Electrode material and method for manufacturing electronic device using same

Abstract

To provide a composition suitable for improving the performance of electronic devices, and a manufacturing method of an electronic device using the same.SOLUTION: A disclosed composition contains a conductive material, a p-type dopant, and a solvent. The solvent contains at least one compound selected from the group consisting of alcohols, aliphatic hydrocarbons, siloxanes, esters, and ethers. The disclosed manufacturing method of the electronic device includes the steps of forming a second electrode 6 using the composition of the present disclosure; and laminating a first electrode 2, a photoelectric conversion layer 3, a hole transport layer 5, and a second electrode 6 in this order.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electrode material and a method for manufacturing an electronic device using the same. [Background technology]

[0002] In many electronic devices, in order to exhibit functions such as light absorption, light emission, amplification, or rectification, a hole transport layer or an electron transport layer is placed in contact with a photoelectric conversion layer, thereby extracting or supplying only holes or electrons in one direction.

[0003] The hole transport layer is a layer that allows holes to enter and exit the valence band of the adjacent photoelectric conversion layer and has the function of insulating electrons from the conduction band of the photoelectric conversion layer. The electron transport layer is a layer that allows electrons to enter and exit the conduction band of the adjacent photoelectric conversion layer and has the function of insulating holes from the valence band of the photoelectric conversion layer.

[0004] Although various hole transport materials exist as the main material constituting a hole transport layer, few materials have a hole concentration sufficient to function alone as a hole transport layer of an electronic device. In many cases, the required hole concentration can be achieved by adding an additive to the hole transport material. That is, the additive has the function of removing electrons from the valence band from the hole transport material.

[0005] A perovskite solar cell has a structure in which, for example, a first electrode, a photoelectric conversion layer, a hole transport layer, and a second electrode are formed in this order. An electron transport layer may also be located between the first electrode and the photoelectric conversion layer. In a perovskite solar cell, the photoelectric conversion layer is a layer that absorbs light and generates electrons and holes. The hole transport layer is a layer that conducts only the holes generated in the photoelectric conversion layer to the second electrode and insulates the electrons. The electron transport layer is a layer that conducts only the electrons generated in the photoelectric conversion layer to the first electrode and insulates the holes (Non-Patent Document 1).

[0006] For example, an organic thin-film solar cell has a structure in which a first electrode, a photoelectric conversion layer, a hole transport layer, and a second electrode are formed in this order. Although the details of the operating principle differ in some respects from perovskite solar cells, they are the same as perovskite solar cells in that the hole transport layer is a layer that does not conduct electrons but conducts only holes to the second electrode (Patent Document 1).

[0007] An organic EL light-emitting device using an organic compound as the light-emitting layer has a structure in which, for example, a first electrode, a light-emitting layer, a hole-transporting layer, and a second electrode are formed in this order. The hole-transporting layer in an organic EL light-emitting device is a functional layer that does not conduct electrons to the light-emitting layer but conducts only holes, and therefore operates differently from the perovskite solar cell and organic thin-film solar cell described above. However, they are the same in that the hole-transporting layer does not conduct electrons but conducts only holes (Patent Document 2).

[0008] Thus, the hole transport layer is a core component for the operation of electronic devices. However, when an electrode is fabricated on the hole transport layer by coating ink, the performance of the electronic device tends to be poor (Non-Patent Document 2).

[0009] Patent Document 3 discloses an electrode containing a dopant for an electron transport layer. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] Materials Chemistry and Physics 256,p.123594(2020) [Non-patent document 2] Journal of Materials chemistry A,3,p.15996(2015) [Patent documents]

[0011] [Patent Document 1] JP 2012-216673 A [Patent Document 2] Patent Publication No. 2019-77685 [Patent Document 3] International Publication No. 2011 / 052546 Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present disclosure is to provide compositions suitable for improving the performance of electronic devices. [Means for solving the problem]

[0013] The composition of the present disclosure includes a conductive material, a p-type dopant, and a solvent, wherein the solvent includes at least one compound selected from the group consisting of alcohols, aliphatic hydrocarbons, siloxanes, esters, and ethers. [Effects of the Invention]

[0014] The present disclosure provides compositions suitable for improving the performance of electronic devices. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a flowchart showing an example of a manufacturing method according to the second embodiment. [Figure 2] FIG. 2 shows a cross-sectional view of a schematic configuration of a solar cell 100 obtained by the manufacturing method according to the second embodiment. [Figure 3] FIG. 3 shows a cross-sectional view of a schematic configuration of a solar cell 200 obtained by the manufacturing method according to the second embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of a manufacturing method according to the third embodiment. [Figure 5] FIG. 5 shows a cross-sectional view of a schematic configuration of a solar cell 300 obtained by the manufacturing method according to the third embodiment. [Figure 6]FIG. 6 shows a cross-sectional view of a schematic configuration of a solar cell 400 obtained by the manufacturing method according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0017] (First embodiment) In the first embodiment, the composition will be described below.

[0018] The composition according to the first embodiment includes a conductive material, a p-type dopant, and a solvent, the solvent including at least one compound selected from the group consisting of alcohols, aliphatic hydrocarbons, siloxanes, esters, and ethers.

[0019] The composition according to the first embodiment is used, for example, as an ink for forming an electrode. The composition according to the first embodiment is used, for example, in an electronic device. The electronic device is, for example, a solar cell, which includes a first electrode, a photoelectric conversion layer, a hole transport layer, and a second electrode in this order.

[0020] For example, when the composition according to the first embodiment is used in the manufacture of an electrode for an electronic device, it is possible to suppress a decrease in the concentration of holes in the hole transport layer, which would otherwise be caused by, for example, the elution of a p-type dopant originally contained in the hole transport layer into the electrode. Therefore, by fabricating an electronic device using the composition according to the first embodiment, it is possible to improve the performance of the electronic device.

[0021] In this specification, a p-type dopant refers to a material that functions as an acceptor when added to a hole transport material that constitutes a hole transport layer in an electronic device, i.e., a material that has the function of extracting electrons in the valence band from the hole transport material. As used herein, a hole transport material is a material that allows the injection and emission of holes and rejects the injection and emission of electrons. Conductive materials are materials that allow the injection and ejection of holes and electrons.

[0022] The conductive material may include at least one selected from the group consisting of a metal, a conductive carbon, and a conductive compound.

[0023] The conductive material may be a powder.

[0024] The metal is not particularly limited as long as it can be made into a metal powder, although alkali metals and alkaline earth metals, which easily combine with oxygen and water, are somewhat difficult to use.

[0025] Conductive carbon comes in various forms depending on the production method, but highly conductive carbon is desirable. Examples of conductive carbon include carbon black, graphene, carbon nanotubes, and graphite. The carbon black may be, for example, carbon black #3030B, #3050B, #3230B, or #3400B manufactured by Mitsubishi Chemical Corporation.

[0026] Examples of conductive compounds are fluorine-doped tin oxide (SnO2:F), indium tin oxide (ITO), Al-doped zinc oxide (ZnO:Al), Ga-doped zinc oxide (ZnO:Ga), Nb-doped titanium oxide (TiO2:Nb), barium tin oxide (BTO), or titanium nitride (TiN).

[0027] When the conductive material is in the form of particles, the particles may have a particle size of 10 μm or less from the viewpoint of forming an ink.

[0028] The p-type dopant may include at least one selected from the group consisting of a metal salt containing a bis(trifluoromethanesulfonyl)imide group, a metal salt containing a bis(fluorosulfonyl)imide group, a metal salt containing a bis(pentafluoroethylsulfonyl)imide group, a metal salt containing a 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine-1,1,3,3-tetraoxide group, tris(pentafluorophenyl)borane (TPFPB), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), SnCl4, SbCl5, FeCl3, and WO3.

[0029] The p-type dopant may be at least one selected from the group consisting of a metal salt containing a bis(trifluoromethanesulfonyl)imide group, a metal salt containing a bis(fluorosulfonyl)imide group, a metal salt containing a bis(pentafluoroethylsulfonyl)imide group, a metal salt containing a 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine-1,1,3,3-tetraoxide group, TPFPB, F4-TCNQ, SnCl4, SbCl5, FeCl3, and WO3.

[0030] The p-type dopant may include at least one selected from the group consisting of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and TFPPB. The p-type dopant may be at least one selected from the group consisting of LiTFSI and TFPPB.

[0031] The solvent may be any material that does not corrode the material that constitutes the surface to which the composition is applied.

[0032] The solvents used were 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, 1,2-propanediol, 1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, hexane, heptane, octane, nonane, decane, undecane, dodecane, and hexamethyldisilane. Disiloxane, Hexamethoxydisiloxane, 1,1,3,3-Tetramethyldisiloxane, 1,1,3,3,5,5,7,7,9,9,11,11-Dodecamethylhexasiloxane, 1,1,5,5-Tetramethyl-3,3-diphenyltrisiloxane, 1,1,1,3,3-Pentamethyldisiloxane, Methyl Acetate, Ethyl Acetate, Propyl Acetate, Butyl Acetate, Methyl Cellosolve, Ethyl Cellosolve, Propyl Cellosolve, Butyl Cellosolve, Dimethyl Cellosolve , phenyl cellosolve, diisopropyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether propionate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether.

[0033] The above solvents are effective in, for example, perovskite solar cells and organic thin-film solar cells.

[0034] The solvent may include 2-propanol.

[0035] The composition according to the first embodiment may contain a binder, which can improve the adhesion of an electrode formed using the composition.

[0036] Examples of binders include polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene, polypropylene, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid, polyvinyl butyral, polyacrylamide, polyurethane, polydimethylsiloxane, epoxy resin, acrylic resin, polyester resin, melamine resin, phenolic resin, various rubbers, lignin, pectin, gelatin, xanthan gum, welan gum, succinoglycan, polyvinyl alcohol, polyvinyl acetal, cellulose-based resin, polyalkylene oxide, polyvinyl ether, polyvinylpyrrolidone, chitins, chitosans, and starch.

[0037] The composition according to the first embodiment may contain a binder in an amount of 2% by mass or more and 10% by mass or less relative to the conductive material in order to suppress aggregation of the conductive material.

[0038] In the composition according to the first embodiment, the concentration of the p-type dopant may be equal to or greater than 0.1% by mass and less than 100% by mass. This configuration makes it possible to prevent a decrease in the dopant concentration in the hole transport layer.

[0039] In the composition according to the first embodiment, the concentration of the p-type dopant may be 0.1% by mass or more and the saturated concentration of the solvent or less. This configuration can prevent a decrease in the dopant concentration in the hole transport layer. Furthermore, the composition can be stored while preventing evaporation of the solvent. The concentration of the p-type dopant may be 0.1% by mass or more and 50% by mass or less, or 0.1% by mass or more and 46.1% by mass or less. This further prevents a decrease in the dopant concentration in the hole transport layer. Furthermore, an increase in the viscosity of the composition can be prevented, facilitating film formation by spin coating.

[0040] (Second embodiment) Hereinafter, in the second embodiment, a method for manufacturing an electronic device using the composition according to the first embodiment will be described.

[0041] FIG. 1 is a flowchart showing an example of a manufacturing method according to the second embodiment.

[0042] The method for manufacturing an electronic device according to the second embodiment includes: (A1) stacking a first electrode, a photoelectric conversion layer, and a hole transport layer in this order; (B1) forming a second electrode on the hole transport layer using the composition according to any one of claims 1 to 8; Includes:

[0043] Regarding the steps in the flowchart showing an example of the manufacturing method according to the second embodiment shown in FIG. 1, S11 is included in the above (A1), and S12 to S14 are included in the above (B1).

[0044] In the above (B1), the second electrode may be formed by applying the composition according to the first embodiment onto the hole transport layer.

[0045] Conventionally, when an electrode is fabricated by applying ink onto a hole transport layer, the performance tends to be poor. This is because the p-type dopant contained in the hole transport layer elutes into the electrode, reducing the hole concentration in the hole transport layer. In the manufacturing method according to the second embodiment, an electrode is fabricated by applying the composition according to the first embodiment onto a hole transport layer. According to the second embodiment, the composition contains a p-type dopant, and this can prevent a decrease in the p-type dopant concentration in the hole transport layer due to elution of the p-type dopant from the hole transport layer into the electrode. As a result, a decrease in the hole concentration in the hole transport layer can be prevented. Therefore, the manufacturing method according to the second embodiment can provide an electronic device with improved performance.

[0046] In the above (A1), the first electrode, the photoelectric conversion layer, and the hole transport layer may be laminated in this order on the substrate.

[0047] In the above (A1), the first electrode, the electron transport layer, the photoelectric conversion layer, and the hole transport layer may be laminated in this order.

[0048] The electronic device manufactured by the manufacturing method according to the second embodiment is not particularly limited as long as it is an electronic device including a first electrode, a photoelectric conversion layer, a hole transport layer, and a second electrode in this order. The electronic device manufactured by the manufacturing method according to the second embodiment is, for example, a solar cell, a light-emitting element, or a photosensor. The electronic device manufactured by the manufacturing method according to the second embodiment may be, for example, a solar cell.

[0049] An example of the configuration when the electronic device manufactured by the manufacturing method according to the second embodiment is a solar cell will be described with reference to FIGS.

[0050] 2 shows a cross-sectional view of the schematic configuration of a solar cell 100 obtained by the manufacturing method according to the second embodiment. The solar cell 100 includes a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, and a second electrode 6 stacked in this order.

[0051] The manufacturing method according to the second embodiment includes: (C1) The method may further include stacking an auxiliary electrode on the second electrode.

[0052] This allows the resulting electronic device to extract current from the second electrode to the outside with little loss.

[0053] 3 shows a cross-sectional view of the schematic configuration of a solar cell 200 obtained by the manufacturing method according to the second embodiment. The solar cell 200 includes a substrate 1, a first electrode 2, an electron transport layer 3, a photoelectric conversion layer 4, a hole transport layer 5, a second electrode 6, and an auxiliary electrode 7 stacked in this order.

[0054] In order to expose the first electrode 2 as a negative electrode, the method may include removing the electron transport layer 3, the photoelectric conversion layer 4, the hole transport layer 5, the second electrode 6, and the auxiliary electrode 7 from the portions where the first electrode 2 is to be exposed, for example, by laser scribing using laser irradiation or mechanical scribing using a metal blade.

[0055] Hereinafter, each component when a solar cell is manufactured by the manufacturing method according to the second embodiment will be described.

[0056] (Substrate 1) The substrate 1 serves to support each layer of the solar cell and is made of a stable material that will not corrode or disappear during the process of forming the first electrode 2, the photoelectric conversion layer 4, the hole transport layer 5, and the second electrode 6 on the substrate 1.

[0057] When the solar cell generates power using light incident from the substrate side, the substrate 1 is made of a light-transmitting material.

[0058] The substrate 1 may be a ceramic substrate such as glass or a plastic substrate. The plastic substrate may be a plastic film.

[0059] If the first electrode 2 has sufficient strength, the layers of the solar cell can be held by the first electrode 2, and therefore the substrate 1 does not need to be provided.

[0060] (first electrode 2) The function of the first electrode 2 is to accept electrons generated in the photoelectric conversion layer 4 and extract them to the outside. The first electrode 2 has electrical conductivity. It is desirable that the first electrode 2 has low electrical resistance.

[0061] Examples of materials that form the first electrode 2 include metals, conductive compounds that exhibit electronic conductivity, and conductive carbon.

[0062] There are no restrictions on the metal, and almost all metals can be used.

[0063] If light transmission is required for the first electrode 2, a conductive compound with light transmission properties is desirable. Examples of conductive compounds include indium, zinc, or tin oxide, titanium oxide and nitride, or organic conductors. Fluorine-doped tin oxide (SnO2:F), indium tin oxide (ITO), aluminum-doped zinc oxide (ZnO:Al), gallium-doped zinc oxide (ZnO:Ga), niobium-doped titanium oxide (TiO2:Nb), or barium tin oxide (BTO) have low volume resistivity and can therefore be used in outdoor solar cells that carry large currents. SnO2:F, ITO, ZnO:Al, ZnO:Ga, TiO2:Nb, and BTO are particularly useful for solar cells because they are also light-transmitting.

[0064] Examples of conductive carbon are carbon black, carbon nanotubes (CNT), graphene, or graphite. Ketjen black and acetylene black are materials classified as carbon black.

[0065] Examples of methods for manufacturing the first electrode 2 include vacuum film formation methods such as sputtering, vapor deposition, or ion plating, screen printing, spraying, or CVD (Chemical Vapor Deposition). CVD is a method for forming a film on the surface of the heated substrate 1 by spraying fine droplets of a special material liquid or gas onto the substrate 1. For example, the first electrode 2 may be formed on the substrate 1 by sputtering ITO so that the sheet resistance is approximately 10 Ω / □ or more and 40 Ω / □ or less.

[0066] (electron transport layer 3) The function of the electron transport layer 3 is to accept electrons in the conduction band of the photoelectric conversion layer 4 and conduct the electrons to the first electrode 2 while insulating holes in the valence band of the photoelectric conversion layer 4 .

[0067] Examples of materials that form the electron transport layer 3 include titanium oxide and tin oxide.

[0068] The electron transport layer 3 can be produced, for example, by spin-coating or spray-coating an alcohol dispersion (concentration: 1% by mass) containing TiO2 nanoparticles, and then heating to 100°C or higher to remove the alcohol. For example, the electron transport layer 3 may be produced by sputtering TiO2 onto the first electrode 2 to a thickness of 10 nm or more and 100 nm or less. Alternatively, the electron transport layer 3 may be produced by forming an aggregate of TiO2 nanoparticles to a thickness of approximately 100 nm or more and 500 nm or less.

[0069] (Photoelectric conversion layer 4) The function of the photoelectric conversion layer 4 is to receive light incident from the substrate side or the opposite side, generate electrons and holes, and diffuse the electrons and holes without recombining.

[0070] The photoelectric conversion layer 4 may contain a perovskite compound. The perovskite compound refers to a compound having a perovskite-type crystal structure represented by the composition formula ABX3 or a structure similar thereto. Here, A is a monovalent cation. Examples of the cation A are monovalent cations such as alkali metal cations or organic cations. Examples of the alkali metal cations include sodium cations (Na + ), potassium cation (K + ), cesium cation (Cs + ), or rubidium cation (Rb + ) An example of an organic cation is the methylammonium cation (CH3NH3 + ) or formamidinium cation (NH2CHNH2 + ) B is a divalent metal cation. Examples of cation B are Pb cation, Sn cation, or Ge cation. X is a monovalent anion. Examples of anion X are halogen anions. Examples of halogen anions are iodine anions or bromine anions. Each site of cation A, cation B, and anion X may be occupied by multiple types of ions.

[0071] An example of a method for producing the photoelectric conversion layer 4 is to apply a solution in which a predetermined material is dissolved in an organic solvent, remove the organic solvent from the coating film, and then perform a heat treatment. The organic solvent can be removed from the coating film, for example, by evaporating the organic solvent by reducing the pressure, or by adding a solvent that is a poor solvent for the predetermined material dissolved in the organic solvent but is compatible with the organic solvent, thereby removing only the organic solvent from the coating film. This method is common. This method is simple and can produce a photoelectric conversion layer 4 with high performance. The photoelectric conversion layer 4 can also be produced by vacuum deposition.

[0072] (Hole transport layer 5) The function of the hole transport layer 5 is to accept only holes from the photoelectric conversion layer 4 and block electrons. The hole transport layer 5 contains a hole transport material. The hole transport material desirably has a HOMO (Highest Occupied Molecular Orbital) level close to the HOMO level of the photoelectric conversion layer 4 and a LUMO (Lowest Unoccupied Molecular Orbital) level higher than the LUMO level of the photoelectric conversion layer 4.

[0073] For example, in the case of a perovskite solar cell, the LUMO level of the photoelectric conversion layer 4 is around -4 eV, and the HOMO level is around -5 eV. Therefore, examples of hole transport materials include poly(bis(4-phenyl)(2,4,6-trimethylphenyl))amine (PTAA), N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’ ,N 7’ -octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine (Spiro-OMeTAD), dithiophenebenzene copolymer (DTB), poly-3-hexylthiophene (P3HT), or poly-3-hexylthiophene-polystyrene block polymer (P3HT-b-PSt).

[0074] The hole transport layer 5 may contain at least one selected from the group consisting of PTAA, Spiro-OMeTAD, DTB, P3HT, and P3HT-b-PSt. Note that these materials alone may not provide sufficient hole density in the hole transport layer. For this reason, the hole transport layer 5 may contain not only a hole transport material but also an additive. The additive has the function of removing electrons from the valence band from the hole transport material. That is, the hole transport layer 5 may contain a p-type dopant. Hereinafter, the p-type dopant contained in the hole transport layer 5 is also referred to as a second p-type dopant.

[0075] The second p-type dopant may be any of the materials exemplified as the p-type dopant contained in the composition according to the first embodiment. The hole transport layer 5 may contain, as the second p-type dopant, the same substance as the p-type dopant contained in the composition according to the first embodiment, or a different substance. When the hole transport layer 5 and the composition according to the first embodiment forming the second electrode 6 contain the same substance as the p-type dopant, the manufacturing process of the electronic device is not complicated. When the hole transport layer 5 and the composition according to the first embodiment forming the second electrode 6 contain different substances as the p-type dopant, p-type dopants with different properties can be used in the electronic device, and their properties can be complemented. For example, when the hole transport layer 5 and the second electrode 6 contain a p-type dopant that is durable against light and a p-type dopant that is durable against heat, the light and heat durability of the electronic device can be improved.

[0076] The hole transport layer 5 may be formed by applying a solution of a hole transport material and a second p-type dopant in an organic solvent onto an underlying layer (e.g., onto the photoelectric conversion layer 4) and drying the solution. The organic solvent used for this is selected to be one that does not dissolve the first electrode 2, the electron transport layer 3, and the photoelectric conversion layer 4. Examples of such organic solvents include benzene, chlorobenzene, toluene, xylene, anisole, and mesitylene.

[0077] (Second electrode 6) The function of the second electrode 6 is to receive holes generated in the photoelectric conversion layer 4 and extract them to the outside.

[0078] The second electrode 6 is formed using the composition according to the first embodiment. The second electrode 6 can be formed, for example, by applying and drying the composition according to the first embodiment. For example, the second electrode 6 may be formed by applying the above-described composition to a hole transport layer and drying it. This can further suppress a decrease in the dopant concentration in the hole transport layer 5. As a result, the performance of the electronic device can be improved.

[0079] (auxiliary electrode 7) The auxiliary electrode 7 is electrically connected to the second electrode 6. The function of the auxiliary electrode 7 is to extract current from the second electrode 6 to the outside with minimal loss. The auxiliary electrode 7 can be made of a low-resistance material. The auxiliary electrode 7 is formed by, for example, vapor deposition.

[0080] (Third embodiment) Hereinafter, in the third embodiment, a method for manufacturing an electronic device using the composition according to the first embodiment will be described. The matters described in the first and second embodiments may be omitted as appropriate.

[0081] FIG. 4 is a flowchart showing an example of a manufacturing method according to the third embodiment.

[0082] The method for manufacturing an electronic device according to the third embodiment includes the steps of: (A2) forming a second electrode using the composition according to any one of claims 1 to 8; and (B2) Laminating a hole transport layer, a photoelectric conversion layer, and a first electrode in this order on the second electrode.

[0083] With regard to the steps in the flowchart showing an example of the manufacturing method according to the third embodiment shown in FIG. 4, S41 to S43 are included in the above (A2), and S44 is included in the above (B2).

[0084] In the above (A2), the second electrode may be formed by applying the composition according to the first embodiment to a substrate.

[0085] In the above (B2), a hole transport layer, a photoelectric conversion layer, an electron transport layer, and a first electrode may be laminated in this order on the second electrode.

[0086] The electronic device manufactured by the manufacturing method according to the third embodiment is, for example, a solar cell.

[0087] An example of the configuration when the electronic device manufactured by the manufacturing method according to the third embodiment is a solar cell will be described with reference to FIGS.

[0088] 5 shows a cross-sectional view of a schematic configuration of a solar cell 300 obtained by the manufacturing method according to the third embodiment. The solar cell 300 includes a substrate 11, a second electrode 16, a hole transport layer 15, a photoelectric conversion layer 14, an electron transport layer 13, and a first electrode 12 stacked in this order.

[0089] The manufacturing method according to the third embodiment includes: (C2) laminating an auxiliary electrode on the second electrode may further be included.

[0090] This allows the resulting electronic device to extract current from the second electrode to the outside with little loss.

[0091] 6 shows a cross-sectional view of a schematic configuration of a solar cell 400 obtained by the manufacturing method according to the third embodiment. The solar cell 400 includes a substrate 11, a second electrode 16, an auxiliary electrode 17, a hole transport layer 15, a photoelectric conversion layer 14, an electron transport layer 13, and a first electrode 12 stacked in this order.

[0092] Hereinafter, each component will be described when a solar cell is manufactured by the manufacturing method according to the third embodiment. The matters described in the second embodiment may be omitted as appropriate.

[0093] The substrate 11 has the same configuration as the substrate 1 described in the second embodiment. The auxiliary electrode 17 has the same configuration as the auxiliary electrode 7 described in the second embodiment. The hole transport layer 15 has the same configuration as the hole transport layer 5 described in the second embodiment. The photoelectric conversion layer 14 has the same configuration as the photoelectric conversion layer 4 described in the second embodiment. The electron transport layer 13 has the same configuration as the electron transport layer 3 described in the second embodiment. The first electrode 12 has the same configuration as the first electrode 2 described in the second embodiment.

[0094] The second electrode 16 is formed using the composition according to the first embodiment. The second electrode 16 can be formed, for example, by applying and drying the composition according to the first embodiment. For example, the second electrode 16 may be formed by applying the above-described composition to the substrate 1 and drying it. This makes it possible to suppress a decrease in the hole concentration in the hole transport layer 15. As a result, an electronic device with improved performance can be provided.

[0095] The method for manufacturing the hole transport layer 15 is the same as that described in the second embodiment.

[0096] An example of a method for manufacturing the photoelectric conversion layer 14 is to apply a solution in which a predetermined material is dissolved in an organic solvent, evaporate and remove the organic solvent by reducing the pressure, and then perform a heat treatment.

[0097] The electron transport layer 13 may be formed, for example, by sputtering TiO2 or SnO2. Alternatively, the electron transport layer 13 may be formed by spin-coating or spray-coating an alcohol dispersion (concentration: 1% by mass) containing TiO2 nanoparticles, heating to 100°C or higher to remove the alcohol, and then sputtering TiO2 or SnO2.

[0098] The first electrode 12 can be formed by vacuum deposition such as sputtering or evaporation of indium tin oxide (ITO), Al-doped zinc oxide (ZnO:Al), Ga-doped zinc oxide (ZnO:Ga), Nb-doped titanium oxide (TiO:Nb), or barium tin oxide (BTO). [Example]

[0099] The present disclosure will now be described in more detail with reference to examples. In the examples, perovskite solar cells were fabricated and their device performance was evaluated.

[0100] Examples 1 to 9 The methods for producing the solar cells according to Examples 1 to 9 will be described below.

[0101] A 25 mm square, 0.7 mm thick glass substrate was prepared. Indium tin oxide (ITO) was sputtered onto one side of the glass to give a sheet resistance of 10 Ω / □. In this way, a first electrode was formed on the substrate.

[0102] Titanium oxide (TiO2) was formed on the first electrode by sputtering to a thickness of 30 nm.

[0103] Furthermore, an aggregate of TiO2 nanoparticles was formed to a thickness of 250 nm, thus forming an electron transport layer on the first electrode.

[0104] Next, a raw material solution for the photoelectric conversion layer was prepared. The raw material solution was prepared by dissolving 2.91 g of formamidinium hydroiodide ((NH2)2CH2I), 0.57 g of methylammonium hydroiodide (CH3NH3I), and 10 g of lead iodide (PbI2) in a mixed solvent of 23.3 mL of N,N-dimethylformamide (DMF) and 5.8 mL of dimethyl sulfoxide (DMSO). The raw material solution (80 μL) was dropped onto the electron transport layer, and the substrate containing the electron transport layer was spun at 4000 rpm for 70 seconds using a spin coater. Thirty to 60 seconds after the start of rotation, 1 mL of toluene was dropped onto the rotating electron transport layer onto which the raw material solution had been dropped using a pipette. The substrate was then heated on a hot plate at 115°C for 30 minutes. In this way, a photoelectric conversion layer was formed on the electron transport layer.

[0105] Next, a hole transport material solution was prepared by adding 4.8 μL of a solution of 500 mg of LiTFSI in 1 mL of acetonitrile to a solution of 10 mg of PTAA and 6 μL of tert-butylpyridine in 1 mL of toluene. The hole transport layer was formed by dropping 60 μL of the hole transport material solution onto the photoelectric conversion layer and spinning it at 4000 rpm for 30 seconds using a spin coater.

[0106] A composition of the present disclosure was prepared as an electrode ink. The electrode ink was prepared by placing 9 parts by mass of acetylene black and 1 part by mass of cellulose in a bead mill, adding 2-propanol in the amount shown in Table 1, stirring, and then adding LiTFSI or TPFPB as a p-type dopant in the amount shown in Table 1. Table 1 shows the concentration of the p-type dopant in the electrode ink. Here, the concentration of the p-type dopant in the electrode ink refers to the mass fraction of the p-type dopant in the electrode ink.

[0107] 500 μL of electrode ink (composition) was dropped onto the hole transport layer, spun at 1000 rpm for 30 seconds using a spin coater, and then heated on a hot plate at 100°C for 2 hours. In this way, a second electrode was formed on the hole transport layer. Au was formed on the second electrode by vapor deposition to a thickness of 200 nm. In this way, an auxiliary electrode was formed.

[0108] In this manner, the solar cells according to Examples 1 to 9 were fabricated.

[0109] (Comparative Example 1) A solar cell of Comparative Example 1 was fabricated in the same manner as in Examples 1 to 9, except that no p-type dopant was added to the electrode ink dropped onto the hole transport layer.

[0110] (Rating 1) The characteristics of the fabricated solar cells of Examples 1 to 9 and Comparative Example 1 were evaluated under fluorescent light. The solar cells were irradiated with fluorescent light (illuminance 200 lx) so that light was incident on the glass substrate side, and a light-shielding mask with an aperture of 0.4 cm × 0.25 cm was attached to the glass surface to define the light-receiving area. A source meter (6246, manufactured by ADC Corporation) was used to measure the current at an operating voltage of 0.6 V. Hereinafter, the operating voltage will also be referred to as "Vop." Table 1 shows the current values ​​at Vop = 0.6 V and an illuminance of 200 lx for the solar cells of Examples 1 to 9 and Comparative Example 1.

[0111] (Rating 2) The characteristics of the solar cells fabricated in Examples 1 to 9 and Comparative Example 1 were evaluated under simulated sunlight. The solar cells were irradiated with 1 sun's light from a solar simulator through a light-shielding mask with an aperture of 0.4 cm x 0.25 cm, with light incident from the glass substrate side. A source meter (6246, manufactured by ADC Corporation) was used to measure the voltage-current characteristics in the voltage range of -0.2 V to +1.2 V, and the output at the maximum output point was determined. The maximum output of the solar cells in Examples 1 to 9 and Comparative Example 1 is shown in Table 1.

[0112] [Table 1]

[0113] (Consideration 1) As shown in Table 1, the current values ​​in Evaluation 1 and the maximum output values ​​in Evaluation 2 of Examples 1 to 7 are greater than those of Comparative Example 1. The characteristics of solar cells are improved by forming a second electrode using an electrode ink containing LiTFSI, a p-type dopant. Furthermore, the characteristics of solar cells are improved when the LiTFSI concentration in the electrode ink is in the range of 0.1% by mass to 46.1% by mass.

[0114] The current values ​​in Evaluation 1 and the maximum output values ​​in Evaluation 2 of Examples 8 and 9 were greater than those of Comparative Example 1. This shows that the solar cell characteristics are improved even when the p-type dopant contained in the electrode ink is TPFPB, while the p-type dopant already present in the hole transport layer is LiTFSI. In other words, it was shown that the p-type dopant contained in the electrode ink is not limited to the dopant contained in the hole transport layer, and may be a different material.

[0115] Examples 10 to 18 The following describes the method for producing the solar cells of Examples 10 to 18. Except for the hole transport layer and the second electrode, the solar cells were produced in the same manner as in Examples 1 to 9, and therefore, the description will be omitted.

[0116] The hole transport layer was formed by dropping 0.06 mL of hole transport material solution onto the semiconductor layer and spinning it at 4000 rpm for 30 seconds using a spin coater. The hole transport material solution was obtained by placing 0.1 g of PTAA in a glass container, adding 10 mL of TFPPB solution obtained by dissolving 1 g of TFPPB powder in 10 mL of toluene, and shaking for 2 hours. That is, the hole transport layers in Examples 10 to 18 differ from Examples 1 to 9 in that the p-type dopant contained therein was TFPPB.

[0117] A composition of the present disclosure was prepared as an electrode ink. The electrode ink was prepared by placing 9 parts by mass of acetylene black and 1 part by mass of cellulose in a bead mill, adding 2-propanol in the amount shown in Table 2, stirring, and then adding LiTFSI or TPFPB as a p-type dopant in the amount shown in Table 2. Table 2 shows the concentration of the p-type dopant in the electrode ink.

[0118] 500 μL of electrode ink was dropped onto the hole transport layer, spun at 1000 rpm for 30 seconds using a spin coater, and then heated on a hot plate at 100°C for 2 hours. In this way, a second electrode was formed on the hole transport layer. A 200 nm thick layer of Au was formed on the second electrode by vapor deposition. In this way, an auxiliary electrode was formed.

[0119] (Comparative Example 2) The solar cell of Comparative Example 2 was fabricated in the same manner as in Examples 10 to 18, except that no p-type dopant was added to the electrode ink.

[0120] (Rating 3) The characteristics of the solar cells fabricated in Examples 10 to 18 and Comparative Example 2 were evaluated under fluorescent light. The solar cells were irradiated with fluorescent light (illuminance 200 lx) so that light was incident on the glass substrate side, and a light-shielding mask with an aperture of 0.4 cm × 0.25 cm was attached to the glass surface to define the light-receiving area. A source meter (6246, manufactured by ADC Corporation) was used to measure the current at an operating voltage of 0.6 V. Table 2 shows the current values ​​at an illuminance of 200 lx and Vop = 0.6 V for the solar cells of Examples 10 to 18 and Comparative Example 2.

[0121] (Rating 4) The characteristics of the fabricated solar cell devices of Examples 10 to 18 and Comparative Example 2 were evaluated under simulated sunlight. The solar cells were irradiated with 1 sun's light from a solar simulator through a 0.4 cm x 0.25 cm light-shielding mask so that light was incident on the glass substrate side. A source meter (6246, manufactured by ADC Corporation) was used to measure the voltage-current characteristics over a voltage range of -0.2 V to +1.2 V, and the output at the maximum output point was determined. The maximum output of the solar cells of Examples 10 to 18 and Comparative Example 2 is shown in Table 2.

[0122] [Table 2]

[0123] (Consideration 2) As shown in Table 2, the values ​​of ratings 3 and 4 for Examples 10 to 16 are greater than the values ​​of ratings 1 and 2 for Comparative Example 2. The characteristics of solar cells are improved by forming a second electrode using an electrode ink containing the p-type dopant TPFPB. Furthermore, the characteristics of solar cells are improved when the TPFPB concentration in the electrode ink is in the range of 0.1% by mass or more and 46.1% by mass or less.

[0124] The current values ​​in Evaluation 3 and the maximum output values ​​in Evaluation 4 of Examples 17 and 18 were greater than those of Comparative Example 2. This indicates that the solar cell characteristics are improved even when the hole transport layer contains TPFPB as the p-type dopant, while the electrode ink contains LiTFSI as the p-type dopant. This indicates that the p-type dopant contained in the electrode ink is not limited to the p-type dopant contained in the hole transport layer, but may be a different material. Furthermore, Tables 1 and 2 indicate that the characteristics of electronic devices are improved by forming a second electrode using an electrode ink containing a p-type dopant, regardless of the p-type dopant contained in the hole transport layer. [Industrial Applicability]

[0125] The compositions and manufacturing methods of the present disclosure are useful because they provide electronic devices that exhibit improved performance in terms of initial and long-term reliability compared to conventional devices. [Explanation of symbols]

[0126] 1, 11 board 2, 12 First electrode 3, 13 Electron transport layer 4, 14 Photoelectric conversion layer 5, 15 Hole transport layer 6, 16 Second electrode 7, 17 Auxiliary electrode 100, 200, 300, 400 solar cells

Claims

1. An electrode material for an electrode formed in contact with a hole transport layer, comprising: a conductive material, a p-type dopant, and a solvent; the solvent comprises at least one compound selected from the group consisting of alcohols, aliphatic hydrocarbons, siloxanes, esters, and ethers; the p-type dopant is a material that functions as an acceptor for the hole transport material that constitutes the hole transport layer in contact with the electrode material; electrode material.

2. The conductive material includes at least one selected from the group consisting of metal, conductive carbon, and conductive compounds. The electrode material according to claim 1 .

3. The p-type dopant may be a metal salt containing a bis(trifluoromethanesulfonyl)imide group, a metal salt containing a bis(fluorosulfonyl)imide group, a metal salt containing a bis(pentafluoroethylsulfonyl)imide group, a metal salt containing a 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine-1,1,3,3-tetraoxide group, tris(pentafluorophenyl)borane, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, or SnCl 4 , SbCl 5 , FeCl 3 , and W.O. 3 At least one selected from the group consisting of: The electrode material according to claim 1 or 2.

4. the p-type dopant includes at least one selected from the group consisting of lithium bis(trifluoromethanesulfonyl)imide and tris(pentafluorophenyl)borane; The electrode material according to claim 3 .

5. The solvent may be 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, 1,2-propanediol, 1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, hexane, heptane, octane, nonane, decane, undecane, dodecane, or hexamethyl Disiloxane, hexamethoxydisiloxane, 1,1,3,3-tetramethyldisiloxane, 1,1,3,3,5,5,7,7,9,9,11,11-dodecamethylhexasiloxane, 1,1,5,5-tetramethyl-3,3-diphenyltrisiloxane, 1,1,1,3,3-pentamethyldisiloxane, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, dimethyl cellosolve Solve, phenyl cellosolve, diisopropyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether propionate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, diethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether, The electrode material according to claim 1 .

6. The solvent comprises 2-propanol. The electrode material according to claim 5 .

7. The concentration of the p-type dopant is 0.1% by mass or more and less than 100% by mass.

7. The electrode material according to claim 1.

8. The concentration of the p-type dopant is 0.1% by mass or more and 46.1% by mass or less. The electrode material according to claim 7.

9. (A1) stacking a first electrode, a photoelectric conversion layer, and a hole transport layer in this order; (B1) forming a second electrode on the hole transport layer using the electrode material according to any one of claims 1 to 8; Including, A method for manufacturing electronic devices.

10. In the step (B1), the second electrode is formed by applying the electrode material onto the hole transport layer. The method of claim 9.

11. (A2) forming a second electrode using the electrode material according to any one of claims 1 to 8; (B2) laminating a hole transport layer, a photoelectric conversion layer, and a first electrode in this order on the second electrode; Including, A method for manufacturing electronic devices.

12. In the step (A2), the second electrode is formed by applying the electrode material onto a substrate. The method of claim 11.

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