JP5742705B2 - Organic photoelectric conversion element - Google Patents

Description

  The present invention relates to an organic photoelectric conversion element. More specifically, the present invention relates to a technique for improving the photoelectric conversion efficiency and the like of an organic photoelectric conversion element.

  In recent years, in order to cope with global warming, reduction of carbon dioxide emissions has been strongly desired. In addition, fossil fuels such as oil, coal, and natural gas are expected to be depleted in the near future, and there is an urgent need to secure alternative earth-friendly energy resources. Therefore, development of power generation technology using sunlight, wind power, geothermal energy, nuclear power, and the like has been actively carried out. Among them, solar power generation is particularly attracting attention because of its high safety.

  In solar power generation, light energy is directly converted into electric power using a photoelectric conversion element utilizing the photovoltaic effect. Generally, a photoelectric conversion element has a structure in which a photoelectric conversion layer (light absorption layer) is sandwiched between a pair of electrodes, and light energy is converted into electric energy in the photoelectric conversion layer. The photoelectric conversion element is a silicon-based photoelectric conversion element using single-crystal / polycrystalline / amorphous Si, GaAs, CIGS (copper (Cu), indium (In), depending on the material used for the photoelectric conversion layer and the form of the element. Compound-based photoelectric conversion elements using a compound semiconductor such as gallium (Ga) and selenium (Se)), dye-sensitized photoelectric conversion elements (Gretzel cells), and the like have been proposed and put to practical use.

  However, the power generation cost when these solar cells are used is still higher than the cost when generating and transmitting power using fossil fuels, which hinders the spread of solar power generation. In addition, since heavy glass must be used for the substrate, reinforcement work is required when it is installed on a roof or the like, which has also contributed to the increase in power generation costs.

  As a technique for reducing power generation costs in solar power generation, a mixture of an electron-donating organic compound (p-type organic semiconductor) and an electron-accepting organic compound (n-type organic semiconductor) between a transparent electrode and a counter electrode A bulk heterojunction (BHJ) type photoelectric conversion element is proposed that includes a photoelectric conversion layer. In 2007, a photoelectric conversion efficiency exceeding 5% was reported (Non-Patent Document 1), and further, it is theoretically expected that a photoelectric conversion efficiency of 10% can be achieved (Non-Patent Document 2). ).

  Bulk heterojunction organic photoelectric conversion elements are lightweight and flexible, and are expected to be applied to various products. In addition, since the structure is relatively simple and a photoelectric conversion layer can be formed by applying a p-type organic semiconductor and an n-type organic semiconductor, cost reduction can be expected by mass production on a roll-to-roll basis. It is thought to contribute to the early dissemination of More specifically, in the bulk heterojunction organic photoelectric conversion element, the electrodes (anode and cathode), the metal oxide layer constituting the hole transport layer, and the like can be formed by a method other than the coating process (for example, vacuum deposition method). Etc.). On the other hand, other layers can be formed using a coating process. Therefore, it is expected that the production of the bulk heterojunction photoelectric conversion element can be performed at high speed and at low cost, and it is considered that there is a possibility that the above-described problem of power generation cost can be solved. Further, unlike the production of conventional silicon-based photoelectric conversion elements, compound-based photoelectric conversion elements, dye-sensitized photoelectric conversion elements, etc., it does not necessarily involve a manufacturing process at a temperature higher than 160 ° C. It is expected that it can be formed on a lightweight plastic substrate.

  However, the organic photoelectric conversion element is still not sufficient in photoelectric conversion efficiency and durability against heat and light as compared with other types of photoelectric conversion elements. Accordingly, various improvements have been made in order to improve photoelectric conversion efficiency and durability. In particular, for the purpose of improving durability, for example, each layer is laminated in the reverse order of a normal organic photoelectric conversion element, electrons are taken out from the transparent electrode side, and holes are taken from the stable metal electrode side having a deep work function. A so-called reverse layer type organic photoelectric conversion element to be taken out has been proposed (Patent Document 1). Such a reverse layer type organic photoelectric conversion element has a configuration in which a hole transport layer composed of a conductive polymer having inferior optical transparency exists between a counter electrode (anode) and a photoelectric conversion layer. In general, the counter electrode (anode) is made of a metal material, but the light reflected by the counter electrode cannot be efficiently reused in the photoelectric conversion layer due to the presence of the hole transport layer having low light transmittance. Therefore, the reverse layer type is a disadvantageous configuration from the viewpoint of utilization of light (Non-Patent Document 3). Therefore, in order to obtain sufficient photoelectric conversion efficiency in the reverse layer type, it is generally necessary to take measures such as increasing the film thickness of the photoelectric conversion layer compared to the normal layer type.

  On the other hand, recently, in an organic thin film solar cell including a normal layer type organic photoelectric conversion element using a conjugated polymer compound having a naphthobisbenzothiadiazole ring structure as a photoelectric conversion material, a photoelectric conversion efficiency exceeding 6% has been achieved. It has been reported (Non-Patent Documents 4 and 5).

JP 2009-146981 A JP 2010-111649 A

A. Heeger et al. , Nature Mat. , Vol. 6 (2007), p497 Christoph J. et al. Brabec et al. , Adv. Mater. 2006, 18, p789 Appl. Phys. Lett. , 98, 043301 (2011) Macromolecules, 2011, 44 (18), pp7184. Polymer Preprints, Japan Vol. 60, no. 2 (2011) p4231

  However, when the conjugated polymer compound having a naphthobisbenzothiadiazole ring structure described in Non-Patent Document 4 or 5 is used for the photoelectric conversion layer of the reverse layer type element advantageous in terms of durability, it is desirable. It has been found that the photoelectric conversion efficiency of 1 can not be obtained.

  Furthermore, it has been found that a new problem occurs that it is difficult to form a hole transport layer on the surface of the photoelectric conversion layer. That is, in the manufacturing process of the reverse layer type element, a hole transport material such as PEDOT: PSS dissolved in an aqueous solvent is usually applied to the surface of the photoelectric conversion layer, and the coating film is dried to thereby form a hole transport layer. However, since the photoelectric conversion material described in Non-Patent Document 4 or 5 has a property of easily repelling the coating film, it is difficult to form the hole transport layer uniformly. It was.

  Therefore, the present invention provides an organic photoelectric conversion element that can improve the film forming property of a layer adjacent to the photoelectric conversion layer and can exhibit sufficient photoelectric conversion efficiency (particularly advantageous in terms of durability). An object of the present invention is to provide an organic photoelectric conversion element that can exhibit excellent photoelectric conversion efficiency even in a reverse layer configuration.

  In order to solve the above problems, the present inventors have conducted intensive research. And, by using a conjugated polymer compound having both a naphthobisbenzothiadiazole ring structure and a thiazolothiazole ring structure or a thienothiophene ring structure, improving the film forming property of a layer adjacent to the photoelectric conversion layer, And an organic photoelectric conversion element that can exhibit sufficient photoelectric conversion efficiency (particularly, an organic photoelectric conversion element that can exhibit excellent photoelectric conversion efficiency even in a reverse layer structure advantageous in terms of durability). The present invention was completed.

That is, the organic photoelectric conversion element of the present invention includes an n-type organic semiconductor and a p-type organic semiconductor that exist between the first electrode, the second electrode, and the first electrode and the second electrode. and a photoelectric conversion layer containing the p-type organic semiconductor is observed containing a conjugated polymer compound containing at least one partial structure represented by the partial structural and formula 2 represented by the following general formula 1 respectively the conjugated polymer compound including a partial structure represented by the partial structure or the following general formula 3B is represented by the following general formula 3A.

In the formula, -X ¹ = independently represents -C (R ³ ) = or -N =, and R ^{1 to} R ³ each independently represents a hydrogen atom (H) or a halogen atom (F , Cl, Br, or I), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a fluorinated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, Fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, fluorinated alkoxy group having 1 to 20 carbon atoms, fluorinated alkylthio group having 1 to 20 carbon atoms, carbon atom number An aryl group having 6 to 30 carbon atoms, a fluorinated aryl group having 6 to 30 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, or a fluorinated heteroaryl group having 1 to 20 carbon atoms is represented.
In the formula, -X ¹ = independently represents -C (R ³ ) = or -N =,
R ^{1 to} R ⁵ are each independently a hydrogen atom (H), a halogen atom (F, Cl, Br, or I), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, carbon Fluoroalkyl group having 1 to 20 atoms, cycloalkyl group having 3 to 20 carbon atoms, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, 1 to 1 carbon atom 20 fluorinated alkoxy groups, fluorinated alkylthio groups having 1 to 20 carbon atoms, aryl groups having 6 to 30 carbon atoms, fluorinated aryl groups having 6 to 30 carbon atoms, heteroaryls having 1 to 20 carbon atoms A group or a fluorinated heteroaryl group having 1 to 20 carbon atoms,
D independently represents a donor-type heteroaromatic ring group or a donor-type heterofused aromatic ring group containing a sulfur atom (S).

  ADVANTAGE OF THE INVENTION According to this invention, in an organic photoelectric conversion element, the organic photoelectric conversion element which can improve the film forming property of the layer adjacent to a photoelectric converting layer, and can exhibit sufficient photoelectric conversion efficiency (especially advantageous in terms of durability). It is possible to provide an organic photoelectric conversion element that can exhibit excellent photoelectric conversion efficiency even in a reverse layer configuration.

It is the cross-sectional schematic which represented typically the normal layer type organic photoelectric conversion element based on one Embodiment of this invention. It is the cross-sectional schematic which represented typically the reverse layer type organic photoelectric conversion element based on other one Embodiment of this invention. It is the cross-sectional schematic which represented typically the organic photoelectric conversion element provided with the tandem-type photoelectric conversion layer based on other one Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described.

<Organic photoelectric conversion element>
One embodiment of the present invention relates to an organic photoelectric conversion element including a conjugated polymer compound having both a naphthobisbenzothiadiazole ring structure and a thiazolothiazole ring structure or a thienothiophene ring structure in a photoelectric conversion layer. That is, the conjugated polymer compound of this embodiment is characterized by having at least one partial structure represented by the following general formula 1 and at least one partial structure represented by the general formula 2.

In General Formula 2, -X ¹ = independently represents -C (R ³ ) = or -N =. That is, when -X ¹ = is -C (R ³ ) =, General Formula 2 represents a thienothiophene ring structure, and when -X ¹ = is -N =, General Formula 2 is a thiazolothiazole ring structure. Represents. Of these, -X ¹ = is preferably -N =. This is because the planarity is higher in the case where -X ¹ = is -N = than in the case where -C (R ³ ) =, and thus high mobility is easily obtained, and the photoelectric conversion efficiency and durability are high. This is because it is possible to further improve the performance. Further, the HOMO level can be made deeper, which is preferable.

In the general formulas 1 and 2, R ^{1 to} R ³ each independently represent a hydrogen atom (H), a halogen atom (F, Cl, Br, or I), a substituted or unsubstituted, 1 carbon atom -20 alkyl group, fluorinated alkyl group having 1 to 20 carbon atoms, cycloalkyl group having 3 to 20 carbon atoms, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms Group, fluorinated alkoxy group having 1 to 20 carbon atoms, fluorinated alkylthio group having 1 to 20 carbon atoms, aryl group having 6 to 30 carbon atoms, fluorinated aryl group having 6 to 30 carbon atoms, carbon atom This represents a heteroaryl group having 1 to 20 carbon atoms or a fluorinated heteroaryl group having 1 to 20 carbon atoms.

  There is no restriction | limiting in particular as said halogen atom, Any of a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), and an iodine atom (I) may be sufficient. Among these, a fluorine atom (F) or a chlorine atom is preferable and a fluorine atom (F) is preferable from the viewpoint that side reactions hardly occur during polymerization (Br and I may react with tin). More preferred.

  The alkyl group having 1 to 20 carbon atoms is not particularly limited. For example, a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, an n-octyl group, an n-decyl group, an n-hexadecyl group, Examples thereof include linear or branched alkyl groups such as 2-ethylhexyl group and 2-hexyldecyl group. Among these, from the viewpoint of improving solubility, an alkyl group having 1 to 12 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms is more preferable.

Although there is no restriction | limiting in particular as said C1-C20 fluorinated alkyl group, For example, the group by which at least 1 of the hydrogen atom contained in the alkyl group illustrated above was substituted by the fluorine atom is mentioned. Among these, from the viewpoint of achieving a higher V _oc (deep HOMO level), the carbon atom closest to the bonding site with the ring (naphthobisbenzothiadiazole ring, thiazolothiazole ring, thienothiophene ring) (that is, in the alkyl group) It is preferable that only the 1st-position carbon atom is a group substituted with a fluorine atom. Specifically, fluoromethyl group, 1-fluoroethyl group, 1-fluoropropyl group, 1-fluorobutyl group, 1-fluorooctyl group, 1-fluorodecyl group, 1-fluorohexadecyl group, 1-fluoro- Monofluoroalkyl groups such as 2-ethylhexyl group and 1-fluoro-2-hexyldecyl group; difluoromethyl group, 1,1-difluoroethyl group, 1,1-difluoropropyl group, 1,1-difluorobutyl group, 1 , 1-difluorooctyl group, 1,1-difluorodecyl group, 1,1-difluorohexadecyl group, 1,1-difluoro-2-ethylhexyl group, 1,1-difluoro-2-hexyldecyl group, etc. Group; a trifluoroalkyl group such as a trifluoromethyl group, and the like. Moreover, it is preferable that it is a C1-C3 fluorinated alkyl group from a viewpoint of maintaining the applicability | paintability of an upper layer. Such a number of carbon atoms is sufficiently shorter than other soluble groups (substituents for imparting solubility generally use C6 or more) and have little influence on the upper layer coating property. It is. Of these, a trifluoromethyl group having 1 carbon atom is more preferable.

  Although there is no restriction | limiting in particular as said C3-C20 cycloalkyl group, For example, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group etc. are mentioned. Among these, a cycloalkyl group having 4 to 8 carbon atoms is preferable from the viewpoint of improving solubility.

The fluorinated cycloalkyl group having 3 to 20 carbon atoms is not particularly limited, and examples thereof include a group in which at least one hydrogen atom contained in the cycloalkyl group exemplified above is substituted with a fluorine atom. . Among these, from the viewpoint of achieving higher V _oc (deep HOMO level), it is preferable that all the hydrogen atoms contained in the cycloalkyl group exemplified above are groups substituted with fluorine atoms. In view of this, the number and position of fluorine atoms are preferably adjusted appropriately. Moreover, it is preferable that it is a C4-C8 fluorinated cycloalkyl group from a viewpoint of improving solubility.

  The alkoxy group having 1 to 20 carbon atoms is not particularly limited, and examples thereof include methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, n-decyloxy group, and n-hexa. A decyloxy group, 2-ethylhexyloxy group, 2-hexyldecyloxy group, etc. are mentioned.

  The aryl group having 6 to 30 carbon atoms is not particularly limited, and examples thereof include non-condensed hydrocarbon groups such as a phenyl group, a biphenyl group, and a terphenyl group; a pentarenyl group, an indenyl group, a naphthyl group, an azulenyl group, Heptalenyl group, biphenylenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylenyl group, pyrenyl group , Condensed polycyclic hydrocarbon groups such as a chrycenyl group and a naphthacenyl group.

The fluorinated aryl group having 6 to 30 carbon atoms is not particularly limited, and examples thereof include a group in which at least one hydrogen atom contained in the aryl group exemplified above is substituted with a fluorine atom. Among these, from the viewpoint of achieving higher V _oc (deep HOMO level), it is preferable that all the hydrogen atoms contained in the aryl group exemplified above are groups substituted with fluorine atoms. In view of the above, the number and position of fluorine atoms are preferably adjusted appropriately.

  The heteroaryl group having 1 to 20 carbon atoms is not particularly limited. For example, pyridyl group, pyrimidyl group, pyrazinyl group, triazinyl group, furanyl group, pyrrolyl group, thiophenyl group (thienyl group), quinolyl group, Furyl group, piperidyl group, coumarinyl group, silafluorenyl group, benzofuranyl group, benzimidazolyl group, benzoxazolyl group, benzthiazolyl group, dibenzofuranyl group, benzothiophenyl group, dibenzothiophenyl group, indolyl group, carbazolyl group, pyrazolyl Group, imidazolyl group, oxazolyl group, isoxazolyl group, thiazolyl group, indazolyl group, benzothiazolyl group, pyridazinyl group, cinnolyl group, quinazolyl group, quinoxalyl group, phthalazinyl group, phthalazine dionyl group, phthalamidyl group, Romonyl, naphtholactamyl, quinolonyl, naphthalidinyl, benzimidazolonyl, benzoxazolonyl, benzothiazolonyl, benzothiazothionyl, quinazolonyl, quinoxalonyl, phthalazonyl, dioxopyrimidinyl Group, pyridonyl group, isoquinolonyl group, isoquinolinyl group, isothiazolyl group, benzisoxazolyl group, benzisothiazolyl group, indazironyl group, acridinyl group, acridonyl group, quinazoline dionyl group, quinoxaline dionyl group, benzoxazine dionyl Group, benzoxazinonyl group, naphthalimidyl group, dithienocyclopentadienyl group, dithienosylcyclopentadienyl group, dithienopyrrolyl group, benzodithiophenyl group and the like.

The fluorinated heteroaryl group having 1 to 20 carbon atoms is not particularly limited, and examples thereof include a group in which at least one hydrogen atom contained in the heteroaryl group exemplified above is substituted with a fluorine atom. . Among these, from the viewpoint of achieving higher V _oc (deep HOMO level), it is preferable that all of the hydrogen atoms contained in the heteroaryl group exemplified above are groups substituted with fluorine atoms. In view of this, the number and position of fluorine atoms are preferably adjusted appropriately.

The substituent optionally present in R ¹ and R ² is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an acyl group, and an alkoxycarbonyl group. Group, amino group, alkoxy group, cycloalkyloxy group, aryloxy group, aryloxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio Group, arylthio group, silyl group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, halogen atom, hydroxyl group, mercapto group, cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfi group It can be exemplified group, a hydrazino group, and an imino group.

  In the present invention, a conjugated polymer compound having both of the above two types of partial structures is included in the photoelectric conversion layer of the organic photoelectric conversion element, so that a layer adjacent to the photoelectric conversion layer (for example, in the case of a reverse layer type element, the normal layer is a normal layer). It becomes possible to improve the film forming property of the (hole transport layer). Moreover, since the photoelectric conversion efficiency excellent with the said conjugated polymer compound can be achieved, the application to the reverse layer type element advantageous in terms of durability is also possible. Note that the conjugated polymer compound of this embodiment can achieve higher photoelectric conversion efficiency and durability than conventional ones even in a normal layer type device.

  Thus, by using the conjugated polymer compound of this embodiment, the film forming property, photoelectric conversion efficiency, and durability are improved as compared with the case of using a conjugated polymer compound having a conventional naphthobisbenzothiadiazole ring structure. The reason for doing this is not clear, but the present inventors presume as follows. That is, when an element having a reverse layer structure is produced using the conjugated polymer compound described in Non-Patent Document 4 or 5, the conjugated polymer compound (p-type organic semiconductor) and fullerenes ( n-type organic semiconductor) has an unfavorable distribution (specifically, in FIG. 2 described later, fullerene is segregated in a relatively upper part of the photoelectric conversion layer (near the side surface where holes are extracted). ). Such a distribution is preferable in the case where electrons are extracted from the upper portion of the photoelectric conversion layer as in the normal layer configuration of FIG. 1 described later. However, in the reverse layer configuration, it is difficult to extract holes, and sufficient photoelectric conversion efficiency is obtained. There was a possibility that it could not be obtained. The reason for this distribution is unknown, but a compound having a large π-conjugated system such as a naphthobisbenzothiadiazole ring structure and a layer below the photoelectric conversion layer (a layer formed immediately before the photoelectric conversion layer) ) Is assumed to show a strong interaction. Particularly in the reverse layer configuration, the hole blocking layer is preferably formed as a layer below the photoelectric conversion layer (as a layer formed immediately before the photoelectric conversion layer). Since it is composed of a compound containing an electron donating group such as an amino group, it is assumed that the interaction with a conjugated polymer compound having a naphthobisbenzothiadiazole ring structure is strong.

  In contrast, the present inventors succeeded in reducing the above-mentioned interaction by introducing a thienothiophene ring structure and a thiazolothiazole ring structure in addition to the naphthobisbenzothiadiazole ring structure into the conjugated polymer compound. did. The thienothiophene ring structure and thiazolothiazole ring structure are units that exhibit liquid crystallinity in small molecules, so they are isotropic above a certain temperature, but when cooled, various liquid crystal structures are generated by self-aggregation. . When such a unit is incorporated into a polymer, the molecules are dissolved by molecular dispersion in a high-temperature solution, but a characteristic that aggregation occurs with a decrease in temperature and solubility decreases can be exhibited.

  When such characteristics are applied to the above coating process, when a solution in which a conjugated polymer compound is dissolved at a high temperature is applied onto a substrate held at a high temperature, the concentration is increased at the lowest temperature by evaporation and precipitation occurs. It starts from the upper layer portion of the coating film, and the conjugated polymer compound (p-type organic semiconductor) can be present in a rich manner in the upper layer portion of the coating film. By such a technique, the distribution of the p-type organic semiconductor and the n-type organic semiconductor in the photoelectric conversion layer can be made preferable for the reverse layer configuration. By utilizing such characteristics, the conjugated polymer compound (p-type organic semiconductor) can be present in a rich state in the lower layer portion of the coating film by temperature control such as keeping the substrate temperature during coating low. It is also possible to obtain a distribution within a layer preferable for a normal layer structure. In order to assist the cohesive force, it is also effective to introduce a polar group into the side chain of the conjugated polymer compound.

  As a further effect, a hole transport layer generally used in an organic thin film solar cell is formed by a coating method using an aqueous solvent, but in a reverse layer configuration, a low polarity polymer, a photoelectric conversion layer made of fullerene is formed. Although it is necessary to form the hole transport layer, the coating property of the hole transport layer is a problem. However, according to the method of the present invention, the repelling at the time of coating the hole transport layer is also reduced. Although the principle that such an effect appears is unknown, the thiazolothiazole group is also assumed to be an effect due to acid / base interaction with PSS or the like in the hole transport layer material.

  The conjugated polymer compound of this embodiment is represented by (1) the above general formula 1 as long as it has at least one partial structure represented by the general formula 1 and at least one partial structure represented by the general formula 2. It may be a copolymer consisting of only a partial structure and a partial structure represented by General Formula 2, or (2) a partial structure represented by General Formula 1 and a partial structure represented by General Formula 2, It may be a copolymer containing one or more other partial structures.

  In addition, the conjugated polymer compound of the present embodiment is a copolymer having a structure in which donor unit (group) and acceptor unit (group) are alternately arranged (hereinafter also referred to as “DA polymer”). It is preferable that Thus, by using a DA polymer, the absorption region can be expanded to a long wavelength region. Therefore, such a conjugated polymer compound can absorb light in a long wavelength region (for example, 700 to 1000 nm) in addition to the absorption region (for example, 400 to 700 nm) of a conventional p-type organic semiconductor. Become.

  In this specification, the “donor unit” means a partial structure (unit) in which the LUMO level or the HOMO level is shallower than a hydrocarbon aromatic ring (benzene, naphthalene, anthracene, etc.) having the same number of π electrons. Say. On the other hand, in this specification, an “acceptor unit” generally means a portion having a LUMO level or a HOMO level deeper than a hydrocarbon aromatic ring (benzene, naphthalene, anthracene, etc.) having the same number of π electrons. Structure (unit). The “unit group” means a partial structure in which two or more units are connected.

  Examples of the donor unit include a unit containing a 5-membered ring such as a thiophene ring, a furan ring, a pyrrole ring, a cyclopentadiene, and a silacyclopentadiene, and a condensed ring thereof. Specific examples include units containing thiophene, thienothiophene, bithiophene, fluorene, silafluorene, carbazole, dithienocyclopentadiene, dithienosilacyclopentadiene, dithienopyrrole, benzodithiophene, and the like. is not. Among them, a donor unit containing a sulfur atom is preferable.

  As a preferable form of the DA polymer including the partial structure represented by the above-mentioned (2) partial structure and the partial structure represented by the general formula 2 and one or more other partial structures, the following general formula Examples thereof include conjugated polymers having at least one partial structure represented by 3A or a partial structure represented by the following general formula 3B.

In the formula 3A or formula 3B, -X ¹ = each independently, -C ^(R 3) = or an -N =. The preferred form of -X ¹ = is the same as described in the general formula 2.

In General Formula 3A or General Formula 3B, R ^{1 to} R ⁵ each independently represent a hydrogen atom (H), a halogen atom (F, Cl, Br, or I), a substituted or unsubstituted carbon atom An alkyl group having 1 to 20 carbon atoms, a fluorinated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, a fluorinated cycloalkyl group having 3 to 20 carbon atoms, and 1 to 20 carbon atoms An alkoxy group having 1 to 20 carbon atoms, a fluorinated alkylthio group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, a fluorinated aryl group having 6 to 30 carbon atoms, A heteroaryl group having 1 to 20 carbon atoms or a fluorinated heteroaryl group having 1 to 20 carbon atoms is represented.

Among them, preferred embodiments of R ¹ to R ³ are the same as described for Formula 1 and 2. On the other hand, each of R ⁴ and / or R ⁵ is preferably independently an alkyl group having 1 to 10 carbon atoms substituted with a polar group. More specifically, R ⁴ and / or R ⁵ are: A group represented by the following general formula 4 is preferable.

In General Formula 4, each L independently represents an alkylene group having 1 to 10 carbon atoms. Specifically, a methylene group (—CH ₂ —), an ethylene group (—CH ₂ CH ₂ —), a trimethylene group (—CH ₂ CH ₂ CH ₂ —), a propylene group (—CH (CH ₃ ) CH ₂ — ) And 2-ethylhexamethylene group (—CH ₂ CH (CH ₂ CH ₃ ) CH ₂ CH ₂ CH ₂ CH ₂ —) and the like, and linear and branched alkylene groups. Among them, a hydrogen atom in the alkylene group, in view of the steric hindrance of the thiophene ring of the main chain, and the carbon atoms of the 3 or 4 position of the thiophene ring of the alkylene group is attached, Y 1 ^(a = 1) or Z (when a = 0) is sufficiently distant from each other (specifically, the carbon atom at the 3-position or 4-position of the thiophene ring and Y ¹ or Z are an ethylene group) _(-CH 2 CH ₂ -) and through at least distance) it is preferred. Accordingly, the number of carbon atoms in the main chain of L is preferably 2 or more. From the viewpoint of ease of synthesis, it is preferably an ethylene group.

In General Formula 4, Y ¹ and Y ² each independently represent an oxygen atom (O) or NR ⁷ . Z represents each independently a carbon atom (C), a sulfur atom (S), or a phosphorus atom (P). a, b, and c represent integers satisfying the relational expressions 2 ≦ a + b + c ≦ 4 and 0 ≦ a, b, c ≦ 2. That is, in the group represented by the general formula 4, the portion excluding L represents a polar group. Specific examples of the polar group include an ester group (—C (O) OR ⁶ ), an amide group (—C (O) NR ⁶ R ⁷ ), a sulfonamide group (—SO ₂ NR ⁶ R ⁷ ), Carbamate group (—OCONR ⁶ R ⁷ or —NR ⁷ C (O) OR ⁶ ), carbonate group (—OCOOR ⁶ ), phosphate group (—PO (OR ⁶ ) ₂ ), urea group (—NR ⁷ CONR ⁶⁾ R ⁷ ), phosphoric acid amide group (—PO (NR ⁶ R ⁷ ) ₂ ), sulfone ester group (—SO ₂ OR ⁶ ) and the like. Thus, when R ⁴ and / or R ⁵ is an alkyl group having a polar group, the intermolecular interaction in the conjugated polymer compound becomes strong, and the durability of the device can be further improved.

Further, R ⁴ and / or R ⁵ are preferably each independently an alkyl group having a strong polar group. Specifically, in the general formula 4, a, b, and c are a + b + c = 3 and An integer satisfying the relational expression of 0 ≦ a, b, c ≦ 2 is preferable. Specific examples of the polar group in this case include a sulfonamide group (—SO ₂ NR ⁶ R ⁷ ), a carbamate group (—OCONR ⁶ R ⁷ or —NR ⁷ C (O) OR ⁶ ), a carbonate group (— OCOOR ⁶ ), phosphoric acid ester group (—PO (OR ⁶ ) ₂ ), urea group (—NR ⁷ CONR ⁶ R ⁷ ), phosphoric acid amide group (—PO (NR ⁶ R ⁷ ) ₂ ), sulfone ester group ( -SO ₂ OR ^6), and the like. Among these, a carbamate group (—OCONR ⁶ R ⁷ or —NR ⁷ C (O) OR ⁶ ) or a carbonate group (—OCOOR ⁶ ) is preferable. Thus, when R ⁴ and / or R ⁵ is an alkyl group having a strong polar group, intermolecular interaction becomes stronger, and further improvement in durability can be expected. In addition, since the hydrophilicity is enhanced by the polar group, the coating liquid is less likely to be repelled when forming a hole transport layer or the like on the photoelectric conversion layer using an aqueous solvent, and a uniform layer can be formed. It becomes.

In General Formula 4, R ⁶ and R ⁷ are each independently a hydrogen atom (H), an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or 2 to 20 carbon atoms. An alkenyl group, an aryl group having 6 to 30 carbon atoms, or a heteroaryl group having 1 to 20 carbon atoms. Here, preferred forms of the alkyl group, cycloalkyl group, aryl group, and heteroaryl group are the same as those described in the above general formulas 1 and 2.

  Although there is no restriction | limiting in particular as said C2-C20 alkenyl group, For example, an ethynyl group, a propynyl group, a butynyl group, an octynyl group, a nonynyl group, a decynyl group etc. are mentioned. Among these, from the viewpoint of improving solubility, an alkenyl group having 6 or more carbon atoms, particularly 6 to 10 carbon atoms is preferable.

  In General Formula 3A or General Formula 3B described above, each D independently represents a donor unit (group) containing a sulfur atom (S) (more specifically, a donor heteroaromatic ring group and / or donor complex). A condensed aromatic ring group). The preferable specific example of a donor property unit is shown below.

  In the donor unit (group) of D1 to D17, each R is independently a hydrogen atom (H), or each independently a substituted or unsubstituted alkyl having 1 to 20 carbon atoms. Group, fluorinated alkyl group having 1 to 20 carbon atoms, cycloalkyl group having 3 to 20 carbon atoms, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, carbon atom A fluorinated alkoxy group having 1 to 20 carbon atoms, a fluorinated alkylthio group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, a fluorinated aryl group having 6 to 30 carbon atoms, and 1 to 20 carbon atoms Or a fluorinated heteroaryl group having 1 to 20 carbon atoms. Preferred forms of these groups are the same as described in the above general formulas 1 and 2.

  Of these donor units (D), a donor unit represented by the following general formula 5 is preferable.

  In General Formula 5, A represents a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge). That is, units represented by D5, D8, and D18 are preferable. Among these, A is preferably a silicon atom (Si). Since these units are units having high solubility and absorption up to a long wavelength, higher photoelectric conversion efficiency can be provided.

In General Formula 5, each R ⁸ independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a fluorinated alkyl group having 1 to 20 carbon atoms, or 3 to 20 carbon atoms. Cycloalkyl group, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, fluorinated alkoxy group having 1 to 20 carbon atoms, fluorinated alkylthio having 1 to 20 carbon atoms Group, an aryl group having 6 to 30 carbon atoms, a fluorinated aryl group having 6 to 30 carbon atoms, a heteroaryl group having 1 to 20 carbon atoms, or a fluorinated heteroaryl group having 1 to 20 carbon atoms . Preferred forms of these groups are the same as described in the above general formulas 1 and 2.

  Hereinafter, although the preferable form (Exemplary compounds 1-35) of the conjugated polymer compound of this form is illustrated, this invention is not necessarily limited only to the following forms.

  The molecular weight of the conjugated polymer compound of this embodiment is not particularly limited, but preferably has an appropriate molecular weight in order to give a good morphology to the conjugated polymer compound. On the other hand, if the molecular weight is too high, the solubility may be lowered. Specifically, the number average molecular weight of the conjugated polymer compound is preferably 10,000 to 100,000, more preferably 15,000 to 70,000, and even more preferably 25,000 to 50,000. In particular, when a bulk heterojunction photoelectric conversion layer is formed using the conjugated polymer compound of this embodiment as a p-type organic semiconductor, a low-molecular compound (for example, a fullerene derivative) is widely used as an n-type organic semiconductor. However, when the molecular weight of the conjugated polymer compound used as the p-type organic semiconductor is within the above range, a microphase separation structure is formed well, and thus carriers that carry holes and electrons generated at the pn junction interface. This is because a pass is easily formed. The number average molecular weight in this specification can be measured by gel permeation chromatography (GPC; standard material polystyrene).

  By using the conjugated polymer compound of the present embodiment as a p-type organic semiconductor of the photoelectric conversion layer, it is possible to obtain an element having excellent durability and sufficient photoelectric conversion efficiency. That is, an organic photoelectric conversion element according to one embodiment of the present invention includes a first electrode, a second electrode, an n-type organic semiconductor that exists between the first electrode and the second electrode, and p. The p-type organic semiconductor contains the conjugated polymer compound described above.

  Hereinafter, the present embodiment will be described with reference to the accompanying drawings. However, the technical scope of the present invention should be determined by the description of the scope of claims, and is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

  FIG. 1 is a schematic cross-sectional view schematically showing a normal layer type organic photoelectric conversion element according to an embodiment of the present invention. Specifically, the organic photoelectric conversion element 10 of FIG. 1 includes an anode (transparent electrode) 11, a hole transport layer 26, a photoelectric conversion layer 14, an electron transport layer 27, and a cathode (counter electrode) 12 on a substrate 25. Are stacked in this order. The substrate 25 is a member that is arbitrarily provided mainly for facilitating the formation of the anode (transparent electrode) 11 thereon by a coating method.

  When the organic photoelectric conversion element 10 shown in FIG. 1 is operated, light is irradiated from the substrate 25 side. In the present embodiment, the anode (transparent electrode) 11 is made of a transparent electrode material (for example, ITO) so that the irradiated light reaches the photoelectric conversion layer 14. The light irradiated from the substrate 25 side reaches the photoelectric conversion layer 14 through the transparent anode (transparent electrode) 11 and the hole transport layer 26.

  The hole transport layer 26 is made of a material having a high hole mobility, and functions to efficiently transport holes generated at the pn junction interface of the photoelectric conversion layer 14 to the anode (transparent electrode) 11. Is responsible. On the other hand, the electron transport layer 27 is formed of a material having high electron mobility, and has a function of efficiently transporting electrons generated at the pn junction interface of the photoelectric conversion layer 14 to the cathode (counter electrode) 12. Yes.

  FIG. 2 is a schematic cross-sectional view schematically showing a reverse layer type organic photoelectric conversion element according to another embodiment of the present invention. The organic photoelectric conversion element 20 in FIG. 2 has the anode 11 and the cathode 12 disposed at opposite positions as compared with the organic photoelectric conversion element 10 in FIG. 1, and the hole transport layer 26, the electron transport layer 27, and the like. Are different in that they are arranged at the opposite positions. That is, in the reverse layer type organic photoelectric conversion element, the first electrode is the cathode (transparent electrode) 12, the second electrode is the anode (counter electrode) 11, and the second electrode and the photoelectric conversion layer 14 It is characterized in that the hole transport layer 26 is included therebetween. In the organic photoelectric conversion element 20 of FIG. 2, a cathode (transparent electrode) 12, an electron transport layer 27, a photoelectric conversion layer 14, a hole transport layer 26, and an anode (counter electrode) 11 are stacked in this order on a substrate 25. It has the composition which becomes. By having such a configuration, electrons generated at the pn junction interface of the photoelectric conversion layer 14 are transported to the cathode (transparent electrode) 12 through the electron transport layer 27, and holes are transported through the hole transport layer 26. It is transported to the anode (counter electrode) 11.

  FIG. 3 is a schematic cross-sectional view schematically illustrating an organic photoelectric conversion element including a tandem (multi-junction type) photoelectric conversion layer according to another embodiment of the present invention. Compared with the organic photoelectric conversion element 10 in FIG. 1, the organic photoelectric conversion element 30 in FIG. 3 replaces the photoelectric conversion layer 14 with a first photoelectric conversion layer 14 a, a second photoelectric conversion layer 14 b, and these The difference is that a stacked body with a charge recombination layer 38 interposed between two photoelectric conversion layers is disposed. In the tandem organic photoelectric conversion element 30 shown in FIG. 3, photoelectric conversion materials (p-type organic semiconductor and n-type organic semiconductor) having different absorption wavelengths are used for the first photoelectric conversion layer 14a and the second photoelectric conversion layer 14b, respectively. By using this, light in a wider wavelength range can be efficiently converted into electricity.

  Hereinafter, each structure of the organic photoelectric conversion element which concerns on this invention is demonstrated in detail.

[electrode]
The organic photoelectric conversion element of this embodiment essentially includes a first electrode and a second electrode. The first electrode and the second electrode each function as an anode or a cathode. In the present specification, “first” and “second” are terms for distinguishing functions as an anode or a cathode. Therefore, the first electrode may function as an anode and the second electrode may function as a cathode. Conversely, the first electrode may function as a cathode and the second electrode may function as an anode. is there. As described above, the carriers (holes / electrons) generated in the photoelectric conversion layer 14 move between the electrodes, and the holes reach the anode 12 and the electrons reach the cathode 16. In the present invention, an electrode through which holes mainly flow is called an anode, and an electrode through which electrons mainly flow is called a cathode. Moreover, when taking a tandem structure, a tandem structure can be achieved by using a charge recombination layer (intermediate electrode). Furthermore, from the functional aspect of whether or not the electrode has translucency, the translucent electrode is sometimes referred to as a transparent electrode, and the non-translucent electrode is sometimes referred to as a counter electrode. In the case of a normal layer configuration, the anode is usually a transparent electrode having a light transmitting property, and the cathode is a counter electrode having no light transmitting property.

  The material used for the electrode of this embodiment is not particularly limited as long as it is driven as a photoelectric conversion element, and an electrode material that can be used in this technical field can be appropriately employed. In particular, the anode is preferably composed of a material having a relatively large work function compared to the cathode, and conversely, the cathode is composed of a material having a relatively small work function compared to the anode. Is preferred.

  The anode 11 in the normal layer type organic photoelectric conversion element 10 shown in FIG. 1 is preferably composed of a transparent electrode material having a relatively large work function and capable of transmitting light of 380 to 800 nm. . On the other hand, the cathode 12 has a relatively small work function (for example, 4 eV or less), and can usually be composed of an electrode material having low translucency.

In such a normal layer type organic photoelectric conversion element 10, examples of electrode materials used for the anode (transparent electrode) include metals such as gold, silver, and platinum; indium tin oxide (ITO), SnO _2. And transparent conductive metal oxides such as ZnO; carbon materials such as metal nanowires and carbon nanotubes. It is also possible to use a conductive polymer as the anode electrode material. Examples of the conductive polymer that can be used for the anode include PEDOT: PSS, polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, and polyphenyl. Examples include acetylene, polydiacetylene, polynaphthalene, and derivatives thereof. These electrode materials may be used alone or as a mixture of two or more materials. It is also possible to form an electrode by laminating two or more layers made of each material.

On the other hand, in the normal layer type organic photoelectric conversion element, as an electrode material used for the cathode (counter electrode), a metal, an alloy, an electron conductive compound, and a mixture thereof can be used. Specifically, sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, indium, Examples include lithium / aluminum mixtures and rare earth metals. Of these, a mixture of a first metal having a low work function and a second metal, which is a metal having a larger work function and more stable than the first metal, from the viewpoint of electron extraction performance and durability against oxidation, etc. For example, it is preferable to use a magnesium / silver mixture, a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum which is a stable metal, or the like. In addition, it is also preferable to use a metal among these materials, so that light that is incident from the first electrode side and transmitted without being absorbed by the photoelectric conversion layer is reflected by the second electrode and is regenerated for photoelectric conversion. The photoelectric conversion efficiency can be improved. These electrode materials may be used alone or as a mixture of two or more materials. It is also possible to form an electrode by laminating two or more layers made of each material. The thickness of the cathode (counter electrode) is not particularly limited, but is usually 10 nm to 5 μm, preferably 50 to 200 nm.

  In the reverse layer type organic photoelectric conversion element shown in FIG. 2, the cathode 12 is located on the substrate 25 side on which light is incident, and the anode 11 is located on the opposite side. Therefore, the anode 11 in the reverse layer type shown in FIG. 2 is preferably composed of an electrode material having a relatively large work function and usually low translucency. On the other hand, the cathode 12 has a relatively small work function and is made of a transparent electrode material.

  In the reverse layer type organic photoelectric conversion element, examples of the electrode material used for the cathode (transparent electrode) include metals such as gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, and indium, metal compounds, And carbon materials such as carbon nanoparticles, carbon nanowires, and carbon nanostructures. Among these, it is preferable to use a transparent conductive metal oxide such as indium tin oxide (ITO). These electrode materials may be used alone or as a mixture of two or more materials. It is also possible to form an electrode by laminating two or more layers made of each material. Among these, it is preferable to use carbon nanowires because a transparent and highly conductive cathode can be formed by a coating method. In addition, when a metal material is used, an auxiliary electrode having a thickness of about 1 to 20 nm is formed on the side facing the anode (counter electrode) using, for example, aluminum, an aluminum alloy, silver, a silver compound, or the like. Then, a cathode (transparent electrode) can be obtained by providing a conductive polymer film exemplified as the anode (transparent electrode) material of the above-mentioned normal layer type organic photoelectric conversion element.

  On the other hand, in the reverse layer type organic photoelectric conversion element, the electrode material used for the anode (counter electrode) is preferably an electrode material having a relatively higher work function than the cathode (transparent electrode). For example, the anode (counter electrode) may be formed using a metal material such as silver, nickel, molybdenum, gold, platinum, tungsten, and copper.

As described above, in the present invention, the organic photoelectric conversion element having the reverse layer structure of FIG. 2 in which a material that hardly deteriorates due to oxygen, moisture, or the like can be used for both the anode and the cathode is preferable. Examples of preferable anode / cathode combinations in the reverse layer structure include, for example, 1) first electrode (cathode) ITO, second electrode (anode) silver 2) first electrode (cathode) PEDOT: PSS, second Electrode (anode) silver 3) first electrode (cathode) ITO, second electrode (anode) copper 4) first electrode (cathode) PEDOT: PSS, second electrode (anode) gold 5) first Electrode (cathode) ITO, second electrode (anode) PEDOT: PSS
Etc.

[Photoelectric conversion layer]
The photoelectric conversion layer has a function of converting light energy into electric energy using the photovoltaic effect. The organic photoelectric conversion element of this embodiment is characterized in that the photoelectric conversion layer essentially includes the n-type organic semiconductor and the conjugated polymer compound of the present invention as a p-type organic semiconductor. When light is absorbed by these photoelectric conversion materials, excitons are generated, which are separated into holes and electrons at the pn junction interface.

  The photoelectric conversion layer of this embodiment essentially contains the above-described conjugated polymer compound of the present invention, and may contain other p-type organic semiconductor materials as necessary. An example of another p-type organic semiconductor material is shown below.

  Examples of the condensed polycyclic aromatic low molecular weight compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, thacumanthracene, bisanthene, zeslene. , Heptazethrene, pyranthrene, violanthene, isoviolanthene, cacobiphenyl, anthradithiophene, etc., porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenedithiotetrathiafulvalene (BEDTTTTF) -perchloric acid complex, and derivatives and precursors thereof.

  Examples of the derivative having the above-mentioned condensed polycycle include WO 03/16599 pamphlet, WO 03/28125 pamphlet, US Pat. No. 6,690,029, JP 2004-107216 A. A pentacene derivative having a substituent described in JP-A No. 2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol127. No. 14.4986, J. MoI. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. 9, acene-based compounds substituted with a trialkylsilylethynyl group described in 2706 and the like.

  As the conjugated polymer, for example, a polythiophene such as poly-3-hexylthiophene (P3HT) and an oligomer thereof, or a technical group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Polythiophene, Nature Material, (2006) vol. 5, p328, a polythiophene-thienothiophene copolymer, a polythiophene-diketopyrrolopyrrole copolymer described in WO2008 / 000664, and a polythiophene-thiazolothiazole copolymer described in Adv Mater, 2007p4160 Nature Mat. vol. 6 (2007), p497 described in PCPDTBT, etc., polypyrrole and its oligomer, polyaniline, polyphenylene and its oligomer, polyphenylene vinylene and its oligomer, polythienylene vinylene and its oligomer, polyacetylene, polydiacetylene, Examples thereof include polymer materials such as σ-conjugated polymers such as polysilane and polygermane.

  In addition, oligomeric materials instead of polymer materials include thiophene hexamer α-sexual thiophene α, ω-dihexyl-α-sexual thiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis (3 Oligomers such as -butoxypropyl) -α-sexithiophene can be preferably used.

  Among these compounds, compounds that have high solubility in organic solvents to the extent that solution processing is possible, can form a crystalline thin film after drying, and can achieve high mobility are preferable. More preferably, it is a compound (a compound capable of forming an appropriate phase separation structure) having appropriate compatibility with the fullerene derivative which is the n-type organic semiconductor material of the present invention.

  In addition, when forming an electron transport layer or a hole blocking layer by a solution process on the bulk heterojunction layer, if it can be further applied on the layer once applied, it can be easily laminated, When a layer is further laminated by a solution process on a layer made of a material that usually has good solubility, there is a problem that the layer cannot be laminated because the underlying layer is dissolved. Therefore, a material that can be insolubilized after application by a solution process is preferable.

  Examples of such materials include materials that can be insolubilized by polymerizing the coating film after coating, such as polythiophene having a polymerizable group described in Technical Digest of the International PVSEC-17, Fukuoka, Japan, 2007, P1225. Or a material in which soluble substituents react and become insoluble (pigmented) by applying energy such as heat, as described in US Patent Application Publication No. 2003/136964, and Japanese Patent Application Laid-Open No. 2008-16834 And so on.

  In addition, as long as the p-type organic semiconductor contained in the photoelectric converting layer of this form contains the above-mentioned conjugated polymer compound, the content of the other p-type organic semiconductor material is not particularly limited. However, in order to achieve higher photoelectric conversion efficiency, with respect to the total amount of the p-type organic semiconductor included in the photoelectric conversion layer (when two or more photoelectric conversion layers are included, the total amount in all layers), The larger the proportion of the conjugated polymer compound described above, the better. Specifically, the ratio of the conjugated polymer compound to the total amount of the p-type organic semiconductor is preferably 50% by mass or more, more preferably 70% by mass or more, and 90% by mass or more. More preferably, it is particularly preferably 95% by mass or more, and most preferably 100% by mass.

  On the other hand, the n-type organic semiconductor used in the photoelectric conversion layer of the present embodiment is not particularly limited as long as it is an organic compound that is acceptor (electron-accepting) with respect to the p-type organic semiconductor, and is used in this technical field. The material which can be used can be employ | adopted suitably. Such a compound may be a compound deeper by 0.2 to 0.5 eV or more than the LUMO level of the p-type organic semiconductor. For example, the p-type organic such as fullerene, carbon nanotube, octaazaporphyrin, etc. Perfluoro compounds (for example, perfluoropentacene and perfluorophthalocyanine) in which hydrogen atoms of a semiconductor are substituted with fluorine atoms, naphthalene tetracarboxylic acid anhydride, naphthalene tetracarboxylic acid diimide, perylene tetracarboxylic acid anhydride, perylene tetracarboxylic acid Examples thereof include aromatic carboxylic acid anhydrides such as diimide and polymer compounds containing the imidized product thereof as a skeleton.

  Of these, fullerenes, carbon nanotubes, or derivatives thereof are preferably used from the viewpoint that charge separation can be efficiently performed with a p-type organic semiconductor at high speed (up to 50 fs). More specifically, fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotube, multi-walled carbon nanotube, single-walled carbon nanotube, carbon nanohorn (conical type), etc. , And some of these are hydrogen atoms, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), substituted or unsubstituted alkyl groups, alkenyl groups, alkynyl groups, aryl groups, heteroaryl groups, And a fullerene derivative substituted with a cycloalkyl group, a silyl group, an ether group, a thioether group, an amino group, or the like.

  In particular, [6,6] -phenyl C61-butyric acid methyl ester (abbreviation PCBM), [6,6] -phenyl C61-butyric acid-nbutyl ester (PCBnB), [6,6] -phenyl C61- Butyric acid-isobutyl ester (PCBiB), [6,6] -phenyl C61-butyric acid-n hexyl ester (PCBH), [6,6] -phenyl C71-butyric acid methyl ester (abbreviation PC71BM), Adv . Mater. , Vol. 20 (2008), p2116, aminated fullerene described in JP-A 2006-199674, metallocene fullerene described in JP-A 2008-130889, US Pat. No. 7,329,709 It is preferable to use a fullerene derivative whose solubility is improved by a substituent, such as fullerene having a cyclic ether group described in the specification. In this embodiment, the n-type organic semiconductor may be used alone or in combination of two or more.

  There is no particular limitation on the junction form of the p-type organic semiconductor and the n-type organic semiconductor in the photoelectric conversion layer of this embodiment, and it may be a planar heterojunction or a bulk heterojunction (bulk heterojunction). Good. A planar heterojunction is a junction in which a p-type organic semiconductor layer containing a p-type organic semiconductor and an n-type organic semiconductor layer containing an n-type organic semiconductor are stacked, and the surface where these two layers contact is the pn junction interface. It is a form. On the other hand, a bulk heterojunction is formed by applying a mixture of a p-type organic semiconductor and an n-type organic semiconductor. In this single layer, a domain of the p-type organic semiconductor and a domain of the n-type organic semiconductor are formed. It has a microphase separation structure. Therefore, in a bulk heterojunction, many pn junction interfaces exist throughout the layer as compared to a planar heterojunction. Therefore, most of the excitons generated by light absorption can reach the pn junction interface, and the efficiency leading to charge separation can be increased. For these reasons, the junction between the p-type organic semiconductor and the n-type organic semiconductor in the photoelectric conversion layer of this embodiment is preferably a bulk heterojunction.

  The bulk heterojunction layer is formed of a single layer (i layer) in which a normal p-type organic semiconductor material and an n-type organic semiconductor layer are mixed, and the i layer is made of a p-type organic semiconductor. In some cases, it has a three-layer structure (p-i-n structure) sandwiched between a p layer and an n layer made of an n-type organic semiconductor. Such a pin structure has higher rectification of holes and electrons, reduces loss due to recombination of charge-separated holes and electrons, and can achieve higher photoelectric conversion efficiency. .

  In the present invention, the mixing ratio of the p-type organic semiconductor and the n-type organic semiconductor contained in the photoelectric conversion layer is preferably in the range of 2: 8 to 8: 2, more preferably 3.3: 6.7. It is the range of -5: 5. Moreover, the film thickness of one photoelectric conversion layer is preferably 50 to 400 nm, more preferably 80 to 300 nm, and particularly preferably 100 to 200 nm. In general, from the viewpoint of absorbing more light, it is preferable that the thickness of the photoelectric conversion layer is larger. However, as the film thickness increases, the extraction efficiency of carriers (holes / electrons) decreases, so the photoelectric conversion efficiency decreases. Tend to. However, when a photoelectric conversion layer is formed using the conjugated polymer compound of the present embodiment described above as a p-type organic semiconductor material, a film having a thickness of 100 nm or more is formed as compared with a photoelectric conversion layer using a conventional p-type organic semiconductor material. Even when the thickness is increased, the extraction efficiency of carriers (holes / electrons) is unlikely to decrease, so that high photoelectric conversion efficiency can be maintained. Therefore, in the reverse layer type photoelectric conversion element, sufficient photoelectric conversion efficiency can be achieved even when the film thickness of the photoelectric conversion layer is increased.

(substrate)
The organic photoelectric conversion element of the present invention may include a substrate as necessary. The substrate has a role as a member to be coated with a coating solution when the electrode is formed by a coating method.

  When light that is photoelectrically converted enters from the substrate side, the substrate is preferably a member that can transmit the light that is photoelectrically converted, that is, a member that is transparent to the wavelength of the light to be photoelectrically converted. As the substrate, for example, a glass substrate, a resin substrate and the like are preferably mentioned, but it is desirable to use a transparent resin film from the viewpoint of light weight and flexibility.

  There is no restriction | limiting in particular in the transparent resin film which can be preferably used as a transparent substrate by this invention, The material, a shape, a structure, thickness, etc. can be suitably selected from well-known things. For example, polyolefins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester resin film such as modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, cyclic olefin resin, etc. Resin films, vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone (PEEK) resin films, polysulfone (PSF) resin films, polyether sulfone (PES) resin films, polycarbonate (PC) resin films , Polyamide resin film, polyimide resin film, acrylic resin film, triacetyl cellulose (TAC) resin film, and the like. If the resin film transmittance of 80% or more in from zero to eight hundred nanomolar), can be preferably applied to a transparent resin film according to the present invention. Among these, from the viewpoint of transparency, heat resistance, ease of handling, strength and cost, it is preferably a biaxially stretched polyethylene terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethersulfone film, or a polycarbonate film. More preferred are a stretched polyethylene terephthalate film and a biaxially stretched polyethylene naphthalate film.

  The transparent substrate used in the present invention can be subjected to a surface treatment or an easy adhesion layer in order to ensure the wettability and adhesiveness of the coating solution. A conventionally well-known technique can be used about a surface treatment or an easily bonding layer. For example, the surface treatment includes surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Examples of the easy adhesion layer include polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, and epoxy copolymer.

  For the purpose of suppressing the permeation of oxygen and water vapor, a barrier coat layer may be formed in advance on the transparent substrate, or a hard coat layer may be formed in advance on the opposite side to which the transparent conductive layer is transferred. Good.

(Hole transport layer)
The organic photoelectric conversion element of this form can contain a positive hole transport layer as needed. The hole transport layer has a function of transporting holes and a property of extremely small ability to transport electrons (for example, 1/10 or less of the mobility of holes). The hole transport layer is provided between the photoelectric conversion layer and the anode and prevents recombination of electrons and holes by blocking the movement of electrons while transporting holes to the anode. Can do.

  There is no restriction | limiting in particular in the hole transport material used for a hole transport layer, The material which can be used in this technical field can be employ | adopted suitably. As an example, for example, PEDOT: PSS such as product name BaytronP manufactured by Clevios, polythienothiophenes described in European Patent No. 1647566, sulfonated polythiophenes described in JP 2010-206146, polyaniline, and the like The dope material, cyan compounds described in International Publication No. 2006/019270 pamphlet and the like can be mentioned.

  Also, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives , Stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers, may also be used.

  Besides these, a porphyrin compound, an aromatic tertiary amine compound, a styrylamine compound, and the like can be used, and among these, it is preferable to use an aromatic tertiary amine compound. In some cases, the hole transport layer may be formed using an inorganic compound such as a metal oxide such as molybdenum, vanadium, or tungsten, or a mixture thereof.

  Furthermore, a polymer material in which a structural unit contained in the above compound is introduced into a polymer chain, or a polymer material having the above compound as the main chain of the polymer can also be used as a hole transport material. JP-A-11-251067, J. Org. Huang et. al. , Applied Physics Letters, 80 (2002), p. A p-type hole transport material as described in 139 can also be used. Furthermore, a hole transport material with high p property doped with impurities can be used. For example, JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like. In addition, these hole transport materials may be used individually by 1 type, and may use 2 or more types together. It is also possible to form a hole transport layer by laminating two or more layers made of each material.

  The thickness of the hole transport layer is not particularly limited, but is usually 1 to 2000 nm. From the viewpoint of further improving the leak prevention effect, the thickness is preferably 5 nm or more. Further, from the viewpoint of maintaining high transmittance and low resistance, the thickness is preferably 1000 nm or less, and more preferably 200 nm or less.

In general, the conductivity of the hole transport layer is preferably as high as possible. However, if the conductivity is too high, the ability to prevent electrons from moving may be reduced, and rectification may be reduced. Therefore, the conductivity of the hole transport layer is preferably 10 ⁻⁵ to 1 S / cm, and more preferably 10 ⁻⁴ to 10 ⁻² S / cm.

(Electron transport layer)
The organic photoelectric conversion element of this form can contain an electron carrying layer as needed. The electron transport layer has a property of transporting electrons and having a remarkably small ability to transport holes. The electron transport layer is provided between the photoelectric conversion layer and the cathode, and prevents the recombination of electrons and holes by blocking the movement of holes while transporting electrons to the cathode. it can.

  There is no restriction | limiting in particular in the electron transport material used for an electron carrying layer, The material which can be used in this technical field is employable suitably. For example, octaazaporphyrin, a perfluoro body of a p-type organic semiconductor (perfluoropentacene, perfluorophthalocyanine, etc.) can be used. Similarly, it is more than the HOMO level of a p-type organic semiconductor used in a photoelectric conversion layer. The electron transport layer having a deep HOMO level is provided with a hole blocking function having a rectifying effect so that holes generated in the photoelectric conversion layer do not flow to the cathode side. Therefore, more preferably, a material deeper than the HOMO level of the n-type organic semiconductor is used as the electron transport material. Examples of such electron transport materials include phenanthrene compounds such as bathocuproine, n-type organic semiconductors such as naphthalenetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide, and oxidation. N-type inorganic oxides such as titanium, zinc oxide, and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride can be used. Moreover, the layer which consists of a n-type organic semiconductor single-piece | unit used for the photoelectric converting layer can also be used. In addition, these electron transport materials may be used individually by 1 type, and may use 2 or more types together. It is also possible to form an electron transport layer by stacking two or more layers made of each material.

  As described above, in the case of an inverted layer type element that is advantageous from the viewpoint of durability, the photoelectric conversion layer is formed after the electron transport layer is formed on the first electrode. A compound that is insoluble in the coating liquid to be contained is preferred as the electron transport material. From such a viewpoint, the electron transport material is preferably an inorganic substance such as titanium oxide or zinc oxide, and a crosslinkable organic substance such as polyethyleneimine or an aminosilane coupling agent described in International Publication No. 2008-134492. Of these, aminosilane coupling agents (3- (2-aminoethyl) -aminopropyltrimethoxysilane, for example) are preferably used.

  Moreover, as a material insoluble with respect to the solvent used when apply | coating a photoelectric converting layer, (pi) conjugated polymer etc. soluble in alcohol can be mentioned, APPLIED PHYSICS LETTERS 95 (2009), p043301, Adv. . Funct. Mat. 2010, p. 1977, Adv. Mater. , 2011, 23, 3086, J.A. Am. Chem. Soc. , 2011, p. 8416, Advanced Materials, 2011 (Vol 23, no. 40), p4636-4463, and the like, and the following polyfluorenes may be used. These polymers are preferable because they can be formed on a normal layer structure, that is, a photoelectric conversion layer, unlike the silane coupling agent and the like described above. In addition, it can function as an electron transport layer / hole blocking layer not only for metal oxides such as ITO but also for metal electrodes such as gold, silver, copper, etc. A metal can be used for the cathode, which is preferable.

  The thickness of the electron transport layer is not particularly limited, but is usually 1 to 2000 nm. From the viewpoint of further enhancing the leak prevention effect, the thickness is preferably 2 nm or more, and more preferably 5 nm or more. Further, from the viewpoint of maintaining high transmittance and low resistance, the thickness is preferably 100 nm or less, and more preferably 20 nm or less.

(Charge recombination layer; intermediate electrode)
In a tandem (multi-junction type) organic photoelectric conversion element having two or more photoelectric conversion layers as shown in FIG. 3, a charge recombination layer (intermediate electrode) is disposed between the photoelectric conversion layers.

  The material used for the charge recombination layer (intermediate electrode) is not particularly limited as long as it is a material having both conductivity and translucency, and examples thereof include ITO, AZO, FTO, and titanium oxide exemplified above. Transparent metal oxides, metals such as Ag, Al, and Au, carbon materials such as carbon nanoparticles and carbon nanowires, and conductive polymers such as PEDOT: PSS and polyaniline can be used. These materials may be used alone or in combination of two or more. It is also possible to form a charge recombination layer by laminating two or more layers made of each material.

The electric conductivity of the charge recombination layer is preferably high from the viewpoint of obtaining high conversion efficiency. Specifically, it is preferably 5 to 50000 S / cm, more preferably 100 to 10,000 S / cm. preferable. The thickness of the charge recombination layer is not particularly limited, but is preferably 1 to 1000 nm, and preferably 5 to 50 nm. By setting the thickness to 1 nm or more, the film surface can be smoothed. On the other hand, by setting the thickness to 1000 nm or less, it is possible to reduce the decrease in the short-circuit current density J _sc (mA / cm ² ).

(Other layers)
The organic photoelectric conversion device of this embodiment may further include other members (other layers) in addition to the above-described members (each layer) in order to improve photoelectric conversion efficiency and improve the lifetime of the device. . Examples of other members include a hole injection layer, an electron injection layer, an exciton block layer, a UV absorption layer, a light reflection layer, and a wavelength conversion layer. Further, a layer such as a silane coupling agent may be provided in order to make the metal oxide fine particles unevenly distributed in the upper layer more stable. Further, a metal oxide layer may be laminated adjacent to the photoelectric conversion layer of the present invention.

  Moreover, the organic photoelectric conversion element of this invention may have various optical function layers for the purpose of more efficient light reception of sunlight. Examples of the optical functional layer include a condensing layer such as an antireflection film and a microlens array, and a light diffusion layer that can scatter the light reflected by the cathode and make it incident on the photoelectric conversion layer again.

  Various known antireflection layers can be provided as the antireflection layer. For example, when the transparent resin film is a biaxially stretched polyethylene terephthalate film, the refractive index of the easy adhesion layer adjacent to the film is 1.57. It is more preferable to set it to ˜1.63 because the interface reflection between the film substrate and the easy adhesion layer can be reduced and the transmittance can be improved. The method for adjusting the refractive index can be carried out by appropriately adjusting the ratio of the oxide sol having a relatively high refractive index such as tin oxide sol or cerium oxide sol and the binder resin. The easy adhesion layer may be a single layer, but may be composed of two or more layers in order to improve adhesion.

  As the condensing layer, for example, it is processed to provide a structure on the microlens array on the sunlight receiving side of the support substrate, or the amount of light received from a specific direction is increased by combining with a so-called condensing sheet. Conversely, the incident angle dependency of sunlight can be reduced.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it is smaller than this, the effect of diffraction is generated and colored.

  Examples of the light scattering layer include various antiglare layers, layers in which nanoparticles or nanowires such as metals or various inorganic oxides are dispersed in a colorless and transparent polymer, and the like.

<Method for producing organic photoelectric conversion element>
There is no restriction | limiting in particular in the manufacturing method of the organic photoelectric conversion element of above-mentioned this form, It can manufacture by referring a conventionally well-known method suitably. Hereinafter, the manufacturing method of the reverse layer type organic photoelectric conversion element as shown in FIG. 2 will be described as an example, and a preferable manufacturing method of the organic photoelectric conversion element of this embodiment will be described. However, each process in the manufacturing method is applied not only to the reverse layer type organic photoelectric conversion element but also to the normal layer type organic photoelectric conversion element as shown in FIG. 1 and the tandem type manufacturing as shown in FIG. Is possible.

  The method for producing an organic photoelectric conversion element of the present embodiment includes a step of forming a cathode, a step of forming a photoelectric conversion layer including a p-type organic semiconductor material and an n-type organic semiconductor material on the cathode, and the photoelectric conversion. Forming an anode on the layer. Hereinafter, each process of the manufacturing method of the organic photoelectric conversion element of this form is demonstrated in detail.

  In the manufacturing method of this embodiment, first, a cathode is formed. The method of forming the cathode is not particularly limited, but is easy to operate and can be produced on a roll-to-roll basis using a device such as a die coater. Preferably, the method is a method of applying and drying. Besides this, a commercially available thin film electrode material may be used as it is.

  After forming the cathode as described above, an electron transport layer may be formed on the cathode as necessary. The means for forming the electron transport layer may be either vapor deposition or solution coating, but is preferably solution coating. In the case of forming an electron transport layer using a solution coating method, a solution obtained by dissolving and dispersing the above-described electron transport material in a suitable solvent is coated on the cathode using a suitable coating method and dried. That's fine. The coating methods used for the solution coating method include cast method, spin coating method, blade coating method, wire bar coating method, gravure coating method, spray coating method, dipping (dipping) coating method, bead coating method, air knife coating method. Ordinary methods such as a curtain coating method, an ink jet method, a screen printing method, a relief printing method, an intaglio printing method, an offset printing method, a flexographic printing method, and a Langmuir-Blodgett (LB) method can be used. Among these, it is particularly preferable to use a blade coating method. In addition, although the solid content concentration of the solution used for the coating method may vary depending on the coating method and the film thickness, it is preferably 1 to 15% by mass, more preferably 1.5 to 10% by mass. In addition, the temperature of the coating liquid and / or the coating surface during coating is not particularly limited, but is preferably 30 to 120 ° C. from the viewpoint of preventing precipitation and unevenness due to temperature fluctuations during coating and drying. More preferably, it is 50-110 degreeC. Furthermore, there is no restriction | limiting in particular also about the specific form of drying, A conventionally well-known knowledge can be referred suitably. An example of the drying conditions is exemplified by conditions such as a temperature of about 80 to 140 ° C. and about several tens of seconds to several tens of minutes. Examples of the apparatus used for drying include a hot plate, hot air drying, an infrared heater, a microwave, and a vacuum dryer. Of course, other drying apparatuses can be used.

  Subsequently, a photoelectric conversion layer including a p-type organic semiconductor and an n-type organic semiconductor is formed on the cathode or the electron transport layer formed as described above. Here, the manufacturing method of this embodiment essentially includes the above-described conjugated polymer compound of the present invention as a p-type organic semiconductor. A specific method for forming the photoelectric conversion layer is not particularly limited, but preferably, a solution in which a p-type organic semiconductor and an n-type organic semiconductor are dissolved or dispersed in an appropriate solvent, respectively or collectively. Then, it may be applied on the cathode or the electron transport layer by using a suitable application method (the specific form is as described above) and dried. A solution in which a p-type organic semiconductor and an n-type organic semiconductor are collectively dissolved and dispersed in a solvent is applied by a coating method. After that, it is preferable to perform heating in order to cause removal of residual solvent, moisture, gas, and improvement of mobility and absorption absorption by crystallization of the semiconductor material. When annealing is performed at a predetermined temperature during the manufacturing process, a part of the particles is microscopically aggregated or crystallized and the photoelectric conversion layer can have an appropriate phase separation structure. As a result, the mobility of holes and electrons (carriers) in the photoelectric conversion layer is improved, and high efficiency can be obtained. In this way, the p-type organic semiconductor and the n-type organic semiconductor are uniformly mixed, and a bulk heterojunction organic photoelectric conversion element can be obtained.

  On the other hand, in the case of forming a photoelectric conversion layer (for example, a p-i-n structure) composed of a plurality of layers having different mixing ratios of a p-type organic semiconductor and an n-type organic semiconductor, the layer is applied after applying one layer. It can be formed by insolubilizing (pigmenting) and then applying another layer.

  Note that the steps after the step of forming the photoelectric conversion layer are preferably performed in a glove box under a nitrogen atmosphere so as not to be exposed to oxygen or moisture. Thus, by performing in a nitrogen atmosphere, it is possible to prevent the p-type organic semiconductor from being deteriorated by oxygen or moisture in the air, and to increase the durability of the element. Specifically, the concentration of oxygen and moisture in the glove box is preferably 1000 ppm or less, and more preferably 100 ppm or less. Most preferably, it is 10 ppm or less.

  Next, an anode is formed on the photoelectric conversion layer formed above. The means for forming the anode is not particularly limited and may be either a vapor deposition method or a solution coating method, but a vapor deposition method (for example, a vacuum vapor deposition method) is preferably used. In addition, when providing a positive hole transport layer between a photoelectric converting layer and an anode, a positive hole transport layer is formed using a vapor deposition method or a solution coating method, Preferably a solution coating method. In addition, it is preferable to perform the process of forming the said positive hole transport layer within the glove box of nitrogen atmosphere similarly to the process of forming the said photoelectric converting layer. Thus, by performing in a nitrogen atmosphere, deterioration of the photoelectric conversion layer due to oxygen or moisture in the air can be prevented, and the durability of the element can be improved. Moreover, the conjugated polymer compound according to the present invention has high solvent affinity. Therefore, when the hole transport layer is formed using the solution coating method, it is possible to effectively prevent the coating solution containing the hole transport material from being repelled on the surface of the photoelectric conversion layer. The film property can be improved.

  Furthermore, when layers other than the various layers described above are included, a step for forming these layers can be appropriately added by using a solution coating method, a vapor deposition method, or the like.

  The electrodes (cathode / anode), photoelectric conversion layer, hole transport layer, electron transport layer, and the like can be patterned as necessary. The patterning method is not particularly limited, and a known method can be appropriately applied. For example, when patterning soluble materials used in bulk heterojunction type photoelectric conversion layers, hole transport layers, electron transport layers, etc., even if only unnecessary portions are wiped off after the entire surface of die coating, dip coating, etc. Alternatively, direct patterning may be performed at the time of application using a method such as an inkjet method or screen printing. On the other hand, in the case of an insoluble material used for an electrode or the like, mask deposition can be performed at the time of deposition by vacuum deposition, or patterning can be performed by a known method such as etching or lift-off. Alternatively, the pattern may be formed by transferring a pattern formed on another substrate.

  Moreover, the organic photoelectric conversion element of this embodiment can be sealed as necessary in order to prevent deterioration due to oxygen, moisture, and the like in the environment. There is no restriction | limiting in particular in the sealing method, It can carry out by the well-known method used with an organic photoelectric conversion element, an organic electroluminescent element, etc. For example, (1) a method of sealing by bonding a cap made of aluminum or glass with an adhesive; (2) a plastic film on which a gas barrier layer such as aluminum, silicon oxide, or aluminum oxide is formed, and organic photoelectric conversion (3) A method of spin-coating an organic polymer material (polyvinyl alcohol, etc.) having a high gas barrier property; (4) An inorganic thin film (silicon oxide, aluminum oxide, etc.) having a high gas barrier property Alternatively, a method of depositing an organic film (parylene or the like) under vacuum; and (5) a method of laminating these in a composite manner may be mentioned.

<Uses of organic photoelectric conversion elements>
According to the other form of this invention, the solar cell which has the above-mentioned organic photoelectric conversion element is provided. Since the organic photoelectric conversion element of this embodiment has excellent durability and can achieve sufficient photoelectric conversion efficiency, it can be suitably used for a solar cell using this as a power generation element.

  Moreover, according to the further another form of this invention, the optical sensor array by which the organic photoelectric conversion element mentioned above is arranged in the array form is provided. That is, the organic photoelectric conversion element of this embodiment can also be used as an optical sensor array that converts an image projected on the optical sensor array into an electrical signal using the photoelectric conversion function.

  The effect of this invention is demonstrated using a following example and a comparative example. However, the technical scope of the present invention is not limited only to the following examples.

<Synthesis of conjugated polymer compound>
[Synthesis of Exemplified Compound 1]

Compound A was synthesized with reference to Non-Patent Document 4 (Macromolecules, 2011, 44 (18), pp7184). HNMR (CDCl ₃ ) = 9.01 ppm (2H), s; 7.95 ppm (2H), s; 2.62 ppm (4H), d; 1.84 ppm (2H), m; 1.35 to 1.25 ppm ( 48H), br; 0.85 ppm (12H), m.

  Compound B was synthesized with reference to WO 2005/111405 pamphlet.

  254 mg (0.25 mmol) of Compound A and 194 mg (0.25 mmol) of Compound B were dissolved in 20 ml of anhydrous toluene. After purging the solution with nitrogen, 6.3 mg (0.007 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 16.7 mg (0.055 mmol) of tris (o-tolyl) phosphine were added. It was. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 200 mg of a pure polymer (Mn = 15000) (Exemplary Compound 1), which was used in the organic photoelectric conversion device 3 of the present invention.

  [Synthesis of Exemplary Compound 3]

  Compound C is disclosed in J. Org. Mater. Chem. , 2009, vol. 19, p3449 was synthesized as a reference.

  After 855 mg (1 mmol) of Compound C was dissolved in 100 ml of dehydrated THF and cooled to −78 ° C., 1.53 ml (4 mmol) of 2.6M n-butyllithium / hexane solution was added and stirred at −78 ° C. for 2 hours. Then, 6.0 ml (6 mmol) of a 1.0 M hexane solution of trimethyltin chloride was added, and the mixture was further stirred at −78 ° C. for 30 minutes, and further stirred at room temperature (25 ° C., the same applies hereinafter) for 1 hour. Pure water and ethyl acetate were added for liquid separation, the organic layer was dried over magnesium chloride, the solvent was distilled off, and recrystallization was performed with acetone to obtain 920 mg of Compound D (yield 90%). .

  254 mg (0.25 mmol) of Compound A and 256 mg (0.25 mmol) of Compound B were dissolved in 20 ml of anhydrous toluene. After purging the solution with nitrogen, 6.3 mg (0.007 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 16.7 mg (0.055 mmol) of tris (o-tolyl) phosphine were added. It was. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 220 mg of a pure polymer (Mn = 21000) (Exemplary Compound 3), which was used for the organic photoelectric conversion device 4 of the present invention.

  [Synthesis of Exemplified Compound 4]

  Compound E was synthesized with reference to WO 2011/085004 pamphlet.

  254 mg (0.25 mmol) of Compound A and 256 mg (0.25 mmol) of Compound E were dissolved in 20 ml of anhydrous toluene. After purging the solution with nitrogen, 6.3 mg (0.007 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 16.7 mg (0.055 mmol) of tris (o-tolyl) phosphine were added. It was. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 220 mg of a pure polymer (Mn = 29000) (Exemplary Compound 4), which was used for the organic photoelectric conversion device 5 of the present invention.

  [Synthesis of Exemplary Compound 12]

  J. et al. AM. CHEM. SOC. Compound F was synthesized with reference to 2009, 131, 7514. Bull. Chem. Soc. Jpn. 1991, p68, compound G was synthesized.

1.40 g (2.4 mmol) of compound F and 434 mg (1.1 mmol) of compound G were dissolved in 50 ml of toluene, 95 mg of tris (dibenzylideneacetone) dipalladium (0) and 126 mg of tris (o-tolyl) phosphine And added. The solution was purged with nitrogen for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 4 hours. After allowing to cool, toluene was distilled off, and purification was performed by silica gel column chromatography using an eluent of toluene: heptane = 100: 0 to 100: 10 (volume ratio) to obtain 400 mg of Compound H (yield 34%). Obtained. HNMR (CDCl ₃ ) = 9.09 ppm, 2H, s; 8.35 ppm, 2H, d; 7.30 ppm, 2H, d; 7.11 ppm, 2H, d; 1.49 ppm, 2H, m; 1.2− 1.4 ppm, 32 H, br; 1.0-1.1 ppm, 8 H, m; 0.84 ppm, 12 H, t.

400 mg (0.37 mmol) of Compound H was dissolved in 20 ml of THF, 145 mg (0.82 mmol) of N-bromosuccinimide (NBS) was added, and the mixture was stirred at 50 ° C. for 3.5 hours. After completion of the reaction, the solvent was distilled off, and purification by silica gel column chromatography with an eluent of toluene: heptane = 100: 0 to 100: 10 (volume ratio) gave 370 mg of Compound I (yield 81%). Obtained. HNMR (CDCl ₃ ) = 9.09 ppm, 2H, s; 8.34 ppm, 2H, d; 7.09 ppm, 2H, d; 1.49 ppm, 2H, m; 1.2-1.4 ppm, 32H, br; 1.0-1.1 ppm, 8H, m; 0.84 ppm, 12H, t.

  185 mg (0.15 mmol) of Compound I and 153 mg (0.15 mmol) of Compound E were dissolved in 20 ml of anhydrous toluene. After purging this solution with nitrogen, 3.9 mg (0.0042 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 10 mg (0.033 mmol) of tris (o-tolyl) phosphine were added. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 290 mg of a pure polymer (Mn = 50000) (Exemplary Compound 12), which was used for the organic photoelectric conversion device 7 of the present invention.

[Synthesis of Exemplified Compound 10]
In the synthesis of the exemplified compound 12, instead of 4,4′-bis- (2-ethylhexyl) -4H-silolo- [3,2-b: 4,5-b ′]-dithiophene as a synthesis raw material of the compound F Except for using 4,4′-bis- (2-ethylhexyl) -4H-cyclopenta- [1,2-b: 5,4-b ′]-dithiophene (synthesized with reference to Macromolecules 2007, 40, p1981) Similarly, Exemplified Compound 10 was synthesized. The yield was 230 mg and Mn = 44000, and it was used for the organic photoelectric conversion device 6 of the present invention.

[Synthesis of Exemplified Compound 16]
In the synthesis of the exemplified compound 12, instead of 4,4′-bis- (2-ethylhexyl) -4H-silolo- [3,2-b: 4,5-b ′]-dithiophene as a synthesis raw material of the compound F 4,8-bis- (2-hexyldecyloxy) -benzo [1,2-b: 4,5-b ′]-dithiophene (synthesized with reference to J. AM. CHEM. SOC. 2009, 131, p56) Exemplified Compound 16 was synthesized in the same manner except that was used. The yield was 180 mg and Mn = 25000, and it was used for the organic photoelectric conversion element 8 of the present invention.

  [Synthesis of Exemplary Compound 21]

  Compound J was synthesized with reference to US 2010/137611.

  Take 5.1 g (27 mmol) of 3-bromothiophene-2-carboxaldehyde and 0.73 g (6.8 mmol) of rubeanic acid and dissolve in 100 ml of N, N-dimethylformamide (DMF) at 150 ° C. for 5 hours. Stir. After stopping the reaction and returning to room temperature, pure water was added and stirred for 30 minutes. The precipitated solid was collected by filtration, washed with methanol, and then vacuum dried at 60 ° C. for 10 hours. It was dissolved in tetrahydrofuran (THF) and purified by silica gel column chromatography to obtain 1.2 g (yield 38%) of Compound 1.

  Compound K is described in J.I. Org. Chem. 1997, 62, 1376-1387. Compound J was dissolved in 1.0 g (2.2 mmol) of dehydrated THF 300 ml, cooled to −78 ° C., and then 6.1 ml (9.7 mmol) of 1.6M hexane solution of t-butyllithium was added dropwise and stirred for 1 hour. Ethylene oxide 5.0 M ether solution (1.5 ml, 2.4 mmol) was added dropwise, and the mixture was stirred for 12 hours while gradually returning to room temperature. After completion of the reaction, brine and ethyl acetate were added to carry out a liquid separation operation, the organic layer was extracted and dried over magnesium sulfate, and then the solvent was distilled off. Thereafter, the residue was purified by silica gel column chromatography to obtain 0.72 g (yield 83%) of Compound K.

  0.72 g (1.8 mmol) of Compound K and 1.53 g (4.7 mmol) of decanoic anhydride were dissolved in 10 ml of pyridine and stirred for 5 hours. After completion of the reaction, brine and ethyl acetate were added to carry out a liquid separation operation, the organic layer was extracted and dried over magnesium sulfate, and then the solvent was distilled off to obtain 1.23 g of Compound L (yield 97%). .

  After dissolving 700 mg (1.0 mmol) of Compound L in 100 ml of dehydrated THF and cooling to −78 ° C., 2.0 ml (4 mmol) of 2.0 M lithium diisopropylamide solution was added, and the mixture was stirred at −78 ° C. for 2 hours. 6.0 ml (6 mmol) of a 1.0 M hexane solution of trimethyltin was added, stirred at −78 ° C. for another 30 minutes, and further stirred at room temperature for 1 hour. Pure water and ethyl acetate were added for liquid separation, the organic layer was dried over magnesium chloride, the solvent was distilled off, and recrystallization was performed with methanol to obtain 833 mg of Compound M (yield 81%). .

  185 mg (0.15 mmol) of Compound I and 154 mg (0.15 mmol) of Compound M were dissolved in 20 ml of anhydrous toluene. After purging this solution with nitrogen, 3.9 mg (0.0042 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 10 mg (0.033 mmol) of tris (o-tolyl) phosphine were added. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 210 mg of a pure polymer (Mn = 28000) (Exemplary Compound 21), which was used for the organic photoelectric conversion device 9 of the present invention.

  [Synthesis of Exemplified Compound 22]

  Compound K (0.72 g, 1.8 mmol) and decyl chloroformate (1.04 g, 4.7 mmol) were dissolved in tetrahydrofuran (10 ml) and triethylamine (1 ml), and the mixture was stirred for 5 hours. After completion of the reaction, brine and ethyl acetate were added to carry out a liquid separation operation, the organic layer was extracted and dried over magnesium sulfate, and then the solvent was distilled off to obtain 1.23 g of Compound N (yield 97%). .

  760 mg (1.0 mmol) of Compound N was dissolved in 100 ml of dehydrated THF, cooled to −78 ° C., 2.0 ml (4 mmol) of 2.0 M lithium diisopropylamide solution was added, and the mixture was stirred at −78 ° C. for 2 hours. 6.0 ml (6 mmol) of 1.0 M hexane solution of trimethyltin was added, and the mixture was further stirred at -78 ° C for 30 minutes, and further stirred at room temperature for 1 hour. Pure water and ethyl acetate were added for liquid separation, the organic layer was dried over magnesium chloride, the solvent was distilled off, and recrystallization was performed with methanol to obtain 816 mg of Compound O (yield 75%). .

  185 mg (0.15 mmol) of Compound I and 163 mg (0.15 mmol) of Compound O were dissolved in 20 ml of anhydrous toluene. After purging this solution with nitrogen, 3.9 mg (0.0042 mmol) of tris (dibenzylideneacetone) dipalladium (0) and 10 mg (0.033 mmol) of tris (o-tolyl) phosphine were added. This solution was purged with argon for an additional 15 minutes. Thereafter, the solution was heated to 110 to 120 ° C. and reacted for 72 hours. Furthermore, in order to perform an end cap, 2-tributyltin thiophene (11 mg, 0.03 mmol) was added and refluxed for 10 hours. Further 2-bromothiophene (10 mg, 0.06 mmol) was added and refluxed for 10 hours. After completion of the reaction, reprecipitation in methanol (500 ml), and the polymer product collected by filtration was extracted with Soxhlet extraction using methanol, acetone, heptane, chloroform, and then orthodichlorobenzene, and reprecipitated in methanol. To obtain 210 mg of a pure polymer (Mn = 22000) (Exemplary Compound 22), which was used in the organic photoelectric conversion device 10 of the present invention.

<Preparation of reverse layer type organic photoelectric conversion element>
With reference to the description of International Publication No. 2008-134492 Panfoot, a reverse layer type organic photoelectric conversion device was produced as follows.

[Comparative Example 1]
An indium tin oxide (ITO) transparent conductive film 150 nm deposited (sheet resistance 12 Ω / square cm ² ) as a first electrode (cathode) on a PET substrate using a normal photolithography technique and wet etching. The first electrode was formed by patterning to a width of 10 mm. The patterned first electrode was cleaned in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning. After this, the substrate was brought into the glove box and operated under a nitrogen atmosphere.

  On this first electrode, a 0.05 mass% methoxyethanol solution of 3- (2-aminoethyl) -aminopropyltrimethoxysilane manufactured by Aldrich was used with a blade coater so that the dry film thickness was about 5 nm. And dried. Thereafter, heat treatment was performed at 120 ° C. for 1 minute on a hot plate to form an electron transport layer.

  Next, 0.8% by mass of Comparative Compound 1 (synthesized based on Non-Patent Document 4), which is a p-type organic semiconductor material, and PC61BM (nanospectra E100H manufactured by Frontier Carbon), which is an n-type organic semiconductor material, are added to o-dichlorobenzene. ) Was mixed at 1.6% by mass (p-type organic semiconductor material: n-type organic semiconductor material = 33: 67 (mass ratio)), and dissolved by stirring all day and night while heating to 110 ° C. in an oven. Then, it apply | coated using the blade coater which hold | maintained the substrate temperature at 80 degreeC so that the dry film thickness might be set to about 200 nm, and it dried at 80 degreeC as it was for 2 minutes, and formed the photoelectric converting layer into a film.

After the drying of the photoelectric conversion layer is completed, the photoelectric conversion layer is taken out again under the air, and then, as a hole transport layer, PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by Helios Co., Ltd.) composed of a conductive polymer and polyanion. , Conductivity 1 × 10 ⁻³ S / cm) was prepared by diluting with an equal amount of isopropanol, and applied and dried using a blade coater so that the dry film thickness was about 30 nm. Then, it heat-processed for 20 second with 90 degreeC warm air, and formed the positive hole transport layer (organic material layer) which consists of organic substance. The temperature and humidity of the atmosphere at the time of application were 23 ° C. and 65%.

Next, the element was set so that the shadow mask with a width of 10 mm was orthogonal to the transparent electrode, the inside of the vacuum deposition apparatus was depressurized to 1 × 10 ⁻³ Pa or less, and then Ag metal was deposited at a deposition rate of 0.5 nm / second. A second electrode (anode) was formed by laminating 200 nm.

The obtained laminate was moved to a nitrogen chamber and sandwiched between UBF-9L (water vapor transmission rate 5.0 × 10 ⁻⁴ g / m ² / d) manufactured by Sumitomo 3M Co., Ltd., and UV curable resin (Nagase Chem) Sealing was performed using UV RESIN XNR5570-B1) manufactured by Tex Co., Ltd., and then taken out into the atmosphere to obtain an organic photoelectric conversion element 1 having a light receiving portion with a size of about 10 × 10 mm.

In addition, after forming the photoelectric conversion layer, the hole transport layer was formed in the glove box as it was without taking it out from the glove box (N ₂ ) (oxygen concentration 10 ppm, dew point temperature −80 ° C.) in a nitrogen atmosphere. Except for, a reverse layer type organic photoelectric conversion element was produced in the same manner.

[Comparative Example 2]
In the formation of the photoelectric conversion layer, a reverse layer type organic material was formed in the same manner as in Comparative Example 1 except that Comparative Compound 2 (synthesized based on Non-Patent Document 5) was used as the p-type organic semiconductor. A photoelectric conversion element was produced.

[ Reference Example 1, Examples 2 to 8]
In the formation of the photoelectric conversion layer, a reverse layer type organic photoelectric conversion element was produced in the same manner as in Comparative Example 1 except that each of the compounds shown in Table 1 below was used as the p-type organic semiconductor. .

[Synthesis of Compound P (Electron Transport Material)]
Compound P was synthesized by the following reaction.

Adv. Mater. Poly (9,9-bis (6-bromohexyl) -4,7-fluorene) was synthesized with reference to 2007, 19, 2010. The weight average molecular weight of this compound was 4400. 1.0 g of this compound and 9.0 g of 3,3′-iminobis (N, N-dimethylpropylamine) (manufactured by Aldrich) were dissolved in a mixed solvent of 100 ml of tetrahydrofuran and 100 ml of N, N-dimethylformamide, and room temperature ( The reaction was carried out at 48 ° C. for 48 hours. After completion of the reaction, the solvent was distilled off under reduced pressure, and reprecipitation was further performed in water to obtain 1.3 g of Compound P (yield 90%). About the obtained compound, the structure was specified by H-NMR. The results are shown below. 7.6-8.0 ppm (br), 2.88 ppm (br), 2.18 ppm (m), 2.08 ppm (s), 1.50 ppm (m), 1.05 ppm (br).
<Preparation of normal layer type organic photoelectric conversion element>
[Example 9]
An indium tin oxide (ITO) transparent conductive film 150 nm deposited (sheet resistance 12 Ω / square cm ² ) as a first electrode (cathode) on a PET substrate using a normal photolithography technique and wet etching. The first electrode was formed by patterning to a width of 10 mm. The patterned first electrode was cleaned in the order of ultrasonic cleaning with a surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally subjected to ultraviolet ozone cleaning. Next, PEDOT-PSS (CLEVIOS (registered trademark) PVP AI 4083, manufactured by Helios Co., Ltd., conductivity 1 × 10 ⁻³ S / cm) made of a conductive polymer and a polyanion is 2.0 as a hole transport layer. An isopropanol solution containing by mass% was prepared, and the substrate was applied and dried using a blade coater whose temperature was adjusted to 65 ° C. so that the dry film thickness was about 30 nm. Then, it heat-processed with the warm air of 120 degreeC for 20 second, and formed the positive hole transport layer on said 1st electrode. After this, the substrate was brought into the glove box and operated under a nitrogen atmosphere. First, the substrate was heat-treated at 120 ° C. for 3 minutes in a nitrogen atmosphere.

  Next, 0.8% by mass of Exemplified Compound 12 as a p-type organic semiconductor material and 1.6% by mass of PC61BM (nanospectra E100H manufactured by Frontier Carbon) as an n-type organic semiconductor material were mixed with o-dichlorobenzene. After preparing an organic photoelectric conversion material composition solution and stirring (60 minutes) while heating to 100 ° C. on a hot plate to completely dissolve it, the substrate is adjusted to 40 ° C. so that the dry film thickness is about 170 nm. It apply | coated using the warm blade coater, and it dried for 2 minutes, and formed the photoelectric converting layer on the said positive hole transport layer.

  Subsequently, the compound P was dissolved in hexafluoroisopropanol so as to be 0.02% by mass, to prepare solutions. This solution was applied and dried using a blade coater whose temperature was adjusted to 65 ° C. so that the dry film thickness was about 5 nm. Thereafter, heat treatment was performed for 2 minutes with warm air at 100 ° C. to form an electron transport layer on the photoelectric conversion layer.

Next, the substrate on which the electron transport layer was formed was placed in a vacuum deposition apparatus. Then, the element was set so that the shadow mask with a width of 10 mm was orthogonal to the transparent electrode, and the inside of the vacuum deposition apparatus was depressurized to 10 ⁻³ Pa or less, and then silver was deposited at a deposition rate of 2 nm / second, and 100 nm was deposited. Then, a second electrode was formed on the electron transport layer.

The obtained organic photoelectric conversion element was moved to a nitrogen chamber, and sandwiched between ^two 3M Ultra Barrier Solar Film UBL-9L (water vapor transmission rate <5 × 10 ⁻⁴ g / m ² / d), UV After sealing using a curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1), it was taken out into the atmosphere, and an organic photoelectric conversion element 11 having a light receiving portion of about 10 × 10 mm size was produced.

<Evaluation of organic photoelectric conversion element>
(Evaluation of open circuit voltage, fill factor, and photoelectric conversion efficiency)
The organic photoelectric conversion elements obtained in Reference Example 1, Examples 2 to 9 and Comparative Examples 1 and 2 were each sealed with an epoxy resin and a glass cap. A solar simulator (AM1.5G filter) is used to irradiate light with an intensity of 100 mW / cm ² , a mask with an effective area of 1 cm ² is overlaid on the light receiving part, and IV characteristics are evaluated, thereby short-circuit current density J _sc (mA / cm ² ), open circuit voltage V _oc (V), and fill factor FF were measured. From the obtained values of J _sc , V _oc and FF, photoelectric conversion efficiency η [%] was calculated according to the following formula 1. The results are shown in Table 1.

(Evaluation of film forming property of hole transport layer on photoelectric conversion layer)
Reference Example 1, Example 2-8 and Comparative Example 1-2, Preparation of reverse phase type organic photoelectric conversion device was tried five times, respectively. And when apply | coating a positive hole transport layer on a photoelectric converting layer, the hydrophilic solvent contained in the dispersion liquid of organic solvent type | system | group PEDOT: PSS on a photoelectric converting layer is favorable, and is not repelled on a photoelectric converting layer. The film forming property was evaluated by the number of times the hole transport layer was formed. The results are shown in Table 1.

(Durability evaluation)
Each organic photoelectric conversion element obtained in Reference Example 1, Examples 2 to 9 and Comparative Examples 1 and 2 was stored in a container maintained at a temperature of 80 ° C. and a humidity of 80%, and taken out periodically to obtain IV characteristics. The initial photoelectric conversion efficiency was set as 100, and the time when the initial efficiency was reduced to 80% of the initial efficiency was evaluated as LT80 [time]. It means that durability is so favorable that the value of LT80 is large. The results are shown in Table 1.

  From the results in Table 1, it was shown that the examples using the conjugated polymer compound of the present invention have better coating properties of the hole transport layer and higher photoelectric conversion efficiency than the comparative examples. .

  As for the durability evaluation of the device, the durability was remarkably improved as compared with the comparative example in each of the examples in which the hole transport layer was formed in the atmosphere and in the glove box.

  Furthermore, the example in which the hole transport layer is formed in a glove box with less oxygen and moisture improves the photoelectric conversion efficiency and the durability of the device further than the example in which the hole transport layer is formed in the atmosphere. It was shown that. On the other hand, in Comparative Examples 1 and 2, when the hole transport layer was applied in the glove box, the hydrophilic solvent was repelled and film formation was extremely difficult.

  In addition, as shown in Example 9, it was shown that the conjugated polymer compound of the present invention can exhibit high photoelectric conversion efficiency even in a normal layer configuration.

10, 20, 30 organic photoelectric conversion element,
11 Anode,
12 cathode,
14 photoelectric conversion layer,
14a 1st photoelectric conversion layer,
14b second photoelectric conversion layer,
25 substrates,
26 hole transport layer,
27 electron transport layer,
38 Charge recombination layer.

Claims (9)

A first electrode;
A second electrode;
A photoelectric conversion layer including an n-type organic semiconductor and a p-type organic semiconductor, which exists between the first electrode and the second electrode;
Have
The p-type organic semiconductor has the following general formula 1 and general formula 2 :
In the formula, -X ¹ = independently represents -C (R ³ ) = or -N =,
R ^{1 to} R ³ are each independently a hydrogen atom (H), a halogen atom (F, Cl, Br, or I), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, carbon Fluoroalkyl group having 1 to 20 atoms, cycloalkyl group having 3 to 20 carbon atoms, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, 1 to 1 carbon atom 20 fluorinated alkoxy groups, fluorinated alkylthio groups having 1 to 20 carbon atoms, aryl groups having 6 to 30 carbon atoms, fluorinated aryl groups having 6 to 30 carbon atoms, heteroaryls having 1 to 20 carbon atoms A group or a fluorinated heteroaryl group having 1 to 20 carbon atoms ;
A conjugated polymer compound each having at least one partial structure represented by
The conjugated polymer compound is represented by the following general formula 3A or general formula 3B:
In the formula, -X ¹ = independently represents -C (R ³ ) = or -N =,
R ^{1 to} R ⁵ are each independently a hydrogen atom (H), a halogen atom (F, Cl, Br, or I), a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, carbon Fluoroalkyl group having 1 to 20 atoms, cycloalkyl group having 3 to 20 carbon atoms, fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, 1 to 1 carbon atom 20 fluorinated alkoxy groups, fluorinated alkylthio groups having 1 to 20 carbon atoms, aryl groups having 6 to 30 carbon atoms, fluorinated aryl groups having 6 to 30 carbon atoms, heteroaryls having 1 to 20 carbon atoms A group or a fluorinated heteroaryl group having 1 to 20 carbon atoms,
Each D independently represents a donor heteroaromatic ring group or a donor heterofused aromatic ring group containing a sulfur atom (S);
The organic photoelectric conversion element which has at least 1 type of the partial structure represented by these .   The organic photoelectric conversion device according to claim 1, wherein the conjugated polymer compound has a number average molecular weight of 10,000 to 100,000. In the general formula 3A and / or the general formula 3B, -X ¹ = represents -N =, the organic photoelectric conversion element according to claim 1 or 2. In the general formula 3A and / or the general formula 3B, R ⁴ or R ⁵ are, each independently represents a group represented by the following general formula 4, organic according to any one of claims 1 to 3 Photoelectric conversion element;
In the formula, each L independently represents an alkylene group having 1 to 10 carbon atoms,
Y ¹ and Y ² each independently represent an oxygen atom (O) or NR ⁷ ;
Each Z independently represents a carbon atom (C), a sulfur atom (S), or a phosphorus atom (P);
R ⁶ and R ⁷ are each independently a hydrogen atom (H), an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, carbon An aryl group having 6 to 30 atoms or a heteroaryl group having 1 to 20 carbon atoms;
a, b, and c represent integers satisfying the relational expressions 2 ≦ a + b + c ≦ 4 and 0 ≦ a, b, c ≦ 2. In the said General formula 4, a, b, and c are the organic photoelectric conversion elements of Claim 4 showing the integer which satisfy | fills the relational expression of a + b + c = 3 and 0 <= a, b, c <= 2. In Formula 3 A and / or the general formula 3B, D each independently represents a partial structure represented by the following general formula 5, organic photoelectric conversion device according to any one of claims 1 to 5 ;
In the formula, each A independently represents a carbon atom (C), a silicon atom (Si), or a germanium atom (Ge),
R ⁸ each independently represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a fluorinated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, Fluorinated cycloalkyl group having 3 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, fluorinated alkoxy group having 1 to 20 carbon atoms, fluorinated alkylthio group having 1 to 20 carbon atoms, carbon atom number A 6-30 aryl group, a C6-C30 fluorinated aryl group, a C1-C20 heteroaryl group, or a C1-C20 fluorinated heteroaryl group is represented. In the said General formula 5 , A represents the silicon atom (Si) each independently, The organic photoelectric conversion element of Claim 6 . The first electrode is a transparent electrode;
The second electrode is a counter electrode;
Between the second electrode and the photoelectric conversion layer further comprises a hole transport layer, an organic photoelectric conversion device according to any one of claims 1-7. The solar cell which has an organic photoelectric conversion element of any one of Claims 1-8 .