PHOTOELECTRIC CONVERSION ELEMENT, METHOD FOR PRODUCING PHOTOELECTRIC CONVERSION ELEMENT AND SOLAR CELL

1 . A photoelectric conversion element comprising a substrate, a first electrode, a photoelectric conversion layer containing a semiconductor and a sensitizing dye, and a hole transport layer, and a second electrode,

wherein said hole transport layer comprises a polymer having a repeating unit (1) represented by the following general formula (1):

wherein R 1 to R 4 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 9 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a polyethylene oxide group having 2 to 18 carbon atoms, or an aryl group, provided that at least one of R 1 to R 4 is a linear or branched alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 9 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a polyethylene oxide group having 2 to 18 carbon atoms, or an aryl group, and the remaining substituents are hydrogen atoms,

or a repeating unit (2) represented by the following general formula (2):

wherein R 5 each independently represents a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 18 carbon atoms, n is an integer from 1 to 3, and m is an integer from 0 to 2n+4, and

said sensitizing dye is represented by the following general formula (3A), (3B) or (3C):

wherein Ar 1 to Ar 3 each independently represent an aromatic group, provided that any two of Ar 1 to Ar 3 may bond each other to form a ring structure, Z represents a group having an acidic group and an electron-attracting group or a group having an acidic group and an electron-attracting ring structure, which is substituted in any of Ar 1 to Ar a , and p is an integer from 1 to 3,

wherein Ar 4 to Ar 7 each independently represent an aromatic group, provided that Ar 4 and Ar 5 or Ar 6 and Ar 7 may bond each other to form a ring structure, Ar 8 represents a divalent aromatic group, Z represents a group having an acidic group and an electron-attracting group or a group having an acidic group and an electron-attracting ring structure, which is substituted in any of Ar 4 to Ar 7 , and q is an integer from 1 to 4,

wherein Ar 9 and Ar 10 each independently represent an aromatic group, R 6 represents a linear or branched alkyl group having 1 to 24 carbon atoms, or a cycloalkyl group having 3 to 9 carbon atoms, provided that Ar 9 and Ar 10 , or Ar 9 or Ar 10 and R 6 may bond each other to form a ring structure, Z represents a group having an acidic group and an electron-attracting group or a group having an acidic group and an electron-attracting ring structure, which is substituted in any of Ar 9 , Ar 10 and R 6 , and r is an integer of 1 to 2.

2 . The photoelectric conversion element according to claim 1 , wherein the polymer having the repeating unit represented by the general formula (1) or (2) has an average absorbance in a wavelength region from 400 to 700 nm of 0.2 to 1.0.

3 . The photoelectric conversion element according to claim 1 , wherein the sensitizing dye has two acidic groups.

4 . The photoelectric conversion element according to claim 1 , wherein the semiconductor is titanium oxide.

5 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (1), at least one of R 1 to R 4 is a linear alkyl group having 6 to 18 carbon atoms, or in the general formula (2), n is 1.

6 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (1), R 1 is a linear alkyl group having 6 to 18 carbon atoms, and R 2 , R 3 and R 4 are a hydrogen atom.

7 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the acidic group in Z is a carboxyl group, a sulfo group, a phosphonic acid group, or a hydroxy group.

8 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the acidic group in Z is a carboxyl group, a sulfo group, or a phosphonic acid group.

9 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the electron-attracting group in Z is a cyano group, a nitro group, a fluoro group, or a chloro group.

10 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the electron-attracting group in Z is a cyano group or a nitro group.

11 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the electron-attracting ring structure in Z is a rhodanine ring, a dirhodanine ring, an imidazolone ring, a pyrazoline ring, a quinone ring, or a thiadiazole ring.

12 . The photoelectric conversion element according to claim 1 , wherein, in the general formula (3A), (3B) or (3C), the electron-attracting ring structure in Z is a rhodanine ring, a dirhodanine ring, an imidazolone ring, or a pyrazoline ring.

13 . The photoelectric conversion element according to claim 1 , wherein the hole transport layer comprises a polymer having a repeating unit (1) represented by the following general formula (1), and the sensitizing dye is represented by the general formula (3A).

14 . The photoelectric conversion element according to claim 1 , wherein the sensitizing dye is represented by the following general formula (3D):

wherein Ar 11 and Ar 12 each independently represent a divalent aromatic group, Ar 13 represents an aromatic group, and, Z 11 and Z 12 each independently represent a group having an acidic group and an electron-attracting group or a group having an acidic group and an electron-attracting ring structure.

15 . The photoelectric conversion element according to claim 14 , wherein, in the general formula (3D), Ar 11 and Ar 12 comprise a thiophene ring.

16 . A method for producing a photoelectric conversion element according to claim 1 , comprising a substrate, a first electrode, a photoelectric conversion layer containing a semiconductor and a sensitizing dye, a hole transport layer, and a second electrode,

wherein said hole transport layer is formed by electrolytic polymerization using a monomer (1) represented by the following general formula (1′):

wherein R 1 to R 4 each independently represent a hydrogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 9 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a polyethylene oxide group having 2 to 18 carbon atoms, or an aryl group, provided that at least one of R 1 to R 4 is a linear or branched alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 3 to 9 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, a polyethylene oxide group having 2 to 18 carbon atoms, or an aryl group, and the remaining substituents are hydrogen atoms,

or a monomer (2) represented by the following general formula (2′):

wherein R 5 each independently represents a halogen atom, a linear or branched alkyl group having 1 to 24 carbon atoms, or an alkoxy group having 1 to 18 carbon atoms, n is an integer from 1 to 3, and m is an integer from 0 to 2n+4,

or a multimer thereof.

17 . The method for producing a photoelectric conversion element according to claim 16 , wherein the electrolytic polymerization of the monomer (1), monomer (2) or multimer thereof is carried out on the photoelectric conversion layer.

18 . A solar cell, comprising the photoelectric conversion element set forth in claim 1 .