JP6412774B2 - Photoelectric conversion element, solar cell, and method of manufacturing photoelectric conversion element - Google Patents

Description

  The present invention relates to a photoelectric conversion element, a solar cell, and a method for manufacturing a photoelectric conversion element.

  Photoelectric conversion elements are used in various optical sensors, copying machines, solar cells, and the like. Solar cells are expected to be put into full-scale practical use as non-depleting solar energy. Among these, a dye-sensitized solar cell using an organic dye or a Ru bipyridyl complex as a sensitizer has been actively researched and developed, and the photoelectric conversion efficiency has reached about 11%.

On the other hand, recently, research results have been reported that solar cells using metal halides as compounds having a perovskite crystal structure can achieve relatively high photoelectric conversion efficiency, and are attracting attention.
For example, Patent Document 1 describes a photovoltaic device having a perovskite crystal structure including a first cation, a second cation, and at least one halide anion or chalcogenide anion. According to Patent Document 1, the first cation is represented by the formula: (R ₁ R ₂ R ₃ R ₄ N) ⁺ or the formula: (R ₅ R ₆ N═CH—R ₇ R ₈ ) ^+. It is an organic cation, and R _{1 to} R ₈ are each considered to be a hydrogen atom, a substituted or unsubstituted C _{1 to} C ₂₀ alkyl group, or a substituted or unsubstituted aryl group. Item 28 and 29).

International Publication No. 2014/045021 Pamphlet

  As described above, a photoelectric conversion element or a solar cell using a compound having a perovskite crystal structure (hereinafter also referred to as “perovskite compound”) has achieved certain results in improving photoelectric conversion efficiency. However, this photoelectric conversion element or solar cell has attracted attention in recent years, and little is known about battery performance other than photoelectric conversion efficiency.

In addition to high photoelectric conversion efficiency, the photoelectric conversion element and the solar cell are required to have durability capable of maintaining initial performance in the field environment where they are actually used.
However, it is known that perovskite compounds are susceptible to damage in a high humidity environment. In fact, photoelectric conversion elements or solar cells using a perovskite compound as a light absorber have a reduced photoelectric conversion efficiency in a high humidity environment.
An object of the present invention is to provide a photoelectric conversion element using a perovskite compound as a light absorber and having excellent moisture resistance, and a solar cell using the photoelectric conversion element. Another object of the present invention is to provide a method for producing a photoelectric conversion element using a perovskite compound as a light absorber and capable of obtaining a photoelectric conversion element having excellent moisture resistance.

  In the production of a photoelectric conversion element or a solar cell using a perovskite compound, the inventors of the present invention provide a photosensitive layer containing a perovskite compound as a light absorber so that the contact angle of water with respect to the surface of the photosensitive layer is within a specific range. It has been found that a photoelectric conversion element or a solar cell can be obtained by forming such that the photoelectric conversion efficiency is hardly lowered even in a high humidity environment. The present invention has been further studied based on these findings and has been completed.

That is, the above-described problems of the present invention have been solved by the following means.
[1]
A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The photosensitive layer surface, the contact angle of water, Ri 70 ° to 150 DEG ° der at 25 ° C.,
The cationic organic group A is Ru cationic organic groups der represented by the following formula (1), the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, and at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom , and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
[2 ]
A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The surface of the photosensitive layer has a water contact angle of 70 ° to 150 ° at 25 ° C.,
The cation of the cationic organic group A consists of an organic cation I of a cationic organic group represented by the following formula (1) and an organic cation II of a cationic organic group represented by the following formula (2).
In the entire perovskite type crystal structure present in the photosensitive layer, the content of the organic cation I and the content of the organic cation II are in a molar ratio: [content of organic cation I]: [content of organic cation II] ] = 99: 1 to 20: 80 meet, the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom , and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
Equation ⁽²⁾ R 2a -NH ₃
In the formula, R ^2a is an unsubstituted hydrocarbon group having 20 or less carbon atoms.
[ 3 ]
The photoelectric conversion element according to [ 2 ], wherein the carbon number of R ^2a is 1 or 2 .
[4 ]
A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The surface of the photosensitive layer has a water contact angle of 70 ° to 150 ° at 25 ° C.,
The photoelectric conversion element whose said cationic organic group A is a cationic organic group represented by following formula (1).
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, and at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.2 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
[ 5 ]
The photoelectric conversion element according to any one of [1] to [4] , wherein R ^1a has at least one trifluoromethyl group.
[ 6 ]
The photoelectric conversion element according to any one of [1] to [5] , wherein the photosensitive layer surface has a water contact angle of 85 ° to 120 ° at 25 ° C.
[ 7 ]
The photoelectric conversion element according to any one of [1] to [6] , which has a hole transport layer between the first electrode and the second electrode.
[ 8 ]
[1] A solar cell using the photoelectric conversion element according to any one of [7] .
[ 9 ]
A method for producing a photoelectric conversion element comprising a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The manufacturing method applies a solution containing MX ₂ , AX, and a solvent on the conductive support, and dries, so that the contact angle of water is 70 ° C. at 25 ° C. on the conductive support. Forming a photosensitive layer having a surface that is between 0 ° and 150 °,
The manufacturing method of the photoelectric conversion element whose said cationic organic group A is a cationic organic group represented by following formula (1).
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.2 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
[ 10 ]
A method for producing a photoelectric conversion element comprising a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The manufacturing method applies a solution containing MX ₂ , AX, and a solvent on the conductive support, and dries, so that the contact angle of water is 70 ° C. at 25 ° C. on the conductive support. Forming a photosensitive layer having a surface that is between 0 ° and 150 °,
The cation of the cationic organic group A consists of an organic cation I of a cationic organic group represented by the following formula (1) and an organic cation II of a cationic organic group represented by the following formula (2). In the entire perovskite type crystal structure present in the photosensitive layer, the content of the organic cation I and the content of the organic cation II are in a molar ratio: [content of organic cation I]: [content of organic cation II] ] = 99: 1-20: 80 satisfy | fills the manufacturing method of the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
Equation ⁽²⁾ R 2a -NH ₃
In the formula, R ^2a is an unsubstituted hydrocarbon group having 20 or less carbon atoms.
[ 11 ]
The method for producing a photoelectric conversion element according to [10] , wherein R ^2a has 1 or 2 carbon atoms.
[ 12 ]
Step of forming the photosensitive layer, the contact angle of water is a step of forming a photosensitive layer having a surface which is 85 ° to 120 ° at 25 ° C., to any one of [9] - [11] The manufacturing method of the photoelectric conversion element of description.
[ 13 ]
Said R ^1a has at least 1 trifluoromethyl group, The manufacturing method of the photoelectric conversion element as described in any one of [9]-[12] .
[ 14 ]
In a solution containing the above MX ₂ and AX and solvent, the solvent is composed of two or more solvents, among the two or more solvents, the most high-boiling solvent solvent polarity parameter E _T, most boiling less than solvent polarity parameter E _T other than high solvent solvent, a method of producing a photoelectric conversion element according to any one of [9] to [13].
[ 15 ]
The method for producing a photoelectric conversion element according to any one of [9] to [14] , wherein the photoelectric conversion element has a hole transport layer between the first electrode and the second electrode.

  In the present specification, a part of each chemical formula may be expressed as a formula for understanding the chemical structure of the perovskite compound. Accordingly, in each chemical formula, the partial structure is referred to as a (substituted) group, ion, atom, or the like. In this specification, these are represented by the above formula in addition to the (substituted) group, ion, atom, or the like. It may mean an element group or an element constituting a (substituent) group or ion.

  In this specification, the notation of a compound is used in the meaning including the compound itself, its salt, and its ion. Furthermore, a group or compound that does not clearly indicate substitution or non-substitution is meant to include a group or compound having an arbitrary substituent as long as a desired effect is obtained.

  In this specification, when there are a plurality of substituents and the like indicated by a specific symbol, or when a plurality of substituents and the like are specified at the same time, the respective substituents are the same as or different from each other unless otherwise specified. May be. The same applies to the definition of the number of substituents and the like. In addition, a ring such as an alicyclic ring, an aromatic ring, or a heterocyclic ring may be further condensed to form a condensed ring.

  Further, in this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  The photoelectric conversion element and solar cell of the present invention are excellent in moisture resistance while using a perovskite compound as a light absorber. Moreover, according to the manufacturing method of the photoelectric conversion element of this invention, the photoelectric conversion element excellent in moisture resistance can be obtained, using the perovskite compound as a light absorber.

It is sectional drawing which showed typically about the preferable aspect of the photoelectric conversion element of this invention. It is sectional drawing which showed typically about the preferable aspect which has a thick photosensitive layer of the photoelectric conversion element of this invention. It is sectional drawing shown typically about another preferable aspect of the photoelectric conversion element of this invention. It is sectional drawing which showed typically about another preferable aspect of the photoelectric conversion element of this invention. It is sectional drawing which showed typically about another preferable aspect of the photoelectric conversion element of this invention.

<< Photoelectric conversion element >>
The photoelectric conversion element of the present invention has a first electrode having a conductive support, a photosensitive layer containing a light absorber, and a second electrode facing the first electrode, preferably the first electrode, A hole transport layer provided between the second electrodes; The photosensitive layer and the second electrode are provided on the conductive support in this order. Moreover, when a photoelectric conversion element has a positive hole transport layer, the photosensitive layer, the positive hole transport layer, and the 2nd electrode are provided on the electroconductive support body in this order.
The light absorber contains at least one perovskite compound described later. The light absorber may contain a light absorber other than the perovskite compound in combination with the perovskite compound. Examples of the light absorber other than the perovskite compound include metal complex dyes and organic dyes.

  In the present invention, “having a photosensitive layer on a conductive support” means an embodiment having a photosensitive layer in contact with the surface of the conductive support, and another layer above the surface of the conductive support. It is meant to include embodiments having a photosensitive layer.

In an embodiment having a photosensitive layer through another layer above the surface of the conductive support, examples of other layers provided between the conductive support and the photosensitive layer include a porous layer, a blocking layer, and an electron. Examples include a transport layer and a hole transport layer.
In the present invention, for example, the photosensitive layer is provided in the form of a thin film on the surface of the porous layer (see FIG. 1). ), An embodiment provided thick on the surface of the porous layer (see FIG. 2), an embodiment provided thin on the surface of the blocking layer, and an embodiment provided in a thick film on the surface of the blocking layer (see FIG. 3), electron transport Examples include a mode in which a thin or thick film (see FIG. 4) is provided on the surface of the layer, and a mode in which a thin or thick film (see FIG. 5) is provided on the surface of the hole transport layer. The photosensitive layer may be provided in a linear or dispersed form, but is preferably provided in a film form.

  The photoelectric conversion element of the present invention is not particularly limited in structure other than the structure defined in the present invention, and a known structure relating to the photoelectric conversion element and the solar cell can be adopted. Each layer constituting the photoelectric conversion element of the present invention is designed according to the purpose, and may be formed in a single layer or multiple layers, for example.

Hereinafter, the preferable aspect of the photoelectric conversion element of this invention is demonstrated.
1 to 5, the same reference numerals mean the same components (members).
1 and 2 show the size of the fine particles forming the porous layer 12 with emphasis. These fine particles are preferably clogged (deposited or adhered) in the horizontal and vertical directions with respect to the conductive support 11 to form a porous structure.

  In this specification, the term “photoelectric conversion element 10” means the photoelectric conversion elements 10A, 10B, 10C, 10D, and 10E unless otherwise specified. The same applies to the system 100 and the first electrode 1. Further, the term “photosensitive layer 13” means the photosensitive layers 13A, 13B and 13C unless otherwise specified. Similarly, the term “hole transport layer 3” means the hole transport layers 3A and 3B unless otherwise specified.

As a preferable aspect of the photoelectric conversion element of the present invention, for example, a photoelectric conversion element 10A shown in FIG. A system 100A shown in FIG. 1 is a system applied to a battery for causing an operation circuit M (for example, an electric motor) to perform work by the external circuit 6 using the photoelectric conversion element 10A.
This photoelectric conversion element 10A has a first electrode 1A, a second electrode 2, and a hole transport layer 3A containing a hole transport material described later between the first electrode 1A and the second electrode 2. Yes.
The first electrode 1A has a conductive support 11 composed of a support 11a and a transparent electrode 11b, a porous layer 12, and a photosensitive layer 13A on the porous layer 12. Further, the blocking layer 14 is provided on the transparent electrode 11 b, and the porous layer 12 is formed on the blocking layer 14. Thus, it is estimated that the photoelectric conversion element 10A having the porous layer 12 improves the charge separation and charge transfer efficiency because the surface area of the photosensitive layer 13A is increased.

  The photoelectric conversion element 10B shown in FIG. 2 schematically shows a preferred embodiment in which the photosensitive layer 13A of the photoelectric conversion element 10A shown in FIG. In the photoelectric conversion element 10B, the hole transport layer 3B is thinly provided. The photoelectric conversion element 10B differs from the photoelectric conversion element 10A shown in FIG. 1 in the film thicknesses of the photosensitive layer 13B and the hole transport layer 3B, but is configured in the same manner as the photoelectric conversion element 10A except for these points. ing.

  A photoelectric conversion element 10 </ b> C shown in FIG. 3 schematically shows another preferred embodiment of the photoelectric conversion element of the present invention. The photoelectric conversion element 10C is different from the photoelectric conversion element 10B illustrated in FIG. 2 in that the porous layer 12 is not provided, but is configured in the same manner as the photoelectric conversion element 10B except for this point. That is, in the photoelectric conversion element 10 </ b> C, the photosensitive layer 13 </ b> C is formed in a thick film shape on the surface of the blocking layer 14.

  The photoelectric conversion element 10D shown in FIG. 4 schematically shows another preferred embodiment of the photoelectric conversion element of the present invention. This photoelectric conversion element 10D is different from the photoelectric conversion element 10C shown in FIG. 3 in that an electron transport layer 15 is provided instead of the blocking layer 14, but is otherwise configured in the same manner as the photoelectric conversion element 10C. Yes. The first electrode 1 </ b> D includes a conductive support 11 and an electron transport layer 15 and a photosensitive layer 13 </ b> C that are sequentially formed on the conductive support 11. This photoelectric conversion element 10D is preferable in that each layer can be formed of an organic material. As a result, the productivity of the photoelectric conversion element is improved, and it is possible to make it thinner or flexible.

The photoelectric conversion element 10E shown in FIG. 5 schematically shows still another preferred embodiment of the photoelectric conversion element of the present invention. A system 100E including the photoelectric conversion element 10E is a system applied to battery use as in the system 100A.
The photoelectric conversion element 10 </ b> E has a first electrode 1 </ b> E, a second electrode 2, and an electron transport layer 4 between the first electrode 1 </ b> E and the second electrode 2. The first electrode 1 </ b> E includes a conductive support 11 and a hole transport layer 16 and a photosensitive layer 13 </ b> C, which are sequentially formed on the conductive support 11. This photoelectric conversion element 10E is preferable in that each layer can be formed of an organic material, like the photoelectric conversion element 10D.

In the present invention, the system 100 to which the photoelectric conversion element 10 is applied functions as a solar cell as follows.
That is, in the photoelectric conversion element 10A, light that has passed through the conductive support 11 or passed through the second electrode 2 and entered the photosensitive layer 13 excites the light absorber. The excited light absorber has electrons with high energy and can emit these electrons. The light absorber that has released electrons with high energy becomes an oxidant.

In the photoelectric conversion elements 10 </ b> A to 10 </ b> D, electrons emitted from the light absorber move between the light absorbers and reach the conductive support 11. At this time, the light absorber that has released electrons with high energy is an oxidant. After the electrons that have reached the conductive support 11 work in the external circuit 6, they pass through the second electrode 2 (if there is a hole transport layer 3, further via the hole transport layer 3), and then the photosensitive layer Return to 13. The light absorber is reduced by the electrons returning to the photosensitive layer 13.
On the other hand, in the photoelectric conversion element 10E, the electrons emitted from the light absorber reach the second electrode 2 from the photosensitive layer 13C through the electron transport layer 4, and after working in the external circuit 6, the conductive support 11 Then, the process returns to the photosensitive layer 13. The light absorber is reduced by the electrons returning to the photosensitive layer 13.
In the photoelectric conversion element 10, the system 100 functions as a solar cell by repeating such excitation and electron transfer cycles of the light absorber.

In the photoelectric conversion elements 10 </ b> A to 10 </ b> D, the way in which electrons flow from the photosensitive layer 13 to the conductive support 11 varies depending on the presence / absence of the porous layer 12 and the type thereof. In the photoelectric conversion element 10 of the present invention, electron conduction in which electrons move between the light absorbers occurs. Therefore, when providing the porous layer 12, the porous layer 12 can be formed with an insulator other than the conventional semiconductor. When the porous layer 12 is formed of a semiconductor, electron conduction in which electrons move inside or between the semiconductor particles of the porous layer 12 also occurs. On the other hand, when the porous layer 12 is formed of an insulator, electron conduction in the porous layer 12 does not occur. When the porous layer 12 is formed of an insulator, a relatively high electromotive force (Voc) can be obtained by using aluminum oxide (Al ₂ O ₃ ) particles as the insulator particles.
Even when the blocking layer 14 as the other layer is formed of a conductor or a semiconductor, electron conduction in the blocking layer 14 occurs.
Also, electron conduction occurs in the electron transport layer 15.

  The photoelectric conversion element and the solar cell of the present invention are not limited to the above-described preferred embodiments, and the configuration of each embodiment can be appropriately combined between the respective embodiments without departing from the spirit of the present invention.

  In this invention, the material and each member which are used for a photoelectric conversion element or a solar cell can be prepared by a conventional method except a light absorber. For a photoelectric conversion element or a solar cell using a perovskite compound, for example, Patent Document 1 can be referred to. As for the dye-sensitized solar cell, for example, JP-A No. 2001-291534, US Pat. No. 4,927,721, US Pat. No. 4,684,537, US Pat. No. 5,084, 365, US Pat. No. 5,350,644, US Pat. No. 5,463,057, US Pat. No. 5,525,440, JP-A-7-249790, JP 2004-220974 A and JP 2008-135197 A can be referred to.

  Hereinafter, the preferable aspect of the main member and compound of the photoelectric conversion element of this invention and a solar cell is demonstrated.

<First electrode 1>
The first electrode 1 has a conductive support 11 and a photosensitive layer 13 and functions as a working electrode in the photoelectric conversion element 10.
As shown in FIGS. 1 to 5, the first electrode 1 preferably has at least one of a porous layer 12, a blocking layer 14, an electron transport layer 15, and a hole transport layer 16.
The first electrode 1 preferably has at least the blocking layer 14 in terms of prevention of short circuit, and more preferably has the porous layer 12 and the blocking layer 14 in terms of light absorption efficiency and prevention of short circuit.
Moreover, it is preferable that the 1st electrode 1 has the electron carrying layer 15 or the positive hole transport layer 16 at the point which can be formed with an organic material.

− Conductive support 11 −
The conductive support 11 is not particularly limited as long as it has conductivity and can support the photosensitive layer 13 and the like. The conductive support 11 includes a conductive material such as a metal, or a glass or plastic support 11a and a transparent electrode 11b as a conductive film formed on the surface of the support 11a. The structure which has is preferable.

Among these, as shown in FIGS. 1 to 5, a conductive support 11 in which a transparent metal electrode 11b is formed by coating a conductive metal oxide on the surface of a glass or plastic support 11a is more preferable. . Examples of the support 11a made of plastic include a transparent polymer film described in paragraph No. 0153 of JP-A No. 2001-291534. As a material for forming the support 11a, ceramic (Japanese Patent Laid-Open No. 2005-135902) and conductive resin (Japanese Patent Laid-Open No. 2001-160425) can be used in addition to glass and plastic. As the metal oxide, tin oxide (TO) is preferable, and fluorine-doped tin oxide such as indium-tin oxide (tin-doped indium oxide; ITO) and fluorine-doped tin oxide (FTO) is particularly preferable. The coating amount of the metal oxide at this time is preferably 0.1 to 100 g per 1 m ² of the surface area of the support 11a. When the conductive support 11 is used, light is preferably incident from the support 11a side.

The conductive support 11 is preferably substantially transparent. In the present invention, “substantially transparent” means that the transmittance of light (wavelength 300 to 1200 nm) is 10% or more, preferably 50% or more, and particularly preferably 80% or more.
The thicknesses of the support 11a and the conductive support 11 are not particularly limited, and are set to appropriate thicknesses. For example, the thickness is preferably 0.01 μm to 10 mm, more preferably 0.1 μm to 5 mm, and particularly preferably 0.3 μm to 4 mm.
When providing the transparent electrode 11b, the film thickness of the transparent electrode 11b is not specifically limited, For example, it is preferable that it is 0.01-30 micrometers, It is more preferable that it is 0.03-25 micrometers, 0.05-20 micrometers It is particularly preferred that

  The conductive support 11 or the support 11a may have a light management function on the surface. For example, even if the surface of the conductive support 11 or the support 11a has an antireflection film in which high refractive films and low refractive index oxide films are alternately stacked as described in JP-A-2003-123859. The light guide function described in JP-A-2002-260746 may be provided.

− Blocking layer 14 −
In the present invention, like the photoelectric conversion elements 10A to 10C, preferably, on the surface of the transparent electrode 11b, that is, the conductive support 11, the porous layer 12, the photosensitive layer 13, the hole transport layer 3, and the like. Between them, the blocking layer 14 is provided.
In the photoelectric conversion element and the solar cell, for example, when the photosensitive layer 13 or the hole transport layer 3 and the transparent electrode 11b are electrically connected, a reverse current is generated. The blocking layer 14 functions to prevent this reverse current. The blocking layer 14 is also referred to as a short circuit prevention layer.
This blocking layer may be provided also when a photoelectric conversion element has an electron carrying layer. For example, in the case of the photoelectric conversion element 10D, it may be provided between the conductive support 11 and the electron transport layer 15, and in the case of the photoelectric conversion element 10E, it is provided between the second electrode 2 and the electron transport layer 4. May be.

The material for forming the blocking layer 14 is not particularly limited as long as it is a material capable of fulfilling the above function, but is a substance that transmits visible light and is an insulating substance for the conductive support 11 (transparent electrode 11b). Preferably there is. Specifically, the “insulating substance with respect to the conductive support 11 (transparent electrode 11b)” specifically refers to a material whose conduction band energy level forms the conductive support 11 (metal oxide forming the transparent electrode 11b). A compound (n-type semiconductor compound) that is higher than the energy level of the conduction band of the material and lower than the energy level of the conduction band of the material constituting the porous layer 12 and the ground state of the light absorber.
Examples of the material for forming the blocking layer 14 include silicon oxide, magnesium oxide, aluminum oxide, calcium carbonate, polyvinyl alcohol, and polyurethane. Moreover, the material generally used for the photoelectric conversion material may be used, and examples thereof include titanium oxide, tin oxide, niobium oxide, and tungsten oxide. Of these, titanium oxide, tin oxide, magnesium oxide, aluminum oxide and the like are preferable.
The film thickness of the blocking layer 14 is preferably 0.001 to 10 μm, more preferably 0.005 to 1 μm, and particularly preferably 0.01 to 0.1 μm.

  In the present invention, the film thickness of each layer can be measured by observing the cross section of the photoelectric conversion element 10 using a scanning electron microscope (SEM) or the like.

− Porous layer 12 −
In the present invention, like the photoelectric conversion elements 10A and 10B, the porous layer 12 is preferably provided on the transparent electrode 11b. When the blocking layer 14 is provided, the porous layer 12 is preferably formed on the blocking layer 14.
The porous layer 12 is a layer that functions as a scaffold for carrying the photosensitive layer 13 on the surface. In the solar cell, in order to increase the light absorption efficiency, it is preferable to increase the surface area of at least a portion that receives light such as sunlight, and it is preferable to increase the entire surface area of the porous layer 12.

The porous layer 12 is preferably a fine particle layer having pores, in which fine particles of the material forming the porous layer 12 are deposited or adhered. The porous layer 12 may be a fine particle layer in which two or more kinds of multi-fine particles are deposited. When the porous layer 12 is a fine particle layer having pores, the amount of light absorbent supported (adsorption amount) can be increased.
In order to increase the surface area of the porous layer 12, it is preferable to increase the surface area of the individual fine particles constituting the porous layer 12. In the present invention, in a state where the fine particles forming the porous layer 12 are coated on the conductive support 11 or the like, the surface area of the fine particles is preferably 10 times or more, more than 100 times the projected area. It is more preferable. Although there is no restriction | limiting in particular in this upper limit, Usually, it is about 5000 times. The particle diameter of the fine particles forming the porous layer 12 is preferably 0.001 to 1 μm as the primary particle in the average particle diameter using the diameter when the projected area is converted into a circle. When the porous layer 12 is formed using a dispersion of fine particles, the average particle diameter of the fine particles is preferably 0.01 to 100 μm as the average particle diameter of the dispersion.

The material for forming the porous layer 12 is not particularly limited with respect to conductivity, and may be an insulator (insulating material), a conductive material, or a semiconductor (semiconductive material). .
Examples of the material for forming the porous layer 12 include metal chalcogenides (eg, oxides, sulfides, selenides, etc.), compounds having a perovskite crystal structure (excluding a light absorber described later), and oxidation of silicon. An object (for example, silicon dioxide, zeolite), or carbon nanotube (including carbon nanowire and carbon nanorod) can be used.

  The metal chalcogenide is not particularly limited, but is preferably titanium, tin, zinc, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, aluminum or tantalum oxide, cadmium sulfide. , Cadmium selenide and the like. Examples of the crystal structure of the metal chalcogenide include an anatase type, brookite type and rutile type, and anatase type and brookite type are preferable.

  Although it does not specifically limit as a compound which has a perovskite type crystal structure, A transition metal oxide etc. are mentioned. For example, strontium titanate, calcium titanate, barium titanate, lead titanate, barium zirconate, barium stannate, lead zirconate, strontium zirconate, strontium tantalate, potassium niobate, bismuth ferrate, strontium barium titanate , Barium lanthanum titanate, calcium titanate, sodium titanate, bismuth titanate. Of these, strontium titanate, calcium titanate and the like are preferable.

  The carbon nanotube has a shape obtained by rounding a carbon film (graphene sheet) into a cylindrical shape. Carbon nanotubes are single-walled carbon nanotubes (SWCNT) in which one graphene sheet is wound in a cylindrical shape, double-walled carbon nanotubes (DWCNT) in which two graphene sheets are wound in a concentric shape, and multiple graphene sheets are concentric Are classified into multi-walled carbon nanotubes (MWCNT) wound in a shape. As the porous layer 12, any carbon nanotube is not particularly limited and can be used.

  Among these materials, the material forming the porous layer 12 is preferably titanium, tin, zinc, zirconium, aluminum or silicon oxide, or carbon nanotube, and more preferably titanium oxide or aluminum oxide.

  The porous layer 12 may be formed of at least one of the above-described metal chalcogenide, compound having a perovskite crystal structure, silicon oxide, and carbon nanotube, and may be formed of a plurality of types. .

  Although the film thickness of the porous layer 12 is not specifically limited, Usually, it is the range of 0.1-100 micrometers, and when using as a solar cell, 0.1-50 micrometers is preferable and 0.3-30 micrometers is more preferable.

− Electron transport layer 15 −
In the present invention, like the photoelectric conversion element 10D, the electron transport layer 15 is preferably provided on the surface of the transparent electrode 11b.
The electron transport layer 15 has a function of transporting electrons generated in the photosensitive layer 13 to the conductive support 11. The electron transport layer 15 is formed of an electron transport material that can exhibit this function. The electron transport material is not particularly limited, but an organic material (organic electron transport material) is preferable. Examples of the organic electron transport material include fullerene compounds such as [6,6] -phenyl-C61-Butylic Acid Methyl Ester (PCBM), perylene compounds such as perylenetetracarboxydiimide (PTCDI), and other tetracyanoquinodimethane (TCNQ). ) And the like, or high molecular compounds.
Although the film thickness of the electron carrying layer 15 is not specifically limited, 0.001-10 micrometers is preferable and 0.01-1 micrometer is more preferable.

− Hole transport layer 16 −
In the present invention, like the photoelectric conversion element 10E, the hole transport layer 16 is preferably provided on the surface of the transparent electrode 11b.
The hole transport layer 16 is the same as the hole transport layer 3 described later except that the position where it is formed is different.

− Photosensitive layer (light absorbing layer) 13 −
The photosensitive layer 13 is preferably a porous layer 12 (photoelectric conversion elements 10A and 10B) or a blocking layer 14 (photoelectric conversion element 10C)) or an electron transport layer 15 (photoelectric conversion element) using a perovskite compound described later as a light absorber. 10D) or the surface of each layer of the hole transport layer 16 (photoelectric conversion element 10E) (including the inner surface when the surface on which the photosensitive layer 13 is provided is uneven).
In the present invention, the light absorber only needs to contain at least one of the specific perovskite compounds described above, and may contain two or more perovskite compounds.
The photosensitive layer 13 may be a single layer or a laminate of two or more layers. When the photosensitive layer 13 has a laminated structure of two or more layers, layers composed of different light absorbers may be laminated, and an intermediate layer containing a hole transport material is laminated between the photosensitive layer and the photosensitive layer. May be.

  The form having the photosensitive layer 13 on the conductive support 11 is as described above. The photosensitive layer 13 is preferably provided on the surface of each of the layers so that excited electrons flow through the conductive support 11. At this time, the photosensitive layer 13 may be provided on the entire surface of each of the above layers, or may be provided on a part of the surface.

The film thickness of the photosensitive layer 13 is appropriately set according to the mode having the photosensitive layer 13 on the conductive support 11 and is not particularly limited. For example, the film thickness of the photosensitive layer 13 (when having the porous layer 12, the total film thickness with the film thickness of the porous layer 12) is preferably 0.1 to 100 μm, more preferably 0.1 to 50 μm, and 0 .3 to 30 μm is particularly preferable.
In the present invention, when the photosensitive layer is provided in the form of a thick film (photosensitive layers 13B and 13C), the light absorber contained in the photosensitive layer may function as a hole transport material.

The photosensitive layer 13 of the photoelectric conversion element of the present invention has a water contact angle of 70 ° to 150 ° with respect to the surface of the photosensitive layer (the surface opposite to the conductive support 11). That is, in the photoelectric conversion element of the present invention, another layer (preferably a hole transport layer) is formed on the surface of the photosensitive layer having a water contact angle of 70 ° to 150 °. Before the other layer is formed, the contact angle of water with respect to the surface of the photosensitive layer is 70 ° to 150 °, thereby increasing the hydrophobicity of the photosensitive layer and reducing the performance of the photoelectric conversion element in a high humidity environment. It can be effectively suppressed.
In this specification, the contact angle of water with the surface of the photosensitive layer is in accordance with the droplet method described on page 97 of “New Experimental Chemistry Course 18: Interface and Colloid” (Maruzen, published in 1977) edited by the Chemical Society of Japan. The measured value is used. That is, in the present invention, the value of the contact angle of water with respect to the surface of the photosensitive layer is 1 μL of water droplets (pure water) at the tip of the needle unless otherwise noted, and this is brought into contact with the surface of the photosensitive layer to form droplets. 1 minute after that, the value which measured the contact angle using DropMaster500 (brand name, Kyowa Interface Science Co., Ltd.) is said, and it measures by the method as described in the below-mentioned Example in detail. In this specification, the temperature at the time of measurement of a contact angle shall be 25 degreeC.
If the contact angle of water on the surface of the photosensitive layer is too small, moisture absorption of the photosensitive layer cannot be sufficiently suppressed, and the resulting photoelectric conversion element is inferior in durability.
On the other hand, if the contact angle of water with the photosensitive layer surface is too large, sufficient durability cannot be obtained. The reason for this is not clear, but it is considered that the stability of the perovskite structure in the photosensitive layer is lowered if the hydrophobicity of the photosensitive layer becomes too high.
In the state before the hole transport layer is formed, the photosensitive layer preferably has a water contact angle of 75 ° to 140 °, more preferably 80 ° to 130 °, and more preferably 85 ° to 130 °. 120 ° is more preferable, and 100 ° to 120 ° is more preferable.
As described later, the contact angle of water with respect to the surface of the photosensitive layer may be such that a hydrophobic group is introduced into the perovskite compound forming the photosensitive layer, or a specific solvent is used as a solvent used when forming the photosensitive layer. Can be adjusted.

[Light absorber of photosensitive layer]
The photosensitive layer 13 includes, as a light absorber, “periodic table group 1 element or cationic organic group A”, “metal atom M other than periodic table group 1 element”, and “anionic atom X”. Containing a perovskite compound.
In the perovskite type crystal structure, the periodic table group 1 element or the cationic organic group A, the metal atom M, and the anionic atom X of the perovskite compound are each a cation (for convenience, sometimes referred to as cation A), a metal cation (for convenience). , Sometimes referred to as cation M) and anion (sometimes referred to as anion X for convenience).
In the present invention, the cationic organic group means an organic group having a property of becoming a cation in the perovskite crystal structure, and the anionic atom means an atom having a property of becoming an anion in the perovskite crystal structure.

In the perovskite compound used in the present invention, the cation A is a cation of a group 1 element of the periodic table or an organic cation composed of a cationic organic group A. The cation A is preferably an organic cation.
The cation of the Group 1 element of the periodic table is not particularly limited, and for example, the cation (Li ⁺ , Na ⁺ , K ⁺ of each element of lithium (Li), sodium (Na), potassium (K), or cesium (Cs). Cs ⁺ ), and a cesium cation (Cs ⁺ ) is particularly preferable.
The organic cation is more preferably an organic cation of a cationic organic group represented by the following formula (1).
Formula (1): R ^1a —NH ₃

In the formula, R ^1a represents a hydrocarbon group having 20 or less carbon atoms, and at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom. R ^1a is an alkyl group having 20 or less carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom (preferably having 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and further preferably 1 to 8 carbon atoms). The alkyl group may be linear or branched but is preferably linear, and a cycloalkyl group (preferably having 3 to 15 carbon atoms, more preferably 4 carbon atoms). -10, more preferably a cycloalkyl group having 5 to 8 carbon atoms), an alkenyl group (preferably an alkenyl group having 2 to 15 carbon atoms, more preferably an alkenyl group having 2 to 10 carbon atoms), an alkynyl group (preferably 2 to 2 carbon atoms). 15, more preferably an alkynyl group having 2 to 10 carbon atoms) or an aryl group (preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms). Among them, an alkyl group having a trifluoromethyl group is preferable, an alkyl group having 1 to 2 trifluoromethyl groups is more preferable, an alkyl group having 1 or 2 trifluoromethyl groups is more preferable, and a trifluoromethyl group is preferable. More preferred is an alkyl group having one of
When R ^1a has a trifluoromethyl group, the contact angle of water with respect to the surface of the photosensitive layer can be within a more preferable range.
R ^1a is preferably a linear alkyl group, and the terminal of this linear alkyl group is preferably a trifluoromethyl group.

The number of fluorine atoms and the number of hydrogen atoms in R ^1a preferably satisfy 0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1, and 0.6 ≦ number of fluorine atoms / ( More preferably, the number of hydrogen atoms + the number of fluorine atoms) ≦ 1 is satisfied, and it is further preferable that 0.7 ≦ the number of fluorine atoms / (the number of hydrogen atoms + the number of fluorine atoms) ≦ 1.

In the present invention, the organic cation of the cationic organic group A (that is, the organic cation when A is a cationic organic group) is an ammonium cation formed by bonding R ^1a in the above formula (1) and NH _3. An organic ammonium cation composed of a functional organic group A is preferred.
Any of an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, and an aryl group that can be adopted as R ^1a may have a substituent other than a fluorine atom. The substituent other than the fluorine atom that R ^1a may have is not particularly limited, and examples thereof include an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heterocyclic group, an alkoxy group, and an alkylthio group. Amino group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, acylamino group, sulfonamide group, carbamoyl group, sulfamoyl group, halogen atom other than fluorine atom, cyano group, hydroxy group or A carboxy group is mentioned. Each substituent that R ^1a may have may be further substituted with a substituent.

The organic cation includes an organic cation of a cationic organic group represented by the above formula (1) (hereinafter also referred to as “organic cation I”) and an organic of a cationic organic group represented by the following formula (2). It is also preferable that it consists of a cation (hereinafter also referred to as organic cation II) (that is, part of the organic cation is organic cation I and the remaining organic cation is organic cation II).
Equation (2): ^{R 2a} -NH ₃

In the formula, R ^2a is an unsubstituted hydrocarbon group having 20 or less carbon atoms. R ^2a is an alkyl group (preferably an alkyl group having 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 7 carbon atoms, still more preferably 1 to 5 carbon atoms. This alkyl group. May be linear or branched, but is preferably linear.), A cycloalkyl group (preferably having 3 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, still more preferably 5 carbon atoms). -8 cycloalkyl group), an alkenyl group (preferably an alkenyl group having 2 to 15 carbon atoms, more preferably an alkenyl group having 2 to 10 carbon atoms), an alkynyl group (preferably 2 to 15 carbon atoms, more preferably 2 to 2 carbon atoms). 10 alkynyl group) or an aryl group (preferably an aryl group having 6 to 20 carbon atoms, more preferably an aryl group having 6 to 15 carbon atoms). Among these, R ^2a is preferably an alkyl group.
R ^2a is preferably a hydrocarbon group having 1 or 2 carbon atoms, and more preferably methyl or ethyl.

When the organic cation is composed of the organic cation I and the organic cation II, the content of the organic cation I in the entire perovskite crystal structure present in the photosensitive layer and the content of the organic cation II The ratio is the molar ratio,
[Content of organic cation I]: [Content of organic cation II] = 99: 1 to 20:80,
[Content of organic cation I]: [Content of organic cation II] = 99: 1 to 30:70 is more preferable,
[Content of organic cation I]: [Content of organic cation II] = 99: 1 to 40:60 is more preferable,
[Content of organic cation I]: [Content of organic cation II] = 99: 1 to 50:50 is more preferable.
By making the ratio of the content of the organic cation I and the content of the organic cation II within the above preferable range, the contact angle of water with respect to the surface of the photosensitive layer can be adjusted within a more preferable range.

  In the perovskite compound used in the present invention, the metal cation M is not particularly limited as long as it is a cation of a metal atom M other than a group 1 element of the periodic table and a cation of a metal atom capable of taking a perovskite crystal structure. Examples of such metal atoms include calcium (Ca), strontium (Sr), cadmium (Cd), copper (Cu), nickel (Ni), manganese (Mn), iron (Fe), cobalt (Co), Metal atoms such as palladium (Pd), germanium (Ge), tin (Sn), lead (Pb), ytterbium (Yb), europium (Eu), indium (In), and the like can be given. Among these, the metal atom M is particularly preferably a Pb atom or an Sn atom. M may be one type of metal atom or two or more types of metal atoms. In the case of two or more kinds of metal atoms, two kinds of Pb atoms and Sn atoms are preferable. In addition, the ratio of the metal atom at this time is not specifically limited.

  In the perovskite compound used in the present invention, the anion X represents an anion of the anionic atom X. This anion is preferably an anion of a halogen atom. As a halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, for example. The anion X may be an anion of one kind of anionic atom or an anion of two or more kinds of anionic atoms. In the case of anions of two or more types of anionic atoms, two types of anions of halogen atoms, particularly anions of bromine atoms and iodine atoms are preferred. In addition, the ratio of the anion of the anionic atom at this time is not particularly limited.

  The perovskite compound used in the present invention is preferably a perovskite compound having a perovskite crystal structure having each of the above constituent ions and represented by the following formula (I).

Formula (I): A _a M _m X _x
In the formula, A represents a group 1 element of the periodic table or a cationic organic group. M represents a metal atom other than Group 1 elements of the periodic table. X represents an anionic atom.
a represents 1 or 2, m represents 1, and a, m, and x satisfy a + 2m = x.

  In the formula (I), the periodic table group 1 element or the cationic organic group A forms the cation A having a perovskite crystal structure. Accordingly, the Group 1 element of the periodic table and the cationic organic group A are not particularly limited as long as they are elements or groups that can form the perovskite crystal structure by becoming the cation A. The Periodic Table Group 1 element or the cationic organic group A has the same meaning as the Periodic Table Group 1 element or the cationic organic group described above for the cation A, and the preferred ones are also the same.

  The metal atom M is a metal atom that forms the metal cation M having a perovskite crystal structure. Therefore, the metal atom M is not particularly limited as long as it is an atom other than the Group 1 element of the periodic table and can form the perovskite crystal structure by becoming the metal cation M. The metal atom M is synonymous with the metal atom described in the metal cation M, and the preferred ones are also the same.

  The anionic atom X forms the anion X having a perovskite crystal structure. Therefore, the anionic atom X is not particularly limited as long as it is an atom that can form the perovskite crystal structure by becoming the anion X. The anionic atom X is synonymous with the anionic atom demonstrated with the said anion X, and its preferable thing is also the same.

When a is 1, the perovskite compound represented by the formula (I) is a perovskite compound represented by the following formula (I-1), and when a is 2, the following formula (I-2) It is a perovskite compound represented.
Formula (I-1): AMX ₃
Formula (I-2): A ₂ MX ₄
In formula (I-1) and formula (I-2), A has the same meaning as A in formula (I), and preferred ones are also the same.
M represents a metal atom other than the Group 1 element of the periodic table, and is synonymous with M in the above formula (I), and preferred ones are also the same.
X represents an anionic atom, and is synonymous with X of the said formula (I), and its preferable thing is also the same.

  The perovskite compound used in the present invention may be either a compound represented by formula (I-1) or a compound represented by formula (I-2), or a mixture thereof. Therefore, in the present invention, at least one perovskite compound only needs to be present as a light absorber, and it is not necessary to clearly distinguish which compound is strictly based on the composition formula, molecular formula, crystal structure, and the like. .

  Specific examples of the perovskite compound that can be used in the present invention are illustrated below, but the present invention is not limited thereto. In the following, the compound represented by the formula (I-1) and the compound represented by the formula (I-2) are described separately. However, even if it is a compound illustrated as a compound represented by a formula (I-1), depending on synthesis conditions etc., it may become a compound represented by a formula (I-2). In some cases, the mixture is a mixture of the compound represented by -1) and the compound represented by formula (I-2). Similarly, even if it is a compound illustrated as a compound represented by a formula (I-2), it may become a compound represented by a formula (I-1), and is represented by a formula (I-1). In some cases, the compound is a mixture of the compound represented by formula (I-2).

Specific examples of the compound represented by formula (I-1) include, for example, CH ₃ NH ₃ PbCl ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBrI ₂ , and CH ₃ NH _{3. PbBr 2 I, CH 3 NH 3} SnBr 3, CH 3 NH 3 SnI 3, CF 3 NH 3 PbCl 3, CF 3 NH 3 PbBr 3, CF 3 NH 3 PbI 3, CF 3 NH 3 PbBrI 2, CF 3 NH 3 _{PbBr 2 I, CF 3 NH 3} SnBr 3, CF 3 NH 3 SnI 3, CHF 2 NH 3 PbCl 3, CHF 2 NH 3 PbBr 3, CHF 2 NH 3 PbI 3, CHF 2 NH 3 PbBrI 2, CHF 2 NH 3 _{PbBr 2 I, CHF 2 NH 3} SnBr 3, CHF 2 NH 3 SnI 3, CH 2 FN _{3 PbCl 3, CH 2 FNH 3} PbBr 3, CH 2 FNH 3 PbI 3, CH 2 FNH 3 PbBrI 2, CH 2 FNH 3 PbBr 2 I, include _{CH 2 FNH 3 SnBr 3, CH} 2 FNH 3 SnI 3.

Specific examples of the compound represented by the formula (I-2) include, for example, (C ₂ H ₅ NH ₃ ) ₂ PbI ₄ , (CH ₂ = CHNH ₃ ) ₂ PbI ₄ , (CH≡CNH ₃ ) ₂ PbI _{4 , (n-C 3 H 7} NH 3) 2 PbI 4, (n-C 4 H 9 NH 3) 2 PbI 4, (C 6 H 5 NH 3) 2 PbI 4, (C 6 H 3 F 2 NH 3 ) ₂ PbI ₄ , (C ₆ F ₅ NH ₃ ) ₂ PbI ₄ , (CF ₃ CH ₂ NH ₃ ) ₂ PbI ₄ , (CHF ₂ CH ₂ NH ₃ ) ₂ PbI ₄ , (CH ₂ FCH ₂ NH ₃ ) ₂ PbI ₄ , (CF ₃ CF ₂ CH ₂ NH ₃ ) ₂ PbI ₄ , ((CF ₃ ) ₂ CHNH ₃ ) ₂ PbI ₄ , (CH ₃ (CF ₂ ) ₅ CH ₂ NH ₃ ) ₂ PbI ₄ , (CF _{3 (CF 2)} 3 (CH 2 ₃ NH _{3) 2} PbI _4, include _{((CF 3) 3 CNH 3} ) 2 PbI 4.

The perovskite compound can be synthesized from MX ₂ and AX. For example, a perovskite compound can be synthesized with reference to Patent Document 1 described above. Also, Akihiro Kojima, Kenjiro Teshima, Yasuo Shirai, and Tsutomu Miyasaka, “Organometric Halide Perovskites as Visible Slightly.” Am. Chem. Soc. , 2009, 131 (17), 6050-6051 as appropriate, a perovskite compound can be synthesized.

  The amount of the light absorber used may be at least a part of the surface on which light is incident among the surfaces of the porous layer 12 or the blocking layer 14, and is preferably an amount covering the entire surface.

<Hole transport layer 3>
The photoelectric conversion element of the present invention preferably has a hole transport layer 3 between the first electrode and the second electrode.
The hole transport layer 3 has a function of replenishing electrons to the oxidant of the light absorber, and is preferably a solid layer. The hole transport layer 3 is preferably provided between the photosensitive layer 13 of the first electrode 1 and the second electrode 2.

The hole transport material for forming the hole transport layer 3 is not particularly limited, but is an inorganic material such as CuI or CuNCS, and the organic hole transport material described in JP-A-2001-291534, paragraphs 0209-0212. Etc. The organic hole transport material is preferably a conductive polymer such as polythiophene, polyaniline, polypyrrole and polysilane, a spiro compound in which two rings share a tetrahedral structure such as C and Si, and triarylamine. And aromatic amine compounds such as triphenylene compounds, nitrogen-containing heterocyclic compounds, and liquid crystalline cyano compounds.
The hole transport material is preferably an organic hole transport material that can be applied by a solution and becomes a solid. Specifically, 2,2 ′, 7,7′-tetrakis- (N, N-di-p-methoxyphenyl) is preferable. Amine) -9,9-spirobifluorene (also referred to as Spiro-OMeTAD), poly (3-hexylthiophene-2,5-diyl), 4- (diethylamino) benzaldehyde diphenylhydrazone, polyethylenedioxythiophene (PEDOT), etc. Is mentioned.

  Although the film thickness of the positive hole transport layer 3 is not specifically limited, 50 micrometers or less are preferable, 1 nm-10 micrometers are more preferable, 5 nm-5 micrometers are further more preferable, and 10 nm-1 micrometer are especially preferable.

  In the present invention, when the porous layer 12 is included, the total film thickness of the porous layer 12, the photosensitive layer 13, and the hole transport layer 3 is not particularly limited, but is preferably 0.1 to 200 μm, for example. 5-50 micrometers is more preferable and 0.5-5 micrometers is still more preferable.

<Electron transport layer 4>
In the present invention, like the photoelectric conversion element 10E, the electron transport layer 4 is preferably provided between the photosensitive layer 13C and the second electrode 2.
The electron transport layer 4 is the same as the electron transport layer 15 except that the electron transport destination is the second electrode and the position where the electron transport layer 4 is formed is different.

<Second electrode 2>
The second electrode 2 functions as a positive electrode in the solar cell. The 2nd electrode 2 will not be specifically limited if it has electroconductivity, Usually, it can be set as the same structure as the electroconductive support body 11. FIG. If the strength is sufficiently maintained, the support 11a is not necessarily required.
The structure of the second electrode 2 is preferably a structure having a high current collecting effect. In order for light to reach the photosensitive layer 13, at least one of the conductive support 11 and the second electrode 2 must be substantially transparent. In the solar cell of this invention, it is preferable that the electroconductive support body 11 is transparent and sunlight is entered from the support body 11a side. In this case, it is more preferable that the second electrode 2 has a property of reflecting light.

Examples of the material for forming the second electrode 2 include platinum (Pt), gold (Au), nickel (Ni), copper (Cu), silver (Ag), indium (In), ruthenium (Ru), palladium ( Examples thereof include metals such as Pd), rhodium (Rh), iridium (Ir), and osnium (Os), the above-described conductive metal oxides, and carbon materials. The carbon material may be a conductive material formed by bonding carbon atoms to each other, and examples thereof include fullerene, carbon nanotube, graphite, and graphene.
The second electrode 2 is preferably a metal or conductive metal oxide thin film (including a thin film formed by vapor deposition), or a glass substrate or a plastic substrate having this thin film. As the glass substrate or plastic substrate, glass having a thin film of gold or platinum or glass on which platinum is deposited is preferable.

  The film thickness of the 2nd electrode 2 is not specifically limited, 0.01-100 micrometers is preferable, 0.01-10 micrometers is more preferable, 0.01-1 micrometer is especially preferable.

<Other configurations>
In the present invention, in order to prevent contact between the first electrode 1 and the second electrode 2, a spacer or a separator can be used instead of the blocking layer 14 or the like or together with the blocking layer 14 or the like.
A hole blocking layer may be provided between the second electrode 2 and the hole transport layer 3.

<< Solar cell >>
The solar cell of this invention is comprised using the photoelectric conversion element of this invention. For example, as shown in FIG. 1 to FIG. 5, a photoelectric conversion element 10 configured to work on the external circuit 6 can be used as a solar cell. The external circuit connected to the first electrode 1 (conductive support 11) and the second electrode 2 can be used without particular limitation.
In the solar cell of the present invention, it is preferable to seal the side surface with a polymer, an adhesive or the like in order to prevent deterioration of the components and transpiration.

<< Photoelectric Conversion Element Manufacturing Method >>
Method of manufacturing a photoelectric conversion element of the present invention, on the conductive support described above, applying a solution containing a solvent MX ₂ and AX, by drying, to the electrically conductive substrate, the water Except for including a step of forming a photosensitive layer having a surface with a contact angle of 70 ° to 150 °, it can be produced according to a known production method, for example, the method described in Patent Document 1.
Below, the manufacturing method of the photoelectric conversion element and solar cell concerning embodiment of this invention is demonstrated easily.

If desired, at least one layer of a blocking layer 14, a porous layer 12, an electron transport layer 15, and a hole transport layer 16 is formed on the surface of the conductive support 11.
The blocking layer 14 can be formed by, for example, a method of applying a dispersion containing the insulating material or a precursor compound thereof to the surface of the conductive support 11 and baking it, or a spray pyrolysis method.

The material forming the porous layer 12 is preferably used as fine particles, and more preferably used as a dispersion containing fine particles.
The method for forming the porous layer 12 is not particularly limited, and examples thereof include a wet method, a dry method, and other methods (for example, a method described in Chemical Review, Vol. 110, page 6595 (2010)). It is done. In these methods, it is preferable that the dispersion (paste) is applied to the surface of the conductive support 11 or the surface of the blocking layer 14 and then baked at a temperature of 100 to 800 ° C. for 10 minutes to 10 hours. Thereby, microparticles | fine-particles can be stuck.
When firing is performed a plurality of times, the firing temperature other than the last firing (the firing temperature other than the last firing) is preferably performed at a temperature lower than the last firing temperature (the last firing temperature). For example, when a titanium oxide paste is used, the firing temperature other than the last can be set within a range of 50 to 300 ° C. Moreover, the last baking temperature can be set so that it may become higher than the baking temperature other than the last in the range of 100-600 degreeC. When a glass support is used as the support 11a, the firing temperature is preferably 60 to 500 ° C.

The amount of the porous material applied when forming the porous layer 12 is appropriately set according to the thickness of the porous layer 12 and the number of times of application, and is not particularly limited. The coating amount of the porous material per 1 m ² of the surface area of the conductive support 11 is preferably, for example, 0.5 to 500 g, and more preferably 5 to 100 g.

Next, the photosensitive layer 13 is provided.
First, a light absorbent solution for forming the photosensitive layer 13 is prepared. The light absorber solution contains MX ₂ , AX, which is a raw material for the perovskite compound, and a solvent. Here, A is the above-described cationic organic group A, M is the above-described metal atom M, and X is the above-described anionic atom X. In this light absorber solution, the molar ratio of MX ₂ to AX is appropriately adjusted according to the purpose.
Next, the prepared light absorber solution is a layer that forms the photosensitive layer 13 on the surface (in the photoelectric conversion element 10, any one of the porous layer 12, the blocking layer 14, the electron transport layer 15 and the hole transport layer 16). And then dried. Thereby, a perovskite compound is formed on the surface of the porous layer 12, the blocking layer 14, the electron transport layer 15 or the hole transport layer 16. The drying is preferably performed by heating, and is usually performed by heating to 20 to 300 ° C, preferably 50 to 170 ° C.

The solvent used in the light absorber solution is not particularly limited as long as MX ₂ and AX can be dissolved, and one or more solvents can be used. It is also preferable to use two or more solvents having different boiling points. In this case, the solvent polarity parameter E _T of the highest boiling solvent of two or more solvents (preferably two solvents) is preferably smaller than the solvent polarity parameter E _T of other solvents. That is, the highest boiling solvent in the solvent used for the light-absorbing agent solution, it is preferred that the solvent polarity parameter E _T is the smallest.
Solvent polarity parameter _{E T} is that of an index that represents the electrical bias of the solvent molecules, Christian Reichardt, Thomas Welton al., "Solvents and Solvent Effects in Organic Chemistry" (Wiley-VCH, 2011 years) Chapter 7 Ya Various parameters and their definitions are described in pages 2591 to 2595 of the Chemical Society of Japan "New Experimental Science Course 14, Synthesis and Reaction V of Organic Compounds" (Maruzen, 1978). In the present invention, and the use of solvers preparative _{E T} values calculated from chromium rhythm of betaine dye, using the values described in the 455 to 461 pages of the above "Solvents and Solvent Effects in Organic Chemistry".
In the case of using two or more solvents to the light absorbent solution, it solvent polarity parameter E _T value of the highest boiling point of the solvent is the smallest, that is, if it contains high-boiling and low-polar solvents, photosensitive In the process of heating and drying to form a layer, the low boiling point solvent is volatilized, so that the high boiling point and low polarity solvent is volatilized from the surface just before the end of drying. The effect of unevenly distributing the polar component on the surface of the photosensitive layer can be expected, and the contact angle of water with the surface of the photosensitive layer can be further increased.
Examples of the highly polar solvent include γ-butyrolactone, N, N-dimethylformamide, 1-hexanol, benzonitrile, acetylacetone and the like. Examples of the low polarity solvent include toluene, p-xylene, mesitylene, tetralin, 1,2,4-trichlorobenzene, 1,2-dimethoxybenzene and the like.

The hole transport layer 3 or the electron transport layer 4 is formed on the photosensitive layer 13 thus provided.
The hole transport layer 3 can be formed by applying a hole transport material solution containing a hole transport material and drying it. The concentration of the hole transport material is 0.1 to 1.0 M in that the hole transport material solution has excellent coating properties, and when the porous layer 12 is provided, the hole transport material solution easily penetrates into the pores of the porous layer 12. (Mol / L) is preferred.
The electron transport layer 4 can be formed by applying an electron transport material solution containing an electron transport material and drying it.

  After forming the hole transport layer 3 or the electron transport layer 4, the second electrode 2 is formed, and a photoelectric conversion element and a solar cell are manufactured.

  The film thickness of each layer can be adjusted by appropriately changing the concentration of each dispersion or solution (coating solution) and the number of coatings. For example, when the thick photosensitive layers 13B and 13C are provided, the coating solution may be applied and dried a plurality of times.

  Each of the above-mentioned coating liquids may contain additives such as a dispersion aid and a surfactant as necessary.

  Examples of the solvent or dispersion medium used in the method for manufacturing the photoelectric conversion element and the solar cell include the solvents described in JP-A No. 2001-291534, but are not particularly limited thereto. In the present invention, an organic solvent is preferable, and an alcohol solvent, an amide solvent, a nitrile solvent, a hydrocarbon solvent, a lactone solvent, and a mixed solvent of two or more of these are more preferable. As the mixed solvent, a mixed solvent of an alcohol solvent and a solvent selected from an amide solvent, a nitrile solvent, or a hydrocarbon solvent is preferable. Specifically, methanol, ethanol, γ-butyrolactone, chlorobenzene, acetonitrile, dimethylformamide (DMF) or dimethylacetamide, or a mixed solvent thereof is preferable.

  The application method of the solution or dispersant forming each layer is not particularly limited, and spin coating, extrusion die coating, blade coating, bar coating, screen printing, stencil printing, roll coating, curtain coating, spray coating, dip coating, inkjet A known coating method such as a printing method or a dipping method can be used. Of these, spin coating, screen printing, dipping, and the like are preferable.

  The photoelectric conversion element produced as described above can be used as a solar cell by connecting an external circuit to the first electrode 1 and the second electrode 2.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

Example 1 and Comparative Example 1
[Production of Photoelectric Conversion Element (Sample No. 101)]
The photoelectric conversion element 10A shown in FIG. 1 was manufactured by the following procedure. In addition, when the film thickness of the photosensitive layer 13 is large, it corresponds to the photoelectric conversion element 10B shown in FIG.

<Formation of blocking layer 14>
A 15% by mass isopropanol solution of titanium diisopropoxide bis (acetylacetonate) (Aldrich) was diluted with 1-butanol to prepare a 0.02M blocking layer solution.
A fluorine-doped SnO ₂ conductive film (transparent electrode 11b) was formed on a glass substrate (support 11a, thickness 2.2 mm) to produce a conductive support 11. A blocking layer 14 (film thickness 50 nm) was formed on the SnO ₂ conductive film at 450 ° C. by spray pyrolysis using the prepared 0.02M blocking layer solution.

<Formation of porous layer 12>
Ethyl cellulose, lauric acid and terpineol were added to an ethanol dispersion of titanium oxide (anatase, average particle size 20 nm) to prepare a titanium oxide paste.
The prepared titanium oxide paste was applied onto the blocking layer 14 by a screen printing method and baked at 500 ° C. for 1 hour. The obtained titanium oxide fired body was immersed in a 40 mM TiCl ₄ aqueous solution, heated at 60 ° C. for 1 hour, and then heated at 500 ° C. for 30 minutes to form a porous layer 12 (thickness of TiO _2). 0.6 μm) was formed.

<Formation of photosensitive layer 13A>
A 40% methanol solution (27.86 mL) of trifluoromethylamine and an aqueous solution of 57% by mass hydrogen iodide (hydroiodic acid, 30 mL) were stirred in a flask at 0 ° C. for 2 hours, then concentrated, A crude product of CF ₃ NH ₃ I was obtained. The obtained crude product of CF ₃ NH ₃ I was dissolved in ethanol and recrystallized from diethyl ether. The precipitated crystals were collected by filtration and dried under reduced pressure at 60 ° C. for 24 hours to obtain purified CF ₃ NH ₃ I.
Then, purified _CF 3 NH ₃ I and PbI ₂ and SnI ₂ and a molar ratio of 2: 0.99: 0.01 in γ- butyrolactone (n1 = 0.01 in formula (IA ^1)), at 60 ° C. After stirring and mixing for 12 hours, the mixture was filtered with a polytetrafluoroethylene (PTFE) syringe filter to prepare a 40 mass% light absorber solution (a).

The prepared light absorbent solution (a) was applied onto the porous layer 12 by spin coating (at 60 rpm for 60 seconds, and then at 3000 rpm for 60 seconds). It was dried at 40 ° C. for 40 minutes to form a photosensitive layer 13A (thickness 0.70 μm, including a porous layer) having a perovskite compound. The photosensitive layer 13A has a perovskite crystal structure having CF ₃ —NH ₃ ⁺ as the cation A, (Pb ²⁺ _0.99 Sn ²⁺ _0.01 ) as the metal cation, and I ⁻ as the anion X, IA ¹ ) :( CF ₃ NH ₃ ) (Pb _(1-n1) Sn _n1 ) I ₃ (where n1 = 0.01) was included in the perovskite compound (P ^A1 ).
In this way, the first electrode 1A was produced.

<Measurement of contact angle>
The contact angle of water (pure water) with respect to the surface of the photosensitive layer 13A formed above was measured by a droplet method. The contact angle was measured using a DropMaster 500 manufactured by Kyowa Interface Science Co., Ltd. A 1 μL water droplet was formed on the needle tip, and a droplet was formed by touching the surface of the photosensitive layer having a perovskite compound. The contact angle was measured after 1 minute. This measurement was repeated at three points separated by 5 mm or more, and the average value of these measured values was taken as the contact angle on the surface of the photosensitive layer 13A. The temperature during the measurement of the contact angle was 25 ° C.
In addition, the sample used for the contact angle measurement was used only for this measurement, and the sample which did not measure the contact angle produced by the same method at the same time for the subsequent operations was used as the first electrode 1A.

<Formation of hole transport layer 3>
Spiro-OMeTAD (180 mg) as a hole transport material was dissolved in chlorobenzene (1 mL). To this chlorobenzene solution, an acetonitrile solution (37.5 μL) in which lithium-bis (trifluoromethanesulfonyl) imide (170 mg) was dissolved in acetonitrile (1 mL) and t-butylpyridine (TBP, 17.5 μL) were added. A hole transport material solution was prepared by mixing.
Next, the hole transport material solution is applied onto the photosensitive layer 13A of the first electrode 1A by spin coating, and the applied hole transport material solution is dried to form a hole transport layer 3 (thickness 0.1 μm). ) Was formed.

<Preparation of the second electrode 2>
Gold (film thickness: 0.1 μm) was vapor-deposited on the hole transport layer 3 by a vapor deposition method to produce the second electrode 2.
In this way, the photoelectric conversion element 10A shown in FIG. 1 was manufactured.

[Production of Photoelectric Conversion Element (Sample Nos. 102 and 103)]
In the production of the photoelectric conversion element (sample No. 101), the mixing ratio (molar ratio) of purified CF ₃ NH ₃ I, PbI ₂ and SnI ₂ in the light absorbent solution (a) was 2: (1-n1). : N1 (n1 is synonymous with n1 in the formula (IA ¹ ) and shown in Table 1), except that the photoelectric conversion element (sample No. 101) was prepared in the same manner as in the production of the photoelectric conversion element (sample No. 102, 103) were produced.
In each manufactured photoelectric conversion element, the photosensitive layer is the same as the perovskite compound (P ^A1 ) included in the photosensitive layer of the photoelectric conversion element (sample No. 101), except that n1 of formula (IA ¹ ) is different. Met.

[Photoelectric Conversion Element (Production of Sample Nos. C11 to C13)
In the manufacture of the photoelectric conversion element (sample No.101~103), in place of the light absorbing agent solution (a), the light absorbing agent produced by using the amine ^(R 1a NH ₂₎ with ^{R 1a} shown in Table 1 Photoelectric conversion elements (Sample Nos. C11 to C13) were manufactured in the same manner as the photoelectric conversion elements (Sample Nos. 101 to 103) except that the solution was used. Sample No. R ^1a in C11 to C13 (comparative examples) is different from R ^1a defined in the present invention. However, for convenience of explanation, Table 1 represents R ^1a regardless of the present invention and comparative examples. The same applies to Tables 2 and 3.
The photosensitive layer of the manufactured photoelectric conversion element is the same perovskite compound (P ^A1 ) as the perovskite compound (P ^A1 ) included in the photosensitive layer of the photoelectric conversion element (sample No. 101), except that the cation of formula (IA ¹ ) and n1 are different. Was included.

Example 2 and Comparative Example 2
[Production of Photoelectric Conversion Element (Sample No. 201)]
In the production of the photoelectric conversion element (sample No. 101), it was the same as the production of the photoelectric conversion element (sample No. 101) except that the following light absorbent solution (b) was used instead of the light absorbent solution (a). Thus, a photoelectric conversion element (Sample No. 201) was produced.
The photosensitive layer of the produced photoelectric conversion element has a perovskite type having CF ₃ CH ₂ —NH ₃ ⁺ as the cation A, (Pb ²⁺ _0.99 Sn ²⁺ _0.01 ) as the metal cation, and I ⁻ as the anion X. A perovskite compound (P ^B1 ) having a crystal structure and represented by the formula (IB ¹ ): (CF ₃ CH ₂ —NH ₃ ) ₂ (Pb _(1-n1) Sn _n1 ) I ₄ (where n1 = 0.01) ).
<Preparation of light absorber solution (b)>
A 40% ethanol solution of 2,2,2-trifluoroethylamine and an aqueous solution of 57% by mass of hydrogen iodide were stirred in a flask at 0 ° C. for 2 hours, then concentrated, and CF ₃ CH ₂ NH ₃ I. A crude product was obtained. The obtained crude product was dissolved in ethanol and recrystallized from diethyl ether. The precipitated crystals were collected by filtration and dried under reduced pressure at 60 ° C. for 12 hours to obtain purified CF ₃ CH ₂ NH ₃ I. Next, purified CF ₃ CH ₂ NH ₃ I, PbI ₂ and SnI ₂ are used in a molar ratio of 3: 0.99: 0.01 (n1 = 0.01 in the above formula (IB ¹ )), and dimethylformamide (DMF) The mixture was stirred and mixed at 60 ° C. for 5 hours, and then filtered through a polytetrafluoroethylene (PTFE) syringe filter to prepare a 40% by mass light absorber solution (b).

[Production of Photoelectric Conversion Elements (Sample Nos. 202 to 208, C21 to C24)]
In manufacture of a photoelectric conversion element (sample No. 201), it replaced with the light absorber solution (b), and used the light absorber solution produced using the amine (R ^1a NH ₂ ) corresponding to R ^1a shown in Table 2. Photoelectric conversion elements (Sample Nos. 202 to 208 and C21 to C24) were manufactured in the same manner as the manufacture of the photoelectric conversion elements (Sample No. 201) except that they were used.
In each of the manufactured samples, the photosensitive layer was made of the same perovskite compound (P ^B1 ) as the perovskite compound (P ^B1 ) included in the photosensitive layer of the photoelectric conversion element (sample No. 201) except that the organic cation of formula (IB ¹ ) was different. Included.

[Evaluation of moisture resistance]
<Measurement of initial photoelectric conversion efficiency>
Photoelectric conversion efficiency was evaluated as follows.
Each sample No. Three specimens of the photoelectric conversion element were manufactured in the same manner as in the above manufacturing method. A battery characteristic test was performed for each of the three specimens, and the photoelectric conversion efficiency (η /%) was measured. The average value of the three specimens is assigned to each sample No. The initial photoelectric conversion efficiency (η /%) of the photoelectric conversion element was determined. The battery characteristic test was performed by irradiating 1000 W / m ² of simulated sunlight from a xenon lamp through an AM1.5 filter using a solar simulator “WXS-85H” (manufactured by WACOM). The current-voltage characteristics were measured using an IV tester, and the photoelectric conversion efficiency (η /%) was determined.

<Evaluation of moisture resistance>
The moisture resistance of the photoelectric conversion element was evaluated as follows.
Each sample No. Each of the three specimens was stored in a constant temperature and humidity chamber at a temperature of 25 ° C. and a humidity of 60% RH for 24 hours, and then a battery characteristic test was performed in the same manner as described above to measure photoelectric conversion efficiency (η /%). . The average value of the three samples was assigned to each sample No. The photoelectric conversion efficiency (η /%) after storage of the photoelectric conversion element was determined.
The moisture resistance of the photoelectric conversion element was evaluated according to the following evaluation criteria from the maintenance ratio of the photoelectric conversion efficiency calculated by the following formula.

Maintenance rate = (photoelectric conversion efficiency after storage) / (initial photoelectric conversion efficiency)

− Evaluation criteria for moisture resistance −
A: Maintenance ratio is 1.0 or less 0.9 or more B: Maintenance ratio is less than 0.9 0.8 or more C: Maintenance ratio is less than 0.8 0.7 or more D: Maintenance ratio is less than 0.7 Shown in Tables 1 and 2 below.

From the results of Tables 1 and 2 above, in the photoelectric conversion element formed such that the contact angle of water with respect to the surface of the photosensitive layer is smaller than that defined in the present invention, the photoelectric conversion efficiency is as follows. The maintenance rate of the photoelectric conversion efficiency in a high-humidity environment was less than 0.7, and the results were greatly inferior in moisture resistance (Sample Nos. C11 to C13, C21 to C24).
On the other hand, in the photoelectric conversion element formed so that the contact angle of water with the surface of the photosensitive layer is within the range specified in the present invention, the decrease in photoelectric conversion efficiency in a high humidity environment was suppressed (Sample No. 101-103, 201-208). And the one where the contact angle of water with respect to the photosensitive layer surface is higher resulted in better moisture resistance (Sample Nos. 101-103, 201, 204-208). As the contact angle with respect to the surface of the photosensitive layer increases, the moisture resistance does not improve. When the contact angle with respect to the surface of the photosensitive layer increases to 149 °, the contact angle is about 110 to 120 °. The moisture resistance was slightly inferior (Sample No. 208).

Example 3 and Comparative Example 3
[Manufacture of photoelectric conversion elements (sample Nos. 301 to 308, C31, C32)]
In the production of the photoelectric conversion element (sample No. 101), a mixture of R ^1a NH ₂ and R ^2a NH _{2 in the} ratio shown in Table 3 was used instead of trifluoromethylamine in the light absorbent solution (a). Produced photoelectric conversion elements (Sample Nos. 301 to 308, C31, C32) in the same manner as Sample 101 of Example 1.
Sample No. Table 3 shows the moisture resistance evaluation results of 301 to 308 and C31 and C32.

From the results shown in Table 3, in the photoelectric conversion element formed so that the contact angle of water with respect to the surface of the photosensitive layer is smaller than that defined in the present invention, the photosensitive layer has a high humidity environment with respect to the initial photoelectric conversion efficiency. The maintenance rate of the photoelectric conversion efficiency below was less than 0.7, and the results were greatly inferior in moisture resistance (Sample Nos. C31 and C32).
On the other hand, in the photoelectric conversion element formed so that the contact angle of water with the surface of the photosensitive layer is within the range specified in the present invention, the decrease in photoelectric conversion efficiency in a high humidity environment was suppressed (Sample No. .301-308).
The results of Table 3 above show that the contact angle of water with respect to the surface of the photosensitive layer is higher than the ratio of R ^1a and R ^2a , that is, the chemical composition of the crystal structure of the perovskite compound constituting the photosensitive layer. It also shows that it is important for gender.

Example 4 and Comparative Example 4
[Production of Photoelectric Conversion Elements (Sample Nos. 401 to 406, C41 to C44)]
In the production of the photoelectric conversion element (sample No. 101), a 1: 1 mixture (molar ratio) of trifluoromethylamine and methylamine was used instead of trifluoromethylamine in the light absorbent solution (a), and γ-butyrolactone was used. A photoelectric conversion element (sample Nos. 401 to 406, C41 to C44) is manufactured in the same manner as the sample 101 of Example 1 except that an equal volume mixed solution of the solvents 1 to 3 shown in Table 4 is used instead. did.
Sample No. Table 4 shows the moisture resistance evaluation results of 401 to 406 and C41 to C44.

From the results of Table 4, in the photoelectric conversion element formed so that the contact angle of water with respect to the surface of the photosensitive layer is smaller than that defined in the present invention, the photosensitive layer has a high humidity environment with respect to the initial photoelectric conversion efficiency. The maintenance rate of the photoelectric conversion efficiency below became less than 0.7, and the results were greatly inferior in moisture resistance (Sample Nos. C41 to C44).
On the other hand, in the photoelectric conversion element formed so that the contact angle of water with the surface of the photosensitive layer is within the range specified in the present invention, the decrease in photoelectric conversion efficiency in a high humidity environment was suppressed (Sample No. 401-406).
Further, in order to increase the contact angle of water with respect to the photosensitive layer surface, using two solvents, it was found that it is effective to the same most E _T is less solvent and the highest boiling solvent.

  From the above results, it was found that the photoelectric conversion element or the solar cell of the present invention showed excellent moisture resistance.

  Moreover, the form of the photoelectric conversion element in the above Examples 1 to 4 is the form shown in FIGS. A test similar to the above was performed at 150 °. As a result, it was found that the obtained photoelectric conversion element was excellent in moisture resistance as in Examples 1-4.

1A, 1B, 1C, 1D, 1E First electrode 11 Conductive support 11a Support 11b Transparent electrode 12 Porous layer 13A, 13B, 13C Photosensitive layer 14 Blocking layer 15 Electron transport layer 16 Hole transport layer 2 Second electrode 3A, 3B Hole transport layer 4 Electron transport layer 6 External circuit (lead)
10A, 10B, 10C, 10D, 10E Photoelectric conversion elements 100A, 100B, 100C, 100D, 100E A system M electric motor using photoelectric conversion elements for battery applications

Claims (15)

A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The photosensitive layer surface, the contact angle of water, Ri 70 ° to 150 DEG ° der at 25 ° C.,
The cationic organic group A is Ru cationic organic groups der represented by the following formula (1), the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom , and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1 A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The surface of the photosensitive layer has a water contact angle of 70 ° to 150 ° at 25 ° C.,
The cation of the cationic organic group A consists of an organic cation I of a cationic organic group represented by the following formula (1) and an organic cation II of a cationic organic group represented by the following formula (2).
In the entire perovskite crystal structure present in the photosensitive layer, the content of the organic cation I and the content of the organic cation II are in molar ratio: [content of organic cation I]: [content of organic cation II] ] = 99: 1 to 20: 80 meet, the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom , and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
Equation ⁽²⁾ R 2a -NH ₃
In the formula, R ^2a is an unsubstituted hydrocarbon group having 20 or less carbon atoms. The number of carbon atoms in R ^2a is 1 or 2, a photoelectric conversion element according to claim 2. A photoelectric conversion element having a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The surface of the photosensitive layer has a water contact angle of 70 ° to 150 ° at 25 ° C.,
The photoelectric conversion element whose said cationic organic group A is a cationic organic group represented by following formula (1).
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.2 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1 Wherein R ^1a has at least one trifluoromethyl group, a photoelectric conversion device according to any one of claims 1 to 4. The photosensitive layer surface, the contact angle of water is 85 ° to 120 ° at 25 ° C., the photoelectric conversion device according to any one of claims 1-5. Wherein a first electrode having a hole transporting layer between the second electrode, the photoelectric conversion device according to any one of claims 1-6. Solar cell using a photoelectric conversion device according to any one of claims 1-7. A method for producing a photoelectric conversion element comprising a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The manufacturing method applies a solution containing MX ₂ , AX, and a solvent on the conductive support and dries, so that the contact angle of water is 70 ° C. at 25 ° C. on the conductive support. Forming a photosensitive layer having a surface that is between 0 ° and 150 °,
The manufacturing method of the photoelectric conversion element whose said cationic organic group A is a cationic organic group represented by following formula (1).
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.2 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1 A method for producing a photoelectric conversion element comprising a first electrode having a photosensitive layer containing a light absorber on a conductive support, and a second electrode facing the first electrode,
A perovskite crystal structure in which the light absorber has a cation of a group 1 element of the periodic table or a cationic organic group A, a cation of a metal atom M other than the group 1 element of the periodic table, and an anion of an anionic atom X Including compounds having
The manufacturing method applies a solution containing MX ₂ , AX, and a solvent on the conductive support and dries, so that the contact angle of water is 70 ° C. at 25 ° C. on the conductive support. Forming a photosensitive layer having a surface that is between 0 ° and 150 °,
The cation of the cationic organic group A consists of an organic cation I of a cationic organic group represented by the following formula (1) and an organic cation II of a cationic organic group represented by the following formula (2). In the entire perovskite crystal structure present in the photosensitive layer, the content of the organic cation I and the content of the organic cation II are in molar ratio: [content of organic cation I]: [content of organic cation II] ] = 99: 1-20: 80 satisfy | fills the manufacturing method of the photoelectric conversion element.
Formula (1) R ^1a —NH ₃
In the formula, R ^1a is a hydrocarbon group having 20 or less carbon atoms, at least one hydrogen atom of the hydrocarbon group is substituted with a fluorine atom, and R ^1a has a number of fluorine atoms and a number of hydrogen atoms. The following formula is satisfied.
0.5 ≦ number of fluorine atoms / (number of hydrogen atoms + number of fluorine atoms) ≦ 1
Equation ⁽²⁾ R 2a -NH ₃
In the formula, R ^2a is an unsubstituted hydrocarbon group having 20 or less carbon atoms. The method for producing a photoelectric conversion element according to claim 10 , wherein R ^2a has 1 or 2 carbon atoms. 12. The process according to claim 9 , wherein the step of forming the photosensitive layer is a step of forming a photosensitive layer having a surface with a water contact angle of 85 ° to 120 ° at 25 ° C. 12. A method for producing a photoelectric conversion element. The method for producing a photoelectric conversion element according to claim 9 , wherein R ^1a has at least one trifluoromethyl group. In a solution containing a solvent wherein the MX ₂ and AX, the solvent comprises two or more solvents, wherein among the two or more solvents, the most high-boiling solvent solvent polarity parameter E _T, most boiling less than solvent polarity parameter E _T other than high solvent solvent, a method for manufacturing a photoelectric conversion device according to any one of claims 9-13. The manufacturing method of the photoelectric conversion element of any one of Claims 9-14 with which the said photoelectric conversion element has a positive hole transport layer between said 1st electrode and said 2nd electrode.

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