JP2011155185A - Organic photoelectric conversion element, solar cell using the same, and optical sensor array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic photoelectric conversion element having high efficiency of photoelectric conversion and durability, a solar cell using the same, and an optical sensor array. <P>SOLUTION: The organic photoelectric conversion element includes a cathode, an anode and a photoelectric conversion layer wherein a p-type semiconductor material and an n-type semiconductor material are mixed. The organic photoelectric conversion element also contains a dye. <P>COPYRIGHT: (C)2011,JPO&INPIT

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 such a 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 are provided between the transparent electrode and the counter electrode. A bulk heterojunction photoelectric conversion element has been proposed in which a photoelectric conversion layer mixed with a layer (n-type semiconductor layer) is sandwiched (for example, Non-Patent Document 1 and 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 above Si-based solar cells, compound semiconductor-based solar cells, dye-sensitized solar cells, etc., there is no process at a temperature higher than 160 ° C., so it is expected that they can be formed on a cheap and lightweight plastic substrate. Is done.

  In Non-Patent Document 1, conversion efficiency exceeding 5% has been achieved. This is achieved by utilizing intramolecular charge transfer between a thiophene ring and a benzothiadiazole ring, which is very long wavelength (˜900 nm). This is because it has become possible to absorb a wide range of sunlight until.

  On the other hand, the solar cell is required to have durability, but the durability of the organic thin film solar cell is still insufficient. In another non-patent document 2 using the above material, it is reported that the photoelectric conversion efficiency is reduced by about 40% in 100 hours.

  In addition, a report that the photoelectric conversion efficiency can be improved by containing an organometallic complex compound as a third component (Patent Document 2), and that the photoelectric conversion efficiency is improved by containing bistrihexylsilyl silicon phthalocyanine are disclosed. (Non-patent Document 3).

  However, the photoelectric conversion efficiency is still not sufficient here, and the durability of the element has not been mentioned.

  In response to these problems, the present inventors have found that high-efficiency and long-life device performance can be achieved by including a phthalocyanine derivative having a specific structure in the bulk heterojunction layer.

JP-T 8-500701 JP 2007-180190 A

A. Heeger; Nature Mat. , Vol. 6 (2007), p497 Science 317 2007 p222 Satoshi Honda, Hideo Okita: ACS Applied Mater. Interfaces, 2009. 1 (4)

  The objective of this invention is providing the organic photoelectric conversion element which has high photoelectric conversion efficiency and durability, a solar cell using the same, and an optical sensor array.

  The above object of the present invention is achieved by the following means.

  1. An organic photoelectric conversion element having a cathode, an anode, and a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, wherein the photoelectric conversion layer contains a dye represented by the following general formula (1) An organic photoelectric conversion element characterized by the above.

(In the formula, M is any one of Si, Ge and Sn, R _{1 to} R ₄ each independently represents a substituent, and Z _{1 to} Z ₄ form a 5- or 6-membered aromatic ring or heterocyclic ring. A to d each represent an integer of 0 or 1 to 4. When ad is 2 or more, adjacent substituents may be bonded to form a 5- or 6-membered ring structure. A ₁ and A ₂ each independently represent a group represented by the following general formula (2).

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted.
2. 2. The organic photoelectric conversion device as described in 1 above, wherein the dye represented by the general formula (1) is a dye represented by the following general formula (3).

(In the formula, M is any one of Si, Ge, and Sn, R _{1 to} R ₄ each independently represents a substituent, and a to d each represents 0 or an integer of 1 to 4. In the case of 2 or more, adjacent substituents may be bonded to each other to form a 5- or 6-membered ring structure, wherein A ₁ and A ₂ are each independently a group represented by the following general formula (2). To express.)

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted.
3. 2. The organic photoelectric conversion device according to 1 above, wherein the dye represented by the general formula (1) is a dye represented by the following general formula (4).

(In the formula, R _{1 to} R ₄ each independently represents a substituent, and each of a to d represents 0 or an integer of 1 to 4. When ad is 2 or more, adjacent substituents are bonded to each other. (It may form a 5- or 6-membered ring structure. A ₁ and A ₂ each independently represent a group represented by the following general formula (2).)

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted.
4). 4. The organic photoelectric conversion element as described in any one of 1 to 3 above, wherein the p-type semiconductor material is a conjugated polymer semiconductor material.

  5. 5. The organic photoelectric conversion element according to any one of 1 to 4, wherein the photoelectric conversion layer is produced by a solution coating method.

  6). It consists of the organic photoelectric conversion element of any one of said 1-5, The solar cell characterized by the above-mentioned.

  7). 7. An optical sensor array, wherein the organic photoelectric conversion elements according to any one of 1 to 6 are arranged in an array.

  According to the present invention, an organic photoelectric conversion element having high photoelectric conversion efficiency and durability, a solar cell using the same, and an optical sensor array can be provided.

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.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be achieved by including a compound having a structure represented by the general formula (1) in the photoelectric conversion layer.

  Bulk heterojunction type photoelectric conversion layer in which p-type conjugated polymer semiconductor material and n-type semiconductor material are mixed can be applied to the blend liquid and then annealed by heat to promote the crystallinity of the p-type conjugated polymer semiconductor material. As a result, a microphase separation structure is formed, and the contact interface between the p-type conjugated polymer semiconductor material and the n-type semiconductor material is increased.

  When light enters the bulk heterojunction photoelectric conversion layer, the electrons of the p-type conjugated polymer semiconductor material change from the highest occupied orbit (hereinafter referred to as “HOMO”) to the lowest empty orbit (hereinafter referred to as “LUMO”). When excited, the electrons move to the conduction band of the n-type semiconductor material, and then move to the conduction band of the p-type conjugated polymer via an external circuit. Electrons generated in the conduction band of the p-type conjugated polymer move to the LUMO level. On the other hand, when light is incident, holes generated at the HOMO level of the p-type conjugated polymer semiconductor material move to the valence band of the n-type semiconductor via the external circuit. Thus, a photocurrent flows in the bulk heterojunction photoelectric conversion layer. Such photocharge separation is considered to be promoted as the contact interface between the p-type conjugated polymer semiconductor material and the n-type semiconductor material increases.

  At this time, it is considered that the photoelectric conversion efficiency can be improved by promoting the photocharge separation by containing the third component and by absorbing the infrared wavelength region of sunlight that is not absorbed by the p-type conjugated polymer semiconductor. ing.

  Crystal growth of a p-type conjugated polymer semiconductor material during annealing by heat by containing a phthalocyanine compound having a bulky substituent having the structure represented by the general formula (1) of the present invention as a third component Can be aligned at the interface between the p-type conjugated polymer semiconductor material and the n-type semiconductor material without being disturbed and incorporated into the crystal of the p-type conjugated polymer semiconductor material, thereby making photocharge separation more efficient It can be promoted. In addition, since the phthalocyanine compound having a specific structure oriented at the interface has absorption in the infrared region corresponding to the fluorescence wavelength of the p-type conjugated polymer semiconductor material, the infrared wavelength of sunlight that is simply not absorbed by the p-type conjugated polymer semiconductor We believe that it not only supplements the region, but also promotes photocharge separation using energy transfer.

  These phthalocyanine compounds having a specific structure are considered to have high stability and long life.

  Hereinafter, details of each component according to the present invention will be sequentially described.

[Regarding dyes or groups represented by general formulas (1) to (4)]
First, the pigment | dye or group which has a structure represented by General formula (1)-(4) in this invention is demonstrated.

In the general formula (1), R _{1 to} R ₄ each independently represent a substituent and is not particularly limited as long as it is a substitutable group. Examples of the substituent include a halogen atom (a fluorine atom, a chloro atom, a bromine). Atoms or iodine atoms), alkyl groups (including aralkyl groups, cycloalkyl groups, and active methine groups, such as methyl groups, ethyl groups, i-propyl groups, t-butyl groups, n-octyl groups, etc.), alkenyls Group, alkynyl group, aryl group (eg, phenyl group, 4-t-butylphenyl group, naphthyl group, etc.), heterocyclic group (regardless of the position of substitution), heterocyclic group containing a quaternized nitrogen atom ( For example, pyridinio group, imidazolio group, quinolinio group, or isoquinolinio group), acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, carbo Si group or a salt thereof, sulfonylcarbamoyl group, acylcarbamoyl group, sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, thiocarbamoyl group, hydroxy group, alkoxy group (ethyleneoxy group or propyleneoxy group unit ), Aryloxy group, heterocyclic oxy group, acyloxy group, (alkoxy or aryloxy) carbonyloxy group, carbamoyloxy group, sulfonyloxy group, amino group, (alkyl, aryl, or heterocyclic ring) Amino group, acylamino group, sulfonamide group, ureido group, thioureido group, imide group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide , Hydrazino group, ammonio group, oxamoylamino group, (alkyl or aryl) sulfonylureido group, acylureido group, acylsulfamoylamino group, nitro group, mercapto group, (alkyl, aryl or heterocycle) thio group, (alkyl) , Aryl, or heterocycle) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group or salt thereof, sulfamoyl group, acylsulfamoyl group, sulfonylsulfamoyl group or salt thereof, phosphate amide or phosphate ester structure , A silyloxy group (for example, trimethylsilyloxy, and t-butyldimethylsilyloxy), a silyl group (for example, trimethylsilyl, t-butyldimethylsilyl, or phenyldimethylsilyl), a nitro group, and the like. These substituents may be further substituted with these substituents.

R _{1 to} R ₄ are preferably a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a nitro group, an alkylthio group, or an arylthio group, more preferably a hydrogen atom, a chloro atom, or an alkyl group. An alkoxy group and a nitro group.

In the general formula (1), Z _{1 to} Z ₄ represent a group of atoms forming a 5- or 6-membered aromatic group or heterocyclic ring, and the formed 5- or 6-membered aromatic group or heterocyclic ring is, for example, a benzene ring , Naphthalene ring, anthracene ring, tetracene ring, pentacene ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazole ring, imidazole ring, pyrrole ring, furan ring, thiophene ring, etc., but preferably benzene ring, naphthalene ring, anthracene A ring, a tetracene ring, or a pentacene ring.

  In the general formula (1), a to d are each 0 or an integer of 1 to 4, preferably 0 to 2, and more preferably 0 or 1. When a to d is 2 or more, adjacent substituents may form a 5- or 6-membered ring. Examples of the ring formed include a benzene ring, naphthalene ring, anthracene ring, tetracene ring, pentacene ring, pyridine ring, pyrimidine ring, quinoline ring, pyrazole ring, imidazole ring, pyrrole ring, furan ring, and thiophene ring. A benzene ring is preferred.

  M is any one of Si, Ge, and Sn, and more preferably Si.

A ₁ and A ₂ each independently represent a group represented by the general formula (2), and R _{5 to} R ₇ are substituted or unsubstituted alkyl groups (preferably having 1 to 20 carbon atoms, more preferably carbon atoms). 1 to 12 and particularly preferably 1 to 8 carbon atoms. Examples thereof include methyl, ethyl, iso-propyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl and the like. Group (preferably having 4 to 8 carbon atoms, such as cyclopentyl, cyclohexyl, etc.), aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 carbon atoms). -12, for example, phenyl, p-methylphenyl, naphthyl, etc.), amino group (preferably having 0 to 20 carbon atoms, more preferably 0 to 10 carbon atoms, Preferably have 0 to 6 carbon atoms such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), heteroaryl group (preferably having 1 to 20 carbon atoms, more preferably 1 carbon atom). And the hetero atom includes, for example, a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc. And alkylsilyl groups (trimethylsilyl group, triethylsilyl group, triisopropylsilyl group, trihexylsilyl) and the like.

  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.

  Q represents any atom or mother nucleus selected from a tetravalent carbon atom, a silicon atom, a germanium atom, a tin atom, an aryl group mother nucleus, and a heteroaryl group mother nucleus. The aryl group mother nucleus is preferably a phenyl group.

  L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group, an ether group, or a divalent linking group obtained by combining these, and may be substituted.

  The alkylene group is preferably an ethylene group, a propylene group, the alkenylene group is preferably a vinylene group, the cycloalkylene group is preferably a cyclohexanediyl group, and the arylene group is preferably a phenylene group. Moreover, as these combinations, an alkyleneoxy group, a phenyleneoxy group, etc. are preferable.

  Further, these linking groups may be substituted, and may be an alkyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, or 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.

  Specific examples of the dye having a structure represented by the general formulas (1) to (4) according to the present invention include the following compounds.

  These compounds can be synthesized by a conventionally known synthesis method, Journal of Organometallic Chemistry; 204; 3; 1981; 315-326, Angelwandte Chemie; 91; 4; 1979; 343; And Functions- "(IPC, 1997), pages 1-62, Ryo Takahashi, Keiichi Sakamoto, and Eiko Okumura," Phthalocyanine as a functional pigment "(IPC, 2004), pages 29-77 , Etc. can be synthesized with reference to.

  Typical methods for synthesizing phthalocyanine derivatives include the Weiler method, phthalonitrile method, lithium method, subphthalocyanine method, and chlorinated phthalocyanine method described in these documents. Any reaction conditions may be used in the phthalocyanine ring formation reaction of the present invention. In the ring formation reaction, it is preferable to add various metals to be the central metal of phthalocyanine, but a desired metal may be introduced after the synthesis of a phthalocyanine derivative having no central metal.

[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 organic photoelectric conversion element 10 has an anode 12, a hole transport layer 17, a bulk heterojunction layer photoelectric conversion section 14, an electron transport layer 18, and a cathode 13 in this order on one surface of a substrate 11. Are stacked.

  The substrate 11 is a member that holds the anode 12, the photoelectric conversion unit 14, and the cathode 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 anode 12 and the cathode 13 on both surfaces of the photoelectric conversion unit 14.

  The photoelectric conversion unit 14 is a layer that converts light energy into electrical energy, and has a p-type semiconductor material, an n-type semiconductor material, and a specific structure represented by the general formulas (1) to (4) as a third component. It has a bulk heterojunction layer mixed with a dye. 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.

  Moreover, in this invention, the pigment | dye which has the specific structure represented by the said General formula (1) is used as a 3rd component, and by orientating in the interface of p-type conjugated polymer semiconductor material and n-type semiconductor material, The present inventors consider that the conversion efficiency is improved.

  In FIG. 1, light incident from the anode 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. 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 function of the anode 12 and the cathode 13 is different, the electrons pass between the electron acceptors and the holes are electron donors due to the potential difference between the anode 12 and the cathode 13. The photocurrent is detected by passing through different electrodes to different electrodes. For example, when the work function of the anode 12 is larger than that of the cathode 13, electrons are transported to the anode 12 and holes are transported to the cathode 13. If the magnitude of the work function is reversed, electrons and holes are transported in the opposite direction. In addition, the transport direction of electrons and holes can be controlled by applying a potential between the anode 12 and the cathode 13.

  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 anode 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 cathode 13 are stacked. By stacking, a tandem structure 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 material)
In the present invention, a known p-type semiconductor material (such as a condensed polycyclic aromatic low-molecular compound or a conjugated polymer) is used as the p-type semiconductor material, and these may be used in combination. Further, a conjugated polymer is preferably used.

  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, cacobiphenyl, 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-2003-136964, a pentacene precursor described in US Patent Application Publication No. 2003/136964, and the like; Amer. Chem. Soc. , Vol. 127, no. 14, 4986, J.A. Amer. Chem. Soc. , Vol. 123, p9482; Amer. Chem. Soc. , Vol. 130 (2008), no. Examples include acene compounds substituted with a trialkylsilylethynyl group described in 9,2706, and porphyrin compounds described in JP-A-2008-16834.

  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, polythiophene-thienothiophene copolymer, polythiophene-diketopyrrolopyrrole copolymer described in WO08 / 000664, Adv. Mater. , 2007, p4160, a polythiophene-thiazolothiazole copolymer, 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, oligomer materials instead of polymer materials include thiophene hexamer α-seccithiophene, α, ω-dihexyl-α-sexualthiophene, α, ω-dihexyl-α-kinkethiophene, α, ω-bis ( Oligomers such as 3-butoxypropyl) -α-sexithiophene can be preferably used.

  In a preferred organic photoelectric conversion device of the present invention having a p-i-n three-layer configuration (FIG. 2), the p-type semiconductor material of the i layer, which is a bulk heterojunction layer (14i layer), has the above conjugate height. Although it is a molecular semiconductor material, as the p-type semiconductor material used for the p layer (14p layer), the above-described polymer material and condensed polycyclic aromatic low-molecular compound or oligomer material can be used.

(N-type semiconductor material)
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 hydrogen atoms of a p-type semiconductor such as fullerene and octaazaporphyrin are substituted with fluorine atoms. 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, US Pat. No. 7,329,709, etc. It is preferable to use a fullerene derivative having a substituent such as fullerene having a cyclic ether group such as a calligraphy and having improved solubility.

(Bulk heterojunction layer formation method)
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. 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. Application methods include casting method, blade coating method, wire bar coating method, spray coating method, dipping (dipping) coating method, bead coating method, air knife coating method, curtain coating method, inkjet method, spin coating method, Langmuir- A usual method such as a Blodgett (LB) method can be used, and it is particularly preferable to use a cast method, a spin coating method, and an ink jet method.

  When a bulk heterojunction layer is formed using a coating method, a material for forming the layer may be a suitable organic solvent (for example, a hydrocarbon solvent such as hexane, octane, decane, toluene, xylene, ethylbenzene, 1-methylnaphthalene, for example, Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, for example, halogenated hydrocarbon solvents such as dichloromethane, chloroform, tetrachloromethane, dichloroethane, trichloroethane, tetrachloroethane, chlorobenzene, dichlorobenzene, chlorotoluene, etc. Ester solvents such as ethyl acetate, butyl acetate, amyl acetate, such as methanol, propanol, butanol, pentanol, hexanol, cyclohexanol, methyl celloso Alcohol solvents such as butyl, ethyl cellosolve, ethylene glycol, for example, ether solvents such as dibutyl ether, tetrahydrofuran, dioxane, anisole, such as N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2 -Polar solvents such as pyrrolidone, 1-methyl-2-imidazolidinone, dimethyl sulfoxide) and / or water can be dissolved or dispersed to form a coating solution, and thin films can be formed by various coating methods. . The concentration of the coloring compound of the present invention in the coating solution is preferably 0.1 to 80% by mass, more preferably 0.1 to 10% by mass, whereby a film having an arbitrary thickness can be formed.

  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.

  As a heating method, the heating temperature is preferably higher than the glass transition temperature of the p-type conjugated polymer semiconductor material, and preferably higher than the boiling point of the solvent used. Moreover, when using a resin film for a board | substrate, the temperature lower than melting | fusing point of a resin film is preferable. Depending on the material used, heating at 130 to 160 ° C. for 3 to 60 minutes is preferable from the viewpoint of productivity.

  The mixing ratio of the p-type semiconductor material and the type semiconductor material of the bulk heterojunction photoelectric conversion layer of the present invention may be a single layer uniformly mixed, but the mixing ratio of the electron acceptor and the electron donor You may comprise by the multiple layer which changed. In this case, the mass ratio is preferably in the range of 2: 8 to 8: 2, more preferably in the range of 4: 6 to 6: 4. The content of the dye represented by the general formula (1), which is the third component of the present invention, is in the range of 0.1 to 20% by mass with respect to the total of the p-type conjugated polymer semiconductor material and the type semiconductor material. Preferably, it is in the range of 1 to 10%, more preferably 2 to 6% by mass.

(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. Examples of such materials include phenanthrene compounds such as bathocuproine, n-type semiconductor materials such as naphthalenetetracarboxylic acid anhydride, naphthalenetetracarboxylic acid diimide, perylenetetracarboxylic acid anhydride, perylenetetracarboxylic acid diimide, and titanium oxide. N-type inorganic oxides such as zinc oxide and gallium oxide, and alkali metal compounds such as lithium fluoride, sodium fluoride, and cesium fluoride can be used. A layer made of a single n-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.

(Hole transport layer / electron block 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 organic photoelectric conversion element of 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, a light diffusion layer that can scatter the 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 becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  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 or 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 is not deteriorated by oxygen, moisture, or the like 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 an organic photoelectric conversion element are pasted with an adhesive. Method, spin coating of organic polymer material (polyvinyl alcohol, etc.) with high gas barrier property, inorganic thin film (silicon oxide, aluminum oxide, etc.) or organic film (parylene etc.) with high gas barrier property are deposited under vacuum Examples thereof include a method 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 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, the optical sensor array 20 is paired with a substrate 21 as a holding member, an anode 22 (for example, ITO) as a lower electrode, a photoelectric conversion unit 24 that converts light energy into electric energy, and an anode 22. A cathode 23 (for example, Al) as an upper electrode 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 P3HT is used as the p-type semiconductor material of the photoelectric conversion layer 24b, and the PCBM is used as 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 light receiving area a in 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 a spin coating method (conditions: rotation 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, on the PEDOT-PSS film, a third component is mixed with a 1: 4 mixed film of P3HT and PCBM, and formed 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 at a ratio of 1: 4, the third component was mixed, and a mixture obtained by stirring (5 minutes) was used. After the formation of the mixed film of P3HT, PCBM, and the third component, 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 and the third component after the annealing treatment was 70 nm.

  Then, using a metal mask having a predetermined pattern opening, 5 nm of BC is deposited as an electron transport layer on a mixed film of P3HT, PCBM and the third component, 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.

  When this photosensor array 20 was irradiated with light having a predetermined pattern, it was confirmed that the photocurrent was detected only from the cells that were exposed to light and functioned as a photosensor.

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

Example [Production of Organic Photoelectric Conversion Elements 1 to 31]
An indium tin oxide (ITO) transparent conductive film deposited on a glass substrate with a thickness of 110 nm (sheet resistance 13 Ω / □) is patterned to a width of 2 mm using a normal photolithography technique and hydrochloric acid etching, and transparent An electrode was formed.

  The patterned transparent electrode was washed 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. 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 atmosphere for 10 minutes.

  After this, the substrate was brought into the glove box and operated under a nitrogen atmosphere. First, the substrate was heat-treated at 140 ° C. for 3 minutes in a nitrogen atmosphere.

  P3HT (Plectotronics, Plexcore OS2100) is 1.0% by mass as p-type semiconductor material, and PCBM (Frontier Carbon) is 1.0% by mass as n-type semiconductor material. A solution in which 0.07% by mass of a pigment such as the exemplified compound according to the present invention and the comparative compounds DR-1, DR-2, DR-3, etc. was dissolved was prepared, and filtered at 700 rpm at 700 rpm while filtering with a 0.45 μm filter. Second, followed by spin coating at 2200 rpm for 1 second, followed by drying at room temperature for 30 minutes to obtain a photoelectric conversion layer.

Next, the substrate on which the organic layer was formed was placed in a vacuum evaporation apparatus. 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 0.5 nm of lithium fluoride and 80 nm of Al were evaporated. Finally, the heating for 30 minutes was performed at 120 degreeC, and the organic photoelectric conversion elements 1-31 were obtained. The vapor deposition rate was 2 nm / second for all, and the size was 2 mm square.

DR-1: 2,3,9,10,16,17,23,24-octakis (octyloxy) -29H, H31-zinc phthalocyanine (manufactured by Aldrich)
DR-2: Bistrihexylsilyl silicon phthalocyanine (Aldrich)
DR-3: Bis (tetrabutylammonium) cis-bis (thiocyanato) bis (2,2'-bipyridyl-4-carboxylic acid-4'-carboxylate) ruthenium (II) complex ("S719", "N719") )
The obtained organic photoelectric conversion elements 1 to 31 were sealed using an aluminum cap and a UV curable resin (manufactured by Nagase ChemteX Corporation, UV RESIN XNR5570-B1) in a nitrogen atmosphere, and then a solar simulator (AM1). .5G) was irradiated at an irradiation intensity of 100 mW / cm ² , voltage-current characteristics were measured, and initial conversion efficiency was measured.

(Evaluation of conversion efficiency)
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)
Solar simulator (AM1.5G) light was irradiated at an irradiation intensity of 100 mW / cm ² , voltage-current characteristics were measured, and initial conversion efficiency was measured. Further, assuming that the initial conversion efficiency at this time is 100 and the resistor is connected between the anode and the cathode, the conversion efficiency after the solar simulator (AM1.5G) light is continuously irradiated for 1000 h at an irradiation intensity of 100 mW / cm ^2. Was evaluated, and a decrease in relative efficiency was calculated.

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

  From Table 1, it can be seen that the use of the phthalocyanine derivative having a specific structure according to the present invention provides a higher conversion efficiency and higher durability.

DESCRIPTION OF SYMBOLS 10 Bulk heterojunction type organic photoelectric conversion element 11 Substrate 12 Anode 13 Cathode 14 Photoelectric conversion layer 14p p layer 14i i layer 14n n layer 14 '1st photoelectric conversion layer 15 Charge recombination layer 16 2nd photoelectric conversion layer 17 Positive 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 (7)

An organic photoelectric conversion element having a cathode, an anode, and a photoelectric conversion layer in which a p-type semiconductor material and an n-type semiconductor material are mixed, wherein the photoelectric conversion layer contains a dye represented by the following general formula (1) An organic photoelectric conversion element characterized by the above.

(In the formula, M is any one of Si, Ge and Sn, R _{1 to} R ₄ each independently represents a substituent, and Z _{1 to} Z ₄ form a 5- or 6-membered aromatic ring or heterocyclic ring. A to d each represent an integer of 0 or 1 to 4. When ad is 2 or more, adjacent substituents may be bonded to form a 5- or 6-membered ring structure. A ₁ and A ₂ each independently represent a group represented by the following general formula (2).

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted. The organic photoelectric conversion device according to claim 1, wherein the dye represented by the general formula (1) is a dye represented by the following general formula (3).

(In the formula, M is any one of Si, Ge, and Sn, R _{1 to} R ₄ each independently represents a substituent, and a to d each represents 0 or an integer of 1 to 4. In the case of 2 or more, adjacent substituents may be bonded to each other to form a 5- or 6-membered ring structure, wherein A ₁ and A ₂ are each independently a group represented by the following general formula (2). To express.)

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted. The organic photoelectric conversion device according to claim 1, wherein the dye represented by the general formula (1) is a dye represented by the following general formula (4).

(In the formula, R _{1 to} R ₄ each independently represents a substituent, and each of a to d represents 0 or an integer of 1 to 4. When ad is 2 or more, adjacent substituents are bonded to each other. (It may form a 5- or 6-membered ring structure. A ₁ and A ₂ each independently represent a group represented by the following general formula (2).)

Wherein R _{5 to} R ₇ represent a substituent selected from a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, heteroaryl group, amino group, and alkylsilyl group, and Q is a tetravalent carbon atom. Represents an atom or mother nucleus selected from silicon atom, germanium atom, tin atom, aryl group mother nucleus, heteroaryl group mother nucleus, and L represents a single bond, an alkylene group, an alkenylene group, a cycloalkylene group, an arylene group. , An ether group, or a divalent linking group in combination of these, which may be substituted.   The organic photoelectric conversion element according to claim 1, wherein the p-type semiconductor material is a conjugated polymer semiconductor material.   The organic photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer is produced by a solution coating method.   It consists of an organic photoelectric conversion element of any one of Claims 1-5, 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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