JP2012049352A - Organic photoelectric conversion element, and solar cell and optical sensor array utilizing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a durable organic thin-film solar cell whose fill factor, open-circuit voltage, and photoelectric conversion efficiency are high, and to provide an organic semiconductor material included in the same.SOLUTION: The organic photoelectric conversion element includes: a negative electrode; a positive electrode; a bulk heterojunction layer where a p-type semiconductor material and an n-type semiconductor material are mixed; and includes, between the bulk heterojunction layer and the negative electrode, at least a layer of a compound represented by the following general formula (1).

Description

  The present invention relates to an organic photoelectric conversion element, a solar cell, and an optical sensor array, and more particularly to a bulk heterojunction type organic photoelectric conversion element, a solar cell using the organic photoelectric conversion element, and an optical array sensor.

  Due to the recent rise in fossil energy, a system that can generate electric power directly from natural energy has been demanded. Solar cells using monocrystalline, polycrystalline, or amorphous Si, compound-based solar cells such as GaAs and CIGS, or Dye-sensitized photoelectric conversion elements (Gretzel cells) have been proposed and put into practical use.

  However, the cost of generating electricity with these solar cells is still higher than the price of electricity generated and transmitted using fossil fuels, which has hindered widespread use. In addition, since heavy glass must be used for the substrate, reinforcement work is required at the time of installation, which is one of the causes that increase the power generation cost.

  In this situation, as a solar cell that can achieve a power generation cost lower than that of fossil fuel, an electron donor layer (p-type semiconductor layer) and an electron acceptor layer ( A bulk heterojunction photoelectric conversion element having a bulk heterojunction layer mixed with an n-type semiconductor layer has been proposed (see, for example, Non-Patent Document 1).

  Since these bulk heterojunction solar cells are formed by a coating process except for the anode and cathode, it is expected that they can be manufactured at high speed and at low cost, and may solve the above-mentioned problem of power generation cost. . Furthermore, unlike the Si solar cells, compound semiconductor solar cells, and dye-sensitized solar cells described above, there is no process at a temperature higher than 160 ° C., so it can be formed on a cheap and lightweight plastic substrate. Is done.

  In addition to the initial manufacturing cost, the power generation cost must be calculated including the power generation efficiency and the durability of the element. In Non-Patent Document 1, in order to efficiently absorb the solar spectrum, a long wavelength is used. By using an organic polymer capable of absorbing up to 5%, conversion efficiency exceeding 5% has been achieved.

  The photoelectric conversion efficiency is calculated by the product of short-circuit current (Jsc) × open-circuit voltage (Voc) × fill factor (FF), but generally includes organic photoelectric conversion elements including the above-described high-efficiency organic thin-film solar cells. The curve factor remains as low as about 0.55, and if these can be improved to values equivalent to silicon solar cells (0.65 to 0.75), it is expected that further photoelectric conversion efficiency can be obtained. .

  The curve factor is closely related to the internal resistance of the photoelectric conversion element, and it is known that lowering the resistance of the organic thin film and improving the charge separation efficiency (improving rectification) are effective for improving the curve factor. Yes.

  There is a disclosure that the charge separation efficiency can be improved and the photoelectric conversion efficiency can be improved by inserting a hole blocking layer made of bathocuproine (BCP) as in the organic EL element (see, for example, Patent Document 1). Since these materials have high crystallinity and low solubility, there is a problem that it is difficult to apply them to a coating method with high productivity.

  Further, although a TiOx layer is disclosed as a hole blocking layer that can be produced by a coating process (see, for example, Non-Patent Document 2), in order to form a TiOx layer, it is necessary to react moisture with titanium alkoxides. An organic photoelectric conversion element that is deteriorated by moisture is not a preferable manufacturing method, and has a problem in durability.

  In addition, in an organic electroluminescence device (OLED) having a similar structure but having the opposite function, a carboline derivative or a diazacarbazole derivative is used for the hole blocking layer in order to improve the light emission efficiency. Although there is a disclosure (see, for example, Patent Documents 2 and 3), generally, whether a hole blocking layer functions as a hole blocking layer is determined by the relationship with the HOMO level of an adjacent layer. Any block layer is not necessarily applicable to an organic photoelectric conversion element. In particular, since the HOMO and LUMO of fullerene derivatives, which are n-type semiconductors included in a bulk heterojunction layer, are relatively deep, the organic photoelectric conversion element is also applicable. The development of a hole blocking layer that can be effectively formed by a non-aqueous coating method is awaited. It was.

  On the other hand, a technique for improving solubility by introducing a silylethynyl group into a fullerene compound or pentacene compound generally used as an n-type semiconductor material is disclosed (for example, see Patent Document 4 and Non-Patent Document 3). . However, no examples of applying a silylethynyl group to a hole blocking layer material have been reported so far.

US Pat. No. 6,580,0027 B2 WO2004 / 053019 WO2004 / 095889 WO2010 / 066792

A. Heeger: Nature Mat. Vol. 6 (2007), p497 A. Heeger: Science; vol. 317 (2007), p222 J. et al. Mater. Chem. , Vol. 19 (2009), p3049

  An object of the present invention is to provide an organic thin film solar cell having high fill factor, open circuit voltage, photoelectric conversion efficiency, and durability, and an organic semiconductor material constituting the organic thin film solar cell.

  The above object of the present invention can be achieved by the following configuration.

  1. An organic photoelectric conversion element having a cathode, an anode, and a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, wherein at least the following general formula (1) is provided between the bulk heterojunction layer and the cathode: It has a layer containing the compound represented, The organic photoelectric conversion element characterized by the above-mentioned.

[Wherein R ¹ , R ² and R ³ each independently represents a substituent selected from a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group and an alkylsilyl group, Q is a tetravalent silicon atom, Represents any atom selected from a germanium atom and a tin atom, L ¹ represents a divalent linking group or a mere bond, L ² represents a divalent or trivalent linking group, or a mere bond, A ¹ represents a 5-membered or 6-membered carbocyclic or heterocyclic ring which may have a condensed ring, and n represents 1 or 2. ]
2. 2. The organic photoelectric conversion device according to 1 above, wherein the atom represented by Q in the general formula (1) is a tetravalent silicon atom.

3. Wherein A ¹ in the general formula (1) is represented by the following general formula (A1) ~ Formula organic photoelectric conversion device according to the 1 or 2, characterized in that either selected from (A7).

[Wherein, X ^{1 to} X ⁸ each independently represents a carbon atom or a nitrogen atom, X ⁹ represents a carbon atom, a silicon atom, a germanium atom, a titanium atom, or a tin atom, and R ^{4 to} R ⁸ each independently represent Substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, alkylsilyl group, alkenyl group, alkynyl group, alkoxy group, cycloalkyloxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryl Oxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group , Hydroxy group, merca At least one group selected from a putto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, or L ² in the general formula (1) N1 and n2 each independently represents an integer of 0 to 4, and at least one of R ⁴ , R ⁵ and R ⁶ in formula (A1) is a bond to L ² , At least one of R ^{5 to} R ⁸ in Formula (A2) is a bond to L ^2, and R ⁵ or R ⁶ in General Formula (A3) is a bond to L ² . ]

[Wherein R ⁹ or R ¹⁰ represents a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), and R ⁹ or R ¹⁰ represents a bond to L ^2. X ¹⁰ represents an oxygen atom, a sulfur atom, or —NR′—, and R ′ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or a sulfonyl group. ]

[Wherein R ¹¹ , R ¹⁶ , R ¹⁷ represent a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), and x, y, and z are each independently R ^{12 to} R ¹⁵ , R ¹⁸ , R ¹⁹ each independently represents a hydrogen atom or a bond to L ² in the general formula (1), and adjacent R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁸ and R ¹⁹ may be bonded to each other to form a condensed ring, and these condensed rings may have a substituent, and R ^{11 to} R ¹⁵ in the general formula (A5), or a condensed ring At least one of the above substituents is a bond to L ^2, and at least one of R ¹² , R ¹³ , R ^{16 to} R ¹⁹ in general formula (A6), or a substituent on the condensed ring is L ^2. It is a joint hand. ]

[Wherein R ²¹ and R ²² represent a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), R ^{23 to} R ²⁶ represent a hydrogen atom, and R ^{4 to} R ^{8 represents} a substituent having the same meaning or a bond to L ² in the general formula (1), and any one of R ^{21 to} R ²⁶ is a bond to L ² . ]
4). 4. The organic photoelectric conversion device according to any one of 1 to 3, wherein A ¹ in the general formula (1) is any one selected from the general formula (A1) to the general formula (A4). .

5). The organic photoelectric conversion element of any one of the 1-4 A ¹ is wherein in formula (A1) or Formula (A4) of the general formula (1).

  6). 6. The organic photoelectric conversion device according to any one of 1 to 5, wherein the layer containing the compound represented by the general formula (1) is produced by a solution coating method.

  7). A solar cell comprising the organic photoelectric conversion device according to any one of 1 to 6 above.

  8). The organic photoelectric conversion element of any one of said 1-6 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

  According to the present invention, it is possible to provide an organic thin film solar cell having high fill factor, open circuit voltage, photoelectric conversion efficiency and durability, and an organic semiconductor material constituting the organic thin film solar cell.

It is sectional drawing which shows the solar cell which consists of a bulk hetero junction type organic photoelectric conversion element. It is sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with the photoelectric converting layer of the three-layer structure of p-i-n. It is sectional drawing which shows the solar cell which consists of an organic photoelectric conversion element provided with a tandem-type bulk heterojunction layer. It is a figure which shows the structure of an optical sensor array.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  When the present inventors diligently examined the above problem, a layer containing a compound having a partial structure represented by the general formula (1) exists between the bulk heterojunction layer and the cathode. The present inventors have found that the above-mentioned problems can be achieved.

  Hereinafter, the present invention will be described in more detail.

(Configuration of organic photoelectric conversion element and solar cell)
FIG. 1 is a cross-sectional view showing an example of a solar cell composed of a bulk heterojunction organic photoelectric conversion element. In FIG. 1, a bulk heterojunction type organic photoelectric conversion element 10 includes a transparent electrode (generally an anode) 12, a hole transport layer 17, a bulk heterojunction layer photoelectric conversion unit 14, and an electron transport layer 18 on one surface of a substrate 11. And a counter electrode (generally a cathode) 13 are sequentially stacked.

  The substrate 11 is a member that holds the transparent electrode 12, the photoelectric conversion unit 14, and the counter electrode 13 that are sequentially stacked. In the present embodiment, since light that is photoelectrically converted enters from the substrate 11 side, the substrate 11 can transmit the light that is photoelectrically converted, that is, with respect to the wavelength of the light to be photoelectrically converted. It is a transparent member. As the substrate 11, for example, a glass substrate or a resin substrate is used. The substrate 11 is not essential. For example, the bulk heterojunction type organic photoelectric conversion element 10 may be configured by forming the transparent electrode 12 and the counter electrode 13 on both surfaces of the photoelectric conversion unit 14.

  The photoelectric conversion unit 14 is a layer that converts light energy into electric energy, and includes a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are uniformly mixed. The p-type semiconductor material functions relatively as an electron donor (donor), and the n-type semiconductor material functions relatively as an electron acceptor (acceptor). Here, the electron donor and the electron acceptor are “an electron donor in which, when light is absorbed, electrons move from the electron donor to the electron acceptor to form a hole-electron pair (charge separation state)”. And an electron acceptor ”, which does not simply donate or accept electrons like an electrode, but donates or accepts electrons by a photoreaction.

  In FIG. 1, light incident from the transparent electrode 12 through the substrate 11 is absorbed by the electron acceptor or electron donor in the bulk heterojunction layer of the photoelectric conversion unit 14, and electrons move from the electron donor to the electron acceptor. Thus, a hole-electron pair (charge separation state) is formed. The generated electric charge is caused by an internal electric field, for example, when the work functions of the transparent electrode 12 and the counter electrode 13 are different, the electrons pass between the electron acceptors due to the potential difference between the transparent electrode 12 and the counter electrode 13, and the holes are The photocurrent is detected as it passes between the donors and is carried to different electrodes. For example, when the work function of the transparent electrode 12 is larger than the work function of the counter electrode 13, electrons are transported to the transparent electrode 12 and holes are transported to the counter electrode 13. If the magnitude of the work function is reversed, electrons and holes are transported in the opposite direction. In addition, by applying a potential between the transparent electrode 12 and the counter electrode 13, the transport direction of electrons and holes can be controlled.

  Although not shown in FIG. 1, other layers such as a hole blocking layer, an electron blocking layer, an electron injection layer, a hole injection layer, or a smoothing layer may be included.

  As a more preferable configuration, the photoelectric conversion unit 14 has a so-called p-i-n three-layer configuration (FIG. 2). A normal bulk heterojunction layer is a 14i layer composed of a mixture of a p-type semiconductor material and an n-type semiconductor layer, but is sandwiched between a 14p layer composed of a single p-type semiconductor material and a 14n layer composed of a single n-type semiconductor material. As a result, the rectification of holes and electrons becomes higher, loss due to recombination of charge-separated holes and electrons is reduced, and higher photoelectric conversion efficiency can be obtained.

  Furthermore, it is good also as a tandem-type structure which laminated | stacked such a photoelectric conversion element for the purpose of the improvement of sunlight utilization factor (photoelectric conversion efficiency). FIG. 3 is a cross-sectional view showing a solar cell composed of an organic photoelectric conversion element including a tandem bulk heterojunction layer. In the case of the tandem configuration, the transparent electrode 12 and the first photoelectric conversion unit 14 ′ are sequentially stacked on the substrate 11, the charge recombination layer 15 is stacked, the second photoelectric conversion unit 16, and then the counter electrode. By stacking 13, a tandem configuration can be obtained. The second photoelectric conversion unit 16 may be a layer that absorbs the same spectrum as the absorption spectrum of the first photoelectric conversion unit 14 'or may be a layer that absorbs a different spectrum, but is preferably a layer that absorbs a different spectrum. is there. Further, the first photoelectric conversion unit 14 ′ and the second photoelectric conversion unit 16 may both have the above-described three-layer configuration of pin.

  Below, the material which comprises these layers is described.

[P-type semiconductor materials]
Examples of the p-type semiconductor material used for the bulk heterojunction layer of the present invention include various condensed polycyclic aromatic low molecular compounds and conjugated polymers.

  Examples of the condensed polycyclic aromatic low-molecular compound include anthracene, tetracene, pentacene, hexacene, heptacene, chrysene, picene, fluorene, pyrene, peropyrene, perylene, terylene, quaterylene, coronene, ovalene, circumanthracene, bisanthene, zesulene, Compounds such as heptazeslen, pyranthrene, violanthene, isoviolanthene, circobiphenyl, anthradithiophene, porphyrin, copper phthalocyanine, tetrathiafulvalene (TTF) -tetracyanoquinodimethane (TCNQ) complex, bisethylenetetrathiafulvalene (BEDTTTTF ) -Perchloric acid complexes, 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.

  Examples of the conjugated polymer include 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 described in WO 2008/000664, a polythiophene-diketopyrrolopyrrole copolymer described in WO 2008/000664, a polythiophene-thiazolothiazole copolymer described in Adv Mater, 2007 p4160, Nature Mat. vol. 6 (2007), p497 described in PCPDTBT, 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, not polymer materials, include thiophene hexamer α-seccithiophene α, ω-dihexyl-α-sexualthiophene, 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 an electron transport layer or a hole blocking layer is further formed on the bulk heterojunction layer by a solution process, it can be easily laminated if it can be further coated on the layer once coated, but usually dissolved. When a layer is further laminated by a solution process on a layer made of a good material, 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 a material include materials that can be insolubilized by polymerizing and crosslinking 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. Alternatively, a soluble substituent reacts and becomes 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. Materials etc. can be mentioned.

[N-type semiconductor materials]
The n-type semiconductor material used for the bulk heterojunction layer of the present invention is not particularly limited. For example, a perfluoro compound (perfluoropentacene or the like) in which a hydrogen atom of a p-type semiconductor such as fullerene or octaazaporphyrin is substituted with a fluorine atom. Perfluorophthalocyanine), naphthalenetetracarboxylic anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide and other aromatic carboxylic acid anhydrides and imidized compounds thereof as a skeleton Etc.

  However, fullerene derivatives that can perform charge separation with various p-type semiconductor materials at high speed (˜50 fs) and efficiently are preferable. Fullerene derivatives include fullerene C60, fullerene C70, fullerene C76, fullerene C78, fullerene C84, fullerene C240, fullerene C540, mixed fullerene, fullerene nanotubes, multi-walled nanotubes, single-walled nanotubes, nanohorns (conical), and the like. Partially by hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkenyl group, alkynyl group, aryl group, heteroaryl group, cycloalkyl group, silyl group, ether group, thioether group, amino group, silyl group, etc. Examples thereof include substituted fullerene derivatives.

  Among them, [6,6] -phenyl C61-butyric acid methyl ester (abbreviation PCBM), [6,6] -phenyl C61-butyric acid-nbutyl ester (PCBnB), [6,6] -phenyl C61-buty Rick acid-isobutyl ester (PCBiB), [6,6] -phenyl C61-butyric acid-n hexyl ester (PCBH), Adv. Mater. , Vol. 20 (2008), p2116, etc., aminated fullerenes such as JP-A 2006-199674, metallocene fullerenes such as JP-A 2008-130889, and cyclics such as US Pat. No. 7,329,709. It is preferable to use a fullerene derivative having a substituent and having improved solubility, such as fullerene having an ether group.

[Method of forming bulk heterojunction layer]
Examples of a method for forming a bulk heterojunction layer in which an electron acceptor and an electron donor are mixed include a vapor deposition method and a coating method (including a casting method and a spin coating method). Among these, the coating method is preferable in order to increase the area of the interface where charges and electrons are separated from each other as described above and to produce a device having high photoelectric conversion efficiency. The coating method is also excellent in production speed.

  After coating, it is preferable to perform heating in order to cause removal of residual solvent, moisture and gas, and improvement of mobility and absorption longwave due to 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 bulk heterojunction layer can have an appropriate phase separation structure. As a result, the carrier mobility of the bulk heterojunction layer is improved and high efficiency can be obtained.

  The photoelectric conversion part (bulk heterojunction layer) 14 may be composed of a single layer in which the electron acceptor and the electron donor are uniformly mixed, but a plurality of the mixture ratios of the electron acceptor and the electron donor are changed. It may consist of layers. In this case, it can be formed by using a material that can be insolubilized after coating as described above.

[Electron transport layer / hole blocking layer]
Since the organic photoelectric conversion element 10 of the present invention can take out charges generated in the bulk heterojunction layer more efficiently by forming the electron transport layer 18 between the bulk heterojunction layer and the cathode. It is preferable to have this layer.

  As the electron transport layer 18, octaazaporphyrin and a p-type semiconductor perfluoro (perfluoropentacene, perfluorophthalocyanine, etc.) can be used. Similarly, a HOMO of a p-type semiconductor material used for a bulk heterojunction layer. The electron transport layer having a HOMO level deeper than the level is given a hole blocking function having a rectifying effect so that holes generated in the bulk heterojunction layer do not flow to the cathode side. More preferably, a material deeper than the HOMO level of the n-type semiconductor is used as the electron transport layer. Moreover, it is preferable to use a compound with high electron mobility from the characteristic of transporting electrons.

  Such an electron transport layer is also called a hole blocking layer, and it is preferable to use an electron transport layer having such a function. In the present invention, the compound represented by the general formula (1) of the present invention having a deep HOMO level and high electron mobility is used as an electron transport layer (also serves as a hole blocking layer), so that the fill factor and photoelectric conversion efficiency are increased. The effect of improvement can be obtained.

In the general formula (1), R ¹ , R ² and R ³ are each independently an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms). , For example, methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, etc.), a cycloalkyl group (preferably having 4 to 8 carbon atoms, such as cyclopentyl, cyclohexyl, etc.) An aryl group (preferably having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyl, p-methylphenyl, naphthyl, etc.), a heteroaryl group (preferably Has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms. Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. If represents imidazolyl, pyridyl, quinolyl, furyl, piperidyl, benzoxazolyl, benzimidazolyl, benzothiazolyl, etc.), alkylsilyl group (trimethylsilyl group, triethylsilyl group, a triisopropylsilyl group).

  Further, these substituents may be substituted, and may be an alkyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, and an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably Has 2 to 8 carbon atoms, and examples thereof include vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, especially Preferably it is C2-C8, for example, propargyl, 3-pentenyl etc. are mentioned), an alkoxy group (preferably C1-C20, more preferably C1-C12, especially preferably C1-C1). -8, for example, methoxy, ethoxy, butoxy, etc.), a cycloalkyloxy group (preferably having 4-8 carbon atoms, For example, cyclopentyloxy, cyclohexyloxy, etc.), an aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, and particularly preferably 6 to 12 carbon atoms). , 2-naphthyloxy, etc.), acyl groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl And pivaloyl), alkoxycarbonyl groups (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl and ethoxycarbonyl). Aryloxycarbonyl group (preferably having 7 to 20 carbon atoms, more preferred) Has 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, and examples thereof include phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, Particularly preferably, it has 2 to 10 carbon atoms, and examples thereof include acetoxy, benzoyloxy, etc.), an acylamino group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 2 carbon atoms). 10 and examples thereof include acetylamino, benzoylamino and the like, and an alkoxycarbonylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms). , For example, methoxycarbonylamino and the like), an aryloxycarbonylamino group (preferably carbon The number is 7 to 20, more preferably 7 to 16, and particularly preferably 7 to 12, and examples thereof include phenyloxycarbonylamino. ), A sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfonylamino and benzenesulfonylamino). Sulfamoyl group (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, phenylsulfamoyl, etc. ), A carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc. An alkylthio group (preferably having 1 carbon atom) 20, More preferably, it is C1-C16, Most preferably, it is C1-C12, for example, a methylthio, ethylthio, etc. are mentioned, An arylthio group (Preferably C6-C20, More preferably C 6 to 16, particularly preferably 6 to 12 carbon atoms, for example, phenylthio, etc.), a sulfonyl group (preferably 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably carbon numbers). 1 to 12, for example, mesyl, tosyl, etc.), sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, , Methanesulfinyl, benzenesulfinyl, etc.), ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to carbon atoms). 6, particularly preferably having 1 to 12 carbon atoms, such as ureido, methylureido, phenylureido, etc.), phosphoric acid amide group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). Particularly preferably having 1 to 12 carbon atoms, such as diethyl phosphoric acid amide and phenylphosphoric acid amide), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, Iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, and the like.

R ¹ , R ² and R ³ are preferably an alkyl group having 1 to 6 carbon atoms and an alkylsilyl group.

  Q represents any atom selected from a tetravalent silicon atom, a germanium atom, and a tin atom, and is preferably a silicon atom.

L ¹ represents a divalent linking group or a simple bond. Examples of the divalent linking group include an alkylene group (eg, methylene group, ethylene group, propane-1,3-diyl group, etc.), vinylene group, ethynyl group, arylene group, oxygen atom, sulfur atom, —SO ₂ —. , —NR ″ — (R ″ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, a sulfonyl group, etc.) and a divalent group formed by combining a plurality of these divalent linking groups. L ¹ is preferably an alkylene group, vinylene group, ethynyl group, or arylene group, more preferably an ethynyl group.

L ² represents a divalent or trivalent linking group or a simple bond. Examples of the divalent linking group include a group similar to the divalent linking group exemplified in L ¹ and a divalent group formed by combining a plurality of these linking groups. Examples of the trivalent linking group include a carbon atom, a nitrogen atom, a phosphorus atom, a boron atom, a methine group, a benzene ring, a triazine ring, or the divalent linking group mentioned in L ¹ to these trivalent linking groups. And a trivalent group formed in the above manner. The divalent group represented by L ² is preferably an alkylene group or an arylene group, and the trivalent group is preferably a benzene ring or a triazine ring.

A ¹ represents a 5-membered or 6-membered carbocyclic or heterocyclic ring which may have a condensed ring.

  Examples of the carbocycle include benzene and cyclopentadiene.

Examples of the heterocyclic ring include pyrrole, pyrazole, imidazole, triazole, tetrazole, oxazole, oxadiazole, thiazole, thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, triazine, tetrazine, furan, thiophene, borole, phosphole, silole, germol, Stanols and heterocyclic rings containing titanium atoms are mentioned. These allow condensed ring, aromatic ring or aromatic heterocyclic ring which is mentioned as A ^1.

A ¹ is preferably the general formulas (A1) to (A7).

In General Formula (A1), X ^{1 to} X ⁸ each independently represent a carbon atom or a nitrogen atom. When X ^{1 to} X ⁸ are carbon atoms, at least one of them preferably has a substituent, and the substituent is not particularly limited, but is preferably an alkyl group of C ₁ to C ₂₀ , C ₁ to C ₂₀ alkoxyl group, aryl group, aromatic heterocyclic group, C ₃ to C ₂₀ cycloalkyl group, halogen group, cyano group, nitro group, or C ₁ to C ₂₀ alkyl group, A C ₁ to C ₂₀ alkoxyl group, an aryl group, an aromatic heterocyclic group, or a sulfinyl group substituted with a C ₃ to C ₂₀ cycloalkyl group is represented. Further, at least one of the carbon atoms represented by X ^{1 to} X ⁸ may be bonded to a bond with L ² in the general formula (1).

Preferably, at least one of X ^{1 to} X ⁸ is a nitrogen atom.

R ^{4 to} R ⁶ represent a substituent or a bond to L ² in the general formula (1), and examples of the substituent include a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group, and an alkylsilyl group. , Alkenyl, alkynyl, alkoxy, cycloalkyloxy, aryloxy, acyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino Group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group, hydroxy group, mercapto group, halogen atom, cyano group, sulfo group, carboxyl group, nitro group, hydroxam Acid groups, Examples thereof include at least one group selected from a sulfino group, a hydrazino group, and an imino group. n1 and n2 each independently represents an integer of 0 to 4, preferably an integer of 0 to 2. At least one of R ⁴ , R ⁵ and R ⁶ is a bond to L ² .

In formula ^{(A2), X 1 ~X 8} , R 5, R 6, n1, n2 are ^X 1 ^{~X 8,} R ^5, the same meaning as R 6, n1, n2 in formula (A1). R ⁷ and R ⁸ have the same meaning as R ⁴ in formula (A1), and at least one of R ^{5 to} R ⁸ is a bond to L ² .

In formula ^(A3), have the same meanings as ^{X 1 ~X 8, R 5,} X 1 ~X 8 R 6, n1, n2 have the general formula in ^{(A1), R 5, R} 6, n1, n2, R ⁵ , at least one of R ⁶ is a bond to L ² .

In General Formula (A4), R ⁹ and R ¹⁰ represent a substituent having the same meaning as R ^{4 to} R ⁸ or a bond with L ² in General Formula (1), and R ⁹ or R ¹⁰ represents L ² and Represents the bond hand.

X ¹⁰ represents an oxygen atom, a sulfur atom, or —NR′—, and R ′ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or a sulfonyl group. X ¹⁰ is preferably an oxygen atom.

In the general formulas (A5) and (A6), x, y and z are each independently 0 or 1, and R ¹¹ , R ¹⁶ and R ¹⁷ are the same as the substituents or general formulas defined above for R ^{4 to} R ^8. This represents a bond with L ² in (1).

R ^{12 to} R ¹⁵ , R ¹⁸ and R ¹⁹ each independently represent a hydrogen atom, a substituent or a bond to L ² in the general formula (1), and adjacent R ¹² and R ¹³ , R ¹⁴ and R ¹⁵ , R ¹⁸ and R ¹⁹ may be bonded to each other to form a condensed ring, and these condensed rings may have a substituent.

In General Formula (A5), at least one of R ^{11 to} R ¹⁵ or a substituent on the condensed ring is a bond with L ² , and in General Formula (A6), R ¹² , R ¹³ , R ^{16 to} R ¹⁹ Or at least one of the substituents on the fused ring is a bond to L ² .

In the general formula (A7), R ²¹ and R ²² represent a substituent having the same meaning as the above R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), and R ^{23 to} R ²⁶ represent a hydrogen atom, A substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1) is represented, and in General Formula (A7), any one of R ^{21 to} R ²⁶ is a bond to L ^2. It is.

Of general formulas (A1) to (A7), A ¹ is preferably general formulas (A1) to (A4), and more preferably general formulas (A1) and (A4). n represents 1 or 2.

The compound represented by the general formula (1) is not particularly limited as long as it has at least one partial structure of A ¹ and (-L ¹ -QR ¹ R ² R ³ ) in the molecule. The structure may further have a substituent, and forms a dimer, trimer or multimer by combining multiple bonds with the above-mentioned divalent linking groups (including simple bonds) or trivalent linking groups. You may do it. Preferably, it is a compound in which a plurality of groups represented by A ¹ in the general formula (1) are present in the molecule.

  Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

  The compound used in the present invention can be easily synthesized by those skilled in the art with reference to known production methods. Although the synthesis example of the compound represented by General formula (1) below is shown, this invention is not limited to these synthesis methods.

  (Compound synthesis example)

1. Synthesis of Compound (7) 7.38 g (20 mmol) of intermediate (1), 0.702 g (1 mmol) of bis (triphenylphosphine) palladium (II) dichloride, 20 mL of triethylamine under ice-cooling in nitrogen atmosphere Cuprous 0.38 g (2 mmol) was added dropwise. The reaction liquid was returned to room temperature after completion | finish of dripping, and it stirred overnight. Ethyl acetate was added to the reaction mixture, and the mixture was washed with a saturated aqueous ammonium chloride solution and then with saturated brine. The ethyl acetate layer was dried over magnesium sulfate and filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane-ethyl acetate) to obtain 6.50 g of yellow amorphous exemplified compound (7) (yield 96%).

  2. Synthesis of exemplary compound (93)

2-1. Synthesis of Intermediate (2) 11 ml of thionyl chloride was added to 7.50 g (30.6 mmol) of 5-bromoisophthalic acid, and the mixture was heated to reflux for 4 hours. After completion of the reaction, excess thionyl chloride was distilled off under reduced pressure to obtain 5-bromoisophthalic acid chloride.

  2- (1H-tetrazol-5-yl) pyridine (2.25 g, 15.3 mmol) was added to 120 ml of dry pyridine, and 5-bromoisophthalic acid chloride obtained above was slowly added with stirring, followed by heating for 8 hours after completion of the addition. Refluxed. After allowing to cool, the reaction mixture was poured into 1000 ml of water, the solid was collected by filtration, washed with water and dried at 80 ° C. The solid was purified by silica gel column chromatography (eluent: methylene chloride-methanol = 20: 1) to obtain 5.20 g of intermediate (2) (11.6 mmol, yield 76%).

2-2. Synthesis of Exemplified Compound (93) Under nitrogen atmosphere, while stirring with ice-cooling in 20 ml of triethylamine, 5.00 g (11.2 mmol) of intermediate (2), 0.393 g (0) of bis (triphenylphosphine) palladium (II) dichloride .56 mmol) and 0.21 g (1.12 mmol) of cuprous chloride were added dropwise. The reaction liquid was returned to room temperature after completion | finish of dripping, and it stirred overnight. Ethyl acetate was added to the reaction mixture, and the mixture was washed with a saturated aqueous ammonium chloride solution and then with saturated brine. The ethyl acetate layer was dried over magnesium sulfate and filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: hexane-ethyl acetate) to obtain 5.93 g of colorless amorphous exemplified compound (93) (10.8 mmol, yield 97%).

  The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method.

[Hole Transport Layer / Electron Blocking Layer]
In the organic photoelectric conversion element 10 of the present invention, the hole transport layer 17 can be taken out between the bulk heterojunction layer and the anode, and charges generated in the bulk heterojunction layer can be taken out more efficiently. It is preferable to have.

  As a material constituting these layers, for example, as the hole transport layer 17, PEDOT such as trade name BaytronP, polyaniline and its doping material, a cyanide compound described in WO2006 / 019270, etc. Etc. can be used. Note that the hole transport layer having a LUMO level shallower than the LUMO level of the n-type semiconductor material used for the bulk heterojunction layer has a rectifying effect that prevents electrons generated in the bulk heterojunction layer from flowing to the anode side. It has an electronic block function. Such a hole transport layer is also called an electron block layer, and it is preferable to use a hole transport layer having such a function. As such a material, a triarylamine compound described in JP-A-5-271166 or a metal oxide such as molybdenum oxide, nickel oxide, or tungsten oxide can be used. A layer made of a single p-type semiconductor material used for the bulk heterojunction layer can also be used. The means for forming these layers may be either a vacuum deposition method or a solution coating method, but is preferably a solution coating method. Forming the coating film in the lower layer before forming the bulk heterojunction layer is preferable because it has the effect of leveling the coating surface and reduces the influence of leakage and the like.

[Other layers]
For the purpose of improving energy conversion efficiency and improving the lifetime of the element, a structure having various intermediate layers in the element may be employed. Examples of the intermediate layer include a hole block layer, an electron block layer, 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.

<Electrode>
The photoelectric conversion element according to the present invention has at least an anode and a cathode. Further, when a tandem configuration is adopted, the tandem configuration can be achieved by using an intermediate electrode. 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.

  Further, because of the function of whether or not there is a light-transmitting property, a light-transmitting electrode may be called a transparent electrode, and a non-light-transmitting electrode may be called a counter electrode. Usually, the anode is a translucent transparent electrode, and the cathode is a non-translucent counter electrode.

〔anode〕
The anode of the present invention is preferably an electrode that transmits light of 380 to 800 nm. As the material, for example, transparent conductive metal oxides such as indium tin oxide (ITO), SnO ₂ and ZnO, metal thin films such as gold, silver and platinum, metal nanowires and carbon nanotubes can be used.

  Also, a conductive material selected from the group consisting of polypyrrole, polyaniline, polythiophene, polythienylene vinylene, polyazulene, polyisothianaphthene, polycarbazole, polyacetylene, polyphenylene, polyphenylene vinylene, polyacene, polyphenylacetylene, polydiacetylene and polynaphthalene. A functional polymer can also be used. Further, a plurality of these conductive compounds can be combined to form an anode.

〔cathode〕
The cathode may be a single layer of a conductive material, but in addition to a conductive material, a resin that holds these may be used in combination. As a conductive material for the cathode, a material having a work function (4 eV or less) metal, alloy, electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include 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 ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the viewpoint of electron extraction performance and durability against oxidation, etc., a mixture of these metals and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, magnesium / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.

  If a metal material is used as the conductive material of the cathode, the light coming to the cathode side is reflected and reflected to the first electrode side, and this light can be reused and absorbed again by the photoelectric conversion layer, further improving the photoelectric conversion efficiency. It is preferable.

  Further, the cathode 13 may be a metal (for example, gold, silver, copper, platinum, rhodium, ruthenium, aluminum, magnesium, indium, etc.), a nanoparticle made of carbon, a nanowire, or a nanostructure. A dispersion is preferable because a transparent and highly conductive cathode can be formed by a coating method.

  When the cathode side is made light transmissive, for example, a conductive material suitable for the cathode, such as aluminum and aluminum alloy, silver and silver compound, is formed with a thin film thickness of about 1 to 20 nm, and By providing a film of the conductive light-transmitting material mentioned in the description, a light-transmitting cathode can be obtained.

[Intermediate electrode]
The intermediate electrode material required in the case of the tandem structure as shown in FIG. 3 is preferably a layer using a compound having both transparency and conductivity. Transparent metal oxides such as ITO, AZO, FTO and titanium oxide, very thin metal layers such as Ag, Al and Au, or layers containing nanoparticles / nanowires, conductive polymer materials such as PEDOT: PSS and polyaniline Etc.) can be used.

  In addition, in the hole transport layer and the electron transport layer described above, there is also a combination that works as an intermediate electrode (charge recombination layer) by appropriately combining and laminating, and with such a configuration, the process of forming one layer This is preferable because it can be omitted.

〔substrate〕
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, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) modified polyester, polyethylene (PE) resin film, polypropylene (PP) resin film, polystyrene resin film, polyolefin resins such as cyclic olefin resin Film, vinyl resin film such as polyvinyl chloride, polyvinylidene chloride, polyether ether ketone (PEEK) resin film, polysulfone (PSF) resin film, polyether sulfone (PES) resin film, polycarbonate (PC) resin film, A polyamide resin film, a polyimide resin film, an acrylic resin film, a triacetyl cellulose (TAC) resin film, and the like can be given. If the resin film transmittance of 80% or more at ~800nm), 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, and biaxially stretched. More preferred are polyethylene terephthalate films and biaxially stretched polyethylene naphthalate films.

  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.

  Further, 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.

(Optical function layer)
The organic photoelectric conversion element of the present invention may have various optical functional layers for the purpose of more efficient reception of sunlight. As the optical functional layer, for example, a light condensing layer such as an antireflection film or a microlens array, or a light diffusion layer that can scatter light reflected by the cathode and enter the power generation layer again may be provided. .

  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 so as 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.

[Patterning]
The method and process for patterning the electrode, the power generation layer, the hole transport layer, the electron transport layer, and the like according to the present invention are not particularly limited, and known methods can be appropriately applied.

  If it is a soluble material such as a bulk heterojunction layer and a transport layer, only unnecessary portions may be wiped after the entire surface of die coating, dip coating, etc., or direct patterning at the time of coating using a method such as an ink jet method or screen printing. May be.

  In the case of an insoluble material such as an electrode material, the electrode can be patterned by a known method such as mask vapor deposition during vacuum deposition or etching or lift-off. Alternatively, the pattern may be formed by transferring a pattern formed on another substrate.

(Sealing)
Moreover, since the produced organic photoelectric conversion element 10 does not deteriorate with oxygen, moisture, etc. in the environment, it is preferable to seal not only the organic photoelectric conversion element but also an organic electroluminescence element by a known method. For example, a method of sealing a cap made of aluminum or glass by bonding with an adhesive, a plastic film on which a gas barrier layer such as aluminum, silicon oxide, or aluminum oxide is formed and the organic photoelectric conversion element top 10 with an adhesive Method of bonding, spin coating of organic polymer materials with high gas barrier properties (polyvinyl alcohol, etc.), inorganic thin films with high gas barrier properties (silicon oxide, aluminum oxide, etc.) or organic films (parylene, etc.) deposited under vacuum And a method of laminating these in a composite manner.

(Optical sensor array)
Next, an optical sensor array to which the bulk heterojunction type organic photoelectric conversion element 10 described above is applied will be described in detail. The optical sensor array is produced by arranging the photoelectric conversion elements in a fine pixel form by utilizing the fact that the bulk heterojunction type organic photoelectric conversion elements generate a current upon receiving light, and projected onto the optical sensor array. A sensor having an effect of converting an image into an electrical signal.

  FIG. 4 is a diagram showing the configuration of the photosensor array. 4A is a top view, and FIG. 4B is a cross-sectional view taken along the line A-A ′ of FIG.

  In FIG. 4, an optical sensor array 20 is paired with an anode 22 as a lower electrode, a photoelectric conversion unit 24 that converts light energy into electric energy, and an anode 22 on a substrate 21 as a holding member. The cathode 23 is sequentially laminated. The photoelectric conversion unit 24 includes two layers, a photoelectric conversion layer 24b having a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are uniformly mixed, and a buffer layer 24a. In the example shown in FIG. 4, six bulk heterojunction type organic photoelectric conversion elements are formed.

  The substrate 21, the anode 22, the photoelectric conversion layer 24b, and the cathode 23 have the same configuration and role as the anode 12, the photoelectric conversion unit 14, and the cathode 13 in the bulk heterojunction photoelectric conversion element 10 described above.

  For example, glass is used for the substrate 21, ITO is used for the anode 22, and aluminum is used for the cathode 23, for example. For example, the BP-1 precursor is used for the p-type semiconductor material of the photoelectric conversion layer 24b, and for example, the exemplified compound 13 is used for the n-type semiconductor material. The buffer layer 24a is made of PEDOT (poly-3,4-ethylenedioxythiophene) -PSS (polystyrene sulfonic acid) conductive polymer (trade name BaytronP, manufactured by Stark Vitec).

  Such an optical sensor array 20 was manufactured as follows.

  An ITO film was formed on the glass substrate by sputtering and processed into a predetermined pattern shape by photolithography. The thickness of the glass substrate was 0.7 mm, the thickness of the ITO film was 200 nm, and the measurement area (light receiving area) of the ITO film after photolithography was 0.5 mm × 0.5 mm. Next, a PEDOT-PSS film was formed on the glass substrate 21 by spin coating (conditions: rotational speed = 1000 rpm, filter diameter = 1.2 μm). Thereafter, the substrate was heated in an oven at 140 ° C. for 10 minutes and dried. The thickness of the PEDOT-PSS film after drying was 30 nm.

  Next, a 1: 1 mixed film of P3HT (poly-3hexylthiophene) and PCBM is formed on the PEDOT-PSS film by spin coating (conditions: rotational speed = 3300 rpm, filter diameter = 0.8 μm). did. In this spin coating, P3HT and PCBM were mixed with a chlorobenzene solvent in a ratio of 1: 1, and a mixture obtained by stirring (5 minutes) was used. After forming the mixed film of P3HT and PCBM, annealing was performed by heating in an oven at 180 ° C. for 30 minutes in a nitrogen gas atmosphere. The thickness of the mixed film of P3HT and PCBM after the annealing treatment was 70 nm.

  Then, using a metal mask having a predetermined pattern opening, 5 nm of compound (I-1) is deposited as an electron transport layer on a mixed film of P3HT and PCBM, and then an aluminum layer as a cathode is formed by a deposition method. (Thickness = 10 nm). Thereafter, 1 μm of PVA (polyvinyl alcohol) was formed by spin coating and baked at 150 ° C. to prepare a passivation layer (not shown). The optical sensor array 20 was produced as described above.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
<Preparation of Comparative Organic Photoelectric Conversion Element 1>
The transparent electrode patterned on the glass substrate was cleaned in the order of ultrasonic cleaning with surfactant and ultrapure water, followed by ultrasonic cleaning with ultrapure water, dried with nitrogen blow, and finally UV ozone cleaning. .

  On this transparent substrate, Baytron P4083 (manufactured by Starck Vitec), which is a conductive polymer, was spin-coated with a film thickness of 30 nm, and then dried by heating at 140 ° C. in the air for 10 minutes.

  After this, the substrate was brought into the glove box and worked under a nitrogen atmosphere. First, the substrate was heat-treated at 140 ° C. for 3 minutes in a nitrogen atmosphere. A solution was prepared by dissolving 1.5 mass% of plexcores OS2100 manufactured by Plextronics as a p-type semiconductor material and 1.5 mass% of E100 (PCBM) manufactured by Frontier Carbon as an n-type semiconductor material in chlorobenzene. While being filtered through a .45 μm filter, spin coating was performed at 500 rpm for 60 seconds, then at 2200 rpm for 1 second, and left at room temperature for 30 minutes.

  Next, a solution in which bathocuproin (BCP) manufactured by Aldrich was mixed with 2,2,3,3-tetrafluoro-1-propanol at a ratio of 0.5% by mass was spin-coated at 1200 rpm, and a hole block having a thickness of 15 nm was formed. A layer was formed.

Next, the substrate on which the series of organic layers was formed was placed in a vacuum deposition apparatus without being exposed to the atmosphere. The element was set so that the shadow mask with a width of 2 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 100 nm of Al was deposited. Finally, heating was performed at 120 ° C. for 30 minutes to obtain a comparative organic photoelectric conversion element 1. The vapor deposition rate was 2 nm / second, and the size was 2 mm square.

  The obtained organic photoelectric conversion element 1 was taken out into the atmosphere after sealing using an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere.

<Preparation of Comparative Organic Photoelectric Conversion Element 2>
In the comparative organic photoelectric conversion element 1, instead of 0.5% 2,2,3,3-tetrafluoro-1-propanol solution of bathocuproine as a hole blocking layer, Ti-isopropoxide was added to ethanol at 25 mmol / l. After the electrode portion was masked and spin-coated at 1500 rpm, the solution was taken out into the atmosphere and left for 60 minutes to hydrolyze Ti-isopropoxide to obtain a film thickness of 15 nm. A comparative organic photoelectric conversion element 2 was produced in the same manner except that a TiOx layer was formed and a hole blocking layer was formed.

<Production of Comparative Organic Photoelectric Conversion Element 3>
In the comparative organic photoelectric conversion element 1, the organic photoelectric conversion element 3 of this invention was produced similarly except having changed the hole block layer into the said comparative compound (I-1) instead of bathocuproine.

<Production of Organic Photoelectric Conversion Elements 4 to 33 of the Present Invention>
In the comparative organic photoelectric conversion element 1, the hole blocking layer was replaced with bathocuproin, and the organic photoelectric conversion elements 4 to 33 of the present invention were produced in the same manner except that the compound of the present invention described in Table 1 below was changed. .

  About the obtained organic photoelectric conversion elements 1-33, the following conversion efficiency and evaluation of a fill factor, and durability evaluation were performed.

(Evaluation of conversion efficiency and fill factor)
Photoelectric conversion elements prepared above, was irradiated with light having an intensity of 100 mW / cm ² solar simulator (AM1.5G filter), a superposed mask in which the effective area 4.0 mm ² on the light receiving portion, the short circuit current density Jsc ( The four light-receiving portions formed on the same element were measured for mA / cm ² ), open-circuit voltage Voc (V), and fill factor (fill factor) FF, and the average value was obtained. Further, energy conversion efficiency η (%) was obtained from Jsc, Voc, and FF according to Equation 1.

Formula 1 Jsc (mA / cm ² ) × Voc (V) × FF = η (%)
(Durability evaluation)
The solar cell (AM1.5G) light was irradiated at an irradiation intensity of 100 mW / cm ² and the initial conversion efficiency measured for voltage-current characteristics was set to 100, and the resistance was connected between the anode and the cathode, and 100 mW / cm. The conversion efficiency after 100 hours of irradiation with an irradiation intensity of ² was evaluated, and the relative reduction efficiency was calculated.

  Formula 2 Relative reduction efficiency (%) = (1−conversion efficiency after exposure / conversion efficiency before exposure) × 100

  From Table 1, it can be seen that the use of the hole blocking layer of the present invention improves the fill factor and provides high conversion efficiency. Moreover, it turns out that the relative reduction efficiency which shows durability is also low and durability is high.

DESCRIPTION OF SYMBOLS 10 Bulk heterojunction type organic photoelectric conversion element 11 Substrate 12 Anode 13 Cathode 14 Photoelectric conversion part (bulk heterojunction layer)
14p p layer 14i i layer 14n n layer 14 'first photoelectric conversion part 15 charge recombination layer 16 second photoelectric conversion part 17 hole transport layer 18 electron transport layer 20 photosensor array 21 substrate 22 anode 23 cathode 24 photoelectric Conversion unit 24a Buffer layer 24b Photoelectric conversion layer

Claims (8)

An organic photoelectric conversion element having a cathode, an anode, and a bulk heterojunction layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, wherein at least the following general formula (1) is provided between the bulk heterojunction layer and the cathode: It has a layer containing the compound represented, The organic photoelectric conversion element characterized by the above-mentioned.

[Wherein R ¹ , R ² and R ³ each independently represents a substituent selected from a substituted or unsubstituted alkyl group, a cycloalkyl group, an aryl group and an alkylsilyl group, Q is a tetravalent silicon atom, Represents any atom selected from a germanium atom and a tin atom, L ¹ represents a divalent linking group or a mere bond, L ² represents a divalent or trivalent linking group, or a mere bond, A ¹ represents a 5-membered or 6-membered carbocyclic or heterocyclic ring which may have a condensed ring, and n represents 1 or 2. ]   The organic photoelectric conversion device according to claim 1, wherein the atom represented by Q in the general formula (1) is a tetravalent silicon atom. The organic photoelectric conversion device according to claim 1, wherein A ¹ in the general formula (1) is any one selected from the following general formula (A1) to general formula (A7).

[Wherein, X ^{1 to} X ⁸ each independently represents a carbon atom or a nitrogen atom, X ⁹ represents a carbon atom, a silicon atom, a germanium atom, a titanium atom, or a tin atom, and R ^{4 to} R ⁸ each independently represent Substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, alkylsilyl group, alkenyl group, alkynyl group, alkoxy group, cycloalkyloxy group, aryloxy group, acyl group, alkoxycarbonyl group, aryl Oxycarbonyl group, acyloxy group, acylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfonylamino group, sulfamoyl group, carbamoyl group, alkylthio group, arylthio group, sulfonyl group, sulfinyl group, ureido group, phosphoric acid amide group , Hydroxy group, merca At least one group selected from a putto group, a halogen atom, a cyano group, a sulfo group, a carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, or L ² in the general formula (1) N1 and n2 each independently represents an integer of 0 to 4, and at least one of R ⁴ , R ⁵ and R ⁶ in formula (A1) is a bond to L ² , At least one of R ^{5 to} R ⁸ in Formula (A2) is a bond to L ^2, and R ⁵ or R ⁶ in General Formula (A3) is a bond to L ² . ]

[Wherein R ⁹ or R ¹⁰ represents a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), and R ⁹ or R ¹⁰ represents a bond to L ^2. X ¹⁰ represents an oxygen atom, a sulfur atom, or —NR′—, and R ′ represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or a sulfonyl group. ]

[Wherein R ¹¹ , R ¹⁶ , R ¹⁷ represent a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), and x, y, and z are each independently R ^{12 to} R ¹⁵ , R ¹⁸ , R ¹⁹ each independently represents a hydrogen atom or a bond to L ² in the general formula (1), and adjacent R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁸ and R ¹⁹ may be bonded to each other to form a condensed ring, and these condensed rings may have a substituent, and R ^{11 to} R ¹⁵ in the general formula (A5), or a condensed ring At least one of the above substituents is a bond to L ^2, and at least one of R ¹² , R ¹³ , R ^{16 to} R ¹⁹ in general formula (A6), or a substituent on the condensed ring is L ^2. It is a joint hand. ]

[Wherein R ²¹ and R ²² represent a substituent having the same meaning as R ^{4 to} R ⁸ or a bond to L ² in the general formula (1), R ^{23 to} R ²⁶ represent a hydrogen atom, and R ^{4 to} R ^{8 represents} a substituent having the same meaning or a bond to L ² in the general formula (1), and any one of R ^{21 to} R ²⁶ is a bond to L ² . ] The organic photoelectric conversion according to any one of claims 1 to 3, wherein A ¹ in the general formula (1) is any one selected from the general formula (A1) to the general formula (A4). element. The organic photoelectric conversion element according to any one of claims 1 to 4, A ¹ is wherein in formula (A1) or Formula (A4) of the general formula (1).   The organic photoelectric conversion element according to claim 1, wherein the layer containing the compound represented by the general formula (1) is produced by a solution coating method.   It has the organic photoelectric conversion element of any one of Claims 1-6, The solar cell characterized by the above-mentioned.   The organic photoelectric conversion element of any one of Claims 1-6 is arrange | positioned at array form, The optical sensor array characterized by the above-mentioned.

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