Photoelectric conversion element and compound

Abstract

To provide a photoelectric conversion element in which the hole transport layer shows excellent photoelectric conversion characteristics and which has high durability.SOLUTION: In order to achieve the aforementioned purpose, the photoelectric conversion element of the present invention has a first electrode (12), a hole transport layer (13), a photoelectric conversion layer (14), an electron transport layer (15), and a second electrode (16) stacked in the order, the photoelectric conversion layer (14) includes a perovskite structure, and the hole transport layer (13) has an ionization potential in the range of -5.4 eV to -5.7 eV.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a photoelectric conversion element and a compound. [Background technology]

[0002] In recent years, solar power generation has been attracting attention as a clean energy source, and the development of solar cells has progressed. As one of these, solar cells using perovskite materials in the light absorption layer have rapidly attracted attention as next-generation solar cells that can be manufactured at low cost. For example, Non-Patent Document 1 reports a solution-type solar cell using a perovskite material in the light absorption layer. In addition, Non-Patent Document 2 also reports that solid-state perovskite-type solar cells exhibit high efficiency.

[0003] Known basic structures of perovskite solar cells include a normal structure in which an electron transport layer, a light absorption layer (perovskite layer), a hole transport layer (also called a hole transport layer), and a back electrode are laminated in this order on an electrode, and an inverted structure in which a hole transport layer, a light absorption layer, an electron transport layer, and a back electrode are laminated in this order on an electrode. An electron transport layer having a porous shape may be provided between the electron transport layer and the perovskite layer. Of these, an organic semiconductor hole transport material is generally used for the hole transport layer (for example, Non-Patent Documents 3 to 10). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Journal of the American Chemical Society, 2009, 131, 6050-6051. [Non-Patent Document 2] Science, 2012, 388, 643-647. [Non-Patent Document 3] ACS Appl. Mater. Interfaces, 2017, 9, 24778-24787. [Non-Patent Document 4] Energy Environ. Sci., 2014, 7, 1454-1460. [Non-Patent Document 5] J. Mater. Chem. A, 2014, 2, 6305-6309. [Non-Patent Document 6] J. Mater. Chem. A, 2015, 3, 12139-12144. [Non-Patent Document 7] J. Mater. Chem. A, 2018, 6, 7950-7958. [Non-Patent Document 8] ACS Appl. Mater. Interfaces, 2015, 7, 11107-11116. [Non-Patent Document 9] Energy & Environmental Science 2014, 7, 2963-2967. [Non-Patent Document 10] Adv. Energy Mater., 2018, 8, 1801892. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the photoelectric conversion efficiency of conventional perovskite solar cells is not sufficient. In order to improve the photoelectric conversion efficiency of solar cells, it is particularly important to improve the properties of the hole transport layer. For example, a trachene compound (Non-Patent Document 3), a diketopyrrolopyrrole compound (Non-Patent Document 4), a thiophene compound (Non-Patent Documents 5 and 6), a dithienopyrrole (Non-Patent Document 7), and the like have been reported as hole transport materials used in the hole transport layer. However, there have been few reports of compounds that can exhibit a photoelectric conversion efficiency that can be said to be useful as a perovskite solar cell. Therefore, Spiro-OMeTAD ([2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamino)-9,9'-spirobifluorene]), which was developed as a hole transport material for dye-sensitized solar cells, has been proposed, but it is known to have low heat resistance (Non-Patent Document 8). In addition, it is known that a polymer material having a triphenylamine skeleton, called PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), also has low light resistance. Furthermore, when these materials are used as hole transport materials for the p-buffer layer, it is necessary to add LiTFSI salt (lithium bis(trifluoromethanesulfonyl)imide) as an additive to improve the conductivity, which is thought to be one of the causes of deterioration of the element (Non-Patent Document 9). In addition, a carbazole-type hole transport material having phosphonic acid has been reported in recent years (Non-Patent Document 10). This compound reacts with an indium tin compound (ITO) used as a transparent electrode to form a monolayer on the transparent electrode. This compound is reported to have a photoelectric conversion efficiency of more than 20%, making it a very effective compound, but on the other hand, the ionization potential (IP) of the compound V1036 adsorbed on ITO is -4.98 eV, making it easily oxidized (i.e., it has low durability). Under these circumstances, there is a demand for a material, particularly for the hole transport layer, that exhibits excellent photoelectric conversion characteristics and has high durability.

[0006] Therefore, an object of the present invention is to provide a photoelectric conversion element and a compound in which a hole transport layer exhibits excellent photoelectric conversion characteristics and has high durability. [Means for solving the problem]

[0007] In order to achieve the above object, a first photoelectric conversion element of the present invention comprises: a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are laminated in the above order; The photoelectric conversion layer includes a perovskite structure, The hole transport layer is characterized in that the ionization potential is in the range of −5.4 eV to −5.7 eV.

[0008] The second photoelectric conversion element of the present invention is a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are laminated in the above order; The photoelectric conversion layer includes a perovskite structure, The hole transport layer is characterized by containing a compound represented by the following chemical formula (I). [ka] In the above chemical formula (I), Ar 1 is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may or may not contain a heteroatom, Ar 1 -L 1 -X 1 may or may not have a substituent other than -L 1 -X 1 may be one or more, and if there are more than one, each L 1 and each X 1 may be the same or different from each other, Each L 1 Ar 1 and X 1 or a covalent bond; each X 1 are groups capable of transferring charges to and from the first electrode.

[0009] The compound of the present invention is characterized by being represented by the following chemical formula (I): [ka] In the above chemical formula (I), Ar 1 is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may or may not contain a heteroatom, Ar 1 -L 1 -X 1 may or may not have a substituent other than -L 1 -X 1 may be one or more, and if there are more than one, each L 1 and each X 1 may be the same or different from each other, Each L 1 Ar 1 and X 1 or a covalent bond; each X 1 are groups capable of donating and receiving charges between the electrodes. Effect of the Invention

[0010] According to the present invention, it is possible to provide a photoelectric conversion element and a compound in which a hole transport layer exhibits excellent photoelectric conversion characteristics and has high durability. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the configuration of a photoelectric conversion element of the present invention. [Diagram 2] FIG. 2 is a 1H NMR chart of the compound prepared in the example. [Diagram 3] FIG. 3 is a 1H NMR chart of another compound prepared in the examples. [Figure 4] FIG. 4 is a 1H NMR chart of yet another compound prepared in the examples. [Diagram 5]FIG. 5 is a 1H NMR chart of yet another compound prepared in the examples. [Figure 6] FIG. 6 is a 1H NMR chart of yet another compound prepared in the examples. [Figure 7] FIG. 7 is a 1H NMR chart of yet another compound prepared in the examples. [Figure 8] FIG. 8 is a 1H NMR chart of yet another compound prepared in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will now be described in more detail with reference to examples, although the present invention is not limited to the following description.

[0013] Hereinafter, unless otherwise specified, the term "photoelectric conversion element of the present invention" includes both the "first photoelectric conversion element of the present invention" and the "second photoelectric conversion element of the present invention".

[0014] In the first photoelectric conversion element of the present invention, for example, the hole transport layer may contain a compound represented by the following chemical formula (I).

[0015] [ka]

[0016] In the above chemical formula (I), Ar 1 is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may or may not contain a heteroatom, Ar 1 -L 1 -X 1 may or may not have a substituent other than -L 1 -X 1 may be one or more, and if there are more than one, each L 1 and each X 1 may be the same or different from each other, Each L 1 Ar 1 and X 1 or a covalent bond; each X 1 are groups capable of transferring charges to and from the first electrode. -L 1 -X 1 The number is not particularly limited, but may be in the range of 1 to 4, for example.

[0017] The photoelectric conversion element of the present invention may, for example, be In the above chemical formula (I), each X 1 may each be a phosphonic acid group (-P=O(OH)2), a carboxy group (-COOH), a sulfo group (-SO3H), a boronic acid group (-B(OH)2), a trihalogenated silyl group (-SiX3, where X is a halo group), or a trialkoxysilyl group (-Si(OR)3, where R is an alkyl group).

[0018] The photoelectric conversion element of the present invention may, for example, be 1 may be represented by the following chemical formula (I-1).

[0019] [ka]

[0020] In the above chemical formula (I-1), Ar 11 is an atomic group containing a cyclic structure, the cyclic structure may be an aromatic ring or a non-aromatic ring, a monocyclic ring, a condensed ring, or a spiro ring, and may or may not contain heteroatoms among the atoms constituting the ring, Ar 12 is an aromatic ring, which may or may not contain heteroatoms among the atoms constituting the ring, Ar 12 assigns one or more atoms to Ar 11 Share with Ar 11 It may be integrated with Ar 12may be one or more, and when there are more than one, they may be the same or different. Ar 12 The number is not particularly limited, but may be in the range of 1 to 4, for example.

[0021] The photoelectric conversion element of the present invention may further include, for example, 11 may be represented by any of the following chemical formulas (a1) to (a10).

[0022] [ka]

[0023] The photoelectric conversion element of the present invention may further include, for example, 12 may each be represented by the following chemical formula (b).

[0024] [ka]

[0025] In the above chemical formula (b), Carbon atom C 1 and C 2 is the Ar in the chemical formula (I-1). 11 and R 1 represents a hydrogen atom, X in the above chemical formula (I) 1 or a substituent, which may or may not contain a hydrogen atom, and at least one of the hydrogen atoms in the substituent is X in the formula (I). 1 may be substituted with Each of the above R 11 may be the same or different, each of which is a hydrogen atom or a substituent, or two adjacent R 11 may form a condensed ring together with the benzene ring to which they are attached, Each of the above R 11may or may not further have a substituent.

[0026] In the photoelectric conversion element of the present invention, for example, the chemical formula (b) may be represented by any one of the following chemical formulas (b1) to (b7).

[0027] [ka] In the above chemical formulas (b1) to (b7), C 1 , C 2 and R 1 are the same as those in the above chemical formula (b).

[0028] In the photoelectric conversion element of the present invention, for example, the compound represented by the chemical formula (I) may be a compound represented by any one of the following chemical formulae A-1 to A-23.

[0029] [ka]

[0030] [ka]

[0031] [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] In the above chemical formulas A-1 to A-23, Each of the above R 1 are each a hydrogen atom or X in the chemical formula (I) 1 or X in the formula (I) 1 which may be the same or different, Each of the above R 1 At least one of the X in the chemical formula (I) 1 or X in the formula (I) 1 is a substituent further substituted with R 2 is a substituent, which may be present in one or more, or may not be present. When there are more than one, each R 2 may be the same or different from each other.

[0036] In the above chemical formulas A-1 to A-23, R 1 In the above chemical formula (I), X 1 If it is a substituent further substituted with X 1 The number of may be one or more. 1 In the above chemical formula (I), X 1 In the case where the substituent is further substituted with, for example, X in the above chemical formula (I) 1 It may be an alkyl group or an alkoxy group further substituted with .

[0037] In the chemical formulae A-1 to A-23, the substituent R 2 The number of the substituents R 2 may be, for example, an alkyl group, an alkoxy group, or a halo group (halogen atom).

[0038] In the photoelectric conversion element of the present invention, for example, the compound represented by chemical formula (I) may be a compound represented by the following chemical formula 4PATAT, 1-legged-3PATAT, 1-legged-3PATAT-H, 2-legged-3PATAT, 4PATTI-C3, or 4PATTI-C4.

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka] [ka] [ka]

[0043] In the photoelectric conversion element of the present invention, for example, the hole transport layer may further contain a co-adsorbent.

[0044] In the photoelectric conversion element of the present invention, for example, the co-adsorbent may be a compound represented by the following chemical formula (II).

[0045] [ka]

[0046] In the above formula (II), L 2 is an alkyl group, an alkoxy group, an aryl group, or a heterocycle; L 2 At least one hydrogen atom of X 2 is replaced by X 2 may or may not have a substituent other than X 2is a group capable of transferring charge between the first electrode and the first electrode, and may be one or more, and when there are more than one, they may be the same or different.

[0047] The photoelectric conversion element of the present invention may, for example, be In the above formula (II), each X 2 may each be a phosphonic acid group (-P=O(OH)2), a carboxy group (-COOH), a sulfo group (-SO3H), a boronic acid group (-B(OH)2), a trihalogenated silyl group (-SiX3, where X is a halo group), or a trialkoxysilyl group (-Si(OR)3, where R is an alkyl group).

[0048] In the photoelectric conversion element of the present invention, for example, the molecular weight of the co-adsorbent may be 2,000 or less.

[0049] In the photoelectric conversion element of the present invention, for example, the photoelectric conversion layer may contain an organic-inorganic perovskite compound.

[0050] In the photoelectric conversion element of the present invention, for example, the organic-inorganic perovskite compound may contain at least one of tin and lead.

[0051] The photoelectric conversion element of the present invention may be, for example, a solar cell.

[0052] The compound of the present invention is, for example, a compound represented by the formula (I): 1 -X 1 The number may be in the range of 1 to 4.

[0053] The compounds of the present invention are, for example, In the above chemical formula (I), each X 1 may each be a phosphonic acid group (-P=O(OH)2), a carboxy group (-COOH), a sulfo group (-SO3H), a boronic acid group (-B(OH)2), a trihalogenated silyl group (-SiX3, where X is a halo group), or a trialkoxysilyl group (-Si(OR)3, where R is an alkyl group).

[0054] The compounds of the present invention are, for example, In the above chemical formula (I), the Ar 1 may be represented by the following chemical formula (I-1).

[0055] [ka]

[0056] In the above chemical formula (I-1), Ar 11 is an atomic group containing a cyclic structure, the cyclic structure may be an aromatic ring or a non-aromatic ring, a monocyclic ring, a condensed ring, or a spiro ring, and may or may not contain heteroatoms among the atoms constituting the ring, Ar 12 is an aromatic ring, which may or may not contain heteroatoms among the atoms constituting the ring, Ar 12 assigns one or more atoms to Ar 11 Share with Ar 11 It may be integrated with Ar 12 may be one or more, and when there are more than one, they may be the same or different. Ar 12 The number is not particularly limited, but may be in the range of 1 to 4, for example.

[0057] The compounds of the present invention are, for example, In the chemical formula (I-1), the Ar 11 may be represented by any of the following chemical formulas (a1) to (a10).

[0058] [ka]

[0059] The compounds of the present invention are, for example, In the chemical formula (I-1), each Ar 12 may each be represented by the following chemical formula (b).

[0060] [ka]

[0061] In the above chemical formula (b), Carbon atom C 1 and C 2 is the Ar in the chemical formula (I-1). 11 and R 1 represents a hydrogen atom, X in the above chemical formula (I) 1 or a substituent, which may or may not contain a hydrogen atom, and at least one of the hydrogen atoms in the substituent is X in the formula (I). 1 may be substituted with Each of the above R 11 may be the same or different, each of which is a hydrogen atom or a substituent, or two adjacent R 11 may form a condensed ring together with the benzene ring to which they are attached, Each of the above R 11 may or may not further have a substituent.

[0062] The compounds of the present invention are, for example, The chemical formula (b) may be represented by any one of the following chemical formulas (b1) to (b7).

[0063] [ka] In the above chemical formulas (b1) to (b7), C 1 , C 2 and R 1 are the same as those in the above chemical formula (b).

[0064] The compounds of the present invention are, for example, The compound represented by the chemical formula (I) may be a compound represented by any one of the following chemical formulae A-1 to A-23.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] In the above chemical formulas A-1 to A-23, Each of the above R 1 are each a hydrogen atom or X in the chemical formula (I) 1 or X in the formula (I) 1 which may be the same or different, Each of the above R 1 At least one of the X in the chemical formula (I) 1 or X in the formula (I) 1 is a substituent further substituted with R 2 is a substituent, which may be present in one or more, or may not be present. When there are more than one, each R 2 may be the same or different from each other.

[0072] In the above chemical formulas A-1 to A-23, R1 In the above chemical formula (I), X 1 If it is a substituent further substituted with X 1 The number of may be one or more. 1 In the above chemical formula (I), X 1 In the case where the substituent is further substituted with, for example, X in the above chemical formula (I) 1 It may be an alkyl group or an alkoxy group further substituted with .

[0073] In the chemical formulae A-1 to A-23, the substituent R 2 The number of the substituents R 2 may be, for example, an alkyl group, an alkoxy group, or a halo group (halogen atom).

[0074] The compounds of the present invention are, for example, The compound represented by formula (I) may be a compound represented by the following formula: 4PATAT, 1-legged-3PATAT, 1-legged-3PATAT-H, 2-legged-3PATAT, 4PATTI-C3, or 4PATTI-C4.

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] [ka] [ka] [ka]

[0079] The compound of the present invention is, for example, X in the above chemical formula (I). 1 However, instead of the group capable of transferring charge to and from the electrode, a group in which at least one hydrogen atom of the group capable of transferring charge to and from the electrode is substituted with a further substituent. The substituent may be, for example, an alkyl group or a halogen atom, and when there are a plurality of substituents, they may be the same or different from each other.

[0080] The compounds of the present invention are, for example, In the above chemical formula (I), each X 1 may be a phosphonate ester group (-P=O(OR)2), a carboxylate ester group (-COOR), a sulfonate ester group (-SO3R), or a boronic ester group (-B(OR)2). 1 In the formula (I), R is a substituent, and when there are a plurality of R, they may be the same or different. 1 wherein each substituent R may be, for example, an alkyl group or a halogen atom.

[0081] The compounds of the present invention are, for example, The compound represented by formula (I) may be a compound represented by the following formula: 4PAE-TAT, 1-legged-3PAE-TAT-H, 1-legged-3PAEE-TAT, 2-legged-3PAH-TAT, 4PATTI-C3, or 4PATTI-C4.

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka] [ka] [ka]

[0086] In the present invention, unless otherwise specified, a chain group or atomic group (e.g., a hydrocarbon group such as an alkyl group or an unsaturated aliphatic hydrocarbon group) may be linear or branched, and the number of carbon atoms is not particularly limited, but may be, for example, 1 to 40, 1 to 32, 1 to 24, 1 to 18, 1 to 12, 1 to 6, or 1 to 2 (2 or more in the case of an unsaturated hydrocarbon group). In addition, in the present invention, the number of ring members (the number of atoms constituting the ring) of a cyclic group or atomic group (e.g., an aromatic ring, an aromatic group, etc., such as an aryl group, a heteroaryl group, etc.) is not particularly limited, but may be, for example, 5 to 32, 5 to 24, 6 to 18, 6 to 12, or 6 to 10. In addition, when an isomer exists in a substituent, etc., any isomer may be used unless otherwise specified, and for example, when simply referring to a "naphthyl group", it may be a 1-naphthyl group or a 2-naphthyl group.

[0087] In the present invention, the "substituent" is not particularly limited, and examples thereof include an alkyl group, an unsaturated aliphatic hydrocarbon group, an alkoxy group, an aralkyl group, an aryl group, a heteroaryl group, a halogen, a hydroxy group (-OH), a mercapto group (-SH), an alkylthio group (-SR, R is an alkyl group), a sulfo group, a nitro group, a diazo group, a cyano group, and a trifluoromethyl group.

[0088] In the present invention, when a compound has isomers such as tautomers or stereoisomers (e.g., geometric isomers, conformational isomers, and optical isomers), any of the isomers can be used in the present invention, unless otherwise specified. In the present invention, when a compound can form a salt, the salt can also be used in the present invention, unless otherwise specified. The salt may be an acid addition salt or a base addition salt. Furthermore, the acid that forms the acid addition salt may be an inorganic acid or an organic acid, and the base that forms the base addition salt may be an inorganic base or an organic base. The inorganic acid is not particularly limited, but examples thereof include sulfuric acid, phosphoric acid, hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, hypofluorite acid, hypochlorous acid, hypobromite acid, hypoiodite acid, fluorite acid, chlorous acid, bromite acid, iodite acid, fluorine acid, chlorine acid, bromine acid, iodic acid, perfluorine acid, perchloric acid, perbromine acid, and periodic acid. The organic acid is also not particularly limited, but examples thereof include p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromobenzenesulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, and acetic acid. The inorganic base is not particularly limited, but examples thereof include ammonium hydroxide, alkali metal hydroxide, alkaline earth metal hydroxide, carbonate, and hydrogen carbonate, and more specifically, examples thereof include sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydroxide, and calcium carbonate. The organic base is also not particularly limited, but examples thereof include ethanolamine, triethylamine, and tris(hydroxymethyl)aminomethane. The method for producing these salts is also not particularly limited, and for example, they can be produced by a method in which the above-mentioned acid or base is appropriately added to the compound by a known method.

[0089] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0090] [Photoelectric conversion element] As described above, the first photoelectric conversion element of the present invention is a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are laminated in the above order; The photoelectric conversion layer includes a perovskite structure, The hole transport layer is characterized in that the ionization potential is in the range of −5.4 eV to −5.7 eV.

[0091] As described above, the second photoelectric conversion element of the present invention comprises: a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are laminated in the above order; The photoelectric conversion layer includes a perovskite structure, The hole transport layer is characterized in that it contains a compound represented by the following chemical formula (I): 1 , L 1 and X 1 The above is the same as above. 1 -X 1 The number is not particularly limited, but may be in the range of 1 to 4, for example. [ka]

[0092] As described above, the photoelectric conversion element of the present invention has the first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode stacked in the above order. The photoelectric conversion element of the present invention may or may not include other components other than the first electrode, the hole transport layer, the photoelectric conversion layer, the electron transport layer, and the second electrode. For example, the first electrode and the hole transport layer may be directly stacked without any other components being present between them, or other components may be present between them. Similarly, the hole transport layer and the photoelectric conversion layer may be directly stacked without any other components being present between them, or other components may be present between them. Similarly, the photoelectric conversion layer and the electron transport layer may be directly stacked without any other components being present between them, or other components may be present between them. Similarly, the electron transport layer and the second electrode may be directly stacked without any other components being present between them, or other components may be present between them.

[0093] Each component in the photoelectric conversion element of the present invention is not particularly limited except that the ionization potential of the hole transport layer is in the range of -5.4 eV to -5.7 eV (first photoelectric conversion element of the present invention) or the hole transport layer contains a compound represented by the chemical formula (I) (second photoelectric conversion element of the present invention), and may be similar to or equivalent to a general photoelectric conversion element (for example, a general photoelectric conversion cell). In the first photoelectric conversion element of the present invention, the hole transport layer is not particularly limited except that the ionization potential is -5.4 eV to -5.7 eV, and may or may not contain a compound represented by the chemical formula (I). In the second photoelectric conversion element of the present invention, the hole transport layer is not particularly limited except that the hole transport layer contains a compound represented by the chemical formula (I), and may or may not have an ionization potential in the range of -5.4 eV to -5.7 eV.

[0094] The configuration and each component of the photoelectric conversion element of the present invention will be described in more detail below with reference to examples. However, the photoelectric conversion element of the present invention is not limited to the following examples. In the following, the photoelectric conversion element of the present invention will be mainly described as a solar cell.

[0095] An example of the configuration of the photoelectric conversion element of the present invention is shown in the cross-sectional view of Fig. 1. For convenience of explanation, Fig. 1 is drawn in a schematic manner with appropriate omissions and exaggerations. As shown in the figure, this photoelectric conversion element 10 has a first electrode 12, a hole transport layer 13, a photoelectric conversion layer 14, an electron transport layer 15, and a second electrode 16 laminated in the above order on a support (also called a substrate, base material, etc.) 11.

[0096] [Support 11] The support 11 is not particularly limited, and may be, for example, a substrate that can be used for a photoelectric conversion element such as a general solar cell. Examples of the substrate include glass, a plastic plate, a plastic film, and an inorganic crystal. In addition, a substrate having at least one film selected from a metal film, a semiconductor film, a conductive film, and an insulating film formed on a part or all of the surface of the substrate can also be suitably used as the support 11. The size, thickness, etc. of the support 11 are also not particularly limited, and may be the same as or equivalent to a photoelectric conversion element such as a general solar cell.

[0097] [First electrode 12] The first electrode 12 is, for example, a layer that supports the hole transport layer 13 and has a function of extracting holes from the photoelectric conversion layer 14. In addition, the first electrode 12 is, for example, a layer that acts as a cathode (positive electrode).

[0098] The first electrode 12 may be formed directly on the support 11, for example. The first electrode 12 may be a transparent electrode formed from a conductor, for example. The transparent electrode is not particularly limited, but examples thereof include a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In2O3) film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide (FTO) film, a laminated film formed by laminating two or more of these, gold, silver, copper, aluminum, tungsten, titanium, chromium, nickel, and cobalt. These may be used alone or in a mixture of two or more, and may be a single layer or a laminate. These films may function as, for example, a diffusion prevention layer. The thickness of the first electrode 12 is not particularly limited, but it is preferable to adjust the sheet resistance to, for example, 5 to 15 Ω / □ (per unit area). The method for forming the first electrode 12 is not particularly limited, but it can be obtained by a known film formation method depending on the material to be formed, for example. The shape of the first electrode 12 is not particularly limited, but may be a film or a lattice such as a mesh. The method of forming the first electrode 12 on the support 11 is not particularly limited, but may be a known method, and vacuum film formation such as vacuum deposition or sputtering is preferable. The first electrode 12 may be patterned. The patterning method is not limited to, but may be, for example, a method of immersing in a laser or etching solution, or a method of patterning using a mask during vacuum film formation, and any method may be used in the present invention. The first electrode 12 may also be used in combination with metal wiring or the like for the purpose of reducing the electrical resistance value. The material of the metal wiring (metal lead wire) is not particularly limited, but may be, for example, aluminum, copper, silver, gold, platinum, nickel, etc. The metal lead wire can be used in combination by forming it on the first substrate by, for example, deposition, sputtering, pressure bonding, etc., and providing an ITO or FTO layer thereon, or providing it on ITO or FTO.

[0099] [Hole transport layer 13] As described above, the hole transport layer 13 has an ionization potential in the range of -5.4 eV to -5.7 eV (first photoelectric conversion element of the present invention) or contains a compound represented by the chemical formula (I) (second photoelectric conversion element of the present invention). Other than this, the hole transport layer 13 is not particularly limited, and may be the same as or equivalent to a hole transport layer of a general photoelectric conversion element (for example, a general storage cell).

[0100] From the viewpoint of suppressing or preventing the hole transport layer 13 from reacting with oxygen and being altered (i.e., improving the durability of the hole transport layer 13), the ionization potential of the hole transport layer 13 is preferably −5.4 eV or less. Moreover, from the viewpoint of suppressing or preventing mismatching in level matching with the perovskite compound used in the photoelectric conversion layer 14 (i.e., improving the photoelectric conversion efficiency), the ionization potential of the hole transport layer 13 is preferably −5.7 eV or more.

[0101] In order to set the ionization potential of the hole transport layer 13 within the range of −5.4 eV to −5.7 eV, for example, the compound represented by the above chemical formula (I) can be used.

[0102] The chemical formula (I) is, for example, as described above. 1 In addition to the above, examples of X include divalent alkylene groups such as 1,1-methylene and 1,2-ethylene groups, and divalent alkoxy groups such as diethoxyethane. 1 It may or may not have a substituent other than the above.

[0103] The X in the chemical formula (I) 1As described above, examples of the group include a phosphonic acid group (-P=O(OH)2), a carboxy group (-COOH), a sulfo group (-SO3H), a boronic acid group (-B(OH)2), a trihalogenated silyl group (-SiX3, where X is a halo group), and a trialkoxysilyl group (-Si(OR)3, where R is an alkyl group). Among these, the phosphonic acid group, the trihalogenated silyl group, and the trialkoxysilyl group are preferred from the viewpoint of being able to bond strongly to the first electrode 12 (e.g., a transparent electrode).

[0104] The compound represented by the chemical formula (I) can be used, for example, as a hole transport compound that forms a monolayer on a transparent conductive film. The transparent conductive film is, for example, the first electrode that is a transparent electrode, and the transparent electrode is, for example, ITO or the like, as described above. The compound represented by the chemical formula (I), for example, as described above, has an ionization potential of -5.4 eV or less, so that it is difficult to react with oxygen, and a device (element) can be stably produced, and a photoelectric conversion element with high durability can be obtained.

[0105] The method for forming the hole transport layer 13 is not particularly limited, but for example, the compound represented by the chemical formula (I) is adsorbed on the first electrode 12 to form a monolayer, thereby forming the hole transport layer 13. The method for adsorbing the compound represented by the chemical formula (I) on the first electrode 12 to form a monolayer is not particularly limited, but for example, the compound represented by the chemical formula (I) may be dissolved in a solvent and brought into contact with the first electrode 12 to be bonded. The bond between the compound represented by the chemical formula (I) and the first electrode 12 is not particularly limited, and may be a physical bond or a chemical bond. The type of the bond is also not particularly limited, and may be, for example, any of a hydrogen bond, an ester bond, a chelate bond, and the like. The solvent for dissolving the compound represented by the chemical formula (I) is also not particularly limited, and may be, for example, one of water and an organic solvent, or both. More specifically, examples of the solvent include water, alcohols such as methanol, ethanol, and 2-propanol, ethers such as diethyl ether and diisopropyl ether, ketones such as acetone and methyl isobutyl ketone, esters such as ethyl acetate, isobutyl acetate, and γ-butyrolactone, heterocycles such as tetrahydrofuran and thiophene, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, sulfoxides such as dimethyl sulfoxide, sulfones such as diethyl sulfone and sulfolane, nitriles such as acetonitrile and 3-methoxypropionitrile, aromatic compounds such as benzene, toluene, and chlorobenzene, halogen-based solvents such as dichloromethane and chloroform, and fluorine-based solvents such as chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons. These may be used alone or in combination of two or more.

[0106] The specific method for adsorbing the compound represented by the chemical formula (I) on the first electrode 12 to form a monolayer is not particularly limited, but examples thereof include known methods such as dipping, spraying, spin coating, and bar coating. The temperature during adsorption is not particularly limited, but is preferably -20°C to 100°C, and more preferably 0°C to 50°C. The adsorption time is also not particularly limited, but is preferably 1 second to 48 hours, and more preferably 10 seconds to 1 hour.

[0107] After the adsorption treatment, for example, washing may or may not be performed. The washing method is not particularly limited, and for example, a known method may be appropriately used.

[0108] After the adsorption treatment or the washing, a heat treatment may or may not be performed. The temperature of the heat treatment is preferably 50° C. to 150° C., more preferably 70° C. to 120° C. The heat treatment time is preferably 1 second to 48 hours, more preferably 10 seconds to 1 hour. The heat treatment may be performed, for example, in the atmosphere or in a vacuum.

[0109] When the compound represented by the chemical formula (I) is adsorbed on the first electrode 12, for example, a co-adsorbent may or may not be used in combination. The co-adsorbent may be added, for example, when the electrode surface cannot be completely covered by the compound represented by the chemical formula (I) alone, or for the purpose of inhibiting the interaction between the compounds represented by the chemical formula (I).

[0110] The co-adsorbent is not particularly limited, but for example, as described above, a compound represented by the chemical formula (II) can be used. 2 and X 2 For example, as described above.

[0111] Specific examples of the compound represented by the chemical formula (II) include, but are not limited to, phosphonic acid compounds such as n-butylphosphonic acid, n-hexylphosphonic acid, n-decylphosphonic acid, n-octadecylphosphonic acid, 2-ethylhexylphosphonic acid, methoxymethylphosphonic acid, 3-acryloyloxypropylphosphonic acid, 11-hydroxyundecylphosphonic acid, and 1H,1H,2H,2H-perfluorophosphonic acid, acetic acid, propionic acid, isobutyric acid, nonanoic acid, fluoroacetic acid, α-chloropropionic acid, and glyoxylic acid, which may be used alone or in combination of two or more kinds.

[0112] The molecular weight of the compound represented by the chemical formula (II) is not particularly limited, and may be, for example, 2,000 or less as described above, for example, 1,500 or less, or may be, for example, 500 or more. The smaller the molecular weight, the higher the coverage when forming a layer on an electrode (e.g., ITO), so the smaller the molecular weight, the more preferable it is.

[0113] The method of adsorbing the co-adsorbent on the first electrode 12 is not particularly limited, but it is preferable to dissolve the co-adsorbent in a solvent and then adsorb it, similar to the compound represented by the chemical formula (I). The solvent is also not particularly limited, but may be, for example, the same as the solvent exemplified for the compound represented by the chemical formula (I). The co-adsorbent may be adsorbed by immersing the first electrode 12 in a solvent in which the co-adsorbent is dissolved after the compound represented by the chemical formula (I) is once adsorbed on the substrate, or may be mixed and dissolved in an organic solvent together with the compound represented by the chemical formula (I).

[0114] [Photoelectric conversion layer 14] The photoelectric conversion layer 14 is not particularly limited, and may be the same as a photoelectric conversion layer used in a photoelectric conversion element such as a general solar cell. The photoelectric conversion layer 14 includes, for example, a perovskite compound. The perovskite compound may be, for example, a compound represented by the following chemical formula (III). XαYβZγ...(III)

[0115] In the chemical formula (III), the ratio of α:β:γ is 3:1:1, and β and γ are integers greater than 1. X represents a halogen ion, Y represents an organic compound having an amino group, and Z represents a metal ion. The perovskite layer is preferably disposed adjacent to the electron transport layer. Note that the ratio of α:β:γ does not necessarily have to be 3:1:1, for example, 3:1.05:0.95.

[0116] X in the chemical formula (III) is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include halogen ions such as chlorine, bromine, iodine, etc. These may be used alone or in combination of two or more.

[0117] Examples of Y in the chemical formula (III) include alkylamine compound ions (organic compounds having an amino group) such as methylamine, ethylamine, n-butylamine, and formamidine, and alkali metal ions such as cesium, potassium, and rubidium, as well as organic ions. The alkylamine compound ions and alkali metal ions may be used alone or in combination of two or more. In addition, organic (alkylamine compound ions) and inorganic (alkali metal ions) may be used in combination, for example, cesium ions and formamidine may be used in combination.

[0118] Z in the chemical formula (III) is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include metals such as lead, indium, antimony, tin, copper, and bismuth. These may be used alone or in combination of two or more. In particular, lead is preferable, and a combination of lead and tin is particularly preferable. In addition, the perovskite layer preferably exhibits a layered perovskite structure in which a layer made of a metal halide and a layer in which organic cation molecules are arranged are alternately laminated. The perovskite layer may contain an alkali metal. If the perovskite layer contains at least an alkali metal, it is advantageous in that the output is high. Examples of the alkali metal include cesium, rubidium, and potassium. Among these, cesium is preferable.

[0119] As described above, the photoelectric conversion layer 14 may be a perovskite layer formed from a perovskite compound. The method for forming such a perovskite layer is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a method in which a solution in which a metal halide and an alkylamine halide are dissolved or dispersed is applied and then dried.

[0120] The method for forming the perovskite layer may be, for example, by dissolving or After applying the dispersed solution and drying, the sample was immersed in a solution containing a halogenated alkylamine. and a two-step precipitation method for forming a perovskite compound.

[0121] Other methods for forming a perovskite layer include, for example, a method in which a solution in which a metal halide and an alkylamine halide are dissolved or dispersed is applied while a poor solvent (a solvent with low solubility) for the perovskite compound is added to precipitate crystals.

[0122] Another method for forming a perovskite layer is to use a solution filled with methylamine, etc. Another method is to deposit a metal halide in the gas.

[0123] As a method for forming a perovskite layer, a method in which a poor solvent for the perovskite compound is added while applying a solution in which a metal halide and an alkylamine halide are dissolved or dispersed is particularly preferred to precipitate crystals. The method for applying these solutions is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include immersion, spin coating, spraying, dipping, roller, and air knife methods. In addition, the method for applying the solution may be, for example, a method in which the solution is precipitated in a supercritical fluid using carbon dioxide or the like. In the method of precipitating crystals by adding a poor solvent as described above, examples of the poor solvent to be used include hydrocarbons such as n-hexane and n-octane; alcohols such as methanol, ethanol and 2-propanol; ethers such as diethyl ether and diisopropyl ether; ketones such as acetone and methyl isobutyl ketone; esters such as ethyl acetate, isobutyl acetate and γ-butyrolactone; nitriles such as acetonitrile and 3-methoxypropionitrile; aromatic hydrocarbon compounds such as benzene, toluene and chlorobenzene; halogen-based solvents such as dichloromethane and chloroform; and fluorine-based solvents such as chlorofluorocarbons, hydrochlorofluorocarbons and hydrofluorocarbons.

[0124] The thickness of the photoelectric transport layer 14 (for example, a light absorbing layer, such as a perovskite layer) is not particularly limited, but is preferably 50 to 1200 nm, more preferably 200 to 600 nm, from the viewpoint of further suppressing performance deterioration due to defects or peeling.

[0125] [Electron transport layer 15] The material used for the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a semiconductor material. The semiconductor material is not particularly limited and any known material can be used, such as an elemental semiconductor, a compound semiconductor, or an organic n-type semiconductor.

[0126] The elemental semiconductor is not particularly limited, but examples thereof include silicon and germanium.

[0127] The compound semiconductor is not particularly limited, but examples thereof include metal chalcogenides, specifically oxides of titanium, tin, zinc, iron, tungsten, zirconium, hafnium, strontium, indium, cerium, yttrium, lanthanum, vanadium, niobium, tantalum, etc.; sulfides of cadmium, zinc, lead, silver, antimony, bismuth, etc.; selenides of cadmium, lead, etc.; tellurides of cadmium, etc. Other compound semiconductors include phosphides of zinc, gallium, indium, cadmium, etc., gallium arsenide, copper-indium-selenide, copper-indium-sulfide, etc.

[0128] The organic n-type semiconductor is not particularly limited, but examples thereof include perylene tetracarboxylic anhydride, perylene tetracarboxydiimide compound, naphthalene diimide-bithiophene copolymer, benzobisimidazobenzophenanthroline polymer, C60, C70, PCBM ([6,6]-phenyl-C 61 -butyric acid methyl ester), carbonyl-bridged bithiazole compounds, ALq3 (tris(8-quinolinolato)aluminum), triphenylene bipyridyl compounds, silole compounds, oxadiazole compounds, and the like can be given.

[0129] Among the above-mentioned materials used for the electron transport layer 15, organic n-type semiconductors are particularly preferred.

[0130] The material used to form the electron transport layer 15 may be one type alone or two or more types in combination. The crystal type of the semiconductor material is not particularly limited and may be appropriately selected depending on the purpose, and may be single crystal, polycrystal, or amorphous.

[0131] The thickness of the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 nm to 1000 nm, more preferably 10 nm to 700 nm.

[0132] The method for forming the electron transport layer 15 is not particularly limited and can be appropriately selected depending on the purpose. For example, a method for forming a thin film in a vacuum (vacuum film-forming method) and a wet film-forming method can be mentioned. Examples of the vacuum film-forming method include a sputtering method, a pulsed laser deposition method (PLD method), an ion beam sputtering method, an ion-assisted method, an ion plating method, a vacuum deposition method, an atomic layer deposition method (ALD method), and a chemical vapor deposition method (CVD method). Examples of the wet film-forming method include a method for forming a film by applying a solvent in which an electron transport material is dissolved, and in the case of an oxide semiconductor, a sol-gel method can be mentioned. The sol-gel method is a method in which a gel is produced from a solution through a chemical reaction such as hydrolysis, polymerization, and condensation, and then densification is promoted by a heat treatment. When the sol-gel method is used, the method of applying the sol solution is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include dipping, spraying, wire bar, spin coating, roller coating, blade coating, and gravure coating, and wet printing methods include letterpress, offset, gravure, intaglio, rubber plate, and screen printing. The temperature during the heat treatment after applying the sol solution is preferably 80° C. or higher, and more preferably 100° C. or higher.

[0133] After forming the electron transport layer 15, an electron injection layer (hole blocking layer) may be formed between the second electrode 16. An example of a material used for the electron injection layer is BCP (bathocuproine), which may be doped with cesium. The electron injection layer is preferably 1 nm to 100 nm, more preferably 3 nm to 20 nm.

[0134] [Second electrode 16] The second electrode 16 (which may be, for example, a back electrode) is, for example, a layer having a function of extracting electrons from the photoelectric conversion layer 14 via an electron transport layer. The second electrode 16 is, for example, a layer that functions as an anode (negative electrode).

[0135] The second electrode 16 may be formed directly on the electron transport layer (also called the electron injection layer) 15. The material of the second electrode 16 is not particularly limited, and for example, the same material as that of the first electrode 12 can be used. The shape, structure, and size of the second electrode 16 are not particularly limited, and can be appropriately selected depending on the purpose. Examples of the material of the second electrode 16 include metals, carbon compounds, conductive metal oxides, and conductive polymers.

[0136] Examples of the metal include platinum, gold, silver, copper, and aluminum.

[0137] Examples of the carbon compound include graphite, fullerene, carbon nanotube, and graphene.

[0138] Examples of the conductive metal oxide include ITO, FTO, and ATO.

[0139] Examples of the conductive polymer include polythiophene and polyaniline.

[0140] The material used to form the second electrode 16 may be one type alone or two or more types in combination.

[0141] The second electrode 16 can be formed on the electron transport layer 15 by using a method such as coating, lamination, vacuum deposition, CVD, or bonding, depending on the type of material used and the type of the hole transport layer 13.

[0142] In the photoelectric conversion element of the present invention, it is preferable that at least one of the first electrode 12 and the second electrode 16 is substantially transparent. When using the photoelectric conversion element of the present invention, it is preferable to make the electrodes transparent and allow incident light to be incident from the electrode side. In this case, it is preferable to use a material that reflects light for the back electrode (the electrode opposite to the transparent electrode, for example, the second electrode), and metals, glass on which conductive oxides are vapor-deposited, plastics, metal thin films, etc. are preferably used. It is also an effective means to provide an anti-reflection layer on the electrode on the incident light side.

[0143] Furthermore, the configuration of the photoelectric conversion element of the present invention is not limited to the configuration of FIG. 1. For example, the support 11 may be disposed on the opposite side to that of FIG. 1 (above the second electrode 16 in FIG. 1), and the second electrode 16, the electron transport layer 15, the photoelectric conversion layer 14, the hole transport layer 13, and the first electrode 12 may be laminated on the support 11 in the above order. Also, for example, as described above, other components may or may not be present between the layers of the support 11, the first electrode 12, the hole transport layer 13, the photoelectric conversion layer 14, the electron transport layer 15, and the second electrode 16. Also, although an example in which the first electrode 12 is a transparent electrode and the second electrode 16 is a back electrode has been described, the photoelectric conversion element of the present invention is not limited to this. For example, in the photoelectric conversion element of the present invention, the first electrode may be a back electrode and the second electrode may be a transparent electrode.

[0144] [Sealing] The photoelectric conversion element of the present invention (e.g., a solar cell) is preferably sealed to protect the device (the photoelectric conversion element of the present invention) from water and oxygen. The sealing structure is not particularly limited, and may be the same as that of a general photoelectric conversion element (e.g., a solar cell). Specifically, for example, a sealing material may be applied only to the outer periphery of the photoelectric conversion element of the present invention and covered with glass or a film, a sealing material may be applied to the entire surface of the photoelectric conversion element of the present invention and covered with glass or a film, or a sealing material may be applied only to the entire surface of the photoelectric conversion element of the present invention.

[0145] The material of the sealing member is not particularly limited and can be appropriately selected depending on the purpose. For example, For example, it is preferable to use epoxy resin or acrylic resin and harden it, but it does not matter if it is not hardened or only partially hardened.

[0146] The epoxy resin is not particularly limited, but examples thereof include water-dispersed, solvent-free, solid, heat-cured, curing agent-mixed, and ultraviolet-cured resins. Of these, heat-cured and ultraviolet-cured resins are preferred, and ultraviolet-cured resins are more preferred. In addition, even in the case of ultraviolet-cured resins, heating is possible, and it is preferred to heat the resins even after ultraviolet curing. Specific examples of epoxy resins include bisphenol A type, bisphenol F type, novolac type, cyclic aliphatic type, long-chain aliphatic type, glycidylamine type, glycidyl ether type, and glycidyl ester type, which may be used alone or in combination of two or more types. In addition, it is preferred to mix a curing agent or various additives into the epoxy resin as necessary. Epoxy resin compositions that are already commercially available can be used in the present invention. Among these, there are also epoxy resin compositions that have been developed and are commercially available for use in solar cells and organic EL elements, which can be used particularly effectively in the present invention. Examples of commercially available epoxy resin compositions include TB3118, TB3114, TB3124, TB3125F (manufactured by ThreeBond Co., Ltd.), WorldRock5910, WorldRock5920, WorldRock8723 (manufactured by Kyoritsu Chemical Industries Co., Ltd.), WB90US(P), and WB90US-HV (manufactured by Moresco).

[0147] The acrylic resin is not particularly limited, but for example, those developed and commercially available for solar cell and organic EL element applications can be effectively used. Examples of commercially available acrylic resin compositions include TB3035B and TB3035C (manufactured by ThreeBond Co., Ltd.).

[0148] The curing agent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include amine-based, acid anhydride-based, polyamide-based, and other curing agents. Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine and triethylenetetramine, and aromatic polyamines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride and hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, pyromellitic anhydride, HET anhydride, and dodecenyl succinic anhydride. Examples of other curing agents include imidazoles and polymercaptan. These may be used alone or in combination of two or more.

[0149] The additives are not particularly limited and can be appropriately selected according to the purpose. Examples of the additives include a filler, a gap agent, a polymerization initiator, a drying agent (moisture absorbent), a curing accelerator, a coupling agent, a flexibilizer, a colorant, a flame retardant assistant, an antioxidant, and an organic solvent. Among these, a filler, a gap agent, a curing accelerator, a polymerization initiator, and a drying agent (moisture absorbent) are preferred, and a filler and a polymerization initiator are more preferred. By including a filler as an additive, it is possible to suppress the intrusion of moisture and oxygen, and further to obtain effects such as reduction in volumetric shrinkage during curing, reduction in the amount of outgassing during curing or heating, improvement in mechanical strength, and control of thermal conductivity and fluidity. Therefore, including a filler as an additive is very effective in maintaining a stable output in various environments.

[0150] Furthermore, with regard to the output characteristics and durability of the photoelectric conversion element, the influence of not only the intrusion of moisture and oxygen but also the outgassing generated when the sealing member is cured or heated cannot be ignored. In particular, the influence of the outgassing generated when heated has a significant effect on the output characteristics during storage in a high-temperature environment. By incorporating a filler, gap agent, or desiccant into the sealing member, these themselves can suppress the intrusion of moisture and oxygen, and the amount of sealing member used can be reduced, thereby achieving the effect of reducing outgassing. Incorporating a filler, gap agent, or desiccant into the sealing member is effective not only during curing, but also when storing the photoelectric conversion element in a high-temperature environment.

[0151] The filler is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include inorganic fillers such as crystalline or amorphous silica, silicate minerals such as talc, alumina, aluminum nitride, silicon nitride, calcium silicate, and calcium carbonate. Among these, hydrotalcite is particularly preferred. These may be used alone or in combination of two or more.

[0152] The average primary particle size of the filler is not particularly limited, but is preferably 0.1 μm to 10 μm, more preferably 1 μm to 5 μm. When the average primary particle size of the filler is within the above preferred range, the effect of suppressing the intrusion of moisture and oxygen can be sufficiently obtained, the viscosity becomes appropriate, the adhesion to the substrate and the defoaming property are improved, and it is also effective in controlling the width of the sealing part and in workability.

[0153] The content of the filler is preferably from 10 to 90 parts by mass, more preferably from 20 to 70 parts by mass, relative to the entire sealing member (100 parts by mass). When the content of the filler is within the above preferred range, a sufficient effect of suppressing the intrusion of moisture and oxygen is obtained, the viscosity is appropriate, and the adhesion and workability are also good.

[0154] The gap agent is also called a gap control agent or a spacer agent. By including a gap agent as an additive, it becomes possible to control the gap of the sealing portion. For example, when a sealing member is applied on a first substrate or a first electrode, and a second substrate is placed thereon to perform sealing, the gap of the sealing portion is aligned to the size of the gap agent because the sealing member contains a gap agent, and therefore the gap of the sealing portion can be easily controlled.

[0155] The gap agent is not particularly limited, but is preferably granular, has a uniform particle size, and has high solvent resistance and heat resistance, and can be appropriately selected according to the purpose. The gap agent is preferably one that has high affinity with epoxy resin and has a spherical particle shape. Specifically, glass beads, silica fine particles, organic resin fine particles, etc. are preferable. These may be used alone or in combination of two or more. The particle size of the gap agent can be selected according to the gap of the sealing part to be set, but is preferably 1 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less.

[0156] The polymerization initiator is not particularly limited, but examples thereof include polymerization initiators that use heat or light to initiate polymerization, and can be appropriately selected according to the purpose, and examples thereof include thermal polymerization initiators and photopolymerization initiators. Thermal polymerization initiators are compounds that generate active species such as radicals and cations by heating, and examples thereof include azo compounds such as 2,2'-azobisbutyronitrile (AIBN) and peroxides such as benzoyl peroxide (BPO). As thermal cationic polymerization initiators, benzenesulfonic acid esters and alkylsulfonium salts are used. As photopolymerization initiators, photocationic polymerization initiators are preferably used in the case of epoxy resins. When a photocationic polymerization initiator is mixed with an epoxy resin and irradiated with light, the photocationic polymerization initiator decomposes to generate acid, which causes polymerization of the epoxy resin, and the curing reaction proceeds. A photocationic polymerization initiator has the effects of having little volume shrinkage during curing, not being inhibited by oxygen, and having high storage stability.

[0157] Examples of the photocationic polymerization initiator include aromatic diazonium salts, aromatic iodonium salts, aromatic sulfonium salts, methacerone compounds, and silanol-aluminum complexes. In addition, photoacid generators having a function of generating an acid by irradiation with light can also be used as polymerization initiators. Photoacid generators act as acids that initiate cationic polymerization, and examples of the photoacid generator include onium salts such as ionic sulfonium salts and iodonium salts that are composed of a cationic portion and an anionic portion. These may be used alone or in combination of two or more.

[0158] The amount of the polymerization initiator to be added is not particularly limited and may vary depending on the material used, but is preferably 0.5 parts by mass to 10 parts by mass, more preferably 1 part by mass to 5 parts by mass, relative to the entire sealing member (100 parts by mass). By adding an amount within the above preferred range, curing can be properly progressed, the amount of uncured material remaining can be reduced, and excessive outgassing can be prevented.

[0159] The desiccant (also called moisture absorbent) is a material that has the function of physically or chemically adsorbing or absorbing moisture, and by including it in the sealing member, the moisture resistance can be further improved and the influence of outgassing can be reduced. The desiccant is not particularly limited and can be appropriately selected depending on the purpose, but particulate desiccant is preferable, and examples of the desiccant include inorganic water-absorbing materials such as calcium oxide, barium oxide, magnesium oxide, magnesium sulfate, sodium sulfate, calcium chloride, silica gel, molecular sieve, and zeolite. Among these, zeolite, which has a high moisture absorption amount, is preferable. These may be used alone or in combination of two or more kinds.

[0160] The curing accelerator (also called a curing catalyst) is a material that accelerates the curing speed, and is mainly used for thermosetting epoxy resins. The curing accelerator is not particularly limited and can be appropriately selected according to the purpose. For example, tertiary amines or tertiary amine salts such as DBU (1,8-diazabicyclo(5,4,0)-undecene-7) and DBN (1,5-diazabicyclo(4,3,0)-nonene-5), imidazoles such as 1-cyanoethyl-2-ethyl-4-methylimidazole and 2-ethyl-4-methylimidazole, phosphines or phosphonium salts such as triphenylphosphine and tetraphenylphosphonium tetraphenylborate, etc. may be used alone or in combination of two or more kinds.

[0161] The coupling agent is not particularly limited as long as it is a material that has the effect of enhancing molecular bonding strength, and can be appropriately selected according to the purpose, and examples thereof include silane coupling agents.Specific examples include silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, N-(2-(vinylbenzylamino)ethyl)3-aminopropyltrimethoxysilane hydrochloride, and 3-methacryloxypropyltrimethoxysilane.These may be used alone or in combination of two or more kinds.

[0162] In the present invention, for example, a sheet-like adhesive can be used. The sheet-like adhesive is, for example, a sheet on which a resin layer has been formed in advance, and the sheet can be made of glass or a film with high gas barrier properties. The sheet may also be made of only the sealing resin. The sheet-like adhesive can also be attached onto the sealing film. It is also possible to form a structure in which a hollow portion is provided on the sealing film and then attach it to the device.

[0163] When the sealing film is used for sealing, it is disposed opposite to the support so as to sandwich the photoelectric conversion device. The base material of the sealing film is not particularly limited in shape, structure, size, and type, and can be appropriately selected according to the purpose. The sealing film forms a barrier layer on the surface of the base material to prevent the passage of moisture and oxygen, and may be formed on only one side or both sides of the base material.

[0164] The barrier layer may be made of a material mainly composed of, for example, a metal oxide, a metal, a mixture formed of a polymer and a metal alkoxide, etc. Examples of the metal oxide include aluminum oxide, silicon oxide, aluminum, etc. Examples of the polymer include polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, etc. Examples of the metal alkoxide include tetraethoxysilane, triisopropoxyaluminum, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc.

[0165] The barrier layer may be transparent or opaque, for example. The barrier layer may be a single layer or a laminated structure of a combination of the above materials. The barrier layer may be formed by a known method, such as vacuum film formation such as sputtering, dipping, roll coating, screen printing, spraying, gravure printing, or other coating methods.

[0166] [wiring] In the photoelectric conversion element (e.g., solar cell) of the present invention, in order to efficiently extract the current generated by light, it is preferable to connect lead wires (wiring) to the electrode and the back electrode. The lead wires are connected to the first electrode and the second electrode, for example, using a conductive material such as solder, silver paste, or graphite. The conductive material may be used alone or in a mixture or laminate structure of two or more kinds. In addition, the part where the lead wire is attached may be covered with an acrylic resin or an epoxy resin from the viewpoint of physical protection.

[0167] The lead wire is a general term for an electric wire used to electrically connect a power source, electronic components, etc. in an electric circuit, and examples of such wire include vinyl wire and enamel wire.

[0168] [application] The use and method of the photoelectric conversion element of the present invention are not particularly limited, and can be widely used for the same use as a general photoelectric conversion element (for example, a general solar cell). The photoelectric conversion element of the present invention (for example, a solar cell) can be applied to a power supply device by combining it with a circuit board that controls the generated current. Examples of devices that use a power supply device include electronic desk calculators and solar radio watches. The solar cell of the present invention can also be applied as a power supply device to mobile phones, electronic paper, thermometers, hygrometers, etc. It can also be applied as an auxiliary power source for extending the continuous use time of rechargeable or battery-powered electrical appliances, or for nighttime use by combining it with a secondary battery. It can also be used as an independent power source that does not require battery replacement or power wiring. EXAMPLES

[0169] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0170] In the following examples, unless otherwise specified, the yield (%) is a yield (mol %) based on the amount of substance (mol). NMR (nuclear magnetic resonance) spectra were measured using AV400M manufactured by Bruker.

[0171] [Example A1: Synthesis of 4-PATAT] According to the procedures of the following Synthesis Examples 1 to 3, 4-PATAT, which is one of the compounds of the present invention (the compound represented by the above chemical formula (I)), was synthesized (produced).

[0172] Synthesis Example 1 Synthesis (production) of 4-Br-TAT

[0173] [ka]

[0174] Compound TAT (345 mg) and N,N-dimethylformamide (DMF, 3.5 ml) in the above scheme 1 were placed in a three-neck flask, and sodium hydride (144 mg) was slowly added while stirring at room temperature under argon gas flow. After 10 minutes, 1,4-dibromobutane (3.24 g) was added while stirring at room temperature, and stirring was continued for another 1.5 hours. Thereafter, water was added to stop the reaction, and the mixture was extracted three times with dichloromethane. The extracted organic layer was washed with a saturated aqueous sodium chloride solution, dried with sodium sulfate, and the solvent was distilled off. The residue thus obtained was purified by silica gel column chromatography (eluent: n-hexane / dichloromethane = 2 / 1 to 1 / 1 (volume ratio)), and 526 mg of white crystalline 4Br-TAT (see the chemical formula in the above scheme 1) was obtained. The yield was 70% based on the raw material TAT.

[0175] Synthesis Example 2 Synthesis (production) of 4-PAE-TAT

[0176] [ka]

[0177] 4Br-TAT (400 mg) and triethyl phosphite (1.06 g) were placed in a three-neck flask and heated and stirred at 150° C. for 19.5 hours under an argon gas stream. After cooling to room temperature, excess triethyl phosphite was distilled off under reduced pressure. The residue was purified by silica gel column chromatography to obtain 597 mg of 4PAE-TAT (see the chemical formula in Scheme 2) as a colorless oil. The yield was quantitative based on the raw material 4Br-TAT.

[0178] Synthesis Example 3 Synthesis (production) of 4-PATAT

[0179] [ka]

[0180] 4PAE-TAT (500 mg) and dichloromethane (15 mL) were placed in a three-neck flask, and trimethylsilane bromide (0.821 mg) was slowly added under argon gas flow while stirring at room temperature. After 15 hours, methanol (10 mL) was added and stirring was continued for another 2 hours. The reaction liquid was slowly distilled off, and the resulting residue was extracted with a solvent of dichloromethane / methanol = 20 / 1 (volume ratio) to obtain 302 mg of 4PATAT (see the chemical formula in Scheme 3 above) as pale blue crystals. The yield was 74% based on the raw material 4PAE-TAT. 1 The H-NMR (DMSO-D6, 400 MHz) spectrum is shown in Figure 2.

[0181] [Example A2: Synthesis of 1-legged-3PATAT] According to the procedures of the following Synthesis Examples 4 to 6, 1-legged-3PATAT, which is one of the compounds of the present invention (compounds represented by the above chemical formula (I)), was synthesized (produced).

[0182] Synthesis Example 4 Synthesis (production) of 1-legged-3PAE-TAT

[0183] [ka]

[0184] Compound TAT (1.04 g) and DMF (10 ml) in the above scheme 4 were placed in a three-neck flask, and sodium hydride (144 mg) was slowly added while stirring at room temperature under an argon gas stream. Next, diethyl (3-bromopropyl)phosphonate (3.90 g) was added dropwise, and after the completion of the dropwise addition, the mixture was heated and stirred at 65°C. After 36 hours, the reaction was stopped and extracted three times with ethyl acetate. The extracted organic layer was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and the solvent was distilled off. The obtained residue was purified by silica gel column chromatography (eluent: dichloromethane / methanol = 100 / 1 to 50 / 1 (volume ratio)), and 240 mg of 1-legged-3PAE-TAT (see the chemical formula in the above scheme 4) was obtained. The yield was 15% based on the raw material TAT. The amount of 1-legged-3PAE-TAT was 1. 1 The H-NMR (DMSO-D6, 400 MHz) spectrum is shown in Figure 3.

[0185] Synthesis Example 5 Synthesis (production) of 1-legged-3PAEE-TAT

[0186] [ka]

[0187] 1-legged-3PAE-TAT (215 mg), ethyl iodide (0.141 mg), and DMF (4.1 mL) were placed in a three-neck flask, and sodium hydride (43.4 mg) was slowly added while stirring at room temperature under an argon gas stream. Stirring was continued for 1.5 hours, water was added to stop the reaction, and the mixture was extracted with ethyl acetate. After drying with sodium sulfate, the solvent was distilled off. The residue was purified by silica gel column chromatography (eluent: toluene) to obtain 147 mg of 1-legged-3PAEE-TAT (see the chemical formula in Scheme 5) as a brown oil. The yield was 63% based on the raw material 1-legged-3PAE-TAT.

[0188] Synthesis Example 6 Synthesis (production) of 1-legged-3PATAT

[0189] [ka]

[0190] 1-legged-3PAEE-TAT (115 mg) and dichloromethane (5.4 mL) were placed in a three-neck flask, and trimethylsilane bromide (0.10 mg) was slowly added under argon gas while stirring at room temperature. After 16 hours, methanol (3.6 mL) was added and stirring was continued for another 15 hours. The reaction solution was slowly distilled off, and the resulting residue was extracted with a solvent (volume ratio) of dichloromethane / methanol = 20 / 1 to obtain 93 mg of 1-legged-3PATAT (see the chemical formula in Scheme 6) as pale blue crystals. The yield was 89% based on the raw material 1-legged-3PAEE-TAT.

[0191] [Example A3: Synthesis of 1-legged-3PATAT-H] According to the procedure of the following Synthesis Example 7, 1-legged-3PATAT-H, which is one of the compounds of the present invention (the compound represented by the above chemical formula (I)), was synthesized (produced).

[0192] Synthesis Example 7 Synthesis of 1-legged-3PATAT-H

[0193] [ka]

[0194] The 1-legged-3PAE-TAT (150 mg) synthesized (produced) in Scheme 4 and dichloromethane (3.2 mL) were placed in a three-neck flask, and trimethylsilane bromide (0.052 mg) was slowly added under argon gas flow while stirring at room temperature. After 22 hours, the reaction solution was slowly distilled off, and the resulting residue was extracted with a solvent of dichloromethane / methanol = 10 / 1 (volume ratio) and washed with dichloromethane to obtain 56.2 mg of 1-legged-3PATAT-H (see the chemical formula in Scheme 7) as pale blue crystals. The yield was 42% based on the raw material 1-legged-3PAE-TAT. The amount of 1-legged-3PATAT-H was 1.0 mg. 1 The H-NMR (DMSO-D6, 400 MHz) spectrum is shown in Figure 4. Mass spectrometry of 1-legged-3PATAT-H was measured using a Bruker TIMS-TOF (IMS-QTOF) and the result was m / z = 466.1324 [M]. - obtained.

[0195] [Example A4: Synthesis of 2-legged-3PATAT] According to the procedures of the following Synthesis Examples 8 to 9, 2-legged-3PATAT, which is one of the compounds of the present invention (the compound represented by the above chemical formula (I)), was synthesized (produced).

[0196] Synthesis Example 8 Synthesis (production) of 2-legged-3PAH-TAT

[0197] [ka]

[0198] TAT (345 mg) and DMF (10 ml) were placed in a three-neck flask, and sodium hydride (48 mg) was slowly added while stirring at room temperature under an argon gas stream. Next, diethyl (3-bromopropyl)phosphonate (0.57 g) was added dropwise, and after the completion of the dropwise addition, the mixture was heated and stirred at 70°C. After 36 hours, the reaction was stopped and extracted three times with dichloromethane. The organic layer was washed with a saturated aqueous sodium chloride solution, dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography (eluent: ethyl acetate / methanol = 1 / 1 to 10 / 1 (volume ratio)), and 157 mg of 2-legged-3PAH-TAT (see the chemical formula in Scheme 8) was obtained. The yield was 22% based on the raw material TAT. The 2-legged-3PAH-TAT 1 The H-NMR (DMSO-D6, 400 MHz) spectrum is shown in Figure 5.

[0199] Synthesis Example 9 Synthesis (production) of 2-legged-3PATAT

[0200] [ka]

[0201] 2-legged-3PAH-TAT (47 mg) and dichloromethane (2.8 mL) were placed in a three-neck flask, and trimethylsilane bromide (0.124 mg) was slowly added under argon gas flow while stirring at room temperature. After 23 hours, the reaction solution was slowly distilled off, and the resulting residue was extracted with a solvent of dichloromethane / methanol = 10 / 1 (volume ratio) and washed with dichloromethane to obtain 15 mg of 2-legged-3PATAT (see the chemical formula in Scheme 9 above) as pale blue crystals. The yield was 37% based on the raw material 2-legged-3PAH-TAT. The 2-legged-3PATAT 1 The H-NMR (DMSO-D6, 400 MHz) spectrum is shown in Figure 6. Mass spectrometry of 2-legged-3PATAT was measured using a Bruker TIMS-TOF (IMS-QTOF) and the result was m / z = 588.1459 [M]. - obtained.

[0202] [Example A5: Synthesis of 4PATTI-C3] According to the procedures of the following Synthesis Examples 10 to 11, 4PATTI-C3, which is one of the compounds of the present invention (the compound represented by the above chemical formula (I)), was synthesized (produced).

[0203] Synthesis Example 10 Synthesis (production) of compound 1

[0204] [ka]

[0205] TTI (23.0 mg, 50 mmol), cesium carbonate (130 mg, 400 mmol), and tetrabutylammonium bromide (6.4 mg, 20 mmol) were dissolved in tetrahydrofuran (1 ml), and diethyl (3-bromopropyl) phosphonate (58 mL, 300 mmol) was added and heated and stirred at 80 ° C for 1 hour. The mixture was cooled to room temperature, and the organic layer extracted with dichloromethane was dried with magnesium sulfate. The yellow oily mixture obtained by vacuum concentration was purified by silica gel chromatography (eluent ethyl acetate:methanol 1:1 → 1:2), and 47.5 mg (41 mmol, yield 81%, yellow oily) of the target compound 1 was obtained.

[0206] Synthesis Example 11 Synthesis (production) of 4PATTI-C3

[0207] [ka]

[0208] Compound 1 (43.5 mg, 37 mmol) was dissolved in dichloromethane (1 ml), and trimethylsilane bromide (63.3 mL, 489 mmol) was added dropwise while stirring. After the dropwise addition, the mixture was stirred at room temperature for 15 h, and then methanol (0.6 mL) was added and stirred for 1 h. The mixture was concentrated under reduced pressure to remove the solvent, and the residual solid was washed several times with dichloromethane to obtain the target compound, 4PATTI-C3 (33 mmol, 87% yield, gray crystals). The 1H-NMR (DMSO-d6, 400 MHz) spectrum of 4PATTI-C3 is shown in Figure 7.

[0209] [Example A6: Synthesis of 4PATTI-C4] According to the procedures of the following Synthesis Examples 12 to 14, 4PATTI-C4, which is one of the compounds of the present invention (the compound represented by the above chemical formula (I)), was synthesized (produced).

[0210] Synthesis Example 12 Synthesis (production) of compound 2

[0211] [ka]

[0212] TTI (23.0 g, 50 mmol), cesium carbonate (130 mg, 400 mmol), and tetrabutylammonium bromide (6.4 mg, 20 mmol) were dissolved in THF (1 ml) and stirred at room temperature for 10 minutes. Then, 1,4-dibromobutane (36 mL, 300 mmol) was added and heated and stirred at 80 ° C for 1 h. The mixture was cooled to room temperature, water was added to stop the reaction, and the mixture was extracted three times with dichloromethane. The separated organic layer was dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The pale red oily residue was purified by silica gel column chromatography (eluent: n-hexane alone → n-hexane / dichloromethane = 1 / 1) to obtain the target compound 2 (30.8 mg, yield 61%, white crystals).

[0213] Synthesis Example 13 Synthesis (production) of compound 3

[0214] [ka]

[0215] Compound 2 (30.8 mg, 31 mmol) was stirred with triethyl phosphite (0.5 ml) at 150° C. for 11 hours. After cooling to room temperature, the mixture was heated to 85° C. under reduced pressure to remove unreacted triethyl phosphite, and the target compound 3 (39.4 g, 32 mmol, yield: quantitative, colorless oil) was obtained.

[0216] Synthesis Example 14 Synthesis (production) of 4PATTI-C4

[0217] [ka]

[0218] Compound 3 (38.4 mg, 31 mmol) was dissolved in dichloromethane (0.8 mL), and bromotrimethylsilane (53 mL, 409 mmol) was added dropwise at room temperature under stirring. Stirring was continued at room temperature, and after 15 h, MeOH (0.6 mL) was added, and stirring was continued for another 1 h. The mixture was concentrated under reduced pressure to remove the solvent, and the residue was washed several times with dichloromethane to obtain the target product, 4PATTI-C4 (24.5 mg, 24 mmol, yield 79%, gray crystals). The 1H-NMR (DMSO-d6, 400 MHz) spectrum of 4PATTI-C4 is shown in Figure 8.

[0219] [Example 1] A solar cell, which is a photoelectric conversion element of the present invention, was prepared (manufactured) in the following manner.

[0220] 100 μL of the DMF solution (0.1 mmol / L) of 4PATAT obtained in Synthesis Example 3 was placed on the ITO of an ITO glass substrate (a glass substrate as a support on which a first electrode was formed), and a monolayer (hole transport layer) was formed on the ITO (first electrode) using a spin coater (3,000 rpm, 30 seconds). The ionization potential of this monolayer (hole transport layer) was measured (BIP-KV-201-P5 photoelectron spectrometer manufactured by Bunkoukeiki Co., Ltd.) and found to be -5.45 eV. Next, a solution of cesium iodide (0.738 g), formamidine iodide (7.512 g), methylamine bromide (0.905 g), lead iodide (23.888 g), and lead bromide (1.022 g) dissolved in DMF (40.0 mL) and dimethyl sulfoxide (DMSO, 12.0 mL) was spin-coated onto the substrate. The spin-coating was performed at 3000 rpm, and chlorobenzene (0.3 mL) was dropped 30 seconds after the start of the spin-coating. The substrate was then heated at 150°C for 10 minutes to obtain a perovskite layer (photoelectric conversion layer). Next, C 60 A photoelectric conversion element was fabricated by vacuum deposition of 20 nm of bismuth oxide (electron transport layer), 8 nm of vasocuproine (BCP) (electron injection layer), and 100 nm of Ag (second electrode). Furthermore, Nagase ChemteX's XNR5516 was applied to the outer periphery of the photoelectric conversion element, which was then bonded to glass in an inert gas atmosphere and irradiated with UV light to fabricate a sealed device.

[0221] The photoelectric conversion characteristics of the encapsulated device produced in Example 1 were measured in accordance with the output measurement method for silicon crystalline solar cells of JISC8913:1998. A solar simulator (SMO-250III model manufactured by Bunkoukeiki Co., Ltd.) combined with an air mass filter equivalent to AM1.5G was used to measure the photoelectric conversion characteristics of the encapsulated device produced in Example 1. The output of the secondary reference Si solar cell was 100 mW / cm 2The light intensity was adjusted to 1000 mA, and used as a measurement light source. While irradiating a test sample of a perovskite solar cell (sealed device prepared in Example 1) with light, the IV curve characteristics were measured using a source meter (Keithley Instruments Inc., 2400-type general-purpose source meter). The short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), short-circuit current density (Jsc), and photoelectric conversion efficiency (PCE) obtained from the IV curve characteristic measurement were calculated using the following formulas 1 and 2. The results are shown in Table 1 below. In addition, this device was placed in a dryer at 85 ° C. in a dark place, and the photoelectric conversion efficiency was measured for 500 hours. The results are also shown in Table 1.

[0222] Equation 1: Short circuit current density (Jsc; mA / cm 2 )=Isc(mA) / Effective photosensitive area S(cm 2 ) Equation 2: Photoelectric conversion efficiency (PCE;%) = Voc (V) × Jsc (mA / cm 2 )×FF×100 / 100(mW / cm 2 )

[0223] [Example 2] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 4PATAT (0.1 mmol / L) and n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP (ionization potential) measured in the same manner as in Example 1 was -5.41 eV.

[0224] [Example 3] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 1-legged-3PATAT (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.64 eV.

[0225] [Example 4] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 1-legged-3PATAT-H (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.68 eV.

[0226] [Example 5] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 2-legged-3PATAT (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.54 eV.

[0227] [Example 6] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 2-legged-3PATAT (0.1 mmol / L) and n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.50 eV.

[0228] [Example 7] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 1-legged-3PATAT (0.1 mmol / L) and n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.45 eV.

[0229] [Example 8] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 4PATTI-C3 (0.1 mmol / L) and n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 2 below. The IP (ionization potential) measured in the same manner as in Example 1 was -5.57 eV.

[0230] [Example 9] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of 4PATAT-C4 (0.1 mmol / L) and n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 2 below. The IP (ionization potential) measured in the same manner as in Example 1 was -5.52 eV.

[0231] [Comparative Example 1] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was changed to a DMF solution of n-butylphosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. The IP measured in the same manner as in Example 1 was -5.48 eV.

[0232] [Comparative Example 2] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was replaced with a DMF solution of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. In addition, the ionization potential when this compound was adsorbed on an ITO substrate was -5.91 eV.

[0233] [Comparative Example 3] A photoelectric conversion element was produced (manufactured) in the same manner as in Example 1, except that the DMF solution of 4PATAT (0.1 mmol / L) in Example 1 was replaced with a DMF solution of [2-(3,6-Dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic Acid (0.1 mmol / L), and the photoelectric conversion efficiency was measured. The results are shown in Table 1 below. In addition, the ionization potential when this compound was adsorbed on an ITO substrate was -5.25 eV.

[0234] [Table 1]

[0235] [Table 2]

[0236] From Tables 1 and 2, it was confirmed that the solar cell (photoelectric conversion element) using the compound of the present invention in the hole transport layer has high durability not only in the initial characteristics but also in the heat resistance test. On the other hand, from Comparative Example 1, it was confirmed that when only alkylphosphonic acid was used, the hole transport ability was insufficient and the initial characteristics were low. Furthermore, in Comparative Examples 2 and 3, a compound having a carbazole skeleton with hole transport ability was used, and thus good initial characteristics were obtained, but the ionization potential of the compound was outside the range of the present invention, and therefore significant deterioration was observed in the heat resistance test. From these results, it was confirmed that the compound of the present invention exhibits excellent photoelectric conversion characteristics and has high durability, and is extremely excellent as a hole transport compound.

[0237] As described above, this example confirmed that a photoelectric conversion element having high performance and high durability can be obtained by using the hole transport material of the present invention in the hole transport layer.

[0238] The present invention has been described above using the embodiments and examples. However, the present invention is not limited to the embodiments and examples described above, and can be arbitrarily and appropriately combined, modified, or selected as necessary without departing from the spirit of the present invention. [Industrial Applicability]

[0239] As described above, according to the present invention, a photoelectric conversion element and a compound in which the hole transport layer exhibits excellent photoelectric conversion characteristics and has high durability can be provided. The photoelectric conversion element of the present invention is useful, for example, as a solar cell. The application and method of use of the photoelectric conversion element of the present invention are not particularly limited, and for example, the application and method of use are similar to those of a general photoelectric conversion element (for example, a general solar cell), and can be applied to a wide range of fields. In addition, the compound of the present invention can be used, for example, in the hole transport layer of the photoelectric conversion element of the present invention to obtain a photoelectric conversion element that exhibits excellent photoelectric conversion characteristics and has high durability. However, the application and method of use of the compound of the present invention are not limited thereto, and can be applied to any wide range of fields.

[0240] This application claims priority based on Japanese Patent Application No. 2021-148447, filed on September 13, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0241] 10 Photoelectric conversion element 11 Support 12 First electrode 13 Hole transport layer 14 Photoelectric conversion layer 15 Electron transport layer 16 Second electrode

Claims

1. a first electrode, a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a second electrode are stacked in the above order; the photoelectric conversion layer includes a perovskite structure, The hole transport layer contains a compound represented by the following chemical formula (I): [Chemical Formula I] In the above chemical formula (I), Ar 1 is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may or may not contain a heteroatom; Ar 1 may or may not have a substituent other than -L 1 -X 1 ; -L 1 -X 1 is plural, and each L 1 and each X 1 may be the same or different; each L 1 is an atomic group connecting Ar 1 and X 1 or a covalent bond; Each X 1 is a group capable of donating or receiving a charge between the first electrode and the X 1 . A photoelectric conversion element characterized by:

2. In the above chemical formula (I), Each X １ are phosphonic acid groups (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), or a trihalogenated silyl group (—SiX ３ , where X is a halo group), trialkoxysilyl group (—Si(OR) ３ 2. The photoelectric conversion element according to claim 1, wherein R is an alkyl group.

3. In the chemical formula (I), the Ar １ The photoelectric conversion element according to claim 1, wherein is represented by the following chemical formula (I-1): [Chemical Formula I-1] In the chemical formula (I-1), Ar １１ represents an atomic group containing a cyclic structure, and the cyclic structure may be an aromatic ring or a non-aromatic ring, a monocyclic ring, a fused ring, or a spiro ring, and may or may not contain heteroatoms among the atoms constituting the ring; Ar １２ is an aromatic ring, which may or may not contain heteroatoms among the atoms constituting the ring, Ar １２ is one or more atoms in Ar １１ Share with Ar １１ It may be integrated with Ar １２ may be one or more, and when there are more than one, they may be the same or different.

4. In the chemical formula (I-1), the Ar １１ The photoelectric conversion element according to claim 3, wherein is represented by any one of the following chemical formulas (a1) to (a10): 【Transform a1-a10】

5. In the chemical formula (I-1), each Ar １２ and each are represented by the following chemical formula (b): 【b】 In the chemical formula (b), Carbon atom C １ and C ２ represents the Ar in the chemical formula (I-1). １１ and also serves as a part of the atoms constituting the cyclic structure in The R １ represents a hydrogen atom, X in the chemical formula (I) １ or a substituent, wherein the substituent may or may not contain a hydrogen atom, and at least one of the hydrogen atoms in the substituent is X in the chemical formula (I). １ may be substituted with Each of the R １１ may be the same or different, and each is a hydrogen atom or a substituent, or two adjacent R １１ may form a condensed ring together with the benzene ring to which they are attached, Each of the R １１ may or may not further have a substituent.

6. 6. The photoelectric conversion element according to claim 5, wherein the chemical formula (b) is represented by any one of the following chemical formulas (b1) to (b7): 【b1-b7】 In the chemical formulas (b1) to (b7), C １ , C ２ and R １ are the same as those in the chemical formula (b).

7. 2. The photoelectric conversion element according to claim 1, wherein the compound represented by the chemical formula (I) is a compound represented by any one of the following chemical formulae A-1 to A-23: [Chemical Formula A1A4] 【Chemical A5A8】 【Hua9A12】 【A13A16】 【Chemical A17A20】 【Hua A21A23】 In the chemical formulas A-1 to A-23, Each of the R １ are each a hydrogen atom or X in the chemical formula (I), １ or X in the chemical formula (I) １ which may be the same or different, and which are further substituted by Each of the R １ At least one of the X in the chemical formula (I) １ or X in the chemical formula (I) １ is a substituent further substituted with The R ２ is a substituent, and may be present in one or more groups, or may not be present. When there are more than one group, each R ２ may be the same or different from each other.

8. The photoelectric conversion element according to claim 1, wherein the compound represented by chemical formula (I) is a compound represented by the following chemical formula: 4PATAT, 1-legged-3PATAT, 1-legged-3PATAT-H, 2-legged-3PATAT, 4PATTI-C3, or 4PATTI-C4. 【4PATAT】 【3PATAT1】 【3PATATH】 【3PATAT2】 【4PATTI-C3】 【4PATTI-C4】

9. 2. The photoelectric conversion element according to claim 1, wherein the photoelectric conversion layer contains an organic-inorganic perovskite compound.

10. 10. The photoelectric conversion element according to claim 9, wherein the organic-inorganic perovskite compound contains at least one of tin and lead.

11. The photoelectric conversion element according to claim 1 , which is a solar cell.

12. A compound represented by the following chemical formula (I): [Chemical Formula I] In the above chemical formula (I), Ar １ is a structure containing an aromatic ring, and the atoms constituting the aromatic ring may or may not contain a heteroatom, Ar １ Is, -L １ -X １ may or may not have a substituent other than -L １ -X １ is plural, and each L １ and each X １ may be the same or different from each other, Each L １ is Ar １ and X １ or a covalent bond, Each X １ are groups capable of donating and receiving charges to and from an electrode.

13. In the above chemical formula (I), Each X １ are phosphonic acid groups (-P=O(OH) ２ ), carboxy group (-COOH), sulfo group (-SO ３ H), boronic acid group (-B(OH) ２ ), trihalogenated silyl group (—SiX ３ , where X is a halo group), or a trialkoxysilyl group (—Si(OR) ３ 13. The compound of claim 12, wherein R is an alkyl group.

14. In the chemical formula (I), the Ar １ The compound according to claim 12, which is represented by the following chemical formula (I-1): [Chemical Formula I-1] In the chemical formula (I-1), Ar １１ represents an atomic group containing a cyclic structure, and the cyclic structure may be an aromatic ring or a non-aromatic ring, a monocyclic ring, a fused ring, or a spiro ring, and may or may not contain heteroatoms among the atoms constituting the ring; Ar １２ is an aromatic ring, which may or may not contain heteroatoms among the atoms constituting the ring, Ar １２ is one or more atoms in Ar １１ Share with Ar １１ It may be integrated with Ar １２ may be one or more, and when there are more than one, they may be the same or different.

15. In the chemical formula (I-1), the Ar １１ The compound according to claim 14, which is represented by any one of the following chemical formulas (a1) to (a10): 【Transform a1-a10】

16. In the chemical formula (I-1), each Ar １２ and each are represented by the following chemical formula (b): 【b】 In the chemical formula (b), Carbon atom C １ and C ２ represents the Ar in the chemical formula (I-1). １１ and also serves as a part of the atoms constituting the cyclic structure in The R １ represents a hydrogen atom, X in the chemical formula (I) １ or a substituent, wherein the substituent may or may not contain a hydrogen atom, and at least one of the hydrogen atoms in the substituent is X in the chemical formula (I). １ may be substituted with Each of the R １１ may be the same or different, and each is a hydrogen atom or a substituent, or two adjacent R １１ may form a condensed ring together with the benzene ring to which they are attached, Each of the R １１ may or may not further have a substituent.

17. The compound according to claim 16, wherein the chemical formula (b) is represented by any one of the following chemical formulas (b1) to (b7): 【b1-b7】 In the chemical formulas (b1) to (b7), C １ , C ２ and R １ are the same as those in the chemical formula (b).

18. The compound according to claim 12, wherein the compound represented by the chemical formula (I) is a compound represented by any one of the following chemical formulas A-1 to A-23: [Chemical Formula A1A4] 【Chemical A5A8】 【Hua9A12】 【A13A16】 【Chemical A17A20】 【Hua A21A23】 In the chemical formulas A-1 to A-23, Each of the R １ are each a hydrogen atom or X in the chemical formula (I), １ or X in the chemical formula (I) １ which may be the same or different, and which are further substituted by Each of the R １ At least one of the X in the chemical formula (I) １ or X in the chemical formula (I) １ is a substituent further substituted with The R ２ is a substituent, and may be present in one or more groups, or may not be present. When there are more than one group, each R ２ may be the same or different from each other.

19. The compound according to claim 12, wherein the compound represented by chemical formula (I) is a compound represented by the following chemical formula: 4PATAT, 1-legged-3PATAT, 1-legged-3PATAT-H, 2-legged-3PATAT, 4PATTI-C3, or 4PATTI-C4. 【4PATAT】 【3PATAT1】 【3PATATH】 【3PATAT2】 【4PATTI-C3】 【4PATTI-C4】

20. X in the chemical formula (I) １ is a group in which at least one hydrogen atom of the group capable of donating or receiving a charge to or from an electrode is substituted with a further substituent, instead of the group capable of donating or receiving a charge to or from an electrode.

21. In the above chemical formula (I), Each X １ are phosphonate ester groups (-P=O(OR) ２ ), a carboxylic acid ester group (—COOR), a sulfonic acid ester group (—SO ３ R), or a boronic ester group (—B(OR) ２ ) wherein each X １ The compound according to claim 20, wherein R is a substituent, and when there are a plurality of Rs, they may be the same or different.

22. Each X in the chemical formula (I) １ 22. The compound according to claim 21, wherein each of the substituents R is an alkyl group or a halogen atom.

23. The compound according to claim 20, wherein the compound represented by chemical formula (I) is a compound represented by the following chemical formula: 4PAE-TAT, 1-legged-3PAE-TAT-H, 1-legged-3PAEE-TAT, 2-legged-3PAH-TAT, 4PATTI-C3, or 4PATTI-C4. 【4PAETAT】 【3PAETAT】 【3PAETAT1】 【3PAHTAT2】 【4PATTI-C3】 【4PATTI-C4】

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