surface was dried, the substrate coated with coating solution 1 was heat-treated at 195 ° C. for 30 seconds in a nitrogen atmosphere. Bicycloporphyrin compound CP-1 is converted into tetrabenzoporphyrin (BP) which is a p-type semiconductor material by heat treatment. Thus, a p-type semiconductor layer having a thickness of about 25 nm was formed on the hole extraction layer.

  Next, a mixture layer was formed on the p-type semiconductor layer. It contains 0.85% by weight of the bicycloporphyrin compound CP-2 synthesized in Synthesis Example 4 and 0.55% by weight of the fullerene compound E2 synthesized in Synthesis Example 3, and further contains 10% by weight of the compound C1 with respect to the fullerene compound E2. A coating solution 2 was prepared by preparing a chloroform: chlorobenzene = 1: 1 (weight ratio) solution and filtering with a 0.2 μm filter. The coating liquid 2 was applied on the p-type semiconductor layer by spin coating at 1500 rpm in a nitrogen atmosphere. After confirming that the surface was dried, the substrate on which the coating liquid 2 was applied on the p-type semiconductor layer was heat-treated at 210 ° C. for 20 minutes in a nitrogen atmosphere. Bicycloporphyrin compound CP-2 is converted into tetrabenzoporphyrin (BP) which is a p-type semiconductor material by heat treatment. Thus, a layer having a thickness of about 100 nm including tetrabenzoporphyrin (BP), fullerene compound E2 and compound C1 was formed on the p-type semiconductor layer.

<Preparation of electron extraction layer>
Subsequently, an electron extraction layer was formed on the active layer. That is, CF ₃ POPy ₂ synthesized in Synthesis Example 5 was placed in a metal boat placed in a vacuum deposition apparatus and heated to deposit CF ₃ POPy ₂ on the active layer until the film thickness reached 4.5 nm. .

<Production of cathode>
Furthermore, aluminum was vapor-deposited with a thickness of 80 nm on the electron extraction layer by using a vacuum vapor deposition apparatus to form a counter electrode (cathode).

  After providing the counter electrode, the produced laminate was heated on a hot plate at 180 ° C. for 5 minutes to produce a photoelectric conversion element.

<Evaluation of organic thin film solar cell element>
About the produced organic thin-film solar cell element, the open circuit voltage Voc [V], the short circuit current density Jsc [mA / cm ² ], the shape factor FF, and the photoelectric conversion efficiency PCE [%] were measured in the same manner as in Example 1. Table 3 shows the measurement results.

[Comparative Example 3-2]
A photoelectric conversion element was prepared and current-voltage characteristics were measured in the same manner as in Example 3-1, except that the compound C1 was not added to the coating solution used for preparing the mixture layer. Table 3 shows the measurement results of the open-circuit voltage Voc [V], the short-circuit current density Jsc [mA / cm ² ], the form factor FF, and the photoelectric conversion efficiency PCE [%].

表３に示すように、ジベンゾピロメテンホウ素キレート化合物を活性層に含有するバルクへテロ型光電変換素子は、ジベンゾピロメテンホウ素キレート化合物を活性層に含有しないものと比較して、開放電圧及び短絡電流密度が増加し、光電変換効率が向上することがわかる。

As shown in Table 3, the bulk hetero-type photoelectric conversion element containing the dibenzopyromethene boron chelate compound in the active layer has an open circuit voltage and a short circuit compared with those not containing the dibenzopyromethene boron chelate compound in the active layer. It can be seen that the current density increases and the photoelectric conversion efficiency improves.

DESCRIPTION OF SYMBOLS 100 Organic thin-film solar cell element 110 Board | substrate 120,160 Electrode 130,150 Buffer layer 140 Active layer 1 Weatherproof protective film 2 Ultraviolet cut film 3,9 Gas barrier film 4,8 Getter material film 5,7 Sealing material
6 Solar cell element 10 Back sheet 12 Base material 13 Solar cell module 14 Thin film solar cell

Claims (3)

An organic thin film solar cell element including at least an active layer and a pair of electrodes,
The active layer contains an additive, a p-type semiconductor compound and an n-type semiconductor compound;
The said additive contains the dibenzopyromethene boron chelate compound represented by the following general formula (A1), The organic thin-film solar cell element characterized by the above-mentioned.

(In formula, R < ¹ > -R < ¹⁷ > shows a monovalent atom or atomic group each independently.)   A solar cell comprising the organic thin-film solar cell element according to claim 1.   A solar cell module comprising the solar cell according to claim 2.

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