JP2018157147A - Solid-state junction photoelectric converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide solid-state junction photoelectric converter having high photoelectric conversion efficiency, in which photoelectric conversion efficiency is less likely to decrease even after long term voltage application.SOLUTION: In a solid-state junction photoelectric converter 10 provided with a first conductive layer 1, a light absorption layer 7 containing an organic perovskite compound, a P type semiconductor layer 5, and a second conductive layer 6, in this order, at least any one of the first and second conductive layers 1, 6 contains at least one kind selected from a group consisting of compounds containing at least one kind of alloy containing more than one kind of metal of periodic table groups 4-15, and at least one kind of element (α) of periodic table groups 4-15 and at least one kind of element (β) of periodic table groups 13-16 (excluding the element (α) and oxygen).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid junction photoelectric conversion element.

  Organic-inorganic hybrid perovskite compounds have attracted attention as sensitizers that can replace the dyes of dye-sensitized solar cells. A photoelectric conversion efficiency of 10.9% for a solid solar cell having no electrolyte solution, in which a P-type semiconductor layer of bifluorene type low molecular weight spiro-OMeTAD is formed on the surface of a crystal layer (perovskite compound layer) made of this perovskite compound Has been reported (see Non-Patent Document 1). Starting with this report, further improvements in photoelectric conversion efficiency have been reported one after another (see Non-Patent Document 2), and development for practical application is thriving.

“Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites” Science, 2012, 338, p643-647. “Solvent engineering for high-performance inorganic-organic hybrid perovskite solar cells” Nature Materials 2014, 13, p897-903.

  As a result of studies by the present inventors, the photoelectric conversion element described in the non-patent document has high photoelectric conversion efficiency before use, but it has been found that the photoelectric conversion efficiency decreases when a voltage is applied for a long period of time. It was. As a cause of this, the present inventors considered that when a voltage is applied for a long period of time, the material (metal) of the electrode moves and diffuses into a crystal layer containing a perovskite compound, thereby reducing the photoelectric conversion efficiency.

  The present invention provides a solid-junction photoelectric conversion element that has high photoelectric conversion efficiency and is less likely to decrease even when a voltage is applied for a long period of time.

[1] A solid junction photoelectric conversion element in which a first conductive layer, a light absorption layer containing an organic / inorganic perovskite compound, a P-type semiconductor layer, and a second conductive layer are provided in this order, An alloy in which at least one of the first conductive layer or the second conductive layer includes two or more metals of Group 4 to Group 15 of the periodic table, and Group 4 to Group 15 element (α) and Group 13 of the periodic table A solid junction photoelectric device comprising at least one selected from the group consisting of compounds each containing at least one element of group -16 element (β) (excluding the element (α) and oxygen). Conversion element.
[2] The first conductive layer contains at least one selected from the group, and the sheet resistance of the first conductive layer is 10Ω / □ or less, or the second conductive layer is selected from the group The solid junction photoelectric conversion element according to [1], wherein the second conductive layer has a sheet resistance of 10Ω / □ or less.
[3] The first conductive layer has a stacked structure in which a low diffusion conductive layer and an auxiliary conductive layer are stacked in this order from the side in contact with the light absorption layer, and at least the low diffusion conductive layer of the stacked structure Including at least one selected from the group, or having a laminated structure in which the second conductive layer is laminated in the order of a low diffusion conductive layer and an auxiliary conductive layer from the side in contact with the light absorption layer, and The solid junction photoelectric conversion element according to [1] or [2], wherein at least the low diffusion conductive layer in the multilayer structure includes at least one selected from the group.
[4] The solid junction photoelectric conversion element according to [3], wherein the sheet resistance Rsh1 of the auxiliary conductive layer and the sheet resistance Rsh2 of the low diffusion conductive layer have a relationship of Rsh1 <Rsh2.
[5] The first conductive layer is composed of only a layer containing at least one selected from the group, or the second conductive layer is composed of only a layer containing at least one selected from the group. ] Or the solid junction type photoelectric conversion element according to [2].

  The solid junction photoelectric conversion element of the present invention exhibits high photoelectric conversion efficiency, and the photoelectric conversion efficiency is not easily lowered even when a voltage is applied for a long period of time.

It is a cross-sectional schematic diagram of the solid junction type photoelectric conversion element of 1st embodiment of this invention. It is a cross-sectional schematic diagram of the solid junction type photoelectric conversion element of 2nd embodiment of this invention.

  Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments, but the present invention is not limited to such embodiments.

  In the present specification, “membrane” and “layer” are not distinguished unless otherwise specified. The solid junction photoelectric conversion element is sometimes referred to as a “solid solar cell”, and the organic / inorganic perovskite compound is simply referred to as a “perovskite compound”. Further, unless otherwise specified, the aggregate (bulk) of perovskite compounds is a crystalline compound.

  The thickness of the “film” or “layer” in the present specification is a value obtained by measuring the thickness of 10 sections using a microscope (for example, an electron microscope) and averaging the cross section in the thickness direction of the solid junction photoelectric conversion element. .

<< Solid-junction photoelectric conversion element >>
The solid junction photoelectric conversion element according to the present invention includes a first conductive layer, an optional block layer, a light absorption layer containing an organic / inorganic perovskite compound, a P-type semiconductor layer, and a second conductive layer. Solid solar cells stacked in this order.
As long as the relative order of the above layers is maintained, other layers may be inserted between any of the layers as long as the gist of the present invention is not impaired.

  The first conductive layer and the second conductive layer may each independently be a single layer made of the same material, or may be a plurality of stacked layers made of different materials or compositions. Each of the plurality of layers is a conductive layer having conductivity. Here, having conductivity means that the sheet resistance of the conductive layer is 1000Ω / □ or less.

In the solid junction photoelectric conversion device according to the present invention, at least one of the first conductive layer and the second conductive layer includes an alloy containing two or more metals of Group 4 to Group 15 of the Periodic Table, and Groups of Groups 4 to 15 of the Periodic Table. At least one selected from the group consisting of compounds each containing at least one group element (α) and one or more elements of group 13 to group 16 of the periodic table (excluding the element (α) and oxygen). Including.
When the first conductive layer is a plurality of layers, one or more layers constituting the plurality of layers include at least one selected from the above group. The same applies when the second conductive layer has a plurality of layers.
The element (α) is a metal element, and the compound is preferably a metal compound.
The element (β) is preferably a nonmetallic element or a semimetallic element.
Both the element (α) and the element (β) may be non-metallic elements or metalloid elements.

When the first conductive layer contains at least one selected from the above group, the sheet resistance of the first conductive layer is preferably 10Ω / □ or less, more preferably 8Ω / □ or less, and further preferably 5Ω / □ or less.
When the second conductive layer contains at least one selected from the above group, the sheet resistance of the second conductive layer is preferably 10Ω / □ or less, more preferably 8Ω / □ or less, and further preferably 5Ω / □ or less.
The total sheet resistance of each of the first conductive layer and the second conductive layer is preferably 50Ω / □ or less, more preferably 48Ω / □ or less, and even more preferably 45Ω / □ or less.
When the sheet resistance of each conductive layer is low as described above, the resistance of the solid solar cell 10 can be reduced and the photoelectric conversion efficiency can be further increased.
Here, the sheet resistance is a value measured in accordance with JIS K 7194: 1994 “Resistivity Test Method for Conductive Plastics Using Four Probe Method”.

  When the first conductive layer is a plurality of layers, the sheet resistance of the first conductive layer is the resistance value of the entire plurality of layers. For example, in the case of a two-layer structure, when the sheet resistance of the first layer is R1 and the second layer is R2, the resistance R of the entire two-layer structure is (R1 × R2) / (R1 + R2). For this reason, when the first conductive layer has a plurality of layers, even if the resistance of the first layer is high (for example, about 1000 to 10,000 Ω / □), if the resistance of the second layer is low, the plurality of layers are good as a whole. Can be a simple electrode. When the first conductive layer is a plurality of layers, all or any one or more of the plurality of layers may contain the alloy or the compound, and the layer closest to the light absorption layer contains the alloy or the compound. It is preferable to include. The same applies when the second conductive layer has a plurality of layers.

As a configuration in which at least one of the first conductive layer and the second conductive layer is a plurality of layers (multilayer), the following configuration can be exemplified.
That is, the first conductive layer has a laminated structure in which a low-diffusion conductive layer and an auxiliary conductive layer are laminated in this order from the side in contact with the light absorption layer, and at least the low-diffusion conductive layer of the laminated structure is separated from the group. A structure including at least one selected from the above; the second conductive layer has a stacked structure in which a low diffusion conductive layer and an auxiliary conductive layer are stacked in this order from the side in contact with the light absorption layer, and at least the low layer of the stacked structure Examples include a configuration in which the diffusion conductive layer includes at least one selected from the above group.

As a configuration in which at least one of the first conductive layer and the second conductive layer is a single layer, the following configuration can be exemplified.
That is, the structure which a 1st conductive layer consists only of a layer containing at least 1 sort (s) chosen from the said group; The structure which a 2nd conductive layer consists only of a layer containing at least 1 sort (s) chosen from the said group, etc. are mentioned.

<< first embodiment >>
As 1st embodiment of the solid solar cell concerning this invention, the solid solar cell 10 which has the laminated structure shown in FIG. 1 is mentioned, for example.
The solid solar cell 10 includes an insulating base material 8, a first conductive layer 1, a block layer 2, a base layer 3 and an upper layer 4 containing a perovskite compound, a P-type semiconductor layer 5, and a second conductive layer. 6, a low diffusion conductive layer 6 </ b> B and an auxiliary conductive layer 6 </ b> A are sequentially stacked.
In this laminated structure, the first conductive layer 1 may be referred to as a cathode, the base layer 3 and the upper layer 4 may be collectively referred to as a light absorption layer 7, and the second conductive layer 6 may be referred to as an anode. .
Hereinafter, each layer will be described in order.

[Base material 8]
The kind in particular of the material which comprises the insulating base material 8 is not restrict | limited, For example, the transparent base material used for the conventional solar cell is mentioned. Examples of the transparent substrate include a substrate made of glass or synthetic resin, a flexible film made of synthetic resin, and the like.

  When the material of the transparent substrate is a synthetic resin, examples of the synthetic resin include polyacrylic resin, polycarbonate resin, polyester resin, polyimide resin, polystyrene resin, polyvinyl chloride resin, and polyamide resin. Among these, polyester resins, particularly polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) are preferable from the viewpoint of manufacturing a thin, light and flexible solar cell.

  The combination of the thickness and material of the base material 8 is not particularly limited, and examples thereof include a glass substrate having a thickness of 1 mm to 10 mm and a resin film having a thickness of 0.01 mm to 3 mm.

[First conductive layer 1]
Examples of the first conductive layer 1 include a transparent conductive layer made of a metal oxide. The transparent conductive layer can impart conductivity to the surface without impairing the transparency of the substrate 8. As the metal oxide, a compound used for a transparent conductive layer of a known solar cell can be applied. For example, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide, tin oxide, antimony dope Examples thereof include tin oxide (ATO), indium oxide / zinc oxide (IZO), and gallium oxide / zinc oxide (GZO). The number of transparent conductive layers made of the metal oxide may be 1 or 2 or more.

  The thickness of the transparent conductive layer is not particularly limited as long as desired conductivity is obtained, and examples thereof include about 1 nm to 10 μm.

[Block layer 2]
Although the block layer 2 is not an essential configuration, the block layer 2 is preferably disposed between the first conductive layer 1 and the light absorption layer 7. When the block layer 2 is disposed, the first conductive layer 1 and the perovskite compound of the light absorption layer 7 are prevented from coming into direct contact. Thereby, the loss of electromotive force is prevented and the photoelectric conversion efficiency is improved.
The block layer 2 is preferably a non-porous dense layer, and more preferably a dense layer formed of an N-type semiconductor, in order to reliably prevent the contact.

The N-type semiconductor constituting the block layer 2 is not particularly limited, and examples thereof include oxide semiconductors excellent in electron conductivity such as ZnO, TiO ₂ , SnO, IGZO, SrTiO _{3 and the} like. Among these, TiO ₂ is particularly preferable because of its excellent electron conductivity.
There may be one kind of N-type semiconductor constituting the block layer 2 or two or more kinds.

The number of block layers 2 may be one, or two or more.
Although the total thickness of the block layer 2 is not specifically limited, For example, about 1 nm-1 micrometer are mentioned. When the thickness is 1 nm or more, the effect of preventing the loss is sufficiently obtained, and when the thickness is 1 μm or less, the internal resistance can be kept low.

[Light absorption layer 7]
The light absorption layer 7 is laminated on the surface of the block layer 2. The light absorption layer 7 has a laminated structure in which an underlayer 3 containing a perovskite compound and an upper layer 4 made of a perovskite compound are formed on the surface of the underlayer 3 and formed of an N-type semiconductor or an insulator. Have. Here, the upper layer 4 is not an essential component, and the base layer 3 containing a perovskite compound may form the light absorption layer 7 alone. Further, the underlayer 3 is not an essential component, and the light absorption layer 7 may be formed only by the upper layer 4 made of a perovskite compound. That is, the light absorption layer 7 is formed by at least one of the base layer 3 and the upper layer 4.

The perovskite compound contained in the light absorption layer 7 is not particularly limited, and a perovskite compound used in a known solar cell is applicable, has a crystal structure, and is obtained by band gap excitation as in a typical compound semiconductor. Those showing light absorption are preferred. For example, CH ₃ NH ₃ PbI ₃ , which is a known perovskite compound, is known to have an extinction coefficient (cm ⁻¹ ) per unit thickness that is an order of magnitude higher than that of a sensitizing dye of a dye-sensitized solar cell. Yes.

[Underlayer 3]
The underlayer 3 is laminated on the surface of the block layer 2. In addition, when the block layer 2 is not provided, the base layer 3 may be laminated on the surface of the first conductive layer 1.
A perovskite compound is supported (supported) on at least one of the inside and the surface of the underlayer 3.

The material of the underlayer 3 is preferably an N-type semiconductor and / or an insulator.
The underlayer 3 may be a porous film or a non-porous dense film, and is preferably a porous film. The perovskite compound is preferably supported by the porous structure of the underlayer 3. Even when the underlayer 3 is a dense film, the dense film preferably contains a perovskite compound. The dense film is preferably formed of an N-type semiconductor.

The type of the N-type semiconductor is not particularly limited, and a known N-type semiconductor can be applied, and examples thereof include an oxide semiconductor constituting a conventional dye-sensitized solar cell. Specific examples include oxide semiconductors excellent in electronic conductivity such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO, SnO ₂ ), IGZO, strontium titanate (SrTiO ₃ ), and the like. . In some cases, a compound semiconductor such as Si, Cd, or ZnS doped with a pentavalent element may be used. Of these, titanium oxide is particularly preferable because of its excellent electron conductivity.
The N-type semiconductor forming the underlayer 3 may be one type or two or more types.

The type of the insulator is not particularly limited, and a known insulator can be used. For example, an oxide constituting an insulating layer of a conventional semiconductor device can be used. Specific examples include zirconium dioxide, silicon dioxide, aluminum oxide (AlO, Al ₂ O ₃ ), magnesium oxide (MgO), and the like. Of these, aluminum (III) oxide (Al ₂ O ₃ ) is particularly preferable.
The insulator forming the underlayer 3 may be one type or two or more types.

  The amount of the perovskite compound contained in the underlayer 3 is not particularly limited, and is appropriately set so as to absorb an amount of light necessary for photoelectric conversion. Usually, the amount of light that can be absorbed increases as the content of the perovskite compound increases.

  The film structure of the underlayer 3 is preferably a porous film that can easily carry more perovskite compounds. As the amount of the perovskite compound contained in the underlayer 3 increases, the light absorption efficiency increases and the photoelectric conversion efficiency can be further improved.

The average pore diameter of the porous film constituting the underlayer 3 is preferably 1 nm to 100 nm or more, more preferably 5 nm to 80 nm, and still more preferably 10 nm to 50 nm.
When it is at least the lower limit of the above range, the perovskite compound is sufficiently supported in the pores.
The intensity | strength of a porous membrane is raised more as it is below the upper limit of the said range.
The average pore diameter can be measured by a known gas adsorption test or mercury intrusion test.

The thickness of the underlayer 3 is not particularly limited, and is preferably 10 nm to 10 μm, more preferably 30 nm to 1 μm, and further preferably 50 nm to 0.5 μm, for example.
When it is at least the lower limit of the above range, a scaffold suitable for crystallization of the perovskite compound constituting the upper layer 4 is obtained. Furthermore, the light absorption efficiency in the underlayer 3 is increased, and more excellent photoelectric conversion efficiency is obtained.
If it is not more than the upper limit of the above range, the efficiency with which the photoelectrons generated in the light absorption layer 7 reach the block layer 2 and the first conductive layer 1 through the underlayer 3 is increased, and a more excellent photoelectric conversion efficiency is obtained. .

[Upper layer 4]
The upper layer 4 laminated on the surface of the underlayer 3 is formed of a perovskite compound. When the perovskite compound is supported inside the underlayer 3, the upper layer 4 is not an essential component. When the upper layer 4 is laminated, the total amount of the perovskite compound contained in the light absorption layer 7 is increased, and the photoelectric conversion efficiency is further increased.

The thickness of the upper layer 4 is not specifically limited, For example, 1 nm-1 micrometer are preferable, 1 nm-500 nm are more preferable, 10 nm-500 nm are more preferable.
A photoelectric conversion efficiency can be improved more as it is more than the lower limit of the said range.
When the upper limit value is not more than the upper limit of the above range, the upper layer 4 is sufficiently adhered to the base layer 3 and the P-type semiconductor layer 5 and is prevented from peeling off.

[P-type semiconductor layer 5]
The P-type semiconductor layer 5 formed on the surface of the light absorption layer 7 is composed of a P-type semiconductor.
When the P-type semiconductor layer 5 having holes (holes) is arranged on the surface of the light absorption layer 7, the generation of reverse current is suppressed, and the holes generated in the light absorption layer 7 by light absorption are transferred to the second conductive layer. It can be easily transported to the layer 6. As a result, the photoelectric conversion efficiency and voltage are increased.

The kind of the P-type semiconductor is not particularly limited, and may be an organic material or an inorganic material. For example, a P-type semiconductor for a hole transport layer of a known solar cell can be applied. Examples of the organic material include 2,2 ′, 7,7′-tetrakis (N, N-di-p-methoxyphenilamine) -9,9′-spirobifluorene (abbreviation: spiro-OMeTAD), Poly (3-hexylthiophene) (Abbreviation: P3HT), polytriarylamine (abbreviation: PTAA), and the like.
Examples of the inorganic material include copper compounds such as CuI, CuSCN, CuO, and Cu ₂ O, and nickel compounds such as NiO.
Of these materials, organic semiconductors are preferable from the viewpoint of further improving power generation performance.

The thickness of the P-type semiconductor layer 5 is not specifically limited, For example, 1 nm-1000 nm are preferable, 5 nm-500 nm are more preferable, 30 nm-500 nm are more preferable.
When it is at least the lower limit of the above range, the contact between the light absorption layer 7 and the second conductive layer 6 can be reliably prevented, and the occurrence of leakage current can be prevented.
If it is not more than the upper limit of the above range, the internal resistance can be further reduced.

[Second conductive layer 6]
The second conductive layer 6 laminated on the surface of the P-type semiconductor layer 5 of the present embodiment includes an alloy containing two or more metals of Group 4 to Group 15 of the periodic table, and elements of Group 4 to Group 15 of the periodic table (α And at least one selected from the group consisting of compounds each containing at least one element of group 13 to group 16 of the periodic table (excluding the element (α) and oxygen).

  The alloy includes, for example, two or more metals of Group 4 to 15 of the periodic table, and the total content of the two or more metals is preferably 50% by mass or more based on the total mass of the alloy. More preferably, an alloy of 80 to 100% by mass is used. Specific examples include nickel alloys, copper alloys, silver alloys, gold alloys, cobalt alloys, chromium alloys, and tungsten alloys. More specifically, for example, there are Ni / Mo / Fe alloys such as Hastelloy B and Inconel 600, Ag / Pd / Cu alloys, Cu / Ni alloys such as Western C7351 and Western C7521, and the like.

The element (α) is a metal element, and the compound is preferably a metal compound.
Examples of the metal compound include metal compounds other than metal oxides, such as metal nitrides, silicides, metal carbides, and metal borides. Specific examples include metal nitrides such as TiN, NbN, and TaN, silicides such as NiSi and TiSi, metal carbides such as TiC and WC, and metal borides such as TiB ₂ and NiB.

When both the element (α) and the element (β) are non-metallic elements or metalloid elements, examples of the compound include conductive compounds such as B ₄ C and SiC.

  The second conductive layer 6 in the present embodiment has a stacked structure in which a low diffusion conductive layer 6B and an auxiliary conductive layer 6A are stacked in this order, which are formed of different materials.

It is preferable that at least one material selected from the group consisting of the alloy and the compound is included in at least one of the low diffusion conductive layer 6B and the auxiliary conductive layer 6A and included in the low diffusion conductive layer 6B.
By including the material in the low diffusion conductive layer 6B, the material (component) of the auxiliary conductive layer 6A is diffused before the diffusion (migration) to the P-type semiconductor layer 5 by an electric field or heat. As a result, the decrease in photoelectric conversion efficiency due to long-term use of the solid solar cell 10 can be suppressed.

When the low diffusion conductive layer 6B includes one or more materials selected from the group consisting of the alloy and the compound, the conductive material constituting the auxiliary conductive layer 6A is not particularly limited. For example, a material having high conductivity Any one or more selected from metals such as gold, silver, copper, nickel, aluminum, tungsten, nickel, and chromium, which are known as:
The metal material such as silver is likely to cause migration, but is suitable as a material for the auxiliary conductive layer 6A because the migration can be suppressed by the low diffusion conductive layer 6B.

  The relationship between the sheet resistance Rsh1 of the auxiliary conductive layer 6A and the sheet resistance Rsh2 of the low diffusion conductive layer 6B is preferably Rsh1 <Rsh2. With this relationship, the photoelectric conversion efficiency is increased, and the effect of suppressing the diffusion (migration) of the material (component) of the auxiliary conductive layer 6A to the P-type semiconductor layer 5 by an electric field or heat is enhanced.

The thickness of 6 A of auxiliary conductive layers is not specifically limited, For example, 10 nm-1000 nm are preferable, 50 nm-500 nm are more preferable, 100 nm-300 nm are further more preferable.
When it is at least the above lower limit value, the resistance is reduced and the photoelectric conversion efficiency is further increased, and when it is at most the above upper limit value, waste of materials can be omitted.

The thickness of the low diffusion conductive layer 6B is not particularly limited, and is preferably 1 nm to 1000 nm, more preferably 10 nm to 200 nm, and still more preferably 25 nm to 100 nm, for example.
When it is at least the lower limit value, the effect of suppressing the migration is further enhanced, and when it is at most the upper limit value, waste of materials can be omitted.

The ratio (H1 / H2) of the thickness H1 of the auxiliary conductive layer 6A and the thickness H2 of the low diffusion conductive layer 6B is not particularly limited, and is preferably 1/5 to 5/1, for example, 1/2 to 3/1. More preferred is 1/1 to 2/1.
From the viewpoint of reducing the resistance by utilizing the high conductivity of the auxiliary conductive layer 6A, increasing the photoelectric conversion efficiency, and suppressing the migration by the low diffusion conductive layer 6B, the relationship of H1> H2 is preferable.

<< Power generation of solid solar cell 10 >>
In the solid solar cell 10, the light absorption layer 7 contains a perovskite compound. When light is incident from the substrate 8 and the first conductive layer 1 side and the crystal of the perovskite compound absorbs light, photoelectrons and holes are generated in the crystal. Photoelectrons are received by the underlayer 3 or the block layer 2 and move to the first conductive layer 1 (anode). The holes move to the second conductive layer 6 (cathode) through the P-type semiconductor layer 5. The current generated by the solid solar cell 10 is taken out to an external circuit through an extraction electrode connected to the anode and the cathode.

  In the solid solar cell 10, even if the component of the auxiliary conductive layer 6 </ b> A of the second conductive layer 6 tries to diffuse (migrate) to the light absorption layer 7 due to electric field or heat due to long-term use, the diffusion is caused by the low diffusion conductive layer 6 </ b> B. Is suppressed. As a result, since the component of the auxiliary conductive layer 6A can be prevented from flowing into the light absorption layer 7 and the photoelectric conversion efficiency is lowered, the durability is excellent. On the other hand, since the alloy and the compound contained in the low diffusion conductive layer 6B are relatively difficult to migrate, there is almost no risk that the components of the low diffusion conductive layer 6B will flow into the P-type semiconductor layer 5 and the light absorption layer 7. .

<Modification>
As a modification of the first embodiment, a solid solar cell in which the auxiliary conductive layer 6A is removed from the solid solar cell 10 shown in FIG. In this configuration, the second conductive layer 6 comprises only a single low diffusion conductive layer 6B. Since the description of the solid solar cell of this modification is the same as the description of the solid solar cell 10 described above except that the auxiliary conductive layer 6A is omitted, the description thereof is omitted.
In the above modification, since the alloy and the compound contained in the second conductive layer 6 are relatively difficult to migrate, the components of the second conductive layer 6 flow into the P-type semiconductor layer 5 and the light absorption layer 7. There is little fear.

<< Second Embodiment >>
As a 2nd embodiment of the solid solar cell concerning this invention, the solid solar cell 20 which has the laminated structure shown in FIG. 2 is mentioned, for example.
The solid solar cell 20 includes an insulating first base material 18, an auxiliary conductive layer 11A and a low diffusion conductive layer 11B constituting the first conductive layer 11, a block layer 12, a base layer 13 containing a perovskite compound, and The upper layer 14, the P-type semiconductor layer 15, the second conductive layer 16, and the insulating second base material 19 are stacked in this order.
In this laminated structure, the first conductive layer 11 may be referred to as a cathode, the base layer 13 and the upper layer 14 may be collectively referred to as a light absorption layer 17, and the second conductive layer 16 may be referred to as an anode. . Hereinafter, each layer will be described in order.

[First base material 18]
The kind in particular of the material which comprises the insulating 1st base material 18 is not restrict | limited, For example, the transparent base material used for the conventional solar cell is mentioned. The first substrate 18 need not be transparent and may be opaque. Since the specific description of the first substrate 18 is the same as the description of the substrate 8 of the solid solar cell 10 of the first embodiment, a description thereof will be omitted.

[First conductive layer 11]
The first conductive layer 11 of the present embodiment includes an alloy containing two or more metals of Group 4 to Group 15 of the periodic table, an element (α) of Groups 4 to 15 of the periodic table, and elements of Groups 13 to 16 of the periodic table It contains at least one selected from the group consisting of compounds each containing (β) (excluding the element (α) and oxygen).
The specific description of the alloy and the compound is the same as the description of the alloy and the compound included in the second conductive layer 6 of the solid solar cell 10 of the first embodiment, and will be omitted.

  The first conductive layer 11 in the present embodiment has a laminated structure in which an auxiliary conductive layer 11A and a low diffusion conductive layer 11B, which are formed of different materials, are laminated in this order.

It is preferable that at least one material selected from the group consisting of the alloy and the compound is included in at least one of the auxiliary conductive layer 11A and the low diffusion conductive layer 11B and included in the low diffusion conductive layer 11B.
By including the material in the low diffusion conductive layer 11B, the low diffusion conductive layer 11B suppresses the diffusion before the material (component) of the auxiliary conductive layer 11A diffuses (migrations) to the block layer 12 due to an electric field or heat. Thus, the decrease in photoelectric conversion efficiency due to long-term use of the solid solar cell 20 can be suppressed.

When the low diffusion conductive layer 11B includes one or more materials selected from the group consisting of the alloy and the compound, the conductive material constituting the auxiliary conductive layer 11A is not particularly limited. For example, a material having high conductivity Any one or more selected from metals such as gold, silver, copper, nickel, aluminum, tungsten, nickel, and chromium, which are known as:
The metal material such as silver is likely to cause migration, but the migration can be suppressed by the low diffusion conductive layer 11B, and thus is suitable as a material for the auxiliary conductive layer 11A.

  The relationship between the sheet resistance Rsh1 of the auxiliary conductive layer 11A and the sheet resistance Rsh2 of the low diffusion conductive layer 11B is preferably Rsh1 <Rsh2. With this relationship, the photoelectric conversion efficiency is increased, and the effect of suppressing the diffusion (migration) of the material (component) of the auxiliary conductive layer 11A to the block layer 12 by an electric field or heat is increased.

The thickness of 11 A of auxiliary conductive layers is not specifically limited, For example, 10 nm-1000 nm are preferable, 50 nm-500 nm are more preferable, 100 nm-300 nm are more preferable.
When it is at least the above lower limit value, the resistance is reduced and the photoelectric conversion efficiency is further increased, and when it is at most the above upper limit value, waste of materials can be omitted.

The thickness of the low diffusion conductive layer 11B is not particularly limited, and is preferably 1 nm to 1000 nm, more preferably 10 nm to 200 nm, and further preferably 25 nm to 100 nm, for example.
When it is at least the lower limit value, the effect of suppressing the migration is further enhanced, and when it is at most the upper limit value, waste of materials can be omitted.

The ratio (H1 ′ / H2 ′) of the thickness H1 ′ of the auxiliary conductive layer 11A and the thickness H2 ′ of the low diffusion conductive layer 6B is not particularly limited, and is preferably 1/5 to 5/1, for example, 1/2 to 3/1 is more preferable, and 1/1 to 2/1 is more preferable.
From the viewpoint of reducing the resistance by utilizing the high conductivity of the auxiliary conductive layer 11A, increasing the photoelectric conversion efficiency, and suppressing the migration by the low diffusion conductive layer 11B, the relationship of H1 ′> H2 ′ is preferable.

[Block layer 12]
Although the block layer 12 is not an essential configuration, the block layer 12 is preferably disposed between the first conductive layer 11 and the light absorption layer 17. Since the specific description of the block layer 12 is the same as the description of the block layer 2 of the solid solar cell 10 of the first embodiment, a description thereof will be omitted.

[Light Absorbing Layer 17]
The light absorption layer 17 is laminated on the surface of the block layer 12. The light absorption layer 17 has a stacked structure in which an underlayer 13 containing a perovskite compound and an upper layer 14 formed of a perovskite compound are stacked on the surface of the underlayer 13 and formed of an N-type semiconductor or an insulator. Have.
Specific descriptions of the light absorption layer 17, the base layer 13, and the upper layer 14 are the same as the description of the light absorption layer 7, the base layer 3, and the upper layer 4 of the solid solar cell 10 of the first embodiment, and thus are omitted. .

[P-type semiconductor layer 15]
The P-type semiconductor layer 15 formed on the surface of the light absorption layer 17 is composed of a P-type semiconductor. Generation of reverse current is suppressed by the P-type semiconductor layer 15, and holes generated in the light absorption layer 17 can be easily transported to the second conductive layer 16. Furthermore, the efficiency with which electrons move from the second conductive layer 16 to the light absorption layer 17 is increased. As a result, the photoelectric conversion efficiency and voltage are increased. Since the specific description of the P-type semiconductor layer 15 is the same as the description of the P-type semiconductor layer 5 of the solid solar cell 10 of the first embodiment, a description thereof will be omitted.

[Second conductive layer 16]
As the 2nd conductive layer 16, the transparent conductive layer which consists of metal oxides is mentioned, for example. When the second conductive layer 16 is a transparent conductive layer, light can be incident on the light absorption layer 17 from the second conductive layer 16 side. As the metal oxide, a compound used for a transparent conductive layer of a known solar cell can be applied. For example, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide, tin oxide, antimony dope Examples thereof include tin oxide (ATO), indium oxide / zinc oxide (IZO), and gallium oxide / zinc oxide (GZO). The number of transparent conductive layers made of the metal oxide may be 1 or 2 or more.

  The thickness of the transparent conductive layer is not particularly limited as long as desired conductivity is obtained, and examples thereof include about 1 nm to 10 μm.

[Second base material 19]
The material constituting the insulating second base material 19 is preferably a transparent base material. Since the second base material 19 and the second conductive layer 16 are transparent, light can be incident on the light absorption layer 17 from the second conductive layer 16 side. Examples of the transparent substrate include transparent substrates used in conventional solar cells, and examples include a substrate made of glass or synthetic resin, a flexible film made of synthetic resin, and the like.
Since the specific description of the transparent substrate is the same as the description of the substrate 8 of the solid solar cell 10 of the first embodiment, a description thereof will be omitted.

<< Power generation of solid solar cell 20 >>
In the solid solar cell 20, the light absorption layer 17 contains a perovskite compound. When light is incident from the second base material 19 and the second conductive layer 16 side and the crystal of the perovskite compound absorbs light, photoelectrons and holes are generated in the crystal. Photoelectrons are received by the underlayer 13 or the block layer 12 and move to the first conductive layer 11 (anode). The holes move to the second conductive layer 16 (cathode) through the P-type semiconductor layer 15. The electric current generated by the solid solar cell 20 is taken out to an external circuit through an extraction electrode connected to the anode and the cathode.

  In the solid solar cell 20, even if the component of the auxiliary conductive layer 11 </ b> A of the first conductive layer 11 tries to diffuse (migrate) to the light absorbing layer 17 due to electric field or heat due to long-term use, the diffusion is caused by the low diffusion conductive layer 11 </ b> B. Is suppressed. As a result, it is possible to suppress the component of the auxiliary conductive layer 11A from flowing into the light absorption layer 17 and reducing the photoelectric conversion efficiency, so that the durability is excellent. On the other hand, the alloy and the compound contained in the low diffusion conductive layer 11 </ b> B are relatively unlikely to migrate, so there is almost no risk that the components of the low diffusion conductive layer 11 </ b> B will flow into the block layer 12 and the light absorption layer 17.

<Modification>
As a modification of the second embodiment, there is a solid solar battery obtained by removing the auxiliary conductive layer 11A from the solid solar battery 20 shown in FIG. In this configuration, the first conductive layer 11 includes only a single low diffusion conductive layer 11B. Since the description of the solid solar cell of this modification is the same as the description of the solid solar cell 20 described above except that the auxiliary conductive layer 11A is omitted, the description thereof is omitted.
In the above modification, the alloy and the compound included in the first conductive layer 11 are relatively less likely to migrate, so that the components of the first conductive layer 11 may flow into the block layer 12 and the light absorption layer 17. Almost no.

<< Method for Manufacturing Solid Solar Cell >>
An example of a method for manufacturing the solid solar cell 10 illustrated in FIG. 1 will be described below.

[Preparation of first conductive layer 1 and substrate 8]
The electroconductive base material provided with the 1st conductive layer 1 and the base material 8 can be produced by a conventional method, and may use a commercial item.

[Formation of Block Layer 2]
The formation method of the block layer 2 is not particularly limited, and a known method capable of forming a dense layer made of an N-type semiconductor with a desired thickness on the surface of the first conductive layer 1 can be applied. Examples thereof include a sputtering method, a vapor deposition method, and a sol-gel method in which a dispersion liquid containing an N-type semiconductor precursor is applied.

Examples of N-type semiconductor precursors include titanium tetrachloride (TiCl ₄ ), peroxotitanic acid (PTA), titanium alkoxide such as titanium ethoxide and titanium isopropoxide (TTIP), zinc alkoxide, alkoxysilane, and zirconium. Examples thereof include metal alkoxides such as alkoxides.

[Formation of Underlayer 3]
The method for forming the underlayer 3 is not particularly limited, and for example, a method for forming a semiconductor layer carrying a sensitizing dye of a conventional dye-sensitized solar cell can be applied.

  As a specific example, for example, a paste containing fine particles made of an N-type semiconductor or an insulator and a binder is applied to the surface of the block layer 2 by a doctor blade method, dried, and fired, whereby a porous underlayer made of fine particles 3 can be formed. In addition, by spraying fine particles onto the block layer 2, a porous or non-porous underlayer 3 made of the fine particles can be formed.

  The method for spraying the fine particles is not particularly limited, and a known method can be applied, for example, an aerosol deposition method (AD method), an electrostatic fine particle coating method (electrostatic spray method) in which fine particles are accelerated by electrostatic force, The cold spray method etc. are mentioned.

  As a material for forming the underlayer 3, one or more types of N-type semiconductor fine particles and one or more types of insulating fine particles may be used in combination.

The average particle diameter r of the fine particles is preferably 1 nm ≦ r <200 nm, more preferably 10 nm ≦ r ≦ 70 nm, and further preferably 10 nm ≦ r ≦ 30 nm.
The larger the value is above the lower limit of the above range, the easier it is to insert the perovskite compound sufficiently into the pores constituting the porous structure of the underlayer 3. The smaller the value is below the upper limit of the above range, the more the interface between the perovskite compound and the N-type semiconductor fine particles increases, the photoelectrons can be easily taken out, and the underlying layer 3 and the P-type semiconductor layer 5 come into contact with each other to thereby lose the electromotive force. Can be prevented.

  The average particle diameter r of the fine particles can be obtained as an average value of particle diameters measured by observing a plurality of fine particles with an electron microscope. In this case, the larger the number of fine particles to be measured, the better. For example, 10 to 50 particles may be measured and the arithmetic average thereof may be obtained. Or it can also determine as a peak value of the particle diameter (volume average diameter) distribution obtained by the measurement of the laser diffraction type particle size distribution measuring apparatus. If the measurement sample of the same fine particles is measured by the above two methods and the measured values are different from each other, whether or not they are included in the above average particle diameter range based on the values obtained by observation with an electron microscope. judge.

  The method for incorporating the perovskite compound in the underlayer 3 is not particularly limited. For example, a method in which the formed underlayer 3 is impregnated with a solution containing the perovskite compound or a precursor thereof, or a material to which the perovskite compound is previously attached is used. And a method of forming the base layer 3. The above two methods may be used in combination.

[Formation of Light Absorbing Layer 7]
When the base layer 3 is formed, if a material to which a perovskite compound is previously attached is used, the light absorption layer 7 composed of the base layer 3 containing the perovskite compound is obtained. By further inserting or laminating a perovskite compound inside or on the surface of the underlayer 3, a light absorbing layer 7 containing a larger amount of perovskite compound is obtained.
On the other hand, when the underlayer 3 not containing the perovskite compound is formed, a light absorbing layer 7 containing a sufficient amount of the perovskite compound is obtained by inserting or laminating the perovskite compound inside and on the surface of the underlayer 3. It is done.

  The method of inserting the perovskite compound into the underlayer 3 and forming the upper layer 4 made of the perovskite compound on the surface of the underlayer 3 is not particularly limited, and examples thereof include the following methods. That is, a raw material solution in which a perovskite compound or a perovskite compound precursor is dissolved is applied to the surface of the underlayer 3 and impregnated inside, and the solvent is dried in a state where a solution layer made of a solution having a desired thickness is present on the surface. It is a method to do.

  At least a part of the raw material solution applied to the underlayer 3 penetrates into the porous film of the underlayer 3, and crystallization proceeds with the drying of the solvent, and the perovskite compound adheres and deposits in the porous film. Further, by applying a sufficient amount of the raw material solution, the raw material solution that has not penetrated into the porous film forms an upper layer 4 made of a perovskite compound on the surface of the underlayer 3 together with the drying of the solvent. The perovskite compound constituting the upper layer 4 and the perovskite compound in the underlayer 3 are integrally formed, and the light absorption layer 7 is integrally formed.

  The reaction for generating the perovskite compound from the precursor can take place at room temperature, but may be heated to promote this reaction. Moreover, you may anneal a perovskite compound at about 40-150 degreeC from a viewpoint of improving photoelectric conversion efficiency. Furthermore, you may heat or sinter at the temperature exceeding 150 degreeC as needed.

The perovskite compound used in the present embodiment is not particularly limited as long as it can generate an electromotive force by light absorption, and a known perovskite compound is applicable. Among these, perovskite-type crystals can be formed, and the following composition formula (1) having an organic component and an inorganic component in a single compound:
ABX ₃ (1)
The perovskite compound represented by these is preferable.

  In the composition formula (1), A represents an organic cation, B represents a metal cation, and X represents a halogen ion. In the perovskite crystal structure, the B site can take octahedral coordination with the X site. It is considered that the metal cation at the B site and the atomic orbital of the halogen ion at the X site are mixed to form a valence band and a conduction band related to photoelectric conversion.

The metal constituting the metal cation represented by B in the composition formula (1) is not particularly limited, and examples thereof include Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, and Eu. Among these, Pb and Sn are preferable because they can easily form a highly conductive band by hybridization with the atomic orbitals of halogen ions at the X site.
The metal cation constituting the B site may be one type or two or more types.

The halogen constituting the halogen ion represented by X in the composition formula (1) is not particularly limited, and examples thereof include F, Cl, Br, and I. Among these, Cl, Br, and I are preferable because they can easily form a highly conductive band by a hybrid orbital with a metal cation at the B site.
There may be one kind of halogen ion constituting the X site, or two or more kinds.

The organic group constituting the organic cation represented by A in the composition formula (1) is not particularly limited, and examples thereof include alkylammonium derivatives and formamidinium derivatives.
The organic cation constituting the A site may be one type or two or more types.

  Examples of the organic cation formed by the alkyl ammonium derivative include carbon such as methyl ammonium, dimethyl ammonium, trimethyl ammonium, ethyl ammonium, propyl ammonium, isopropyl ammonium, tert-butyl ammonium, pentyl ammonium, hexyl ammonium, octyl ammonium, and phenyl ammonium. Examples include primary or secondary ammonium having an alkyl group of 1 to 6. Of these, methylammonium, which can easily obtain perovskite crystals, is preferred.

  Examples of the organic cation formed by the formamidinium derivative include formamidinium, methylformamidinium, dimethylformamidinium, trimethylformamidinium, and tetramethylformamidinium. Of these, formamidinium is preferred because it can easily obtain a perovskite crystal.

As a suitable perovskite compound represented by the composition formula (1), for example, CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _3-h Cl _h (h represents 0 to ₃ ), CH ₃ NH ₃ PbI _{The following} composition formula (2) such as _3-j Br _j (j represents 0 to 3):
RNH ₃ PbX ₃ (2)
The alkylamino lead halide represented by these is mentioned. In the composition formula (2), R represents an alkyl group, and X represents a halogen ion. Since the perovskite compound having this composition formula has a wide absorption wavelength range and can absorb a wide wavelength range of sunlight, excellent photoelectric conversion efficiency can be obtained.

  The alkyl group represented by R in the composition formula (2) is preferably a linear, branched or cyclic saturated or unsaturated alkyl group having 1 to 6 carbon atoms. It is more preferably a chain saturated alkyl group, and further preferably a methyl group, an ethyl group, or an n-propyl group. With these preferable alkyl groups, perovskite crystals can be easily obtained.

In the formation of the light absorption layer 7, examples of the precursor contained in the raw material solution include a halide (BX) containing the metal ions at the B site and the halogen ions at the X site, and the A site described above. A halide (AX) containing an organic cation and a halogen ion at the X site.
A single raw material solution containing halide (AX) and halide (BX) may be applied to the underlayer 3, or two raw material solutions each containing halide individually may be applied in turn to the underlayer 3. You may apply to.

  The solvent of the raw material solution is not particularly limited as long as it dissolves the raw material and does not impair the underlayer 3. For example, ester, ketone, ether, alcohol, glycol ether, amide, nitrile, carbonate, halogenated hydrocarbon , Hydrocarbons, sulfones, sulfoxides, formamides and the like.

  As an example, a halogenated alkylamine and a lead halide are dissolved in a mixed solvent of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO), and the solution is applied to the underlayer 3 and dried, whereby the composition formula (2 A perovskite crystal composed of a perovskite compound represented by Furthermore, as described in Non-Patent Document 2, after applying a solvent miscible with GBL or DMSO, such as toluene or chloroform, on the perovskite crystal, annealing is performed at about 100 ° C. You may add the process to do. This additional treatment may improve crystal stability and increase photoelectric conversion efficiency.

  The concentration of the raw material in the raw material solution is not particularly limited, and is preferably a concentration that is sufficiently dissolved and exhibits a viscosity that allows the raw material solution to penetrate into the porous membrane.

  The amount of the raw material solution applied to the underlayer 3 is not particularly limited. For example, the raw material solution penetrates all or at least a part of the porous film and has an upper layer having a thickness of about 1 nm to 1 μm on the surface of the porous film. A coating amount such that 4 is formed is preferable.

The method for applying the raw material solution to the underlayer 3 is not particularly limited, and known methods such as a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a dip method, and a die coating method can be applied.
Application | coating of the said raw material solution with respect to the base layer 3 may be completed by 1 time, and you may repeat application | coating after the 2nd time after drying. The application amount after the second time may be the same as or different from the first application amount.

The method for drying the raw material solution applied to the underlayer 3 is not particularly limited, and known methods such as natural drying, reduced pressure drying, and hot air drying can be applied.
The drying temperature of the raw material solution applied to the underlayer 3 may be a temperature at which the crystallization of the perovskite compound proceeds sufficiently, and examples include a range of 40 to 150 ° C.

[Formation of P-type semiconductor layer 5]
The method for forming the P-type semiconductor layer 5 is not particularly limited. For example, a solution in which the P-type semiconductor is dissolved or dispersed in a solvent in which the perovskite compound constituting the light absorption layer 7 is difficult to dissolve is prepared. The method of obtaining the P-type semiconductor layer 5 by apply | coating to the surface of the layer 7 and drying is mentioned.

The concentration of the P-type semiconductor in the solution is not particularly limited, and may be appropriately adjusted according to the content of the P-type semiconductor in the P-type semiconductor layer 5 to be formed.
The amount of the solution applied to the light absorption layer 7 is not particularly limited, and the amount of application may be adjusted as appropriate according to the thickness of the P-type semiconductor layer 5 to be formed.
The method of applying the solution to the light absorbing layer 7 and the method of drying are not particularly limited, and examples thereof include the same method as the method of applying the perovskite compound raw material solution to the underlayer 3 and drying.

[Formation of Second Conductive Layer 6]
The formation method of the low diffusion conductive layer 6B and the auxiliary conductive layer 6A constituting the second conductive layer 6 is not particularly limited. For example, a sputtering method or a vapor deposition method using a target having the same composition as or close to the composition of the target conductive layer. A known film forming method such as the above can be applied.

  Although the method for manufacturing the solid solar cell 10 of the first embodiment has been described above, the solid solar cell 20 of the second embodiment is similarly manufactured by applying a known film forming method and sequentially laminating each layer. be able to.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

[Example 1]
A transparent resin substrate (PEN substrate) having a transparent conductive layer made of ITO formed on the surface thereof was prepared. Unnecessary portions of the ITO layer were etched with hydrochloric acid. The purpose of this etching is to arrange a conductive material having a first conductive layer (cathode) made of an ITO layer and a second conductive layer (anode) facing each other in a later step, and further connecting terminals and the like. This is to prevent the first conductive layer and the second conductive layer from being unintentionally short-circuited (leaked).
Next, the surface of the first conductive layer (ITO layer) was rubbed by rubbing against the surface.
Subsequently, a slurry in which titanium oxide particles (a mixture of an average particle size of 10 nm and 30 nm) are dispersed in ethanol is applied onto the first conductive layer by spin coating, and then dried at 100 ° C. for 5 minutes to obtain a thickness. A 200 nm porous block layer was formed. Thereafter, a DMF solution in which 1M CH ₃ NH ₃ I and PbI ₂ are dissolved is spin-coated on the block layer, and is heated and dried at 100 ° C. for 60 minutes to form a 400 nm-thick light absorption layer containing perovskite crystals. did. Furthermore, a 200 nm-thick P-type semiconductor layer was formed by spin-coating a 9 wt% chlorobenzene solution of Spiro-OMETAD (Merck) on the light absorption layer.
Finally, a single-layer second conductive layer (low diffusion conductive layer) made of Ni / Mo / Fe alloy (Hastelloy B) and having a thickness of 200 nm was formed on the P-type semiconductor layer by DC sputtering.
By the above method, a solid solar cell having a configuration in which the auxiliary conductive layer 6A was removed from the solid solar cell 10 shown in FIG. 1 was obtained.

[Examples 2 to 9]
Instead of Hastelloy B, a solid solar cell was formed in the same manner as in Example 1 except that a single-layer second conductive layer (low diffusion conductive layer) having a thickness of 200 nm made of the alloy or compound shown in Table 1 was formed by DC sputtering. A battery was manufactured.

[Examples 10 to 15]
Instead of Hastelloy B, a low diffusion conductive layer having a thickness of 50 nm made of the alloy or compound shown in Table 1 is formed by DC sputtering, and an auxiliary conductive layer having a thickness of 50 nm is further formed on the low diffusion conductive layer by DC sputtering. A solid solar cell was manufactured in the same manner as in Example 1 except that the second conductive layer was formed and formed of a low diffusion conductive layer and an auxiliary conductive layer.

[Comparative Examples 1-4]
A solid solar cell was manufactured in the same manner as in Example 1 except that a second conductive layer having a thickness of 50 nm to 200 nm made of the material shown in Table 1 was formed instead of Hastelloy B.

<Evaluation>
The following evaluation was performed about the solar cell obtained by the Example and the comparative example. The results are shown in Table 1.
(1) Measurement of sheet resistance (Ω / □) The sheet resistance of the second conductive layer of the solid solar cell was measured using a 4-probe resistivity meter (MCP-T610, manufactured by Mitsubishi Chemical Analytical Co.).
(2) Measurement of photoelectric conversion efficiency Immediately after manufacturing a solid solar cell, a power source (made by KEITHLEY, 236 model) is connected between the electrodes of the solar cell before use, and a solar simulation simulator (Yamashita Denso Co., Ltd.) with an intensity of 100 mW / cm ² The photoelectric conversion efficiency was measured using the product, and the obtained photoelectric conversion efficiency was defined as the initial conversion efficiency.
The case where the measured value was 10% or more was evaluated as “◯”, and the case where it was less than 10% was evaluated as “×”.
(3) Durability evaluation when a voltage is applied for a long period of time Connect a power supply (made by KEITHLEY, 236 model) between the electrodes of the solid solar cell, and install a solar simulation simulator (made by Yamashita Denso Co., Ltd.) with an intensity of 100 mW / cm ^2. A voltage of 0.7 V was applied at 25 ° C. while irradiating, and the photoelectric conversion efficiency after 24 hours was measured. The obtained photoelectric conversion efficiency was defined as the conversion efficiency after light irradiation.
The maintenance rate was determined as (conversion efficiency after light irradiation) / (initial conversion efficiency). The case where the maintenance ratio was 90% or more was evaluated as “◯”, and the case where it was less than 90% was evaluated as “×”.

From the above results, the solid solar cell of the example provided with the second conductive layer containing a specific alloy or compound has both high initial conversion efficiency and post-use conversion efficiency, and photoelectric conversion even when a long-term voltage is applied. It is clear that the efficiency is hardly lowered and the durability is excellent.
On the other hand, the post-use photoelectric conversion efficiency of the solid solar cell of the comparative example was significantly lower than that of the example.

  The configurations and combinations thereof in the embodiments described above are examples, and the addition, omission, replacement, and other modifications of the configurations can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... First conductive layer, 2 ... Block layer, 3 ... Underlayer, 4 ... Upper layer, 5 ... P-type semiconductor layer, 6 ... Second conductive layer, 6A ... Auxiliary conductive layer, 6B ... Low diffusion conductive layer, 7 ... light absorption layer, 8 ... base material, 10 ... solid junction photoelectric conversion element (solid solar cell);
DESCRIPTION OF SYMBOLS 11 ... First conductive layer, 11A ... Auxiliary conductive layer, 11B ... Low diffusion conductive layer, 12 ... Block layer, 13 ... Underlayer, 14 ... Upper layer, 15 ... P-type semiconductor layer, 16 ... Second conductive layer, 17 ... light absorption layer, 18 ... first substrate, 19 ... second substrate, 20 ... solid junction photoelectric conversion element (solid solar cell)

Claims (5)

A solid junction photoelectric conversion element in which a first conductive layer, a light absorption layer containing an organic / inorganic perovskite compound, a P-type semiconductor layer, and a second conductive layer are provided in this order,
An alloy in which at least one of the first conductive layer or the second conductive layer includes two or more metals of Group 4 to Group 15 of the periodic table, and Group 4 to Group 15 element (α) and Periodic Table 13 A solid junction type comprising at least one selected from the group consisting of compounds each containing one or more elements of group 16 to group 16 (excluding the element (α) and oxygen) Photoelectric conversion element. The first conductive layer contains at least one selected from the group, and the sheet resistance of the first conductive layer is 10Ω / □ or less, or
The second conductive layer contains at least one selected from the group, and the sheet resistance of the second conductive layer is 10Ω / □ or less,
The solid junction photoelectric conversion element according to claim 1. The first conductive layer has a laminated structure in which a low-diffusion conductive layer and an auxiliary conductive layer are laminated in this order from the side in contact with the light absorption layer, and at least the low-diffusion conductive layer of the laminated structure is separated from the group. Contains at least one selected, or
The second conductive layer has a laminated structure in which a low-diffusion conductive layer and an auxiliary conductive layer are laminated in this order from the side in contact with the light absorption layer, and at least the low-diffusion conductive layer of the laminated structure is separated from the group. Including at least one selected,
The solid junction photoelectric conversion element according to claim 1 or 2.   The solid junction photoelectric conversion element according to claim 3, wherein the sheet resistance Rsh1 of the auxiliary conductive layer and the sheet resistance Rsh2 of the low diffusion conductive layer have a relationship of Rsh1 <Rsh2. The first conductive layer consists only of a layer containing at least one selected from the group, or
The second conductive layer consists only of a layer containing at least one selected from the group,
The solid junction photoelectric conversion element according to claim 1 or 2.

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