KR20250147527A - Heat transfer interlayer for improved photovoltaic performance and device operational stability of perovskite solar cells - Google Patents

Abstract

The present invention relates to a heat transfer layer comprising a fullerene derivative doped with an n-type dopant and a perovskite solar cell comprising the same.

Description

Heat transfer interlayer for improved photovoltaic performance and device operational stability of perovskite solar cells

The present invention relates to a heat transfer layer for a high-efficiency, high-stability perovskite solar cell.

Solar cells are a core component of solar power generation, converting light energy into electricity. Because the efficiency of solar cells is directly related to the amount of power generated, research into materials to improve this efficiency has continued. Solar cells have evolved continuously, from first-generation solar cells made of polycrystalline or single-crystalline silicon, to second-generation thin-film solar cells, and now to third-generation solar cells, including perovskite solar cells (PSCs).

Various methods are being studied to improve the stability and performance of perovskite solar cells, and to enhance their efficiency. By treating the perovskite surface with materials containing carbonyl and pyridine functional groups, defects between the perovskite layer and the hole transport layer can be controlled, facilitating charge transport. Furthermore, by enhancing the stability of the perovskite phase, high-efficiency, high-stability devices can be fabricated. However, because only defects on the perovskite surface are controlled, the effects of heat on the perovskite interior are not considered, which is a limitation. (Adv. Sci., 2023 , 10, 2301603) In addition, the thermal stability of the device was improved by treating the two-dimensional material h-BN with high thermal conductivity inside the perovskite layer to increase the heat transfer rate inside the perovskite layer and delay the rate at which the perovskite is damaged by heat, but only the improvement in the thermal stability of the device was considered, and no analysis was conducted on the improvement in device efficiency by using h-BN. (Nat. Comm. 13. 1. (2022) 4417) ,

The background technology described above is something that the inventor possessed or acquired in the process of deriving the disclosure of the present application, and cannot necessarily be said to be a publicly known technology disclosed to the general public prior to the present application.

The present invention aims to solve the above-described problem by providing a heat transfer layer for a high-efficiency, high-stability perovskite solar cell.

Specifically, according to the present invention, a heat transfer layer including a material having improved electrical and thermal conductivity through doping is treated between a photoactive layer and an electron transport layer, so that heat existing inside the perovskite is rapidly diffused to the outside due to high thermal conductivity, an appropriate energy level is formed between the photoactive layer and the electron transport layer, and electron-hole recombination occurring at the interface is reduced to improve the stability of the device and improve the overall performance, thereby providing a high-efficiency, high-stability perovskite solar cell.

However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by a person having ordinary skill in the relevant technical field from the description below.

The fullerene derivative of the present invention is doped with an n-type dopant.

According to one embodiment, the fullerene derivative may include at least one selected from the group consisting of PC ₆₁ B-TEG, PC ₆₁ B-BiTEG, and [6,6]-phenyl-C ₆₁ -butyric acid n-butyl ester (PCBNB).

In one embodiment, the fullerene derivative may comprise one or more side chains per unit.

In one embodiment, the side chain is selected from the group consisting of oligoethylene glycol, carboxylate (-CO ₂ ^- ), carbonate (-OCO ₂ ^- ), phosphate (-PO ₄ ^2- ), phosphonate (-PO ₃ ^2- ), phosphite (-OPO ₂ ^2- ), sulfonate (-SO ₃ ^- ), sulfate (-SO ₄ ^- ), halogen anion, BF ₄ ^- , ClO ₄ ^- , BrO ₄ ^- , AsF ₆ ^- , PF ₆ ^- , SbF ₆ ^- , ammonium functional group (-N ⁺ R ₃ , R is H, alkyl group, or aryl group), sodium (Na ⁺ ), potassium (K ⁺ ), lithium (Li ⁺ ), ammonium (NR ₄ ⁺ , R is H, alkyl group, or aryl group), and phosphonium (PR ₄ ⁺ , R may include at least one selected from the group consisting of H, an alkyl group, or an aryl group.

According to one embodiment, the n-type dopant is 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole; 2-(2,4-dichlorophenyl)-1,3-dimethyl-2,3-dihydro-1H-benzimidazole (Cl-DMBI); (4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenyl)-dimethyl-amine (N-DMBI); 2-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenol (OH-DMBI); 4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-diphenylaniline (N-DPBI); 1,3-dimethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1H-benzo[d]imidazole (TP-DMBI); 2,2'-Bis(4-dimethylaminophenyl)-bibenzo[d]imidazole (N-DMBI)2; 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole (Cyc-DMBI)2; triaminomethane (TAM) and tetrakis(dimethylamino)ethylene (TDAE).

According to one embodiment, the molar % of the n-type dopant in the fullerene derivative may be from 13 mol % to 80 mol %.

The perovskite solar cell of the present invention comprises: a first electrode; a hole transport layer formed on the first electrode; a photoactive layer including a perovskite compound formed on the hole transport layer; an electron transport layer formed on the photoactive layer; a second electrode formed on the electron transport layer; and a heat transfer layer formed on the first electrode, the hole transport layer, the photoactive layer, or the electron transport layer, and including the fullerene derivative of claim 1.

According to one embodiment, the thickness of the heat transfer layer may be 10 nm to 15 nm.

According to one embodiment, the thickness ratio of the heat transfer layer to the overall thickness of the perovskite solar cell may be 1:0.003 to 1:0.008.

According to one embodiment, the weight % of the heat transfer layer in the perovskite solar cell may be 0.4 wt % to 0.8 wt %.

In one embodiment, the perovskite solar cell may have a photovoltaic efficiency of 90% or more when operated at 85°C for 2400 hours.

According to one embodiment, the heat transfer layer, when formed on the photoactive layer, may suppress electron-hole recombination at the interface and increase the temperature difference between the upper and lower layers of the photoactive layer to increase the heat diffusion rate.

According to one embodiment, the first electrode may include at least one selected from the group consisting of a flexible transparent electrode substrate, indium tin oxide (ITO), fluorine tin oxide (FTO), aluminum zinc oxide (AZO), boron-doped zinc oxide (BZO), niobium titanium oxide (NTO), zinc tin oxide (ZTO), and indium zinc tin oxide (IZTO), and the second electrode may include at least one selected from the group consisting of silver (Ag), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni), palladium (Pd), and carbon (C).

According to one embodiment, the electron transport layer is a fullerene derivative selected from among ZnO, ZnO:Al, ZnO:B, ZnO:Ga, ZnO:N, SnO, SnO ₂ , ITO, TiO ₂ , Cs ₂ CO ₃ , 6,6-phenyl-C61-butyric acid methyl ester (PCBM(C61)), PCBM(C60), PCBM(C70), PCBM(C71), PCBM(C76), PCBM(C80), PCBM(C82), indene-C60 bisadduct (ICBA) and 6,6-phenyl-C61-butyric acid cholesteryl ester (PCBCR), polybenzimidazole, perylene, poly[[N,N'-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)](NDI2OD-T2), naphthalene diimide(NDI)-selenophene copolymer(PNDIS-HD), poly[(E)-2,7-bis(2-decyltetradecyl)-4-methyl-9-(5-(2-(5-methylthiophen-2-yl)vinyl)thiophen-2-yl)benzo[lmn][3,8] phenanthroline-1,3,6,8(2H,7H)-tetraone] (PNDI-TVT), It may include at least one selected from the group consisting of poly[[N,N'-bis(2-hexyldecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-thiophene] (PNDI2HD-T), NiO _x , and a P-type oxide semiconductor.

According to one embodiment, the hole transport layer comprises Spiro-OMeTAL, PTAA (poly(triarylamine)), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), PEDOT:PSS (Poly(3,4-ethylenediocythiophene doped with poly(styrenesulfonic acid), cyclopenta-[2,1-b;3,4-b']-dithiophene), benzothiadiazole, diketopyrrolopyrrole, thieno[3,4-b]thiophene, benzodithiophene, carbazole, fluorene, PEDOT:PSS (poly(3,4-ethylenedioxythiophene) It may include at least one selected from the group consisting of poly(styrenesulfonate), PS-PAA (polystyrene-polyacrylic acid block copolymer), poly-TPD (Poly(4-butylphenyl-diphenyl-amine)), PPV (polypheylene vinylene), PVP (polyvinylpyrrolidone), NiO _x , and p-type oxide materials.

The present invention can provide a heat transfer layer for a high-efficiency, high-stability perovskite solar cell.

The heat transfer layer according to the present invention includes a material having improved electrical conductivity and thermal conductivity through doping, and the heat transfer layer has high thermal conductivity, so that when formed on a photoactive layer, it can increase the heat transfer rate within the perovskite and delay the deterioration phenomenon. In addition, the heat transfer layer can suppress electron-hole recombination occurring at the interface by eliminating the difference between the conduction band level of the perovskite and the conduction band level of the heat transfer layer, thereby increasing the photoelectric efficiency. The heat transfer layer has the advantage of being a thin interfacial layer that can be introduced through a simple solution process. The heat transfer layer can improve the long-term stability of the perovskite solar cell and enhance the overall performance of the device. The perovskite solar cell according to the present invention can exhibit high stability to light and heat, and can provide a perovskite solar cell with improved charge factor and photoelectric efficiency.

FIG. 1 is a cross-sectional view of a perovskite solar cell according to an embodiment of the present invention.
FIG. 2 illustrates that electron-hole recombination is suppressed in a perovskite solar cell by a heat transfer layer according to an embodiment of the present invention.
FIG. 3 shows the molecular structure of a fullerene derivative doped with an n-type dopant included in a heat transfer layer according to an embodiment of the present invention.
Figure 4 shows the results of comparing the heat diffusion rates of perovskite films according to examples and comparative examples of the present invention.
Figure 5 is a graph showing the thermal stability of perovskite solar cells according to examples and comparative examples of the present invention.
FIG. 6 is a graph of (a) a JV curve, (b) an energy level change graph, (c) a band gap change graph, (d) an energy level schematic diagram, and (e) a PL graph of a perovskite film according to an embodiment and a comparative example of the present invention.

Hereinafter, embodiments are described in detail with reference to the attached drawings. However, the embodiments may be modified in various ways, and the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, or alternatives to the embodiments are included within the scope of the patent application.

The terms used in the examples are for illustrative purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments pertain. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

In addition, when describing with reference to the attached drawings, the same components will be given the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted. When describing an embodiment, if a detailed description of a related known technology is judged to unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted. In addition, when describing components of the embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms.

Components included in one embodiment and components with common functions will be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in one embodiment may also apply to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

Hereinafter, the heat transfer layer for the high-efficiency, high-stability perovskite solar cell of the present invention will be described in detail with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

The fullerene derivative of the present invention is doped with an n-type dopant.

FIG. 3 shows the molecular structure of a fullerene derivative doped with an n-type dopant included in a heat transfer layer according to an embodiment of the present invention.

Referring to FIG. 3, the fullerene derivative may be PC ₆₁ B-TEG, and may be a compound acting as a host. The n-type dopant may be (4-(1,3-dimethyl-2,3-dihydro-1Hbenzoimidazol-2-yl)-phenyl)-dimethyl-amine (N-DMBI).

According to one embodiment, the perovskite solar cell of the present invention may include a heat transfer layer, and the heat transfer layer may include the fullerene derivative.

According to one embodiment, the heat transfer layer including the fullerene derivative may be formed on the first electrode, the hole transport layer, the photoactive layer, or the electron transport layer depending on the structural change of the perovskite solar cell.

According to one embodiment, the heat transfer layer including the fullerene derivative can increase the temperature difference with the lower layer by lowering the temperature of the upper part of the photoactive layer, thereby increasing the heat diffusion rate, and can improve the stability of the device by reducing the time that heat remains inside the photoactive layer. In addition, the heat transfer layer has a conduction band energy level similar to that of perovskite, and by introducing it between the photoactive layer and the electron transport layer, the possibility of electron holes recombinating at the interface can be suppressed, thereby improving the photocurrent and photoelectric efficiency of the perovskite solar cell.

According to one embodiment, the heat transfer layer comprising the fullerene derivative can be introduced into a perovskite solar cell by forming a single compound into a thin interfacial layer through a solution process.

According to one embodiment, the fullerene derivative may include at least one selected from the group consisting of PC ₆₁ B-TEG, PC ₆₁ B-BiTEG, and [6,6]-phenyl-C ₆₁ -butyric acid n-butyl ester (PCBNB).

According to one embodiment, the fullerene derivative may be at least one selected from the group consisting of fullerene (C60); and C70, C76, C78, C80, C82, and C84. Specifically, the fullerene derivative may include at least one selected from the group consisting of fullerene (C60), (6,6)-phenyl-C61-butyric acid methyl ester (PCBM), (6,6)-phenyl-C61-butyric acid-cholesteryl ester (PCBCR), (6,6)-phenyl-C71-butyric acid methyl ester (C70-PCBM), and (6,6)-thienyl-C61-butyric acid methyl ester (ThCBM).

According to one embodiment, the fullerene derivative is [6,6]-phenyl-Cn-butyric acid 2-[2-(2-methoxyethoxy)ethoxy]ethyl ester (PC _n B-TEG), [6,6]-phenyl-Cn-butyric acid 1-methyl 3-[2-(2,5,8,11-tetraoxadodec-1-yl)-4,7,10,13-tetra-oxatetradec1-yl]ester (PC _n B-BiTEG), [6,6]-phenyl-Cn-butyric acid-(3,4,5-tris(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)phenyl)methyl ester (PC _n B-OEG), [6,6]-phenyl-Cn-butyric acid-3,5-bis[3-[(3-methyl-3-oxetanyl)methoxy]propoxy]phenyl ester (C-PC _n BOD) and fullerene end-capped polyethylene glycol (PC _n -PEG), wherein n may be 61, 71 or 85.

In one embodiment, a fullerene derivative is a functionalized fullerene, which is a spherical carbon nanomaterial formed by pentagonal and hexagonal rings of carbon-carbon bonds, by adding an adduct to increase the solubility in a solvent. Fullerene derivatives have high electron mobility and an appropriate LUMO level as an electron transport layer in electronic devices, and are therefore actively used in electronic devices such as organic transistors (OFETs, organic field-effect transistors), organic photovoltaics (OPVs, organic photovoltaics), and perovskite solar cells. In particular, in perovskite solar cells, which have recently been in the spotlight as next-generation solar cells and are actively researched, fullerene derivatives are most widely used as electron transport materials because they can be dissolved in an organic solvent that does not damage the perovskite photoactive layer and spin-coated.

In one embodiment, the fullerene derivative may comprise one or more side chains per unit.

In one embodiment, the fullerene derivative may include two or more, three or more, or five or more side chains per unit. The fullerene derivative may include one or more side chains per unit, so that the perovskite solar cell including the fullerene derivative may have improved efficiency and performance. The fullerene derivative may exhibit various characteristics depending on the characteristics of the side chains, and may be included in a heat transfer layer to increase the heat diffusion rate.

In one embodiment, the side chain is selected from the group consisting of oligoethylene glycol, carboxylate (-CO ₂ ^- ), carbonate (-OCO ₂ ^- ), phosphate (-PO ₄ ^2- ), phosphonate (-PO ₃ ^2- ), phosphite (-OPO ₂ ^2- ), sulfonate (-SO ₃ ^- ), sulfate (-SO ₄ ^- ), halogen anion, BF ₄ ^- , ClO ₄ ^- , BrO ₄ ^- , AsF ₆ ^- , PF ₆ ^- , SbF ₆ ^- , ammonium functional group (-N ⁺ R ₃ , R is H, alkyl group, or aryl group), sodium (Na ⁺ ), potassium (K ⁺ ), lithium (Li ⁺ ), ammonium (NR ₄ ⁺ , R is H, alkyl group, or aryl group), and phosphonium (PR ₄ ⁺ , R may include at least one selected from the group consisting of H, an alkyl group, or an aryl group.

According to one embodiment, the halogen anion may preferably be F ^- , Cl ^- , Br ^- or I ^- .

According to one embodiment, the n-type dopant is 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole; 2-(2,4-dichlorophenyl)-1,3-dimethyl-2,3-dihydro-1H-benzimidazole (Cl-DMBI); (4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenyl)-dimethyl-amine (N-DMBI); 2-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenol (OH-DMBI); 4-(1,3-dimethyl-2,3dihydro-1H-benzimidazol-2-yl)-N,N-diphenylaniline (N-DPBI); 1,3-dimethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1H-benzo[d]imidazole (TP-DMBI); 2,2'-Bis(4-dimethylaminophenyl)-bibenzo[d]imidazole (N-DMBI)2; 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole (Cyc-DMBI)2; triaminomethane (TAM) and tetrakis(dimethylamino)ethylene (TDAE).

According to one embodiment, when the fullerene derivative is n-doped with the n-type dopant, the thermal conductivity and electrical conductivity characteristics of the perovskite solar cell can be evaluated and the stability and improvement of the device can be confirmed, and the heat transfer layer including the fullerene derivative doped with the n-type dopant can improve the performance and stability of the perovskite solar cell.

According to one embodiment, the molar % of the n-type dopant in the fullerene derivative may be from 13 mol % to 80 mol %.

In one embodiment, the mole % of the n-type dopant in the fullerene derivative is 13 mol% to 80 mol%; 13 mol% to 75 mol%; 13 mol% to 70 mol%; 13 mol% to 65 mol%; 13 mol% to 60 mol%; 13 mol% to 55 mol%; 13 mol% to 50 mol%; 13 mol% to 45 mol%; 13 mol% to 40 mol%; 13 mol% to 30 mol%; 13 mol% to 20 mol%; 13 mol% to 18 mol%; 15 mol% to 80 mol%; 20 mol% to 80 mol%; 30 mol% to 80 mol%; 40 mol% to 80 mol%; 50 mol% to 80 mol%; 60 mol% to 80 mol%; It may be 70 mol% to 80 mol%.

According to one embodiment, if the mol % of the n-type dopant in the fullerene derivative is less than 13 mol %, the improvement in thermal conductivity due to doping may be minimal, so that heat transfer within the perovskite may not occur smoothly, and if it exceeds 80 mol %, as the number of electrons in the fullerene derivative becomes excessive, collisions between electrons may occur frequently, which may interfere with charge extraction, and an excessive increase in the Fermi level may interfere with electron extraction, which may result in a decrease in the photoelectric efficiency of the device.

The perovskite solar cell of the present invention comprises: a first electrode; a hole transport layer formed on the first electrode; a photoactive layer including a perovskite compound formed on the hole transport layer; an electron transport layer formed on the photoactive layer; a second electrode formed on the electron transport layer; and a heat transfer layer formed on the first electrode, the hole transport layer, the photoactive layer, or the electron transport layer, and including the fullerene derivative of claim 1.

FIG. 1 is a cross-sectional view of a perovskite solar cell according to an embodiment of the present invention.

Referring to FIG. 1, the left drawing of FIG. 1 is a cross-sectional view of a conventional perovskite solar cell, which includes a first electrode; a hole transport layer formed on the first electrode; a photoactive layer including a perovskite compound formed on the hole transport layer; an electron transport layer formed on the photoactive layer; and a second electrode formed on the electron transport layer. In a conventional perovskite solar cell, in an extreme environment (high temperature), the temperature difference between the upper and lower layers of the photoactive layer is small, so the heat diffusion rate may be slow, and the photoactive layer may be rapidly damaged, and the performance of the perovskite solar cell may deteriorate.

The right drawing of Fig. 1 is a cross-sectional view of a perovskite solar cell according to an embodiment of the present invention, comprising: a first electrode; a hole transport layer formed on the first electrode; a photoactive layer including a perovskite compound formed on the hole transport layer; a heat transfer layer formed on the photoactive layer; and an electron transport layer formed on the heat transfer layer; and a second electrode formed on the electron transport layer. The heat transfer layer including the fullerene derivative can be introduced between the photoactive layer and the electron transport layer to improve the heat diffusion rate. The heat transfer layer can increase the temperature difference between the upper portion of the photoactive layer and the lower portion by lowering the temperature, thereby increasing the heat diffusion rate, and can improve the stability of the device by reducing the time that heat remains inside the photoactive layer. The perovskite solar cell of the present invention, including the heat transfer layer including the fullerene derivative, can exhibit high stability against light and heat, and can improve the photoelectric efficiency, thereby improving the overall performance of the device.

In one embodiment, the perovskite may be an inorganic metal halide perovskite, an organic-inorganic hybrid perovskite, or the like. For example, the perovskite may have a structure represented by chemical formulas such as ABX ₃ , A ₂ BX ₄ , ABX ₄ , APbX ₃ , A _n-1 Pb _n I _3n+1 (wherein n is an integer from 2 to 6). In some examples, in the chemical formula, A is an alkali metal, an organic cation (e.g., organoammonium), and/or an inorganic cation, B is a metal substance, and X may be selected from a halogen anion, a chalcogenide anion, and SCN-(thiocyanate). For example, A may be an alkali metal such as Na, K, Rb, Cs, or Fr; (CH ₃ NH ₃ ) _n , ((C _x H _2x+1 ) _n NH ₃ ) ₂ (CH ₃ NH ₃ ) _n , (RNH ₃ ) ₂ , (C _n H _2n+1 NH ₃ ) ₂ , (CF ₃ NH ₃ ), (CF ₃ NH ₃ ) _n , ((C _x F2 _x+1 ) _n NH ₃ ) ₂ (CF ₃ NH ₃ ) _n , ((C _x F _2x+1 ) _n NH3) ₂ or (C _n F _2n+1 NH ₃ ) ₂ (n is an integer greater than or equal to 1, x is an integer greater than or equal to 1), B is a divalent transition metal, rare earth metal, alkaline earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, etc., and X can be P, Cl, Br, I, etc. In some examples, the perovskite may be CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbBr ₃ , CH ₃ NH ₃ PbI ₂ Cl, CH ₃ NH ₃ PbI ₂ Br, etc. In some examples, when two or more kinds of the perovskite compounds are included, the ratio of the first perovskite compound to the second perovskite compound may be 5:5 to 9:1. In some examples, further, compounds represented by chemical formulas such as NaX', ZnX', KX', and CsX' (wherein X is selected from Cl, Br, and I) may be included, and may be included in an amount of 10% or less; or 5% or less, of the total perovskite compound.

According to one embodiment, the photoactive layer may serve to separate electrons and holes into two electrodes and separate electrons and holes into an electron transport layer and a hole transport layer, respectively.

According to one embodiment, the size of the perovskite crystal grains in the photoactive layer may be 1 nm to 900 nm; 1 nm to 800 nm; 5 nm to 600 nm; 5 nm to 300 nm; 10 nm to 300 nm; 10 nm to 100 nm; or 10 nm to 50 nm.

According to one embodiment, the thickness of the photoactive layer may be 500 nm to 800 nm; 550 nm to 700 nm; and preferably, 550 nm to 650 nm for improved performance of the photoactive layer.

According to one embodiment, when forming the first electrode, the first electrode mentioned in the present invention is prepared, and a conductive material layer may be formed on a substrate coated with a conductive material layer or on a substrate using sputtering, CVD, deposition, solution process, coating, printing, etc.

According to one embodiment, when forming the hole transport layer, the hole transport layer may be formed using sputtering, CVD, deposition, solution process coating, printing, etc., but is not limited thereto.

According to one embodiment, when forming the photoactive layer, a coating or deposition process may be used, and for example, the perovskite layer may be formed by at least one method selected from spin coating, spray coating, slot die coating, blade coating, and deposition. For example, the deposition may use at least one or more of chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma-enhanced atomic layer deposition (PEALD), molecular beam epitaxy deposition, and physical vapor deposition, but is not limited thereto.

According to one embodiment, when forming the electron transport layer, a coating process may be used, and the coating process may use at least one method selected from spin coating, spray coating, slot die coating, and blade coating, but is not limited thereto.

According to one embodiment, when forming the heat transfer layer, the heat transfer layer may be formed using direct doping, overcoating, overcoating + waiting, sputtering, CVD, deposition, solution process coating, printing, etc., but is not limited thereto.

According to one embodiment, when forming the second electrode, the electrode may be formed by a high-temperature process, for example, the electrode may be formed by a sputtering process under at least one of process conditions of 10 W to 200 W, a temperature of 25° C. to 100° C., and an oxygen flow rate of 0 sccm to 100 sccm.

According to one embodiment, the above-mentioned sputtering may use ion-beam sputtering, reactive sputtering, ion-assisted deposition, high-target-utilization sputtering (HiTUS), high-power impulse magnetron sputtering (HiPIMS), gas flow sputtering, plasma sputtering, etc., and the deposition may use CVD, thermal evaporation, plasma sputtering, e-beam evaporation, atomic layer deposition (ALD), etc. The coating may use a solution process and may mean a process of forming a film using a liquid solvent such as spin coating, spray coating, dip coating, ink jet printing, roll-to-roll printing, screen printing, etc.

According to one embodiment, the thickness of the heat transfer layer may be 10 nm to 15 nm.

In one embodiment, the thickness of the heat transfer layer may be 10 nm to 15 nm; 11 nm to 15 nm; 12 nm to 15 nm; 13 nm to 15 nm; 14 nm to 15 nm; 10 nm to 14 nm; 10 nm to 13 nm; 10 nm to 12 nm; 10 nm to 11 nm; 11 nm to 14 nm; 12 nm to 13 nm.

According to one embodiment, if the thickness of the heat transfer layer is less than 10 nm, uniformity may be poor due to failure to completely cover the upper part of the perovskite, and if it is more than 15 nm, charge extraction may become difficult due to the thickness being excessively thicker than the mobility of electrons within the heat transfer layer material.

According to one embodiment, the thickness ratio of the heat transfer layer to the overall thickness of the perovskite solar cell may be 1:0.003 to 1:0.008.

According to one embodiment, the thickness ratio of the heat transfer layer to the entire thickness of the perovskite solar cell is 1:0.003 to 1:0.008; 1:0.004 to 1:0.008; 1:0.005 to 1:0.008; 1:0.006 to 1:0.008; 1:0.007 to 1:0.008; 1:0.003 to 1:0.007; 1:0.003 to 1:0.006; 1:0.003 to 1:0.005; 1:0.003 to 1:0.004; 1:0.004 to 1:0.005; It may be 1:0.005 to 1:0.006; 1:0.004 to 1:0.007;

In one embodiment, if the thickness ratio of the heat transfer layer to the entire thickness of the perovskite solar cell is less than 1:0.003, the thickness may be excessively thick compared to the mobility that electrons may have in the heat transfer layer material, making it difficult to extract charges. If it exceeds 1:0.008, one heat transfer layer may not function as one energy level, making it difficult to achieve the effect of suppressing electron-hole recombination due to conduction band level matching with the perovskite.

According to one embodiment, the weight % of the heat transfer layer in the perovskite solar cell may be 0.4 wt % to 0.8 wt %.

According to one embodiment, the weight % of the heat transfer layer in the perovskite solar cell may be 0.4 wt % to 0.8 wt %; 0.4 wt % to 0.75 wt %; 0.4 wt % to 0.7 wt %; 0.4 wt % to 0.65 wt %; 0.4 wt % to 0.6 wt %; 0.4 wt % to 0.55 wt %; 0.4 wt % to 0.5 wt %; 0.45 wt % to 0.8 wt %; 0.5 wt % to 0.8 wt %; 0.6 wt % to 0.8 wt %; 0.7 wt % to 0.8 wt %; 0.5 wt % to 0.65 wt %; 0.55 wt % to 0.75 wt %.

According to one embodiment, if the weight % of the heat transfer layer in the perovskite solar cell is less than 0.4 wt %, the heat transfer layer may not completely cover the upper part of the perovskite, resulting in poor uniformity, and if it exceeds 0.8 wt %, the thickness of the heat transfer layer may become excessively thick, making it difficult to extract charges.

In one embodiment, the perovskite solar cell may have a photovoltaic efficiency of 90% or more when operated at 85°C for 2400 hours.

Figure 5 is a graph showing the thermal stability of perovskite solar cells according to examples and comparative examples of the present invention.

Referring to FIG. 5, a graph showing the thermal stability of a perovskite solar cell including a heat transfer layer including a fullerene derivative doped with an n-type dopant according to an embodiment of the present invention, a reference solar cell not using a heat transfer layer used as a comparative example, and a perovskite solar cell including a heat transfer layer including a fullerene derivative is shown. In the case of the solar cell of the comparative example, it may have shown low thermal stability and rapid deterioration of cell performance. In the case of the perovskite solar cell of the comparative example, the photoelectric efficiency decreased to less than 90% in only 500 hours in an environment of 85°C, but in the case of the perovskite solar cell of the embodiment, it can be confirmed that it can be safely operated for more than 2400 hours. Therefore, the embodiment may show improved photoelectric efficiency compared to the comparative example.

FIG. 6 is a graph of (a) a J-V curve, (b) an energy level change graph, (c) a band gap change graph, (d) an energy level schematic diagram, and (e) a PL graph of a perovskite film according to an embodiment and a comparative example of the present invention.

Referring to (a) of FIG. 6, a graph showing the charging rate of perovskite solar cells according to examples and comparative examples of the present invention is provided, and the examples may show an improved charging rate compared to the comparative examples.

Referring to (b) and (c) of FIG. 6, the graphs of energy level changes and band gap changes of perovskite solar cells according to examples and comparative examples of the present invention can confirm the change in values depending on the presence or absence of a doping layer including an n-type dopant of a fullerene derivative included in the heat transfer layer of the perovskite solar cell.

Referring to (d) and (e) of FIG. 6, a schematic diagram of the energy level of a perovskite solar cell according to an example and a comparative example of the present invention and a PL graph of a perovskite film are shown. Since the conduction band level of PC ₆₁ B-TEG, a material used as a host, is similar to the conduction band level of perovskite, when introduced between a photoactive layer and an electron transport layer, electron-hole recombination at the interface may be suppressed, thereby improving the photoelectric efficiency of an inverted structure solar cell.

Table 1 below shows the characteristics of perovskite solar cells according to examples and comparative examples of the present invention, and it can be confirmed that the performance of the perovskite solar cell according to the present invention is improved.

V _oc [V] Jsc[mA/cm ² ] FF[%] PCE[%] Ref. 1.07 23.45 81.39 20.42 PC ₆₁ B-TEG 1.10 24.64 80.02 21.69 n-doped PC ₆₁ B-TEG 1.15 24.60 79.66 22.54

According to one embodiment, the heat transfer layer, when formed on the photoactive layer, may suppress electron-hole recombination at the interface and increase the temperature difference between the upper and lower layers of the photoactive layer to increase the heat diffusion rate.

FIG. 2 illustrates that electron-hole recombination is suppressed in a perovskite solar cell by a heat transfer layer according to an embodiment of the present invention.

Referring to Fig. 2, the left drawing of Fig. 2 shows electron-hole recombination of a conventional perovskite solar cell. Due to the difference in conduction band energy levels between the photoactive layer and the electron transport layer, electrons and holes easily recombine, reducing the photocurrent, which may result in a deterioration in device performance.

The right drawing of FIG. 2 illustrates a perovskite solar cell according to an embodiment of the present invention, wherein the heat transfer layer has a conduction band energy level similar to that of perovskite, and by introducing it between the photoactive layer and the electron transport layer, the possibility of electron holes recombining at the interface can be suppressed, thereby improving the photocurrent and photoelectric efficiency of the perovskite solar cell, and thus the performance of the device can be improved.

Figure 4 shows the results of comparing the heat diffusion rates of perovskite films according to examples and comparative examples of the present invention.

Referring to FIG. 4, the thermal diffusion speed of a conventional perovskite film and a perovskite film including a heat transfer layer according to an embodiment of the present invention are compared, and it can be confirmed that the thermal diffusion speed of the perovskite film according to an embodiment of the present invention is fast.

According to one embodiment, the first electrode may include at least one selected from the group consisting of a flexible transparent electrode substrate, indium tin oxide (ITO), fluorine tin oxide (FTO), aluminum zinc oxide (AZO), boron-doped zinc oxide (BZO), niobium titanium oxide (NTO), zinc tin oxide (ZTO), and indium zinc tin oxide (IZTO), and the second electrode may include at least one selected from the group consisting of silver (Ag), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni), palladium (Pd), and carbon (C).

According to one embodiment, the flexible transparent electrode substrate comprises at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene sulfone (PES), polyethylene naphthalate (PEN), polycarbonate (PC), polymethyl methacrylate (PMMA), polyimide (PI), ethylene vinyl acetate (EVA), amorphous polyethylene terephthalate (APET), polypropylene terephthalate (PPT), polyethylene terephthalate glycerol (PETG), polycyclohexylenedimethylene terephthalate (PCTG), modified triacetyl cellulose (TAC), cycloolefin polymer (COP), cycloolefin copolymer (COC), dicyclopentadiene polymer (DCPD), cyclopentadiene polymer (CPD), polyarylate (PAR), polyetherimide (PEI), polydimethylsiloxane (PDMS), silicone resin, fluororesin, and modified epoxy resin. It may include.

In one embodiment, the first electrode may be a cathode or an anode electrode and may further include a carbon allotrope such as a carbon nanotube (CNT), graphene, or graphite, and a conductive polymer material such as polyacetylene, polyaniline, polythiophene, or polypyrrole. In addition, the first electrode may have a thickness of 10 nm to 200 nm; or 50 nm to 150 nm.

According to one embodiment, the second electrode may be a cathode or an anode electrode, and may include, for example, a transparent conductive material, a semitransparent conductive material, etc., and may include at least one selected from the group consisting of Co, Ir, Ta, Cr, Mn, Mo, Tc, W, Re, Fe, Sc, Ti, Ge, Sb, Al, Pt, Ni, Cu, Rh, Au, V, Nb, Ag, Pd, Zn, Ni, Si, Sn, and Ru; alloys thereof; and oxides thereof; and the oxide may include at least one transparent conductive oxide (TCO) such as ITO, ZITO, ZIO, GIO, ZTO, FTO, AZO, and GZO. In addition, the second electrode may further include a carbon allotrope such as carbon nanotubes (CNT), graphene, and graphite, and a conductive polymer material such as polyacetylene, polyaniline, polythiophene, and polypyrrole. Additionally, the second electrode may have a thickness of 10 nm to 200 nm; or 50 nm to 150 nm.

According to one embodiment, the electron transport layer is a fullerene derivative selected from among ZnO, ZnO:Al, ZnO:B, ZnO:Ga, ZnO:N, SnO, SnO ₂ , ITO, TiO ₂ , Cs ₂ CO ₃ , 6,6-phenyl-C61-butyric acid methyl ester (PCBM(C61)), PCBM(C60), PCBM(C70), PCBM(C71), PCBM(C76), PCBM(C80), PCBM(C82), indene-C60 bisadduct (ICBA) and 6,6-phenyl-C61-butyric acid cholesteryl ester (PCBCR), polybenzimidazole, perylene, poly[[N,N'-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)](NDI2OD-T2), naphthalene diimide(NDI)-selenophene copolymer(PNDIS-HD), poly[(E)-2,7-bis(2-decyltetradecyl)-4-methyl-9-(5-(2-(5-methylthiophen-2-yl)vinyl)thiophen-2-yl)benzo[lmn][3,8] phenanthroline-1,3,6,8(2H,7H)-tetraone] (PNDI-TVT), It may include at least one selected from the group consisting of poly[[N,N'-bis(2-hexyldecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'- thiophene] (PNDI2HD-T), NiO _x , and a P-type oxide semiconductor.

According to one embodiment, the electron transport layer can be formed using a material such as aluminum tris(8-hydroxyquinoline) (Alq3), lithium fluoride (LiF), lithium complex (8-hydroxy-quinolinato lithium, Liq), a non-conjugated polymer, a non-conjugated polymer electrolyte, a conjugated polymer electrolyte, an n-type metal oxide, a low-dimensional carbon-based material, etc. The n-type metal oxide can be, for example, TiOx, ZnO, or _{Cs2CO3 .} In addition, a self-assembled thin film of a metal layer can be used as the electron transport layer. The low-dimensional carbon-based material may include at least one selected from the group consisting of fullerene compounds such as low-dimensional carbon-based organic matter, inorganic matter, or both, for example, C60, C70, C71, C76, C78, C80, C82, C84, C92 PC60BM, PC61BM, PC71BM, ICBA, BCP, PC70BM, IC70BA, PC84BM, indene C60, indene C70, endohydral fullerene; perylene, PTCDA, PTCBI, BCP (bathocuproine), Bphen (4, 7-diphenyl-1,10-phenanthroline), TpPyPB, and DPPS, but is not limited thereto.

In one embodiment, the electron transport layer may have a thickness of 1 nm to 100 nm; 1 nm to 90 nm; 1 nm to 50 nm; 1 nm to 20 nm; or 1 nm to 10 nm. When within the above range, the electron transport layer may function as a protective layer to prevent damage to the light absorption layer, as well as an electron transport layer.

In one embodiment, the hole transport layer comprises Spiro-OMeTAL, PTAA (poly(triarylamine), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), PEDOT:PSS (Poly(3,4-ethylenediocythiophene doped with poly(styrenesulfonic acid), cyclopenta-[2,1-b;3,4-b']-dithiophene), benzothiadiazole, diketopyrrolopyrrole, thieno[3,4-b]thiophene, benzodithiophene, carbazole, fluorene, PEDOT:PSS (poly(3,4-ethylenedioxythiophene) It may include at least one selected from the group consisting of poly(styrenesulfonate), PS-PAA (polystyrene-polyacrylic acid block copolymer), poly-TPD (Poly(4-butylphenyl-diphenyl-amine)), PPV (polypheylene vinylene), PVP (polyvinylpyrrolidone), NiO _x , and p-type oxide materials. In addition, it may include a polymer and/or copolymer containing the above-mentioned compound as a unit.

In one embodiment, the hole transport layer comprises an electron and/or hole transport material, and may comprise a conjugated polymer electrolyte, a metal oxide, or a hydrophobic charge transport layer. In addition, the hole transport layer may have a thickness of 1 nm to 100 nm; 1 nm to 90 nm; 1 nm to 50 nm; 1 nm to 20 nm; or 1 nm to 10 nm.

In one embodiment, the metal oxide may be nickel oxide (NiO _x ), copper oxide (CuO _x ), copper thiocyanate (CopperThiocyanate), copper gallium oxide (CuGaO ₂ ), copper chromium oxide (CuCrO ₂ ), and may include at least one or more of nickel oxide (NiO), copper(II) oxide (CuO), cobalt(II) oxide (CoO), vanadium pentoxide (V ₂ O ₅ ), vanadium(V) oxide (VO ₂ ), cobalt(IV)cobalt(II) oxide (Co ₃ O ₄ ), and combinations thereof, but is not limited thereto.

According to one embodiment, the hole transport layer is formed on the first electrode, and holes generated and separated within the perovskite photoactive layer can be injected when light is irradiated.

Although the embodiments have been described above, those skilled in the art will appreciate that various technical modifications and variations can be made based on the above. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and/or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted by other components or equivalents.

Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims (15)

Doped with n-type dopant,
Fullerene derivatives.
In the first paragraph,
The above fullerene derivative is,
Comprising at least one selected from the group consisting of PC ₆₁ B-TEG, PC ₆₁ B-BiTEG and [6,6]-phenyl-C ₆₁ -butyric acid n-butyl ester (PCBNB),
Fullerene derivatives.
In the first paragraph,
The above fullerene derivative comprises at least one side chain per unit.
Fullerene derivatives.
In the third paragraph,
The above side chain is,
Oligoethylene glycol, carboxylate (-CO ₂ ^- ), carbonate (-OCO ₂ ^- ), phosphate (-PO 4 ^2- ), phosphonate (-PO ₃ 2-), phosphite (-OPO ₂ ^2- ), sulfonate (-SO ₃ ^- ), sulfate (-SO ₄ ^- ), halogen anion, BF ₄ ^- , _{ClO 4 -, BrO 4 -, AsF 6 -, PF 6 -, SbF 6 -} ^, _ammonium ^functional _group ⁽ _-N ⁺ _R ^{3 , R} _is H, alkyl group, or aryl group), sodium (Na ⁺ ), potassium (K ⁺ ), lithium (Li ⁺ ), ammonium (NR ₄ ⁺ , R is H, alkyl group, or aryl group), and phosphonium (PR ₄ ⁺ , R is H, Containing at least one selected from the group consisting of an alkyl group, or an aryl group,
Fullerene derivatives.
In the first paragraph,
The above n-type dopant is,
1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole; 2-(2,4-dichlorophenyl)-1,3-dimethyl-2,3-dihydro-1H-benzimidazole (Cl-DMBI); (4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenyl)-dimethyl-amine (N-DMBI); 2-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-phenol (OH-DMBI); 4-(1,3-dimethyl-2,3-dihydro-1H-benzimidazol-2-yl)-N,N-diphenylaniline (N-DPBI); 1,3-dimethyl-2-(3,4,5-trimethoxyphenyl)-2,3-dihydro-1H-benzo[d]imidazole (TP-DMBI); 2,2'-Bis(4-dimethylaminophenyl)-bibenzo[d]imidazole (N-DMBI)2; 2,2'-dicyclohexyl-1,1',3,3'-tetramethyl-2,2',3,3'-tetrahydro-2,2'-bibenzo[d]imidazole (Cyc-DMBI)2; triaminomethane (TAM) and tetrakis(dimethylamino)ethylene (TDAE),
Fullerene derivatives.
In the first paragraph,
The molar % of the n-type dopant among the above fullerene derivatives is 13 mol% to 80 mol%.
Fullerene derivatives.
First electrode;
A hole transport layer formed on the first electrode;
A photoactive layer comprising a perovskite compound formed on the hole transport layer;
An electron transport layer formed on the photoactive layer;
A second electrode formed on the electron transport layer; and
A heat transfer layer formed on the first electrode, the hole transport layer, the photoactive layer or the electron transport layer, and including the fullerene derivative of claim 1;
Perovskite solar cells.
In paragraph 7,
The thickness of the above heat transfer layer is 10 nm to 15 nm,
Perovskite solar cells.
In paragraph 7,
The thickness ratio of the heat transfer layer to the overall thickness of the perovskite solar cell is 1:0.003 to 1:0.008.
Perovskite solar cells.
In paragraph 7,
The weight % of the heat transfer layer in the perovskite solar cell is 0.4 wt % to 0.8 wt %,
Perovskite solar cells.
In paragraph 7,
The above perovskite solar cell,
The photoelectric efficiency is more than 90% at 85 ℃, 2400 hours of operation.
Perovskite solar cells.
In paragraph 7,
When the above heat transfer layer is formed on the photoactive layer,
It suppresses electron-hole recombination at the interface,
The temperature difference between the upper and lower layers of the photoactive layer is increased to increase the heat diffusion rate.
Perovskite solar cells.
In paragraph 7,
The above first electrode,
A flexible transparent electrode substrate comprising at least one selected from the group consisting of indium tin oxide (ITO), fluorine tin oxide (FTO), aluminum zinc oxide (AZO), boron-doped zinc oxide (BZO), niobium titanium oxide (NTO), zinc tin oxide (ZTO), and indium zinc tin oxide (IZTO).
The second electrode is,
Containing at least one selected from the group consisting of silver (Ag), aluminum (Al), platinum (Pt), tungsten (W), copper (Cu), molybdenum (Mo), gold (Au), nickel (Ni), palladium (Pd), and carbon (C).
Perovskite solar cells.
In paragraph 7,
The electron transport layer is selected from among ZnO, ZnO:Al, ZnO:B, ZnO:Ga, ZnO:N, SnO, SnO ₂ , ITO, TiO ₂ , Cs ₂ CO ₃ , 6,6-phenyl-C61-butyric acid methyl ester (PCBM(C61)), PCBM(C60), PCBM(C70), PCBM(C71), PCBM(C76), PCBM(C80), PCBM(C82), indene-C60 bisadduct (ICBA) and 6,6-phenyl-C61-butyric acid cholesteryl ester (PCBCR), polybenzimidazole, perylene, poly[[N,N'-bis(2-octyldodecyl)-napthalene-1,4,5,8-bis(dicarboximide)-2,6- diyl]-alt-5,5'-(2,2'-bithiophene)](NDI2OD-T2), naphthalene diimide(NDI)-selenophene copolymer(PNDIS-HD), poly[(E)-2,7-bis(2-decyltetradecyl)-4-methyl-9-(5-(2-(5-methylthiophen-2-yl)vinyl)thiophen-2-yl)benzo[lmn][3,8] phenanthroline-1,3,6,8(2H,7H)-tetraone] (PNDI-TVT), poly[[N,N'-bis(2-hexyldecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′- thiophene] (PNDI2HD-T), comprising at least one selected from the group consisting of NiO _x and P-type oxide semiconductors.
Perovskite solar cells.
In paragraph 7,
The above hole transport layer is,
Spiro-OMeTAL, PTAA (poly(triarylamine), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), PEDOT:PSS (Poly(3,4-ethylenediocythiophene doped with poly(styrenesulfonic acid), cyclopenta-[2,1-b;3,4-b']-dithiophene), benzothiadiazole, diketopyrrolopyrrole, thieno[3,4-b]thiophene, benzodithiophene, carbazole, fluorene, PEDOT:PSS (poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), PS-PAA (polystyrene-polyacrylic acid block copolymer), poly-TPD (Poly(4-butylphenyl-diphenyl-amine)), PPV (polypheylene vinylene), PVP (polyvinylpyrrolidone), NiO _x , and a p-type oxide material, comprising at least one selected from the group consisting of
Perovskite solar cells.