JP2003051344A - Manufacturing method for photoelectric conversion element and photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a dye-sensitized photoelectric conversion element showing excellent conversion efficiency, the photoelectric conversion element manufactured by the method, and a photocell using the photoelectric conversion element. SOLUTION: In this manufacturing method for the photoelectric conversion element having a conductive support body and a layer of semiconductor fine particles with adsorbed dye, the semiconductor fine particle is treated by a compound represented by the following formula: (A1 -L)n1 -A2 .M (wherein, A1 is a group with a negative charge; A2 is a basic group; M is a cation neutralizing the negative charge of (A1 -L)n1 -A2 ; L is a divalent bonding group or a mere bond; and n1 is an integer of 1-3).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a photoelectric conversion element, and more particularly to a method for producing a photoelectric conversion element using dye-sensitized semiconductor fine particles, a photoelectric conversion element produced by this method, and this photoelectric conversion. The present invention relates to a photovoltaic cell using an element.

[0002]

2. Description of the Related Art Photoelectric conversion elements are used in various optical sensors, copying machines, photovoltaic devices, and the like. Various types of photoelectric conversion elements such as those using metals, those using semiconductors, those using organic pigments and dyes, and those combining these have been put into practical use.

US Pat. Nos. 4,927,721, 4,884,537, and 5084.
365, 5350644, 5463057, 5525440, WO98
/ 50393, JP-A-7-249790 and JP-A-10-504521, a photoelectric conversion element using semiconductor fine particles sensitized by a dye (hereinafter, referred to as "dye-sensitized photoelectric conversion element") and this The materials and manufacturing techniques for making the are disclosed. The advantage of this dye-sensitized photoelectric conversion element is that an inexpensive oxide semiconductor such as titanium dioxide can be used without purification to a high degree of purity, so that it can be manufactured relatively inexpensively. However, such a photoelectric conversion element does not always have sufficiently high conversion efficiency, and further improvement in conversion efficiency is desired.

Further, Japanese Patent Laid-Open No. 1-220380 describes that the conversion efficiency of a dye-sensitized photoelectric conversion element is improved by post-treating semiconductor particles having a dye adsorbed thereon with t-butylpyridine. . However, this photoelectric conversion element also does not always have sufficiently high conversion efficiency.

[0005]

An object of the present invention is to provide a method for producing a dye-sensitized photoelectric conversion element exhibiting excellent conversion efficiency, a photoelectric conversion element prepared by this method, and a photovoltaic cell using this photoelectric conversion element. Is to provide.

[0006]

The method for producing a photoelectric conversion element of the present invention is a method for producing a photoelectric conversion element having a layer of semiconductor fine particles on which a dye is adsorbed and a conductive support,
It is characterized in that semiconductor fine particles are treated with a compound represented by the following general formula (I). (A ₁ -L) _{n 1} -A ₂ · M (I) In the general formula (I), A ₁ represents a group having a negative charge, A ₂ represents a basic group, and M represents (A ₁ -L) represents a cation to neutralize the negative charge of _n1 -A _2, L represents a divalent linking group or a single bond, n1 represents an integer of 1 to 3.

In the above general formula (I), A ₁ preferably has N ⁻ and A ₂ is particularly preferably a pyridyl group.

In the method for producing a photoelectric conversion element of the present invention, it is preferable to treat semiconductor particles with a compound represented by the general formula (I) and a compound represented by the following general formula (II).

[Chemical 2] In the general formula (II), X represents an oxygen atom, a sulfur atom, a selenium atom or NR ³ , R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group, -OR ⁴ , -N (R
^{5) (R 6), -} C (= O) R 7, -C (= S) represents R ⁸ or SO ₂ R ^9, Y is a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group, -O
Represents R ⁴ , -N (R ⁵ ) (R ⁶ ) or -SR ¹⁰ . R ³ represents a hydrogen atom, an aliphatic hydrocarbon group, a hydroxy group or an alkoxy group, R ⁴ represents a hydrogen atom or an aliphatic hydrocarbon group, R ⁵
And R ⁶ have the same meaning as R ¹ and R ² , R ⁷ , R ⁸ and R ⁹ have the same meaning as Y, and R ¹⁰ has the same meaning as R ⁴ .

In the general formula (II), X preferably represents an oxygen atom, and Y particularly preferably represents -N (R ⁵ ) (R ⁶ ).
Further, the compound represented by the general formula (II) is -Si (R ¹¹ ) (R ¹² ) (R
^It is particularly preferable to have a substituent represented by ¹³ ). However, R ¹¹ , R ¹² and R ¹³ are each independently a hydroxy group,
It represents an alkyloxy group, an isocyanate group, a halogen atom or an aliphatic hydrocarbon group, and at least one of R ¹¹ , R ¹² and R ¹³ is an alkyloxy group, an isocyanate group or a halogen atom.

After adsorbing the dye on the semiconductor fine particles, it is particularly preferable to treat with the compound represented by the general formula (I) and / or the compound represented by the general formula (II). The dye is particularly preferably a ruthenium complex dye.

The photoelectric conversion element of the present invention is characterized by being manufactured by the above-described manufacturing method of the present invention, and the photovoltaic cell of the present invention comprises the photoelectric conversion element.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a photoelectric conversion element of the present invention is a method for producing a photoelectric conversion element having a photosensitive layer and a conductive support, and the photosensitive layer is composed of semiconductor fine particles to which a dye is adsorbed. In the method of the present invention, by treating the semiconductor fine particles with a compound represented by the general formula (I) described later,
The conversion efficiency of the photoelectric conversion element is improved. In the present invention,
It is preferable to treat the semiconductor fine particles with the compound represented by the general formula (I) and the compound represented by the general formula (II) described later. Hereinafter, in the present invention, the compound represented by the general formula (I) is referred to as "compound (I)", and the compound represented by the general formula (II) is referred to as "compound (II)".

[I] Compound (I) The general formula (I) is shown below. (A ₁ -L) _n1 -A ₂・ M ・ ・ ・ (I)

In the general formula (I), A ₁ represents a group having a negative charge. The negative charge may be localized or delocalized, and its valence is not particularly limited. Examples thereof include groups having a negative charge on oxygen atom ^{_{(-SO 3 -, -CO 2 -}} , -PO 3 2-,
-O ^-, etc.), a group having a negative charge on the nitrogen atom (RSO ₂ N ^{- -,} RS
^{_{O 2 N - SO 2 -,}} RCON - -, RCON - CO-, RSO 2 N - CO-, RR'PON - -, R
R'PON ^- CO-, etc.), groups having a negative charge on the sulfur atom (-SO ₂ S
_{^{-, -S (= O) 2}} -, -S - , etc.), a group having a negative charge on the carbon atom (RCOCH ^- CO-, etc.), a group having a charge on the phosphorus atom (RCOP ^-
-Etc.) Etc. A ₁ is preferably a group having a negative charge on the nitrogen atom, ie A ₁ preferably has N ⁻ . A ₁ is more preferably ^{_{RSO 2 N - -, RSO 2}} N - SO 2 -, RCO
N ^{- -,} RCON ^- CO- or RSO ₂ N ^- is CO-, particularly preferably RS
O ₂ N ^{- -} a.

R and R'represent a hydrogen atom or a substituent, which may be the same or different, and examples of the substituent include an aliphatic hydrocarbon group, an aryl group and a heterocycle. Group, amino group, hydroxy group, alkyloxy group and the like. Specific examples of the aliphatic hydrocarbon group represented by R and R ′ include a linear or branched unsubstituted alkyl group having 1 to 18 carbon atoms (methyl group, ethyl group, i-propyl group, n-propyl group, n -Butyl group, t-butyl group, 2-pentyl group, n-hexyl group, n-octyl group, t-octyl group, 2-
(Ethylhexyl group, 1,5-dimethylhexyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group, etc.), C1-C18 linear or branched substitution Alkyl group (trifluoromethyl group, trifluoroethyl group, tetrafluoroethyl group, pentafluoroethyl group, perfluorobutyl group, methoxycarbonylmethyl group, n-butoxypropyl group, methoxyethoxyethyl group, polyethoxyethyl group, acetyl Oxyethyl group, methylthiopropyl group, 3- (N-ethylureido) propyl group, etc.), a substituted or unsubstituted cyclic alkyl group having 3 to 18 carbon atoms (cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, Adamantyl group, cyclododecyl group, etc.), alkenyl group having 2 to 16 carbon atoms (allyl group, 2-butenyl group, 3-pentane group) Thenyl group), 2 carbon atoms
To alkynyl groups (propargyl group, 3-pentynyl group, etc.), aralkyl groups having 6 to 16 carbon atoms (benzyl group, etc.) and the like. Specific examples of the aryl group represented by R and R'include a substituted or unsubstituted phenyl group having 6 to 20 carbon atoms (phenyl group, methylphenyl group, octylphenyl group, cyanophenyl group, ethoxycarbonylphenyl group, trifluoro group). Methylphenyl group, pentafluorophenyl group, methoxycarbonylphenyl group, butoxyphenyl group, etc.), substituted or unsubstituted naphthyl group (naphthyl group, 4-
Sulfonaphthyl group) and the like. Specific examples of the heterocyclic group represented by R and R ′ include a substituted or unsubstituted nitrogen-containing hetero 5-membered ring group, a substituted or unsubstituted nitrogen-containing hetero 6-membered ring group (triazino group, etc.), a furyl group, and thiofuryl. Groups and the like. Specific examples of the amino group represented by R and R ′ include:
Examples thereof include a dimethylamino group. Specific examples of the alkyloxy group represented by R and R ′ include an ethyloxy group and a methyloxy group. Of these, R and R ′ are preferably a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group, and at least 1
Particularly preferred is an alkyl group substituted with one fluorine atom.

In the general formula (I), A ₂ represents a basic group. Here, the basic group means a group in which the pKa of the conjugate acid of the compound obtained by adding hydrogen thereto is 3 to 15. However, the pKa is 25
Tetrahydrofuran (THF) and water mixed solvent (T
Values in HF: water = 1: 1). The pKa of the conjugate acid of the compound obtained by adding hydrogen to A ₂ is preferably 4 to 14, more preferably 5 to 13. Examples of this basic group include a pyridyl group, an imidazolyl group, an amino group, a guanidino group,
Examples thereof include a hydrazino group. Of these, a pyridyl group, an imidazolyl group and an amino group are preferable, and a pyridyl group is particularly preferable. These basic groups may have a substituent other than (A ₁ -L) _{n 1-} .

In the general formula (I), M represents a cation that neutralizes the negative charge of (A ₁ -L) _{n 1} -A ₂ . Examples of the cations include alkali metal cations (lithium cation, sodium cation, potassium cation, rubidium cation, cesium cation, etc.), alkaline earth metal cations (magnesium cation, calcium cation, strontium cation, etc.), substituted or unsubstituted. Ammonium cation (unsubstituted ammonium cation, triethylammonium cation, tetramethylammonium cation, tetra-n-butylammonium cation, tetra-n-hexylammonium cation, eryltrimethylammonium cation, etc.), substituted or unsubstituted imidazolium cation (1 , 3-Dimethylimidazolium cation, 1-ethyl-3
-Methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 2,3-dimethyl-1-propylimidazolium cation, etc.), substituted or unsubstituted pyridinium cation (N-methylpyridinium cation, 4-phenylpyridinium) Cation etc.) and the like. M is preferably an alkali metal cation, an alkaline earth metal cation, a quaternary ammonium cation, an imidazolium cation or a pyridinium cation, more preferably an alkali metal cation or an imidazolium cation, and particularly preferably a lithium cation or 1,3. -A dialkyl imidazolium cation. In addition, M represents the type and number of cations, for example, (A ₁ -L) _{n 1} -A ₂
Has a total negative charge of 1, and the type of cation
When it is Mg ²⁺ , M is “1/2 (Mg ²⁺ )”.

In the general formula (I), L is a divalent linking group or a simple linking group.
Represents a match. Examples of the divalent linking group include a group having 1 to 18 carbon atoms.
A substituted or unsubstituted linear or branched alkylene group (methylene
Group, ethylene group, trimethylene group, tetramethylene group,
Isopropylene group, tetrafluoroethylene group, etc.), charcoal
Oxyalkylene group having a prime number of 1 to 18 (-CH₂CH₂OCH₂CH₂-,-
CH₂CH₂OCH₂CH₂OCH₂CH₂-Etc.), Alkille having 1 to 18 carbon atoms
And phenyleneoxy groups (-CH₂CH₂O-, -CH₂CH₂
CH₂O-, -CH₂CH₂OCH₂CH₂O-, -PhO-, etc.), having 1 to 18 carbon atoms
Alkyleneamino group and phenyleneamino group (-(CH₂C
H₂)₂N-,-(OCH₂CH ₂)₂N-, -PhNH-, etc.), having 1 to 18 carbon atoms
Alkylenethio group or phenylenethio group (-CH₂CH₂S-,-
CH₂CH₂CH₂S-, -CH₂CH₂OCH₂CH₂CH₂S-, -PhS-, etc.), carbon
Substituted or unsubstituted phenylene group of formula 6 to 20, sulfamo
Yl linking group (-SO₂NH-), carbamoyl linking group (-CONH
-), Amide linking group (-NHCO-), sulfonamide linking group
(-NHSO₂-), Ureido linking group (-NHCONH-), thioure
Id linking group (-NHCSNH-), urethane linking group (-OCONH
-), Thiourethane linking group (-OCSNH-), oxycarboni
Linking group (-OCO-), carbonyloxy linking group (-CO
₂-), Heterocyclic linking groups, combinations thereof, and the like.
Be done. L is an alkylene group having 1 to 6 carbon atoms or a simple bond
Is preferred, and a simple bond is particularly preferred.
Yes.

In the general formula (I), n1 representing the number of (A ₁ -L) is 1 to
It is an integer of 3. n1 is preferably 1.

In the general formula (I), A ₁ is a group having a negative charge on the nitrogen atom, A ₂ is a pyridyl group, an imidazolyl group or an amino group, M is an alkali metal cation or an imidazolium cation. , L are simple bonds and n1 is 1. Furthermore, A ₁ is R ₁ SO
₂ N ^- - a (R ₁ represents at least one alkyl group substituted with a fluorine atom), A ₂ is a pyridyl group, M is a lithium cation or an imidazolium cation,
It is especially preferred that L is a bond and n1 is 1.

Specific examples of the compound (I) are shown below, but the present invention is not limited thereto.

[0022]

[Chemical 3]

[0023]

[Chemical 4]

[0024]

[Chemical 5]

[0025]

[Chemical 6]

[0026]

[Chemical 7]

[0027]

[Chemical 8]

Compound (I) can be easily prepared by applying a known method.
Can be synthesized. For example, A₁Is N ^-Is a group having
In case of amine or amide and electrophile (acid halogenation
Compounds, acid anhydrides, alkyl halides, halogen-substituted hete
Ring compounds, etc.), nucleophilic substitution reactions, amines or amides and acids
Amides and imides due to condensation reaction with (carboxylic acids, etc.)
Etc. and prepare a base (hydroxide of alkali metal, etc.)
Addition of cations and cation exchange to form salts
Therefore, compound (I) can be obtained easily and in high yield.
It

[II] Compound (II) In the method for producing a photoelectric conversion element of the present invention, semiconductor fine particles are combined with compound (I) and compound (I) represented by the following general formula (II).
Treatment with I) is preferred.

[Chemical 9]

In the general formula (II), X is an oxygen atom, a sulfur atom,
Represents a selenium atom or NR ³ . R ³ represents a hydrogen atom, an aliphatic hydrocarbon group, a hydroxy group or an alkoxy group, and as the aliphatic hydrocarbon group represented by R ³ , a substituted or unsubstituted straight chain having 1 to 10 carbon atoms, branched, or Examples thereof include cyclic alkyl groups (eg, methyl group, ethyl group, n-propyl group, i-propyl group, cyclohexyl group, carboxymethyl group, etc.), and alkoxy groups include methoxy group, ethoxy group, i-
Examples include propyloxy group and the like.

In the general formula (II), R¹And R²Each independently
Hydrogen atom, aliphatic hydrocarbon group, aryl group, heterocycle
Group, -OR^Four, -N (R^Five) (R⁶), -C (= O) R⁷, -C (= S) R⁸Or SO₂R⁹
Represents Where R^FourAnd R^TenAre hydrogen atom or fat
Represents an aliphatic hydrocarbon group, R^FiveAnd R ⁶Is R¹And R²Synonymous with
R⁷, R⁸And R⁹Is synonymous with Y described later.

When R ¹ and R ² represent an aliphatic hydrocarbon group,
Examples thereof include linear or branched unsubstituted alkyl groups having 1 to 30 carbon atoms (for example, methyl group, ethyl group, i-propyl group,
n-propyl group, n-butyl group, t-butyl group, 2-pentyl group, n-hexyl group, n-octyl group, t-octyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, n- Decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group, etc.), a linear or branched substituted alkyl group having 1 to 30 carbon atoms (for example, N, N-dimethylaminopropyl group, Trifluoroethyl group, tri-n-hexylammoniumpropyl group, pyridylpropyl group, triethoxysilylpropyl group, trimethoxysilylpropyl group, trichlorosilylmethyl group, carboxymethyl group, sulfoethyl group, sulfomethyl group, phosphopropyl group, Dimethoxyphosphopropyl group, n-butoxypropyl group, methoxyethoxyethyl group, polyethoxyethyl group, acetyloxyethyl group, methylthiopropyl group 3- (N-ethylureido) propyl group, etc., a substituted or unsubstituted cyclic alkyl group having 3 to 18 carbon atoms (eg, cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, adamantyl group, cyclododecyl group, etc. ), An alkenyl group having 2 to 16 carbon atoms (eg, allyl group, 2-butenyl group, 3-pentenyl group, etc.), an alkynyl group having 2 to 10 carbon atoms (eg, propargyl group, 3-pentynyl group, etc.), 6 carbon atoms To 16 aralkyl groups (eg, benzyl group) and the like. R ¹
And when R ² represents an aryl group, examples thereof include a substituted or unsubstituted phenyl group having 6 to 30 carbon atoms (eg, an unsubstituted phenyl group, a methylphenyl group, an octylphenyl group, a cyanophenyl group, an ethoxycarbonylphenyl group). , Diethylphosphomethylphenyl group, sulfophenyl group, dimethylaminophenyl group, trimethoxysilylphenyl group, trifluoromethylphenyl group, carboxyphenyl group, butoxyphenyl group, etc.), naphthyl group (eg, unsubstituted naphthyl group, 4-sulfo) Naphthyl group, etc.) and the like. When R ¹ and R ² represent a heterocyclic group, examples thereof include a substituted or unsubstituted nitrogen-containing hetero 5-membered ring (eg, imidazolyl group, benzimidazolyl group, pyrrole group, etc.), substituted or unsubstituted nitrogen-containing hetero 6 Membered ring (eg pyridyl group,
Quinolyl group, pyrimidyl group, triazino group, morpholino group, etc.), furyl group, thiofuryl group and the like. Further, when R ¹ and R ² represent —OR ⁴ , examples of the aliphatic hydrocarbon group represented by R ⁴ are the same as the examples of the aliphatic hydrocarbon group represented by R ¹ and R ² described above. There are things. R ¹ and R ² are
-N (R ⁵⁾ R ⁵ and R ⁶ when it represents a (R ⁶⁾ has the same meaning as R ¹ and ^{R 2, -C (= O)} R 7, -C (= S) R 8 and SO ₂ R ⁷ and R ⁸ when representing R ⁹
And R ⁹ are synonymous with Y shown below.

R¹And R²Are hydrogen atom and charcoal independently
Substituted or unsubstituted alkyl group having a prime number of 1 to 20, carbon number of 6 to 20
Substituted or unsubstituted phenyl group, nitrogen-containing heterocyclic group, -N (R
^Five) (R ⁶), -C (= O) R⁷Or SO₂R⁹Is preferred,
Hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms,
Substituted or unsubstituted phenyl group having 6 to 18 carbon atoms or nitrogen-containing
A hetero 6-membered ring is more preferable, and a hydrogen atom or carbon
Substituted or unsubstituted alkyl group having 1 to 16 primes or 6 carbon atoms
It is particularly preferred that they are substituted or unsubstituted phenyl groups of
R¹Represents a hydrogen atom, and R²Is hydrogen atom, carbon number
1 to 16 substituted or unsubstituted alkyl group or 6 to 16 carbon atoms
Most preferably represents a substituted or unsubstituted phenyl group
Yes.

In the general formula (II), Y represents a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group, -OR ⁴ , -N (R ⁵ ) (R ⁶ ), or -SR ¹⁰ . Examples of the aliphatic hydrocarbon group represented by Y, the aryl group, the heterocyclic group, -OR ⁴ , and -N (R ⁵ ) (R ⁶ ) are the same as those of the above R ¹ and R ^2. Can be mentioned. In the case of representing -SR ¹⁰ , R ¹⁰ has the same meaning as R ⁴ above.

Y is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 16 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 16 carbon atoms, a nitrogen-containing heterocyclic group or -N (R ⁵ ) (R ⁶ ). Is preferably a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group having 6 to 12 carbon atoms,
A nitrogen-containing hetero 6-membered ring or -N (R ⁵ ) (R ⁶ ) is more preferable, -N (R ⁵ ) (R ⁶ ) is particularly preferable, and -NH ₂
Is most preferably represented.

Further, X, Y, R ¹ and R ² in the general formula (II) may be linked to each other to form a ring.

Preferred R ⁵ and R ⁶ are R ¹ and R ² above.
Preferred examples of R ⁷ and R ⁸
Examples of R ⁹ and R ⁹ include the same as the above-mentioned preferred examples of Y.

X is preferably an oxygen atom.

The compound (II) used in the present invention is X,
R¹, R²And / or Y may have a substituent. The
Preferred examples of the substituent include -C (= O) OR ', -P (= O) (OR')
₂, -S (= O) OR ', -OR', -B (OR ')₂, -Si (R¹¹) (R¹²) (R¹³)etc
Is mentioned. R'is independently a hydrogen atom or an aliphatic
Represents a hydrocarbon group (eg, methyl group, ethyl group, etc.), R
¹¹, R¹²And R¹³Are independently hydroxy group,
Ruoxy group (eg methoxy group, ethoxy group, i-propy
Group, etc.), isocyanate group, halogen atom (eg salt)
Elementary atom) or an aliphatic hydrocarbon group (eg methyl group, ether
(Such as a chill group), R¹¹, R¹²And R¹³At least of
One is alkyloxy group, isocyanate group or halogen
Atom. Further, a more preferable substituent is -C
(= O) OR ', -P (= O) (OR')₂And -Si (R¹¹) (R¹²) (R¹³) Is listed
And particularly preferably --Si (R¹¹) (R¹²) (R ¹³).

When the compound (II) has an electric charge, it may have an anion or a cation as a counter ion for neutralizing the electric charge. The anion or cation is not particularly limited and may be an organic ion or an inorganic ion. Typical examples of anions include halide ions (fluoride ion, chloride ion, bromide ion, iodide ion), perchlorate ion, tetrafluoroborate ion, hexafluorophosphate ion, acetate ion, trioxide ion. Examples include fluoroacetate ion, methanesulfonate ion, paratoluenesulfonate ion, trifluoromethanesulfonate ion, bis (trifluoroethanesulfonyl) imide ion, tris (trifluoromethanesulfonyl) methide ion, and the like, and examples of cations include alkali metal ions. (Lithium ion, sodium ion, potassium ion, etc.), alkaline earth metal ion (magnesium ion, calcium ion, etc.), substituted or unsubstituted ammonium ion (unsubstituted ammonium ion, triethylammonium ion) Ion, tetramethylammonium ion, etc.), substituted or unsubstituted pyridinium ion (unsubstituted pyridinium ion, 4-phenylpyridinium ion, etc.), substituted or unsubstituted imidazolium ion (N-methylimidazolium ion, etc.), etc. To be

The compounds preferably used in the present invention are as follows:
Specific examples of (II) are shown below, but the invention is not limited thereto.

[0042]

[Chemical 10]

[0043]

[Chemical 11]

[0044]

[Chemical 12]

[0045]

[Chemical 13]

[III] Treatment Method (A) Treatment Method Using Only Compound (I) The term “treatment” as used herein means that the semiconductor fine particles are brought into contact with the compound (I) for a certain period of time before the charge transport layer is installed. This means an operation, and the compound (I) may or may not be adsorbed on the semiconductor fine particles after the contact. Further, the semiconductor fine particles to be subjected to the treatment may be in any state in the process of producing the photoelectric conversion element, but it is preferable to perform the treatment after the semiconductor fine particle film is formed, and to adsorb the dye to the semiconductor fine particles. It is particularly preferable to carry out the treatment after the treatment. On the other hand, the compound (I) to be treated is preferably used as a solution dissolved in a solvent (hereinafter referred to as a treatment solution) or a dispersed dispersion (hereinafter referred to as a treatment dispersion), but the compound itself is a liquid. In the case of, it may be used without a solvent. Treatment using a treatment solution is more preferable, and the solvent is preferably an organic solvent.

When an organic solvent is used, it can be appropriately selected depending on the solubility of the compound (I). For example, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.), nitromethane, halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.) ), Ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N, N-dimethylformamide, N, N-dimethylacetamide, etc.), N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.),
Carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.), mixed solvents of these are used. it can. Of these, nitriles, alcohols and amides are particularly preferred solvents.

As a method of treating using a treatment solution or a treatment dispersion (hereinafter, both liquids are collectively referred to as a treatment liquid),
A preferable method is a method of immersing the semiconductor fine particle film in the treatment liquid (hereinafter referred to as an immersion treatment method). Further, a method of spraying the treatment liquid in a spray shape for a certain period of time (hereinafter referred to as a spray method) can also be applied. When performing the dipping treatment method, the temperature of the treatment liquid and the time taken for the treatment may be set arbitrarily,
It is preferable to perform the immersion treatment at a temperature of ℃ to 80 ℃ for 30 seconds to 24 hours. It is preferable to wash with a solvent after the immersion treatment. The solvent used for washing is preferably the same composition as the solvent used for the treatment liquid, or a polar solvent such as nitriles, alcohols and amides.

The treatment liquid contains at least 1 compound (I).
The seed and, optionally, a substance other than this may be contained as an additive. As an example of using an additive, there is a case where a colorless compound having a surface active property and a structure is added to a dye in order to reduce an interaction such as aggregation between dyes, and the compound is co-adsorbed on semiconductor fine particles. . Examples of the additives include steroid compounds having a carboxyl group (for example, chenodeoxycholic acid, cholic acid, etc.), ultraviolet absorbers, surfactants and the like.

The concentration of the compound (I) in the treatment liquid is preferably 1 × 10 ^{−6 to 2} mol / L, more preferably 1 × 10 ^{−6 to 2} mol / L.
It is × 10 ^{-5 to} 5 × 10 ^-1 mol / L.

(B) Treatment Method Using Compound (I) and Compound (II) As described above, in the present invention, semiconductor fine particles are treated with compound (I).
Is preferably treated with compound (II). As used herein, the term "treatment" means an operation of bringing the semiconductor fine particles into contact with the compound (I) and the compound (II) for a certain period of time before the charge transport layer is installed, and after the contact, the compound is added to the semiconductor fine particles.
It does not matter whether (I) or compound (II) is adsorbed. Further, the semiconductor fine particles to be subjected to the treatment may be in any state in the process of producing the photoelectric conversion element, but it is preferable to perform the treatment after the semiconductor fine particle film is formed, and to adsorb the dye to the semiconductor fine particles. It is particularly preferable to carry out the treatment after the treatment. On the other hand, the compound (I) and the compound (II) to be treated are preferably used as a treatment solution or dispersion, but when the compound itself is a liquid, it may be used without a solvent. Treatment using a treatment solution is more preferable, and the solvent is preferably an organic solvent. When an organic solvent is used, the same organic solvent as in the case of treating with the compound (I) alone can be used.

The treatment with the compound (I) and the treatment with the compound (II) may be carried out simultaneously or separately, and are preferably carried out simultaneously. When carried out at the same time, it is particularly preferable to use a solution in which both compound (I) and compound (II) are dissolved and to treat as a mixed solution.

When the treatment with the mixed treatment liquid of the compound (I) and the compound (II) is performed, the dipping treatment method can be preferably used as in the case of the treatment with only the compound (I). The temperature of the treatment liquid when performing the dipping treatment method and the time required for the treatment are
It may be set arbitrarily as in the case of processing only with (I).

Further, to the treatment liquid, an additive such as a steroid compound having a carboxyl group, an ultraviolet absorber or a surfactant, or a base may be added as in the case of treating with only the compound (I).

When the treatment with the compound (II) is carried out using a treatment liquid containing the compound, the concentration of the compound (II) in the treatment liquid is preferably 1 × 10 ^{−6 to 2} mol / L, and It is preferably 1 × 10 ^{−5 to} 5 × 10 ⁻¹ mol / L. This preferable concentration is the same when treating with a mixed treatment liquid of compound (I) and compound (II).

[IV] Photoelectric Conversion Element The photoelectric conversion element of the present invention is produced by the production method of the present invention. The photoelectric conversion element of the present invention is preferably, as shown in FIG. 1, a conductive layer 10, an undercoat layer 60, a photosensitive layer 20, a charge transport layer.
30 and the counter conductive layer 40 are laminated in this order, and the photosensitive layer 20 is dyed.
Semiconductor fine particles 21 sensitized by 22 and the semiconductor fine particles
The charge transporting material 23 permeates the voids between the two. The charge transport material 23 in the photosensitive layer 20 is typically the charge transport layer 30.
It is the same material used for. A substrate 50 may be provided as a base of the conductive layer 10 and / or the counter conductive layer 40 in order to impart strength to the photoelectric conversion element. In the present invention, the conductive layer
The layer composed of 10 and the substrate 50 optionally provided is called a "conductive support", and the layer composed of the counter conductive layer 40 and the substrate 50 optionally provided is called a "counter electrode". The conductive layer 10, the counter conductive layer 40, and the substrate 50 in FIG. 1 may be the transparent conductive layer 10a, the transparent counter conductive layer 40a, and the transparent substrate 50a, respectively. A photocell is made for the purpose of generating electric power by connecting the photoelectric conversion element to an external load (power generation), and a photosensor is made for the purpose of sensing optical information. Of the photovoltaic cells, the case where the charge transport material mainly consists of the ion transport material is called a photoelectrochemical cell, and the case where the main purpose is power generation by sunlight is called a solar cell.

In the photoelectric conversion element shown in FIG. 1, when the semiconductor fine particles are n-type, the light incident on the photosensitive layer 20 containing the semiconductor fine particles 21 sensitized by the dye 22 excites the dye 22 and the like. High-energy electrons in the dye 22 and the like are passed to the conduction band of the semiconductor fine particles 21 and further reach the conductive layer 10 by diffusion. At this time, molecules such as the dye 22 are oxidants. In the photovoltaic cell, the electrons in the conductive layer 10 return to the oxidant such as the dye 22 via the counter conductive layer 40 and the charge transport layer 30 while working in the external circuit, and the dye 22 is regenerated. The photosensitive layer 20 functions as a negative electrode (photoanode), and the counter conductive layer 40 functions as a positive electrode. Boundary of each layer (eg conductive layer 10
The boundary between the photosensitive layer 20 and the photosensitive layer 20, the boundary between the photosensitive layer 20 and the charge transport layer 30, the boundary between the charge transport layer 30 and the counter electrode conductive layer 40, etc.) even if the constituent components of each layer are diffusely mixed with each other. Good. Each layer will be described in detail below.

(A) Conductive Support The conductive support is composed of (1) a single layer of a conductive layer, or (2) two layers of a conductive layer and a substrate. In the case of (1), a material that can sufficiently maintain strength and hermeticity as a conductive layer, for example, a metal material (platinum, gold, silver, copper, zinc, titanium, aluminum,
Alloys including these) can be used. In the case of (2), it is possible to use a substrate having a conductive layer containing a conductive agent on the photosensitive layer side. Preferred conductive agents include metals (platinum, gold, silver, copper, zinc, titanium, aluminum, indium, alloys containing these, etc.), carbon, and conductive metal oxides (indium-tin composite oxide, tin oxide and fluorine. Or antimony-doped ones). The thickness of the conductive layer is preferably about 0.02 to 10 μm.

The lower the surface resistance of the conductive support, the better. The surface resistance is preferably 50 Ω / □ or less, more preferably 20 Ω / □ or less.

When the conductive support is irradiated with light, the conductive support is preferably substantially transparent.
Substantially transparent means visible to near infrared region (400 to 120
(0 nm) light has a transmittance of 10% or more in a part or the whole area, preferably 50% or more, and 80% or more.
The above is more preferable. In particular, it is preferable that the photosensitive layer has a high transmittance in a wavelength range in which the photosensitive layer has sensitivity.

The transparent conductive support is preferably a transparent conductive layer made of a conductive metal oxide formed on the surface of a transparent substrate such as glass or plastic by coating or vapor deposition. The preferred transparent conductive layer is tin dioxide or indium-tin oxide (ITO) doped with fluorine or antimony. For transparent substrates, in addition to glass substrates such as soda glass, which is advantageous in terms of low cost and strength, non-alkali glass that is not affected by alkali elution,
A transparent polymer film can be used. Materials for the transparent polymer film include triacetyl cellulose (TAC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), syndiotactic polystyrene (SPS), polyphenylene sulfide (PPS),
Polycarbonate (PC), polyarylate (PAr), polysulfone (PSF), polyester sulfone (PE
S), polyimide (PI), polyetherimide (PEI),
Cyclic polyolefin, brominated phenoxy resin and the like can be used. In order to ensure sufficient transparency, the amount of conductive metal oxide applied is a glass or plastic support 1
It is preferably 0.01 to 100 g per m ² .

It is preferable to use metal leads for the purpose of reducing the resistance of the transparent conductive support. The material of the metal lead is preferably a metal such as platinum, gold, nickel, titanium, aluminum, copper or silver. Metal leads are installed on a transparent substrate by vapor deposition, sputtering, etc., and conductive tin oxide or IT is placed on top of them.
It is preferable to provide a transparent conductive layer composed of an O film. The decrease in the amount of incident light due to the installation of the metal leads is preferably within 10%, more preferably 1 to 5%.

(B) Photosensitive layer In the photosensitive layer, the semiconductor acts as a photoconductor, absorbs light and separates charges to generate electrons and holes. In a dye-sensitized semiconductor, light absorption and generation of electrons and holes due to light absorption mainly occur in the dye, and the semiconductor fine particles play a role of receiving and transmitting this electron (or hole). The semiconductor used in the present invention is preferably an n-type semiconductor in which a conductor electron serves as a carrier under photoexcitation and gives an anode current.

(1) Semiconductor As a semiconductor, silicon, a single semiconductor such as germanium, a III-V group compound semiconductor, a metal chalcogenide (oxide, sulfide, selenide, a compound thereof, etc.), a perovskite structure And the like (strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, etc.) and the like can be used.

Preferred metal chalcogenides include titanium, tin, zinc, iron, tungsten, zirconium,
Hafnium, strontium, indium, cerium,
Examples thereof include yttrium, lanthanum, vanadium, niobium or tantalum oxide, cadmium, zinc, lead, silver, antimony or bismuth sulfide, cadmium or lead selenide, and cadmium telluride. Examples of other compound semiconductors include phosphides such as zinc, gallium, indium, and cadmium, gallium-arsenic or copper-indium selenides, and copper-indium sulfides. Furthermore, M _x O _y S _z or M _1x M _2y O _z (M, M ₁ and M ₂ are metal elements respectively, O is oxygen, and x, y and z are the number of combinations having a neutral valence) Compounds such as can also be preferably used.

Preferred specific examples of the semiconductor used in the present invention are Si, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , ZnO, Nb ₂ O ₅ , CdS and Z.
nS, PbS, Bi ₂ S ₃ , CdSe, CdTe, SrTiO ₃ , GaP, InP, GaA
s, CuInS ₂ , CuInSe _2, etc., more preferably TiO ₂ , Zn
O, SnO ₂ , Fe ₂ O ₃ , WO ₃ , Nb ₂ O ₅ , CdS, PbS, CdSe, SrTi
O ₃ , InP, GaAs, CuInS ₂ or CuInSe ₂ is particularly preferable, TiO ₂ or Nb ₂ O ₅ is most preferable, and TiO ₂ is most preferable. TiO ₂ containing anatase 70% among TiO ₂
Is preferred, and 100% anatase type TiO ₂ is particularly preferred. It is also effective to dope a metal for the purpose of increasing electron conductivity in these semiconductors. The metal to be doped is preferably a divalent or trivalent metal. It is also effective to dope the semiconductor with a monovalent metal for the purpose of preventing a reverse current from flowing from the semiconductor to the charge transport layer.

The semiconductor used in the present invention may be a single crystal or a polycrystal, but a polycrystal is preferable from the viewpoints of manufacturing cost, securing of raw materials, energy payback time and the like, and the layer of semiconductor fine particles is particularly a porous film. preferable. Also,
It may include a part of an amorphous part.

The particle size of the semiconductor fine particles is generally on the order of nm to μm, but the average particle size of the primary particles obtained from the diameter when converting the projected area into a circle is preferably 5 to 200 nm, and 8 to 100 nm is more preferred. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is preferably 0.01 to 30 μm. Two or more types of fine particles having different particle size distributions may be mixed, and in this case, the average size of the small particles is preferably 25 nm or less, more preferably 10 nm or less.
For the purpose of scattering incident light and improving the light capture rate, it is also preferable to mix semiconductor particles having a large particle size, for example, about 100 to 300 nm.

Two or more kinds of semiconductor fine particles of different kinds may be mixed and used. When two or more kinds of semiconductor fine particles are mixed and used, one of them is preferably TiO ₂ , ZnO, Nb ₂ O ₅ or SrTiO ₃ . The other is preferably SnO ₂ , Fe ₂ O ₃ or WO ₃ . Further preferred combinations include combinations of ZnO and SnO ₂ , ZnO and WO ₃ , ZnO and SnO ₂ and WO _{3, and the} like. When two or more kinds of semiconductor fine particles are mixed and used, each particle size may be different. In particular, a combination of TiO ₂ , ZnO, Nb ₂ O ₅ or SrTiO ₃ having a large particle size and a small SnO ₂ , Fe ₂ O ₃ or WO ₃ is preferable. Preferably, particles having a large particle size are 100 nm or more and particles having a small particle size are 15 nm or less.

As a method for producing semiconductor fine particles, Sakubana Sio's "Sol-Gel Method Science" Agne Jofusha (1998), Technical Information Institute "Sol-Gel Method Thin Film Coating Technology" (1995 ), Etc., and Tadao Sugimoto, "Synthesis and Size Morphology Control of Monodisperse Particles by New Synthesis Gel-Sol Method," Materia, Vol. 35, No. 9, 1012-1018.
The gel-sol method described in page (1996) and the like is preferable. Also
A method developed by Degussa to produce an oxide by high-temperature hydrolysis of a chloride in an oxyhydrogen salt can also be preferably used.

When the semiconductor fine particles are titanium oxide, the sol-gel method, gel-sol method, and high-temperature hydrolysis method in chloride oxyhydrogen salt are all preferable. Applied Technology "Gihodo Publishing (1997)
It is also possible to use the sulfuric acid method or the chlorine method described in 1. Furthermore, as a sol-gel method, Barbe et al.
American Ceramic Society, Volume 80, Volume 12
No., pages 3157-3171 (1997), and Burnside
Rano Chemistry of Materials, Volume 10, No. 9
No. 2419 to 2425 is also preferable.

(2) Semiconductor fine particle layer In order to coat the semiconductor fine particles on the conductive support, in addition to the method of coating the dispersion or colloidal solution of the semiconductor fine particles on the conductive support, the above-mentioned sol-gel is used. Laws and the like can also be used. In consideration of mass production of photoelectric conversion elements, physical properties of semiconductor fine particle liquid, flexibility of conductive support, and the like, a wet film forming method is relatively advantageous. As a wet film forming method, a coating method, a printing method, an electrolytic deposition method and an electrodeposition method are typical. Also, a method of oxidizing a metal, a method of depositing a metal solution in a liquid phase by ligand exchange or the like (LPD method), a method of depositing by a sputtering method, a CVD method, or a metal that is thermally decomposed on a heated substrate The SPD method of spraying an oxide precursor to form a metal oxide can also be used.

As a method for producing a dispersion liquid of semiconductor fine particles, in addition to the above-mentioned sol-gel method, a method of crushing with a mortar, a method of dispersing while pulverizing with a mill, a method of synthesizing a semiconductor in a solvent And a method of precipitating it as fine particles and using it as it is.

As the dispersion medium, water and various organic solvents (eg, methanol, ethanol, isopropyl alcohol, citronellol, terpineol, dichloromethane, acetone, acetonitrile, ethyl acetate) can be used. At the time of dispersion, a polymer such as polyethylene glycol, hydroxyethyl cellulose or carboxymethyl cellulose, a surfactant, an acid or a chelating agent may be used as a dispersion aid, if necessary. By changing the molecular weight of polyethylene glycol, the viscosity of the dispersion liquid can be adjusted, and a semiconductor layer that is more resistant to peeling can be formed.
It is preferable to add polyethylene glycol because the porosity of the semiconductor layer can be controlled.

As a coating method, a roller method, a dip method or the like as an application system, an air knife method, a blade method or the like as a metering system, and as a method capable of making the application and the metering in the same part, Japanese Patent Publication No. 58-4.
Wirebar method disclosed in US Pat. No. 26812.
The slide hopper method, the extrusion method, the curtain method and the like described in No. 94, No. 2761419, No. 2761791 and the like are preferable. A spin method or a spray method is also preferable as a general-purpose machine. As the wet printing method, three major printing methods of letterpress, offset and gravure, intaglio, rubber plate, screen printing and the like are preferable. From these, the film forming method may be selected according to the liquid viscosity and the wet thickness.

The semiconductor fine particle layer is not limited to a single layer, but a dispersion of semiconductor fine particles having different particle diameters may be applied in multiple layers, or semiconductor fine particles of different types (or different binders and additives).
It is also possible to apply multiple layers of coating layers containing.
Multi-layer coating is effective even when the film thickness is insufficient after one coating.

Generally, as the thickness of the semiconductor fine particle layer (same as the thickness of the photosensitive layer) increases, the amount of supported dye per unit projected area increases, so that the light capture rate increases, but the diffusion distance of generated electrons increases. Therefore, the loss due to charge recombination becomes large. Therefore, the preferable thickness of the semiconductor fine particle layer is
0.1 to 100 μm. When used in a photovoltaic cell, the thickness of the semiconductor fine particle layer is preferably 1 to 30 μm, more preferably 2 to 25 μm. The coating amount of semiconductor fine particles per 1 m ² of support is 0.
5-100 g is preferable and 3-50 g is more preferable.

After the semiconductor fine particles are coated on the conductive support, the semiconductor fine particles are brought into electronic contact with each other, and
It is preferable to perform heat treatment in order to improve the strength of the coating film and the adhesion to the support. The preferred heating temperature range is 40 to 700 ° C, more preferably 100 to 600 ° C. The heating time is about 10 minutes to 10 hours. When a support having a low melting point or softening point such as a polymer film is used, high temperature treatment is not preferable because it causes deterioration of the support.
Also, from the viewpoint of cost, the temperature is as low as possible (for example 50 to 35
0 ° C.) is preferred. The temperature can be lowered by heat treatment in the presence of small semiconductor fine particles of 5 nm or less, mineral acid, or metal oxide precursor, and by irradiation with ultraviolet rays, infrared rays, microwaves, etc., or electric field or ultrasonic waves. You can also do it. At the same time, for the purpose of removing unnecessary organic substances and the like, it is preferable to appropriately combine and use the above-mentioned irradiation and application, as well as heating, decompression, oxygen plasma treatment, pure water cleaning, solvent cleaning, gas cleaning and the like.

After the heat treatment, for the purpose of increasing the surface area of the semiconductor fine particles, increasing the purity in the vicinity of the semiconductor fine particles, and increasing the electron injection efficiency from the dye to the semiconductor fine particles, for example, chemical plating treatment using an aqueous solution of titanium tetrachloride or Electrochemical plating treatment using a titanium trichloride aqueous solution may be performed. Further, it is also effective to adsorb an organic substance having a low electron conductivity other than a dye on the surface of the particles for the purpose of preventing a reverse current from flowing from the semiconductor fine particles to the charge transport layer. The organic substance to be adsorbed is preferably one having a hydrophobic group.

The semiconductor fine particle layer preferably has a large surface area so that many dyes can be adsorbed. The surface area of the semiconductor fine particle layer coated on the support is preferably 10 times or more the projection area, and more preferably 100 times or more. This upper limit is not particularly limited, but is usually about 1000 times.

(3) Dye The sensitizing dye used in the photosensitive layer may be any compound as long as it has absorption in the visible region and near infrared region and can sensitize a semiconductor, but it is a metal complex dye or a methine dye. , Porphyrin dyes or phthalocyanine dyes are preferable, and metal complex dyes are particularly preferable. In addition, two or more kinds of dyes can be used in combination or mixed in order to widen the wavelength range of photoelectric conversion as much as possible and increase the conversion efficiency. In this case, the dyes to be used or mixed and the ratio thereof can be selected so as to match the wavelength range and intensity distribution of the target light source.

Such a dye is a suitable interlocking group capable of adsorbing to the surface of semiconductor particles.
It is preferable to have As a preferable linking group,
-COOH group, -OH group, -SO ₂ H group, -P (O) (OH) ₂ group and -OP (O) (O
H) acidic groups such as ₂ groups, as well as oximes, dioximes,
Mention may be made of chelating groups having π conductivity such as hydroxyquinoline, salicylates and α-ketoenolates. Of these, a —COOH group, a —P (O) (OH) ₂ group and a —OP (O) (OH) ₂ group are particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an intramolecular salt.
In the case of a polymethine dye, if the methine chain contains an acidic group as in the case of forming a squarylium ring or a croconium ring, this portion may be used as a binding group. The preferred sensitizing dyes used in the photosensitive layer will be specifically described below.

(A) When the metal complex dye is a metal complex dye, a metal phthalocyanine dye, a metal porphyrin dye or a ruthenium complex dye is preferable, and a ruthenium complex dye is particularly preferable. Examples of ruthenium complex dyes include US Pat.
4537, 5084365, 5350644, 5463057, 5
525440, JP-A-7-249790, JP-A-10-504512, WO9
Examples thereof include those described in 8/50393 and JP-A 2000-26487.

The ruthenium complex dye used in the present invention is preferably represented by the following general formula (III): (A ₃ ) _p Ru (Ba) (Bb) (Bc) ... (III). In the general formula (III), A ₃ is 1
Or a bidentate ligand, preferably Cl, SCN, H ₂ O, B
It is a ligand selected from the group consisting of r, I, CN, NCO, SeCN, β-diketone derivatives, oxalic acid derivatives and dithiocarbamic acid derivatives. p is an integer of 0 to 3. Ba, Bb
And Bc each independently represent an organic ligand represented by any of the following formulas B-1 to B-10.

[0085]

[Chemical 14]

In formulas B-1 to B-10, each R ₁₁ represents a hydrogen atom or a substituent, and examples of the substituent include a halogen atom,
A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, the aforementioned acidic group ( These acidic groups may form a salt) and chelating groups. Here, the alkyl part of the alkyl group and aralkyl group may be linear or branched,
The aryl group and the aryl portion of the aralkyl group may be monocyclic or polycyclic (condensed ring, ring assembly). Ba, Bb and B-
c may be the same or different, any one or two
You can choose one.

Specific examples of preferable metal complex dyes are shown below, but the present invention is not limited thereto.

[0088]

[Chemical 15]

[0089]

[Chemical 16]

(B) Methine Dyes Preferred methine dyes that can be used in the present invention are polymethine dyes such as cyanine dyes, merocyanine dyes and squarylium dyes. Examples of preferable polymethine dyes include JP-A-11-35836, JP-A-11-67285, and JP-A-11-8.
6916, JP11-97725A, JP11-158395A, JP11-163378A, JP11-214730A, JP11-214731A.
No. 11-238905, 2000-26487, European Patent 8
Examples thereof include dyes described in Nos. 92411, 911841 and 991092. Specific examples of preferable methine dyes are shown below.

[0091]

[Chemical 17]

[0092]

[Chemical 18]

(4) Adsorption of Dye to Semiconductor Fine Particles To adsorb the dye to the semiconductor fine particles, the conductive support having a well-dried semiconductor fine particle layer is immersed in a solution of the dye, or the solution of the dye is applied to the semiconductor fine particles. The method of applying to a layer can be used. In the former case, a dipping method, a dipping method, a roller method, an air knife method or the like can be used. In the case of the dipping method, the dye may be adsorbed at room temperature.
It may be carried out by heating under reflux as described in No. 9790. Examples of the latter coating method include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method and a spray method. Alternatively, a dye may be applied in an image form by an inkjet method or the like, and the image itself may be used as a photoelectric conversion element.

The solvent used for the dye solution (adsorption liquid) is preferably alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.). , Nitromethane, halogenated hydrocarbons (dichloromethane, dichloroethane, chloroform, chlorobenzene, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), dimethyl sulfoxide, amides (N,
N-dimethylformamide, N, N-dimethylacetamide, etc.), N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.), carbonates ( Diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.) or mixed solvents thereof.

The total adsorption amount of the dye is preferably 0.01 to 100 mmol per unit area (1 m ² ) of the semiconductor fine particle layer. The amount of the dye adsorbed on the semiconductor fine particles is preferably in the range of 0.01 to 1 mmol per 1 g of the semiconductor fine particles. With such an amount of dye adsorbed, a sufficient sensitizing effect on the semiconductor can be obtained. On the other hand, if the amount of the dye is too small, the sensitizing effect becomes insufficient, and if the amount of the dye is too large, the dye not attached to the semiconductor floats, which causes a decrease in the sensitizing effect. In order to increase the adsorption amount of the dye, it is preferable to perform heat treatment before the adsorption. After heat treatment, the temperature of the semiconductor fine particle layer should be 60-150 ℃ without returning to room temperature to avoid water adsorption on the surface of the semiconductor fine particles.
It is preferable to quickly perform the dye adsorption operation between the two.

The non-adsorbed dye is preferably removed by washing immediately after adsorption. It is preferable that the cleaning is performed using a wet cleaning tank with a polar solvent such as acetonitrile or an organic solvent such as an alcohol solvent.

(5) Additives to Dye Adsorbing Liquid A colorless compound is added to the dye adsorbing liquid for the purpose of reducing interactions such as aggregation between dyes and increasing the amount of adsorbed dye. May be co-adsorbed with. Preferred examples of such colorless compounds include steroid compounds having a carboxyl group (chenodeoxycholic acid etc.),
Sulfonic acid compound, compound having ureido group (hereinafter,
Ureide compounds), alkali metal salts, alkaline earth metal salts and the like. Among them, ureide compounds and alkali metal salts are more preferable, and alkali metal salts are particularly preferable. Among the alkali metal salts, the lithium salt is most preferable.

Preferred specific examples of the ureido compound are shown below. The addition amount of the ureido compound is preferably 0.1 to 1000 times mol, more preferably 1 to 5 times, relative to the dye.
The molar amount is 00 times, and particularly preferably 10 to 100 times.

[0099]

[Chemical 19]

In the above-mentioned alkali metal salt and alkaline earth metal salt, the anion species forming a salt by forming a pair with an alkali metal cation or an alkaline earth metal cation is not particularly limited. These salts include halogen salts (fluorine salt, chlorine salt, bromine salt, iodine salt, etc.), carboxylate salt, sulfonate salt, phosphonate salt, sulfonamide salt, sulfonylimide salt (bistrifluoromethanesulfonimide salt, bispenta salt). Fluoroethanesulfonimide salt, etc.), sulfonylmethide salt, sulfate, thiocyanate, cyanate,
It may be perchlorate, tetrafluoroborate, hexafluorophosphate, etc., preferably iodine salt, bistrifluoromethanesulfonimide salt, thiocyanate,
Tetrafluoroborate or hexafluorophosphate, more preferably iodine salt, bistrifluoromethanesulfonimide salt or tetrafluoroborate salt, particularly preferably iodine salt. The addition amount of the alkali metal salt or the alkaline earth metal salt is preferably 0.1 to 1000 times mol, more preferably 1 to 500 times mol, and particularly preferably 10 to 100 times mol to the dye.

For the purpose of reducing agglomeration between dyes, a steroid compound having a carboxyl group (chenodeoxycholic acid or the like) having a surface active property and the following sulfonates may be added to the dye adsorbing solution. .

[0102]

[Chemical 20]

(C) Charge Transport Layer The charge transport layer is a layer containing a charge transport material having a function of replenishing the dye oxidant with electrons. The charge-transporting material used in the present invention may be (i) a charge-transporting material involving ions or (ii) a charge-transporting material involving carrier transfer in a solid. (i) As a charge transport material involving ions, a molten salt electrolyte composition containing a redox counter ion, a solution in which ions of the redox pair are dissolved (electrolyte), a solution of the redox pair in a gel of a polymer matrix Examples thereof include a so-called gel electrolyte composition and a solid electrolyte composition that have been impregnated, and (ii) examples of the charge transport material involved in carrier transfer in a solid include an electron transport material and a hole transport material. A plurality of these charge transport materials can be used in combination. In the present invention, it is preferable to use a molten salt electrolyte composition or an electrolytic solution for the charge transport layer.

(1) Molten Salt Electrolyte Composition A molten salt electrolyte is preferably used as a charge transport material from the viewpoint of achieving both photoelectric conversion efficiency and durability. The molten salt electrolyte is a liquid at room temperature, or an electrolyte having a low melting point, for example, WO95 / 18456, JP-A-8-259543,
Pyridinium salts, imidazolium salts, triazolium salts and the like described in Electrochemistry, Vol. 65, No. 11, page 923 (1997) and the like can be mentioned. The melting point of molten salt is 100 ℃
The following is preferable, and a liquid state at around room temperature is particularly preferable.

In the present invention, the following general formulas (Ya), (Yb) and
The molten salt represented by any of (Yc) can be preferably used.

[0106]

[Chemical 21]

Q _y1 in the general formula (Ya) represents an atomic group forming a 5- or 6-membered aromatic cation together with a nitrogen atom. Q
_y1 is preferably composed of an atom selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, oxygen atom and sulfur atom. The 5-membered ring formed by Q _y1 is an oxazole ring, a thiazole ring, an imidazole ring, a pyrazole ring, an isoxazole ring, a thiadiazole ring, an oxadiazole ring,
It is preferably a triazole ring, an indole ring or a pyrrole ring, more preferably an oxazole ring, a thiazole ring or an imidazole ring, particularly preferably an oxazole ring or an imidazole ring. The 6-membered ring formed by Q _y1 is a pyridine ring, a pyrimidine ring, a pyridazine ring,
A pyrazine ring or a triazine ring is preferable, and a pyridine ring is particularly preferable.

A _y1 in the general formula (Yb) represents a nitrogen atom or a phosphorus atom.

R _{y1 to} R in the general formulas (Ya), (Yb) and (Yc)
_y11 is independently a substituted or unsubstituted alkyl group (preferably having 1 to 24 carbon atoms, may be linear or branched, or may be cyclic, for example, a methyl group , Ethyl group, propyl group, isopropyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group,
t-octyl group, decyl group, dodecyl group, tetradecyl group, 2-hexyldecyl group, octadecyl group, cyclohexyl group, cyclopentyl group, etc., or a substituted or unsubstituted alkenyl group (preferably having 2 to 24 carbon atoms) ,
It may be linear or branched and represents, for example, a vinyl group or an allyl group. R _{y1 to} R _y11 each independently represent, more preferably, an alkyl group having 2 to 18 carbon atoms or an alkenyl group having 2 to 18 carbon atoms, and particularly preferably an alkyl group having 2 to 6 carbon atoms.

[0110] Two or more of the general formula (Yb) R _y2 ~R _y5 in is linked to each other may form a non-aromatic ring containing A _y1, R _y6 ~ in the general formula (Yc) Two or more of R _y11 may be linked to each other to form a ring.

The above Q _y1 and R _{y1 to} R _y11 may have a substituent. Preferred examples of this substituent include a halogen atom (F, Cl, Br, I, etc.), a cyano group, an alkoxy group (methoxy group, ethoxy group, methoxyethoxy group, methoxyethoxyethoxy group, etc.), aryloxy group (phenoxy group, etc.). Etc.), alkylthio group (methylthio group, ethylthio group, etc.), alkoxycarbonyl group (ethoxycarbonyl group, etc.), carbonic acid ester group (ethoxycarbonyloxy group, etc.), acyl group (acetyl group, propionyl group, benzoyl group, etc.), sulfonyl Group (methanesulfonyl group, benzenesulfonyl group, etc.), acyloxy group (acetoxy group, benzoyloxy group, etc.), sulfonyloxy group (methanesulfonyloxy group, toluenesulfonyloxy group, etc.), phosphonyl group (diethylphosphonyl group, etc.), Amido group (acetylamino group, benzoyl group Amino group, etc.), carbamoyl group (N, N-dimethylcarbamoyl group, etc.), alkyl group (methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, 2-carboxyethyl group, benzyl group, etc.) , Aryl groups (phenyl group, toluyl group, etc.), heterocyclic groups (pyridyl group, imidazolyl group,
Furanyl group etc.), alkenyl group (vinyl group, 1-propenyl group etc.), silyl group, silyloxy group and the like.

The molten salt represented by any of the general formulas (Ya), (Yb) and (Yc) may form a multimer via Q _y1 and R _{y 1 to} R _y11. .

In formulas (Ya), (Yb) and (Yc), X ⁻ represents an anion. Preferred examples of X ⁻ are halide ions (I ⁻ , Cl ⁻ , Br ^−, etc.), SCN ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ ,
_{(CF 3 SO 2) 2 N} -, (CF 3 CF 2 SO 2) 2 N -, CH 3 SO 3 -, CF 3 SO 3 -, CF 3
COO ⁻ , Ph ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , and the like. X ^- is I ^-,
More preferably, it is SCN ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ or BF ₄ ⁻ .

Specific examples of the molten salt preferably used in the present invention are shown below, but the present invention is not limited thereto.

[0115]

[Chemical 22]

[0116]

[Chemical 23]

[0117]

[Chemical 24]

[0118]

[Chemical 25]

[0119]

[Chemical 26]

[0120]

[Chemical 27]

The molten salt may be used alone or in combination of two or more kinds. In addition, other iodine salts such as LiI and LiB
Alkali metal salts such as F ₄ , CF ₃ COOLi, CF ₃ COONa, LiSCN and NaSCN can also be used together. The amount of the alkali metal salt added is preferably 0.02 to 2% by mass, more preferably 0.1 to 1% by mass, based on the entire composition.

The molten salt electrolyte is preferably in a molten state at room temperature, and it is preferable not to use a solvent in the composition containing the molten salt electrolyte. The solvent described below may be added, but the content of the molten salt is preferably 50% by mass or more, and particularly preferably 90% by mass or more, based on the entire composition.
Further, it is preferable that 50 mass% or more of the salt contained in the composition is an iodine salt.

Iodine is preferably added to the molten salt electrolyte composition, and in this case, the content of iodine is preferably 0.1 to 20% by mass, and 0.5 to 5% by mass based on the whole composition.
More preferably, it is mass%.

(2) Electrolyte Solution The electrolyte solution is preferably composed of an electrolyte, a solvent and additives. The electrolyte contains I ₂ and iodide (Li
Combinations of metal iodides such as I, NaI, KI, CsI, and CaI ₂ , quaternary ammonium compound iodine salts such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc., Br ₂ and bromide (LiBr, N
aBr, KBr, CsBr, CaBr _{2 and} other metal bromides, tetraalkylammonium bromide, pyridinium bromide and other quaternary ammonium compound bromine salts, etc.), as well as ferrocyanate-ferricyanate and ferrocene-ferricinium ions. And the like, sodium polysulfide, sulfur compounds such as alkylthiol-alkyldisulfide, viologen dyes, hydroquinone-quinone, and the like can be used. Among these, an electrolyte in which I ₂ and LiI or a quaternary ammonium compound iodine salt such as pyridinium iodide or imidazolium iodide is combined is preferable. You may mix and use the above-mentioned electrolyte.

The electrolyte concentration in the electrolytic solution is preferably 0.1 to 1
It is 0M, and more preferably 0.2 to 4M. When iodine is added to the electrolytic solution, the preferable addition concentration of iodine is 0.01 to 0.5M.

The solvent used in the electrolytic solution is a compound which has a low viscosity and improves the ion mobility, or a high dielectric constant and the effective carrier concentration, and which can exhibit excellent ionic conductivity. desirable. As such a solvent, ethylene carbonate, a carbonate compound such as propylene carbonate, a heterocyclic compound such as 3-methyl-2-oxazolidinone, dioxane, an ether compound such as diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether,
Chain ethers such as polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, ethylene glycol , Propylene glycol, polyethylene glycol, polypropylene glycol, polyhydric alcohols such as glycerin, acetonitrile, glutadinitrile, methoxyacetonitrile,
Examples thereof include nitrile compounds such as propionitrile and benzonitrile, aprotic polar substances such as dimethylsulfoxide and sulfolane, water and the like, and these can be mixed and used.

Also, J. Am. Ceram. Soc., 80 (12) 3157.
-3171 (1997) as described in tert-butylpyridine, 2-picoline, a basic compound such as 2,6-lutidine, the above compound (I) a molten salt electrolyte composition or electrolytic solution as described above. To the compound (I), more preferably to the compound (I). When the basic compound or compound (I) is added to the electrolytic solution, the preferred concentration range is 0.05 to 2M. When added to the molten salt electrolyte composition, the mass ratio of the basic compound or compound (I) to the entire composition is preferably 0.1 to 40 mass%, more preferably 1 to 20 mass%.
Is.

(3) Gel Electrolyte Composition In the present invention, the above-mentioned molten salt electrolyte composition or electrolytic solution is prepared by a technique such as addition of a polymer, addition of an oil gelling agent, polymerization containing polyfunctional monomers, and crosslinking reaction of a polymer. It can also be used by gelling (solidifying). When gelling by adding a polymer, use “Polymer Electrolyte Re
The compounds described in views-1 and 2 "(JR MacCallum and CA Vincent co-edited, ELSEVIER APPLIED SCIENCE) can be used, but polyacrylonitrile and polyvinylidene fluoride are particularly preferably used. Gels can be added by adding an oil gelling agent. In case of chemical conversion, Journal of Industrial Science (J. Chem. Soc. Japan, Ind. Chem. Sec.), 46, 779
(1943), J. Am. Chem. Soc., 111, 5542 (1989), J. Che.
m. Soc., Chem. Commun., 1993, 390, Angew. Chem. In
t. Ed. Engl., 35, 1949 (1996), Chem. Lett., 1996,
Although the compounds described in 885 and J. Chem. Soc., Chem. Commun., 1997, 545 can be used, preferred compounds are compounds having an amide structure in the molecular structure. An example of gelling an electrolytic solution is disclosed in JP-A-11-185863.
Examples of gelling the molten salt electrolyte are also described in JP-A-2000-58140, and these are also applicable to the present invention.

When the polymer is gelated by a crosslinking reaction, it is desirable to use a polymer having a crosslinkable reactive group and a crosslinking agent together. In this case, the preferred crosslinkable reactive group is an amino group, a nitrogen-containing heterocycle (pyridine ring, imidazole ring, thiazole ring, oxazole ring, triazole ring, morpholine ring, piperidine ring, piperazine ring, etc.) The agent is a bifunctional or higher functional reagent capable of undergoing an electrophilic reaction with respect to a nitrogen atom (halogenated alkyls, halogenated aralkyls, sulfonic acid esters, acid anhydrides, acid chlorides, isocyanate compounds, α, β-unsaturated compounds). Saturated sulfonyl compounds, α, β-unsaturated carbonyl compounds, α, β-unsaturated nitrile compounds, etc.), and the crosslinking techniques described in JP-A Nos. 2000-17076 and 2000-86724 can also be applied.

(4) Hole Transport Material In the present invention, a solid hole transport material which is organic or inorganic or a combination of both may be used in place of the ion conductive electrolyte such as molten salt.

(A) Organic Hole Transport Material As an organic hole transport material applicable to the present invention, J. Hag
en, et al., Synthetic Metal, 89, 215-220 (1997), N
ature, Vol.395, 8 Oct., p583-585 (1998) and WO97 / 10.
617, JP-A-59-194393, JP-A-5-234681, U.S. Pat.No. 4,923,774, JP-A-4-308688, U.S. Pat.No. 4,764,6
No. 25, JP-A No. 3-269084, JP-A No. 41-29271, JP-A No. 4-
175395, JP 4-264189, JP 4-290851, JP 4-364153, JP 5-25473, JP 5-239455,
JP-A-5-320634, JP-A-6-1972, JP-A7-138562
Aromatic amines shown in JP-A-7-252474, JP-A-11-144773 and the like, JP-A-11-149821, JP-A-11-14
The triphenylene derivatives described in 8067, JP-A-11-176489 and the like can be preferably used. Also, Adv.Ma
ter., 9, No.7, p557 (1997), Angew. Chem. Int. Ed.
Engl., 34, No.3, p303-307 (1995), JACS, Vol.120, N
o.4, p664-672 (1998), etc., oligothiophene compounds, K. Murakoshi, et al., Chem. Lett. p471.
(1997), polypyrrole, “Handbook of Organic
Conductive Molecules and Polymers, Vol. 1,2,3,4 ”
(NALWA, WILEY Publishing), polyacetylene and its derivatives, poly (p-phenylene) and its derivatives, poly (p-phenylenevinylene) and its derivatives, polythienylenevinylene and its derivatives, polythiophene and its derivatives. Conductive polymers such as polyaniline and its derivatives and polytoluidine and its derivatives can be preferably used.

For the hole transport material, Nature, Vol. 395, 8 Oc
t., p583-585 (1998) to add or oxidize compounds containing cation radicals such as tris (4-bromophenyl) aminium hexachloroantimonate to control dopant levels. A salt such as Li [(CF ₃ SO ₂ ) ₂ N] may be added in order to control the potential of the surface of the semiconductor layer (compensation of the space charge layer).

(B) Inorganic hole transport material A p-type inorganic compound semiconductor is used as the inorganic hole transport material.
Can be P-type inorganic compound semiconductor for this purpose
Preferably has a bandgap of 2 eV or more,
It is more preferably 2.5 eV or more. Also, p-type mineralization
The ionization potential of the compound semiconductor reduces the holes of the dye
From the conditions that can be achieved, the ionization potential of the dye adsorption electrode
It needs to be smaller. P depending on the dye used
Of ionization potential of type inorganic compound semiconductor
The range will be different, but generally 4.5eV or more and 5.5eV or less
It is preferable that it is 4.7 eV or more and 5.3 eV or less.
And are preferred. The preferred p-type inorganic compound semiconductor is monovalent
A compound semiconductor containing copper, which is a compound semiconductor containing monovalent copper
Examples of conductors are CuI, CuSCN, CuInSe₂, Cu (In, Ga) S
e ₂, CuGaSe₂, Cu₂O, CuS, CuGaS₂, CuInS₂, CuAlSe₂etc
Is mentioned. Among these, CuI and CuSCN are preferable, and Cu
I is the most preferred. Other p-type inorganic compound semiconductors
GaP, NiO, CoO, FeO, Bi₂O₃, MoO₂, Cr₂O₃Etc.
Can be

(5) Formation of Charge Transport Layer There are two methods for forming the charge transport layer. One is a method in which a counter electrode is attached to the photosensitive layer first, and a liquid charge transport layer is sandwiched in the gap. The other method is to apply the charge transport layer directly on the photosensitive layer, and the counter electrode will be applied thereafter.

In the case of the former method, as a method for sandwiching the charge transport layer, an atmospheric pressure process utilizing a capillary phenomenon due to dipping or the like, or a vacuum process in which the gas phase in the gap is replaced with a liquid phase by making the pressure lower than atmospheric pressure. Available.

In the case of the latter method, the counter electrode is provided in the wet charge transport layer in an undried state, and a measure for preventing liquid leakage at the edge portion is taken. In the case of a gel electrolyte, there is a method of applying it by a wet method and solidifying it by a method such as polymerization. In that case, a counter electrode can be provided after drying and fixing. As a method of applying the wet organic hole transporting material and the gel electrolyte in addition to the electrolytic solution, the same method as the method of applying the semiconductor fine particle layer and the dye can be used.

In the case of a solid electrolyte or a solid hole transport material, it is also possible to form a charge transport layer by a dry film forming process such as a vacuum vapor deposition method or a CVD method, and then apply a counter electrode. The organic hole transport material can be introduced into the electrode by a method such as a vacuum vapor deposition method, a casting method, a coating method, a spin coating method, a dipping method, an electrolytic polymerization method or a photoelectrolytic polymerization method. Also in the case of an inorganic solid compound, it can be introduced into the electrode by a method such as a casting method, a coating method, a spin coating method, a dipping method, an electrolytic deposition method and an electroless plating method.

(D) Counter Electrode The counter electrode may have a single-layer structure of a counter electrode conductive layer made of a conductive material, or may be composed of a counter electrode conductive layer and a supporting substrate, like the above-mentioned conductive support. As the conductive material used for the counter conductive layer, metals (platinum, gold, silver, copper, aluminum, magnesium, indium, etc.), carbon, and conductive metal oxides (indium-tin composite oxide, fluorine-doped tin oxide, etc.) Is mentioned. Among these, platinum, gold,
Silver, copper, aluminum and magnesium can be preferably used. The support substrate used for the counter electrode is preferably a glass substrate or a plastic substrate, and the conductive material is applied or vapor-deposited on the support substrate. Although the thickness of the counter conductive layer is not particularly limited, it is preferably 3 nm to 10 μm. The lower the surface resistance of the counter conductive layer, the better. The preferred surface resistance range is 50Ω / □ or less, more preferably 20Ω / □.
/ □ or less.

Since light may be irradiated from either or both of the conductive support and the counter electrode, in order for the light to reach the photosensitive layer, at least one of the conductive support and the counter electrode is substantially transparent. I wish I had it. From the viewpoint of improving power generation efficiency, it is preferable to make the conductive support transparent and allow light to enter from the side of the conductive support. In this case, the counter electrode preferably has a property of reflecting light. As such a counter electrode, glass or plastic deposited with a metal or a conductive oxide,
Alternatively, a thin metal film can be used.

For the counter electrode, a conductive agent is applied directly on the charge transport layer,
It may be plated or vapor-deposited (PVD, CVD), or attached to the conductive layer side of a substrate having a conductive layer. Further, as in the case of the conductive support, it is preferable to use a metal lead for the purpose of reducing the resistance of the counter electrode, especially when the counter electrode is transparent. The preferable material and installation method of the metal lead, the decrease in the amount of incident light due to the installation of the metal lead, and the like are the same as in the case of the conductive support.

(E) Other layers In order to prevent a short circuit between the counter electrode and the conductive support, a dense thin film layer of a semiconductor is previously coated as an undercoat layer between the conductive support and the photosensitive layer. It is preferable. The method of preventing a short circuit by this undercoat layer is particularly effective when an electron transport material or a hole transport material is used for the charge transport layer. The subbing layer is preferably TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , ZnO or Nb ₂
It consists of O ₅ , and more preferably TiO ₂ . The undercoat layer can be applied by, for example, a spray pyrolysis method described in Electrochim. Acta, 40, 643-652 (1995), a sputtering method, or the like. The thickness of the undercoat layer is preferably 5 to 1000 nm, more preferably 10 to 500 nm.

Further, a functional layer such as a protective layer or an antireflection layer may be provided on the outer surface of one or both of the counter electrode and the conductive support acting as an electrode, or between the conductive layer and the substrate or between the substrates. Good. For forming these functional layers, a coating method, a vapor deposition method, a sticking method or the like can be used depending on the material.

(F) Specific Example of Internal Structure of Photoelectric Conversion Element As described above, the internal structure of the photoelectric conversion element can be variously formed according to the purpose. If roughly divided into two, it is possible to have a structure in which light can enter from both sides and a structure in which light can enter from only one side. 2 to 9 exemplify the internal structure of the photoelectric conversion element which is preferably applicable to the present invention.

In the structure shown in FIG. 2, the photosensitive layer 20 and the charge transport layer 30 are interposed between the transparent conductive layer 10a and the transparent counter electrode conductive layer 40a, and light is incident from both sides. Has become. In the structure shown in FIG. 3, the metal substrate 11 is partially provided on the transparent substrate 50a, the transparent conductive layer 10a is provided thereon, and the undercoat layer 60, the photosensitive layer 20, the charge transport layer 30, and the counter electrode conductive layer 40 are arranged in this order. And the support substrate 50 is further arranged,
The structure is such that light enters from the conductive layer side. The structure shown in FIG. 4 has a conductive layer 10 on a supporting substrate 50 and an undercoat layer 60.
The photosensitive layer 20 is provided via the above, the charge transport layer 30 and the transparent counter electrode conductive layer 40a are further provided, and the transparent substrate 50a partially provided with the metal lead 11 is arranged with the metal lead 11 side inside. The structure in which light is incident from the counter electrode side. In the structure shown in FIG. 5, a metal lead 11 is partially provided on a transparent substrate 50a, and a transparent conductive layer 10a (or 40a) is further provided between a set of an undercoat layer 60, a photosensitive layer 20, and a charge transport layer 30. Is a structure in which light is incident from both sides. The structure shown in FIG. 6 includes a transparent conductive layer 10a, an undercoat layer 60, and a transparent conductive layer 10a on a transparent substrate 50a.
The photosensitive layer 20, the charge transport layer 30, and the counter electrode conductive layer 40 are provided, and the support substrate 50 is disposed on the photosensitive layer 20, and the light is incident from the conductive layer side. The structure shown in FIG. 7 has a supporting substrate 50.
Having the conductive layer 10 on the top, the photosensitive layer 20 is provided via the undercoat layer 60, further the charge transport layer 30 and the transparent counter electrode conductive layer 40a are provided,
The transparent substrate 50a is arranged on this, and the structure is such that light enters from the counter electrode side. In the structure shown in FIG. 8, the transparent conductive layer 10a is provided on the transparent substrate 50a, the photosensitive layer 20 is provided via the undercoat layer 60, and the charge transport layer 30 and the transparent counter conductive layer 40 are further provided.
a is provided, and the transparent substrate 50a is arranged on this,
The structure is such that light enters from both sides. In the structure shown in FIG. 9, the conductive layer 10 is provided on the support substrate 50, the photosensitive layer 20 is provided via the undercoat layer 60, and the solid charge transport layer 30 is further provided.
A part of the counter electrode conductive layer 40 or the metal lead 11 is provided on this, and the structure is such that light enters from the counter electrode side.

[V] Photocell The photocell of the present invention is one in which the photoelectric conversion element of the present invention is caused to work by an external load. Of the photovoltaic cells, the case where the charge transport material mainly consists of the ion transport material is called a photoelectrochemical cell, and the case where the main purpose is power generation by sunlight is called a solar cell.

The side surface of the photovoltaic cell is preferably sealed with a polymer, an adhesive or the like in order to prevent deterioration of the constituents and volatilization of the contents. The external circuit itself, which is connected to the conductive support and the counter electrode via the lead, may be a known one.

When the photoelectric conversion element of the present invention is applied to a solar cell, the internal structure of the cell is basically the same as that of the photoelectric conversion element described above. Further, the dye-sensitized solar cell using the photoelectric conversion element of the present invention can basically have the same module structure as the conventional solar cell module. In the solar cell module, cells are generally formed on a supporting substrate such as metal or ceramic, and the structure is covered with a filling resin or protective glass to take in light from the opposite side of the supporting substrate. It is also possible to use a transparent material such as tempered glass for the supporting substrate and construct a cell on the transparent material to take in light from the transparent supporting substrate side. Specifically, a module structure called super straight type, substrate type, potting type,
A substrate-integrated module structure used in an amorphous silicon solar cell or the like is known, and a dye-sensitized solar cell using the photoelectric conversion element of the present invention is also selected as appropriate depending on the purpose of use, place of use and environment. it can. Specifically, the structures and aspects described in Japanese Patent Application No. 11-8457 and Japanese Patent Application Laid-Open No. 2000-268892 are preferable.

[0148]

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

Synthesis Example 1 Synthesis of Compound Ib-1 A solution consisting of 3.8 g of 3-aminopyridine, 5.7 ml of triethylamine and 50 ml of acetonitrile was added to a solution of 6.8 ml of trifluoromethanesulfonic anhydride and 50 m under a nitrogen atmosphere.
A solution consisting of 1 methylene chloride was slowly added dropwise at -50 ° C. The obtained reaction liquid was stirred as it was for 1 hour, the temperature was raised to room temperature, and further stirred for 1 hour. The filtrate obtained by filtering this was concentrated, and the residue was purified by silica gel column chromatography to obtain 6.4 g of 3-trifluoromethanesulfonamide pyridine. 0.4 g of 3-trifluoromethanesulfonamide pyridine was dissolved in an aqueous solution of 1.2 g of sodium hydroxide and 80 ml of water, and to this was added an aqueous solution of 4.6 g of silver nitrate and 20 ml of water. The reaction solution was stirred at 40 ° C. for 2 hours, and then the precipitate formed in the reaction solution was filtered and washed with acetonitrile. The washed precipitate was added to 50 ml of acetonitrile, to which was added an aqueous solution consisting of 2.7 g of 1-ethyl-3-methylimidazolium bromide and 50 ml of water. The resulting mixture is 2 at 40 ° C.
After stirring for hours, the precipitated silver bromide was removed by filtration,
Then, the filtrate was concentrated, the residue was purified by silica gel column chromatography, and dried by a vacuum pump to obtain 3.0 g of compound Ib-1. The obtained compound Ib-1 was a low viscosity liquid at room temperature. The structure of compound Ib-1 is ¹ H-NMR and MASS.
Confirmed by spectrum. The ¹ H-NMR peak shift value of compound Ib-1 is shown below. ¹ H-NMR (δ value, heavy dimethyl sulfoxide): 9.33 (s,
1H), 8.28 (s, 1H), 8.08 (d, 1H), 7.51 (d, 1H), 7.
31 (s, 1H), 7.30 (s, 1H), 7.07 (dd, 1H), 4.09 (q,
2H), 3.89 (s, 3H), 1.49 (t, 3H).

Example 1 1. Preparation of Titanium Dioxide Particle Coating Solution Same as the method described in Barbe et al., Journal of American Ceramic Society, Volume 80, page 3157, except that the autoclave temperature was 230 ° C. By the method described above, a titanium dioxide particle dispersion having a titanium dioxide concentration of 11 mass% was obtained. The average size of the titanium dioxide particles in this dispersion was about 10 nm. 20 to titanium dioxide in this dispersion
Mass% polyethylene glycol (molecular weight 20000, Wako Pure Chemical Industries, Ltd.) was added and mixed to obtain a titanium dioxide particle coating solution.

2. Preparation of dye-adsorbing titanium dioxide electrode (1) Preparation of dye-adsorbing electrode Transparent conductive glass coated with fluorine-doped tin oxide (manufactured by Nippon Sheet Glass, surface resistance: about 10 Ω / cm ² ).
After applying the titanium dioxide particle coating solution to the conductive surface side of the above with a doctor blade to a thickness of 120 μm and drying at 25 ° C for 30 minutes, use an electric furnace ("Muffle furnace FP-32 type" manufactured by Yamato Scientific Co., Ltd.) It was baked at 450 ° C. for 30 minutes and cooled to form a titanium dioxide layer to obtain a titanium dioxide electrode. The amount of titanium dioxide applied per unit area of the transparent conductive glass was 18 g / m ² , and the film thickness of the titanium dioxide layer was 12 μm. The obtained titanium dioxide electrode was applied to the ruthenium complex dye R-1 (cis- (dithiocyanate) -N, N'-bis (2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium (II) complex. Was immersed in a dye-adsorbing solution containing) for 16 hours at 25 ° C., and sequentially washed with ethanol and acetonitrile to prepare a dye-adsorbing electrode T-1. The dye adsorbing liquid is the ruthenium complex dye R-1.
And a mixed solvent of ethanol and acetonitrile (ethanol: acetonitrile = 1: 1 (volume ratio)), and the concentration of the ruthenium complex dye R-1 in the dye adsorption liquid is 3 × 10 ^−4.
Mol / liter. In addition, the dye adsorbing electrode T-2 was prepared in the same manner as the dye adsorbing electrode T-1 except that lithium iodide was added to the dye adsorbing liquid to a concentration of 1 × 10 ^-2 mol / liter. It was made. Further, a dye adsorption electrode T-3 was prepared in the same manner as the dye adsorption electrode T-1 except that the ruthenium complex dye R-10 was used in place of the ruthenium complex dye R-1.

(2) Preparation of Treatment Electrodes Any of the above dye adsorption electrodes T-1 to T-3 was immersed in any of the treatment liquids A-1 to A-5 shown in Table 1 below at 40 ° C. for 1.5 hours. Then
After washing with acetonitrile, it was dried in a dark place under a nitrogen stream to prepare treated electrodes TA-1 to TA-11. Table 1 shows compound (I), compound (II) and additives contained in each treatment liquid.
Shown in. The concentrations of compound (I), compound (II) and additives in each treatment liquid were 0.01 mol / liter, and acetonitrile was used as a solvent for the treatment liquid. Table 1 also shows the pKa values of the compound (I) and t-butylpyridine used.

[0153]

[Table 1]

3. Preparation of photoelectric conversion element (1) Photoelectric conversion element using electrolytic solution Dye-adsorbing titanium oxide electrode T-1 (2 cm ×) obtained as described above
2 cm) was overlaid with platinum vapor-deposited glass of the same size. Next, an electrolyte solution (1,3-dimethylimidazolium iodide (0.65mol /
l) and iodine (0.05 mol / l) in acetonitrile) were soaked and introduced into a titanium oxide electrode to obtain a photoelectric conversion element CS-1 for comparison. As shown in FIG. 10, this photoelectric conversion element comprises a conductive glass 1 (glass 2 on which a conductive layer 3 is provided), a dye-adsorbed titanium dioxide layer 4, a charge transport layer 5, a platinum layer 6 and a glass. 7 has a structure in which layers are sequentially stacked. Further, the photoelectric conversion elements CS-2 to CS-6 for comparison and the photoelectric conversion element of the present invention were prepared by the same method as in the production of the photoelectric conversion element CS-1 except that the electrodes were changed to those shown in Table 2 below. CS
-7 to CS-14 were prepared respectively.

(2) Photoelectric conversion element using molten salt electrolyte composition A 25 μm thick thermoplastic resin (1.5 cm) having a round hole with a diameter of 1 cm on the titanium dioxide layer (2 cm × 2 cm) of the electrode T-1. ×
(1.5 cm) was placed and pressure-bonded at 100 ° C. for 20 seconds. Then, in the hole of this thermoplastic resin, 2: 1 of 1-methyl-3-propylimidazolium iodide (Y6-8) and 1-ethyl-3-methylimidazolium tetrafluoroborate (Y6-2).
(Mass ratio) 10 μl of a molten salt electrolyte composition prepared by dissolving ₂ % by mass of iodine I ₂ in a mixed solution was poured, and the molten salt electrolyte composition was allowed to stand for 12 hours at 50 ° C. Soaked in the titanium electrode. Subsequently, platinum vapor-deposited glass (2 cm x 3 cm) was placed on this electrode, and the excess molten salt electrolyte composition that had squeezed out was wiped off.
A second photoelectric conversion element CM-1 for comparison was produced by pressure bonding for seconds.
All of these operations were performed in a dry room with a dew point of -50 ° C or lower. As shown in FIG. 10, the photoelectric conversion element includes a conductive glass 1 (a glass 2 on which a conductive layer 3 is provided), a dye-adsorbed titanium dioxide layer 4, a charge transport layer 5,
It has a structure in which a platinum layer 6 and a glass 7 are sequentially stacked.
Further, the photoelectric conversion elements CM-2 to CM-6 for comparison and the photoelectric conversion element of the present invention were prepared by the same method as in the production of the photoelectric conversion element CM-1 except that the electrodes were changed to those shown in Table 3 below. CM-7 ~
Each CM-14 was produced.

4. Measurement of photoelectric conversion efficiency Simulated sunlight was generated by passing light of a 500 W xenon lamp (manufactured by USHIO) through a spectral filter ("AM1.5" manufactured by Oriel). The intensity of this simulated sunlight is vertical
It was 100 mW / cm ² . Each photoelectric conversion element CS-1 to CS-14 and CM
-1 to CM-14 were coated with silver paste on the ends of the conductive glass to form a negative electrode, and the negative electrode and platinum vapor-deposited glass (positive electrode) were connected to a current-voltage measuring device (Keithley SMU238 type). The photoelectric conversion efficiency was obtained by measuring the current-voltage characteristics while irradiating each photoelectric conversion element vertically with simulated sunlight. Tables 2 and 3 show the conversion efficiency of each photoelectric conversion element.

[0157]

[Table 2]

[0158]

[Table 3]

From Tables 2 and 3, the semiconductor fine particles were compounded.
Comparative photoelectric conversion elements CS-1 to CS-6 not processed by (I)
And, compared with CM-1 ~ CM-6, the photoelectric conversion elements CS-7 ~ CS-14 and CM-7 ~ CM-14 of the present invention treated with the compound (I), the type of the dye adsorbed or. It can be seen that the conversion efficiency is high regardless of the type of charge transport material. It is also found that the conversion efficiency is further improved by treating the semiconductor fine particles with the compound (I) and the compound (II).

Example 2 As shown in Table 4 below, a photoelectric conversion element for comparison was prepared in the same manner as in Example 1 except that a merocyanine dye M-3 or a squarylium dye M-1 was used instead of the ruthenium complex dye.
CO-1, CO-2, CO-4 and CO-5, and photoelectric conversion elements CO-3 and CO-6 of the present invention were produced. The molten salt electrolyte composition was used as the charge transport material. The concentration of each dye in the dye adsorbing liquid was 1 × 10 ^-4 mol / l. When the conversion efficiency of each photoelectric conversion element was measured in the same manner as in Example 1 above, as shown in Table 4, the photoelectric conversion elements CO-3 and CO-6 of the present invention in which the semiconductor fine particles were treated with the compound (I) were shown. Showed excellent conversion efficiency.

[0161]

[Table 4]

[0162]

As described in detail above, by treating the semiconductor fine particles with the compound (I), a dye-sensitized photoelectric conversion element having a higher conversion efficiency than before can be obtained. Further, the conversion efficiency can be further improved by treating the semiconductor fine particles with the compound (I) and the compound (II).

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a structure of a preferable photoelectric conversion element of the present invention.

FIG. 2 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 3 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 4 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 5 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 6 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 7 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 8 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 9 is a partial cross-sectional view showing the structure of a preferable photoelectric conversion element of the present invention.

FIG. 10 is a partial cross-sectional view showing a structure of a photoelectric conversion element manufactured in an example.

[Explanation of symbols]

10 ... Conductive layer 10a ... Transparent conductive layer 11 ... Metal leads 20 ... Photosensitive layer 21 ... Semiconductor fine particles 22 ... Dye 23 ... Charge transport material 30 ... Charge transport layer 40 ... Counter electrode conductive layer 40a: Transparent counter electrode conductive layer 50 ... Substrate 50a ... Transparent substrate 60 ... Undercoat layer 1 ... Conductive glass 2 ... glass 3 ... Conductive layer 4 ... Dye adsorption titanium dioxide layer 5 ... Charge transport layer 6 ... Platinum layer 7 ... glass

Claims (10)

[Claims] 1. A method for producing a photoelectric conversion element having a layer of semiconductor fine particles having a dye adsorbed thereon and a conductive support,
A method for producing a photoelectric conversion element, which comprises treating the semiconductor fine particles with a compound represented by the following general formula (I). (A ₁ -L) _{n 1} -A ₂ · M (I) In the general formula (I), A ₁ represents a group having a negative charge, A ₂ represents a basic group, and M represents (A ₁ -L) represents a cation to neutralize the negative charge of _n1 -A _2, L represents a divalent linking group or a single bond, n1 represents an integer of 1 to 3. 2. The method for producing a photoelectric conversion element according to claim 1, wherein the A ₁ has N ⁻ . 3. The method for producing a photoelectric conversion element according to claim 1 or 2, wherein A ₂ is a pyridyl group. 4. The method for producing a photoelectric conversion element according to claim 1, wherein the semiconductor fine particles are represented by the compound represented by the general formula (I) and the general formula (II) below. A method for producing a photoelectric conversion element, which comprises treating with a compound. [Chemical 1] In the general formula (II), X represents an oxygen atom, a sulfur atom, a selenium atom or NR ³ , R ¹ and R ² are each independently a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group, -OR ⁴ , -N (R
^{5) (R 6), -} C (= O) R 7, -C (= S) represents R ⁸ or SO ₂ R ^9, Y is a hydrogen atom, an aliphatic hydrocarbon group, an aryl group, a heterocyclic group, -O
Represents R ⁴ , -N (R ⁵ ) (R ⁶ ) or -SR ¹⁰ . R ³ represents a hydrogen atom, an aliphatic hydrocarbon group, a hydroxy group or an alkoxy group, R ⁴ represents a hydrogen atom or an aliphatic hydrocarbon group, R ⁵
And R ⁶ have the same meaning as R ¹ and R ² , R ⁷ , R ⁸ and R ⁹ have the same meaning as Y, and R ¹⁰ has the same meaning as R ⁴ . 5. The method for producing a photoelectric conversion element according to claim 4, wherein X represents an oxygen atom and Y represents —N (R ⁵ ) (R
⁶ ) A method for producing a photoelectric conversion element, characterized in that 6. The method for producing a photoelectric conversion element according to claim 4 or 5, wherein the compound represented by the general formula (II) is
A method for producing a photoelectric conversion element, which has a substituent represented by -Si (R ¹¹ ) (R ¹² ) (R ¹³ ). However, R ¹¹ , R ¹² and R ¹³ each independently represent a hydroxy group, an alkyloxy group, an isocyanate group, a halogen atom or an aliphatic hydrocarbon group, and at least one of R ¹¹ , R ¹² and R ¹³ is alkyl. It is an oxy group, an isocyanate group or a halogen atom. 7. The method for producing a photoelectric conversion element according to claim 1, wherein after adsorbing the dye on the semiconductor fine particles, a compound represented by the general formula (I) and / or A method for producing a photoelectric conversion element, which comprises treating with a compound represented by the general formula (II). 8. The method for producing a photoelectric conversion element according to claim 1, wherein the dye is a ruthenium complex dye. 9. A photoelectric conversion element manufactured by the method according to claim 1. 10. A photovoltaic cell comprising the photoelectric conversion element according to claim 9.