Organic compound, hole transport layer, perovskite solar cell and preparation method

Abstract

The invention belongs to the photovoltaic field, and particularly relates to an organic compound, a hole transport layer, a perovskite solar cell and a preparation method. The structure of the organic compound is shown as a formula I-1 or a formula I-2. In the formula I-1 and the formula I-2, R1, R2, R3, R4 and R5 are independently selected from a halogen atom, a linear or branched alkoxy group of C1-C6, a linear or branched alkyl sulfenyl group of C1-C6, a linear or branched alkyl group of C1-C10, a cyano group and a hydrogen atom respectively; r6 is a benzene ring or a linear or branched alkylene group of C1 to C10; and R7 is-SO3H,-COOH or-PO (OH) 2. According to the hole transport layer prepared from the organic compound, the quality of a perovskite thin film is improved, and the open-circuit voltage and the photoelectric conversion efficiency of a perovskite solar cell are improved. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and specifically relates to an organic compound, a hole transport layer, a perovskite solar cell and a preparation method thereof. Background Art

[0002] Since perovskite solar cells first achieved a photoelectric conversion efficiency of 3.8% in 2009, perovskite materials have become a hot semiconductor material. Currently, the highest photoelectric efficiency of perovskite solar cells has exceeded 26.1%, exceeding the performance level of traditional silicon solar cells.

[0003] Hole transport layer (HTM) materials play a vital role in perovskite solar cells, and undertake functions such as hole extraction, transport and electron blocking at the perovskite / HTM interface. However, the hole transport layer materials reported so far have problems such as energy level mismatch and poor wettability, which are not suitable for large-scale preparation, increase the process cost of device preparation, and are in urgent need of improvement. For example, [2-(9H-carbazole-9-yl)ethyl]phosphonic acid is the most common self-assembled monolayer hole transport material in trans-perovskite devices, but due to its mismatch with the perovskite energy level, the open circuit voltage is low, which is not conducive to efficiency improvement; at the same time, due to its poor wettability, it will lead to poor uniformity of perovskite film formation, reduce the quality of perovskite film, and is not conducive to large-scale production and efficiency improvement.

[0004] Therefore, it is urgent to develop a hole transport layer material that can improve the photoelectric performance of perovskite solar cells. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an organic compound, a hole transport layer, a perovskite solar cell and a preparation method. The organic compound of formula I-1 or formula I-2 of the present invention is used as a hole transport layer material, which can synergistically improve the photoelectric performance of the perovskite solar cell and is suitable for the preparation of large-area perovskite solar cells.

[0006] Specifically, the present invention provides an organic compound, the structure of which is shown in Formula I-1 or Formula I-2;

[0007]

[0008] In formula I-1 and formula I-2, R1, R2, R3, R4, and R5 are each independently selected from a halogen atom, a C1-C6 straight-chain or branched alkoxy group, a C1-C6 straight-chain or branched alkylthio group, a C1-C10 straight-chain or branched alkyl group, a cyano group, and a hydrogen atom; R6 is a benzene ring or a C1-C10 straight-chain or branched alkylene group; R7 is -SO3H, -COOH, or -PO(OH)2.

[0009] In one or more embodiments, in Formula I-1 and Formula I-2, R1 is selected from hydrogen atom, methyl, ethyl, methoxy, ethoxy, cyano, R2, R3, R4, R5 are each independently selected from halogen atoms and hydrogen atoms, R6 is a straight-chain alkylene of C1-C4, and R7 is -PO(OH)2.

[0010] The present invention provides a method for preparing the organic compound of the present invention, the method comprising the following steps:

[0011] (1) placing compound A, compound B and NaH in a first solvent for reaction to obtain compound C;

[0012] (2) hydrolyzing compound C to obtain an organic compound represented by formula I-1 or formula I-2;

[0013] Among them, the structure of compound A is The structure of compound B is The structure of compound C is

[0014] In compound A, compound B and compound C, R1, R2, R3, R4, R5 and R6 are as defined in formula I-1 and formula I-2; R7 ’ It is -SO3R8, -COOR8 or -PO(OR8)2, wherein R8 is a C1-C10 straight-chain or branched alkyl group.

[0015] In one or more embodiments, in step (1), the first solvent is selected from one or more of N,N-dimethylformamide, tetrahydrofuran and 1,4-dioxane.

[0016] In one or more embodiments, in step (1), the molar ratio of compound A to compound B is 1:1.1-1.

[0017] In one or more embodiments, in step (1), the ratio of compound A to NaH is 1:1.1-1.5.

[0018] In one or more embodiments, in step (1), the reaction is carried out in a protective atmosphere.

[0019] In one or more embodiments, in step (1), the reaction temperature is -5-5°C.

[0020] In one or more embodiments, in step (2), the hydrolysis reaction comprises: placing compound C and trimethylsilyl bromide in a second solvent for a first-stage reaction to obtain a compound intermediate, and mixing the compound intermediate, methanol and water for a second-stage reaction to obtain an organic compound of formula I-1 or formula I-2.

[0021] In one or more embodiments, in step (2), the second solvent is 1,4-dioxane and / or dichloromethane.

[0022] In one or more embodiments, in step (2), the molar ratio of compound C to trimethylsilyl bromide is 1:10-20.

[0023] In one or more embodiments, in step (2), the first stage reaction is carried out in a protective atmosphere.

[0024] In one or more embodiments, in step (2), the first stage reaction temperature is 10-30°C.

[0025] In one or more embodiments, in step (2), the second stage reaction temperature is 10-30°C.

[0026] The present invention provides a hole transport layer comprising the organic compound of the present invention.

[0027] In one or more embodiments, the hole transport layer has a thickness of 1-3 nm.

[0028] The present invention provides a method for preparing the hole transport layer of the present invention, the method comprising mixing an organic compound and a third solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare the hole transport layer.

[0029] In one or more embodiments, the third solvent is selected from one or more of methanol, isopropanol, ethanol, N,N-dimethylformamide and chlorobenzene.

[0030] In one or more embodiments, the concentration of the organic compound in the hole transport layer precursor solution is 0.1-1 mg / mL.

[0031] In one or more embodiments, the coating is performed by spin coating, knife coating or slot coating.

[0032] In one or more embodiments, the annealing temperature is 100-150°C.

[0033] In one or more embodiments, the annealing time is 10-20 min.

[0034] The present invention provides a perovskite solar cell comprising the hole transport layer of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Perovskite solar cells prepared according to some embodiments of the present invention. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0037] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0038] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0039] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0040] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0041] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0042] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0043] Certain chemical groups defined herein are preceded by simplified symbols to indicate the total number of carbon atoms present in the group. For example, a C1-C6 alkyl group refers to an alkyl group as defined below having a total of 1 to 6 carbon atoms. The total number of carbon atoms in the simplified symbols does not include carbons that may be present in substituents of the group.

[0044] As used herein, "alkyl" refers to a straight or branched monovalent saturated hydrocarbon group having a specified number of carbon atoms, and specific alkyl groups are those having 1 to 20 carbon atoms ("C1-C20 alkyl"), usually containing 1-16 carbon atoms (C1-C16 alkyl), preferably containing 1-10 carbon atoms (C1-C10 alkyl), and more preferably containing 1-6 carbon atoms (C1-C6 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like. In some embodiments, the alkyl group suitable for the present invention can be a C1-C20 alkyl group, such as a C1 alkyl group, a C2 alkyl group, a C3 alkyl group, a C4 alkyl group, a C5 alkyl group, a C6 alkyl group, a C7 alkyl group, a C8 alkyl group, a C9 alkyl group, a C10 alkyl group, a C11 alkyl group, a C12 alkyl group, a C13 alkyl group, a C14 alkyl group, a C15 alkyl group, a C16 alkyl group, a C17 alkyl group, a C18 alkyl group, a C19 alkyl group, and a C20 alkyl group.

[0045] As used herein, "alkoxy" refers to alkyl-O-, and the definition of alkyl is as described above. Preferred alkoxy is C1-C20 alkoxy, such as C1-C16 alkoxy, C1-C10 alkoxy, C1-C8 alkoxy, C1-C6 alkoxy, C1-C4 alkoxy, which includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexyloxy, 1,2-dimethylbutoxy, etc.

[0046] As used herein, "alkylthio" refers to an alkyl-S- group, wherein alkyl is as defined above.

[0047] As used herein, "halo" or "halogen" refers to an element of Group 17 with an atomic number of 9 to 85. "Halogen" or "halogen atom" refers to F, Cl, Br, and I. "Halogenated" means substituted with an atom selected from F, Cl, Br, and I.

[0048] As used herein, "cyano" refers to -CN.

[0049] As used herein, "phosphate group" refers to -PO(OH)2.

[0050] The structure of the organic compound provided by the present invention is as shown in Formula I-1 or Formula I-2; in Formula I-1 and Formula I-2, R1, R2, R3, R4, and R5 are each independently selected from a halogen atom, a C1-C6 straight-chain or branched alkoxy group, a C1-C6 straight-chain or branched alkylthio group, a C1-C10 straight-chain or branched alkyl group, a cyano group, and a hydrogen atom; R6 is a benzene ring or a C1-C10 straight-chain or branched alkylene group; R7 is -SO3H, -COOH, or -PO(OH)2; preferably, in Formula I-1 and Formula I-2, R1 is selected from a hydrogen atom, a methyl group, an ethyl group, a methoxy group, an ethoxy group, and a cyano group; R2, R3, R4, and R5 are each independently selected from a halogen atom and a hydrogen atom; R6 is a C1-C4 straight-chain alkylene group, and R7 is -PO(OH)2. In the present invention, an indazole small molecule organic compound having a phosphate group at the end is used as a hole transport material, which is beneficial to improving the long-term stability of the perovskite solar cell; the introduction of heteroatoms (atoms with lone electron pairs such as nitrogen, halogen, oxygen, sulfur, etc.) in the organic compound of the present invention enhances the intermolecular force, which is beneficial to improving the short-circuit current and photoelectric conversion efficiency of the perovskite solar cell.

[0051]

[0052] In some embodiments, the organic compound is

[0053] Using the above organic compounds as hole transport layer materials can improve the photoelectric performance of perovskite solar cells.

[0054] The present invention provides a method for preparing the organic compound of the present invention, the method comprising the following steps:

[0055] (1) placing compound A, compound B and NaH in a first solvent for reaction to obtain compound C;

[0056] (2) hydrolyzing compound C to obtain an organic compound represented by formula I-1 or formula I-2;

[0057] Among them, the structure of compound A is The structure of compound B is The structure of compound C is In compound A, compound B and compound C, R1, R2, R3, R4 and R5 are each independently selected from a halogen atom, a C1-C6 straight-chain or branched alkoxy group, a C1-C6 straight-chain or branched alkylthio group, a C1-C10 straight-chain or branched alkyl group, a cyano group and a hydrogen atom; R6 is a benzene ring or a C1-C10 straight-chain or branched alkylene group; R7 is -SO3H, -COOH or -PO(OH)2; R8 is a C1-C10 straight-chain or branched alkyl group.

[0058] In step (1), the first solvent may be one or more selected from N,N-dimethylformamide, tetrahydrofuran and 1,4-dioxane; preferably, N,N-dimethylformamide is ultra-dry N,N-dimethylformamide. In step (1), the molar ratio of compound A to compound B may be 1:1.1-1.5, such as 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5. In step (1), the molar ratio of compound A to NaH may be 1:1.1-1.5, such as 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5. In step (1), the molar concentration of compound A in the first solvent may be 0.1-0.5 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L. In step (1), the reaction can be carried out in a protective atmosphere; preferably, the protective atmosphere can be nitrogen and / or argon. In step (1), the reaction temperature can be -5-5°C, such as -5°C, -4°C, -2°C, 0°C, 2°C, 4°C.

[0059] In step (2), the hydrolysis reaction includes: placing compound C and trimethylsilyl bromide in a second solvent for a first-stage reaction to obtain a compound intermediate, and mixing the compound intermediate, methanol (MeOH) and water for a second-stage reaction to obtain an organic compound of formula I-1 or formula I-2.

[0060] In step (2), the second solvent may be 1,4-dioxane and / or dichloromethane. In step (2), the molar ratio of compound C to trimethylsilyl bromide may be 1:10-20, for example, 1:10, 1:12, 1:14, 1:16, 1:18, 1:20. In step (2), the molar concentration of compound C in the second solvent may be 0.1-0.5 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L. In step (2), the first stage reaction may be carried out in a protective atmosphere; preferably, the protective atmosphere may be nitrogen and / or argon. In step (2), the first stage reaction temperature may be 10-30°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C. In step (2), the second stage reaction temperature can be 10-30°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C.

[0061] The present invention provides a hole transport layer comprising the organic compound of the present invention. Since direct contact between the perovskite layer and the TCO layer will produce many defects and reduce the photoelectric performance of the battery, it is necessary to add a hole transport material between the perovskite layer and the TCO layer to reduce the energy level mismatch and recombination center at the interface, thereby reducing the defects at the interface and improving the photoelectric performance of the device.

[0062] The thickness of the hole transport layer may be 1-3 nm, for example, 1 nm, 1.5 nm, 2 nm, 2.5 nm, or 3 nm.

[0063] The present invention provides a method for preparing the hole transport layer of the present invention, the method comprising mixing an organic compound and a third solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare the hole transport layer.

[0064] In the hole transport layer precursor solution of the present invention, the third solvent may be one or more selected from methanol, isopropanol, ethanol, N,N-dimethylformamide and chlorobenzene. In the hole transport layer precursor solution of the present invention, the concentration of the organic compound shown in Formula I-1 or Formula I-2 may be 0.1-1 mg / mL, for example 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, 0.7 mg / mL, 0.8 mg / mL, 0.9 mg / mL, 1.0 mg / mL. In the present invention, the concentration of the organic compound shown in Formula I-1 or Formula I-2 is controlled within the above range, which is beneficial to improving the photoelectric performance of the perovskite solar cell.

[0065] In the present invention, the coating method of the hole transport layer precursor solution can be spin coating, blade coating or slit coating. In the present invention, the annealing temperature can be 100-150° C., for example, 100° C., 110° C., 120° C., 130° C., 140° C., 150° C. In the present invention, the annealing time can be 10-20 min, for example, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min.

[0066] The present invention provides a perovskite solar cell comprising a hole transport layer of the present invention. In the present invention, the perovskite solar cell may include a single-junction perovskite solar cell or a stacked perovskite solar cell. In the present invention, the perovskite solar cell may be an inverted single-junction perovskite solar cell or an inverted stacked perovskite solar cell.

[0067] In the present invention, the inverted single junction perovskite solar cell may include a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer and an electrode layer in sequence. In some embodiments, the inverted single junction perovskite solar cell further includes an interface barrier layer, which is located between the electron transport layer and the electrode layer. In the present invention, the inverted stacked perovskite solar cell may include a bottom electrode, a bottom cell, a tunneling layer, an inverted perovskite top cell and a top electrode in sequence, and the inverted top cell may include a hole transport layer, a perovskite layer and an electron transport layer in sequence.

[0068] In the present invention, the transparent conductive substrate may include a base and a transparent conductive layer. The base may be made of glass. The transparent conductive layer may be made of a transparent metal conductive oxide (TCO). The TCO may be tin-doped indium oxide (ITO) or fluorine-doped tin oxide (FTO). In the present invention, the material of the perovskite layer may be a perovskite structure material. The chemical formula of the perovskite structure material is ABX3, wherein A may be selected from cesium ions (Cs + ), rubidium ions (Rb + ), methylamine ion (CH3NH3 + , M.A. + ) and formamidinium ion (CH(NH2)2 + , F.A. + ), B can be selected from lead ions (Pb 2+ ), tin ions (Sn 2+ ) and manganese ions (Mn 2+ ), X may be a halogen ion, preferably selected from iodide ion (I - ), bromide ion (Br - ), chloride ion (Cl - ) and fluoride ion (F -) or more. In the present invention, the material of the electron transport layer may be one or more selected from [6,6]-phenyl-C61-butyric acid methyl ester, C60 and tin oxide. In the present invention, the material of the interface barrier layer may be 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) or zirconium acetylacetonate. In the present invention, the material of the electrode layer may be silver, copper, TCO or carbon.

[0069] The method for preparing a transverse single-junction perovskite solar cell of the present invention comprises:

[0070] (1) depositing a hole transport layer on the surface of a transparent conductive substrate;

[0071] (2) depositing a perovskite layer on the surface of the hole transport layer;

[0072] (3) depositing an electron transport layer on the surface of the perovskite layer;

[0073] (4) A back electrode is deposited on the surface of the electron transport layer to obtain an inverted single-junction perovskite solar cell.

[0074] The method for preparing an inverted stacked perovskite solar cell of the present invention comprises:

[0075] (1) depositing a bottom electrode and a tunneling layer on both sides of the bottom cell;

[0076] (2) depositing a hole transport layer on the surface of the tunneling layer;

[0077] (3) depositing a perovskite layer on the surface of the hole transport layer;

[0078] (4) depositing an electron transport layer on the surface of the perovskite layer;

[0079] (5) A top electrode is deposited on the surface of the electron transport layer to obtain an inverted stacked perovskite solar cell.

[0080] Compared with the prior art, the present invention has the following beneficial effects:

[0081] (1) The organic compound of the present invention comprises an indazole unit. Compared with the conventional carbazole unit, the indazole unit has fewer conjugated units and a wider molecular absorption band gap. The organic compound itself has high photothermal stability, which is beneficial to reduce the decomposition of the hole transport layer under photothermal conditions, thereby improving the long-term stability of the perovskite solar cell.

[0082] (2) In the organic compound of the present invention, heteroatoms (atoms with lone electron pairs such as nitrogen, halogen, oxygen, and sulfur) are introduced into the core unit to enhance the interaction between the small molecule hole transport layer and the perovskite, improve wettability, and facilitate the preparation of large-area devices; at the same time, the enhancement of the intermolecular interaction optimizes its arrangement on the substrate surface, improves the coverage and order of the hole transport layer on the substrate, thereby reducing the lower surface defects caused by direct contact between the perovskite and the substrate and inducing the formation of a high-quality perovskite film, which is beneficial to improving the short-circuit current and photoelectric conversion efficiency of the perovskite solar cell;

[0083] (3) The organic compound of the present invention introduces a variety of functional groups with different push-pull electron effects. Through the combination of different functional groups, a variety of small molecule hole transport materials with different energy levels are realized, thereby achieving excellent energy level matching with perovskite, improving the open circuit voltage of perovskite solar cells, and further improving the photoelectric conversion efficiency of perovskite solar cells; at the same time, the functional groups of the organic compound of the present invention synergistically increase the molecular dipole moment, which is conducive to the formation of a built-in electric field, inhibiting non-radiative recombination, and further improving the photoelectric conversion efficiency and stability of perovskite solar cells;

[0084] (4) In summary, the present invention is suitable for the preparation of large-area perovskite solar cells while synergistically improving the efficiency and stability of perovskite solar cells, and is suitable for large-scale industrial applications.

[0085] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0086] Total yield = molar amount of the organic compound of formula I-1 or formula I-2 produced / molar amount of the initial compound A.

[0087] Example 1

[0088] This embodiment synthesizes YZ-1, and the specific steps are as follows:

[0089] 1. Under nitrogen protection, 2H-indazole (591 mg, 5.00 mmol) and sodium hydride (220 mg, 5.5 mmol) were mixed in a flask (100 mL), and dissolved in anhydrous DMF (50 mL) under argon protection. Diethyl 2-bromobutylphosphonate (1496 mg, 5.5 mmol) was dropped into the flask at 0°C, slowly heated to 25°C, and stirred overnight; after the reaction was completed, ice water was used to quench, and the organic layer was extracted with ethyl acetate (3×50 mL), and the organic layer was dried with MgSO4. The dried organic layer was evaporated under reduced pressure to obtain a crude product, and the crude product was purified by silica gel column chromatography with n-hexane / ethyl acetate (1:1) as the eluent to obtain compound C1 (1132 mg, 3.65 mmol), and the yield of C1 was 73%;

[0090] 2. Under nitrogen protection, compound C1 (1132 mg, 3.65 mmol), trimethylsilyl bromide (6.71 g, 45.6 mmol) and 1,4-dioxane (40 mL) were added to a 100 mL round-bottom flask in sequence, and the mixture was reacted for 12 hours to obtain an organic intermediate. After the reaction, the mixture was spin-dried, and then methanol (30 mL) was added. Deionized water was added dropwise until the reaction solution became a white suspension, and the reaction was continued for 7 hours. After the reaction, the mixture was filtered, washed with deionized water, and dried. The dried solid was dissolved in tetrahydrofuran (THF), and then added dropwise into n-hexane, filtered, and finally washed with n-hexane to obtain YZ-1 (770 mg, 3.03 mmol). The yield of YZ-1 was 83%, so the total yield of YZ-1 was 60.59%.

[0091]

[0092] The results of hydrogen nuclear magnetic spectrum of YZ-1 prepared by the above method are: 1H NMR (500MHz, Chloroform-d) δ8.21–8.17 (m, 1H), 7.96 (d, J=7.9, 1H), 7.95 (s, 2H), 7.56–7.50 (m, 2H), 7.32 (td, J=7.5, 1.6Hz, 1H), 4.06–4.00 (m, 2H), 2.01–1.85 (m, 4H), 1.77–1.66 (m, 2H).

[0093] The mass spectrometry results of YZ-1 prepared by the above method are as follows: HRMS (ESI / Q-TOF, m / z): Calcd for [M+H] + C 11 H 16 N2O3P + :255.0893,found:255.0842.

[0094] Example 2

[0095] This example is the same as Example 1 in other conditions, except that in this example, the equimolar amount of 2H-indazole in the initial raw material is replaced by 6-bromo-3-methyl-2H-indazole, and the total yield of the product YZ-2 is 57%.

[0096]

[0097] The H NMR spectrum of YZ-2 prepared by the above method is as follows: 1H NMR 500MHz, Chloroform-d) δ7.95 (s, 2H), 7.90 (d, J = 8.4 Hz, 1H), 7.53–7.43 (m, 2H), 3.86 (t, J = 5.0 Hz, 2H), 2.43 (s, 3H), 1.99–1.87 (m, 4H), 1.78–1.67 (m, 2H).

[0098] The mass spectrometry results of YZ-2 prepared by the above method are as follows: HRMS (ESI / Q-TOF, m / z): Calcd for [M+H] + C 12 H 17 BrN2O3P + :347.0155,found:347.0103.

[0099] Example 3

[0100] The other conditions of this example are the same as those of Example 1, except that in this example, the equimolar amount of 2H-indazole in the initial raw material is replaced by 4-bromo-1H-indazole, and the total yield of the product YZ-3 is 51%.

[0101]

[0102] The results of hydrogen nuclear magnetic spectrum of YZ-3 prepared by the above method are: 1H NMR (500MHz, Chloroform-d) δ8.19 (s, 1H), 7.95 (s, 2H), 7.61 (dd, J = 7.2, 1.4 Hz, 1H), 7.35 (dd, J = 7.4, 1.4 Hz, 1H), 7.32 (d, J = 7.2 Hz, 1H), 4.13 (t, J = 4.9 Hz, 2H), 2.00–1.89 (m, 4H), 1.78–1.67 (m, 2H).

[0103] The mass spectrometry results of YZ-3 prepared by the above method are as follows: HRMS (ESI / Q-TOF, m / z): Calcd for [M+H] + C 11 H 15 BrN2O3P+ :332.9998,found:332.9987.

[0104] Example 4

[0105] Preparation of this example Figure 1 The perovskite solar cell shown specifically comprises the following steps:

[0106] 1. The tin-doped indium oxide (ITO) conductive glass was ultrasonically cleaned with deionized water, acetone and isopropanol for 15 minutes respectively, and finally dried in a drying oven at 75°C for standby use; the dried ITO conductive glass was placed in a UV ozone machine for 5 minutes to remove organic impurities on its surface and optimize its surface wettability to obtain a transparent conductive substrate;

[0107] 2. Dissolve 0.5 mg of organic compound YZ-1 in 1 mL of ethanol and stir at 25 °C until completely dissolved to obtain an organic hole transport material solution; take 30 μL of the organic hole transport material solution and drop it on a transparent conductive substrate, spin-coat it at 5000 rpm for 30 seconds, and place the transparent conductive substrate coated with the hole transport material on a hot stage for heating and annealing at 100 °C for 10 minutes to form a hole transport layer with a thickness of 3 nm;

[0108] 3. Dissolve 722.08 mg of lead iodide and 238.50 mg of iodomethylamine in 1 mL of N,N-dimethylformamide (DMF), stir at room temperature until completely dissolved, and obtain a perovskite precursor solution; in a nitrogen glove box, take 30 μL of the perovskite precursor solution and drop it onto the transparent conductive substrate that forms the hole transport layer, first spin-coat it at 1000 rpm for 10 seconds, then spin-coat it at 5000 rpm for 30 seconds, and quickly drop 125 μL of chlorobenzene at 25 seconds in this process, and then put it on a hot stage and heat it at 100 ° C for 40 minutes to form a perovskite layer with a thickness of 350 nm;

[0109] 4. Dissolve 20 mg of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) in 1 mL of chlorobenzene and stir at 20°C to obtain a [6,6]-phenyl-C61-butyric acid methyl ester solution; take 30 μL of the [6,6]-phenyl-C61-butyric acid methyl ester solution and spin coat it on a transparent conductive substrate with a perovskite layer at 3000 rpm for 60 seconds to form an electron transport layer with a thickness of 30 nm;

[0110] 5. Dissolve 0.5 mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in 1 mL of isopropanol and stir at 20°C to obtain an interface barrier layer solution; take 40 μL of the interface barrier layer solution and drop it onto the electron transport layer, and spin coat at 5000 rpm for 35 seconds to form an interface barrier layer with a thickness of 6 nm;

[0111] 6. Transfer the transparent conductive substrate with the interface barrier layer, electron transport layer, perovskite layer and hole transport layer to the vacuum coating instrument and wait until the vacuum degree reaches 3×10 -4 Silver is evaporated at 1.5 Pa to form an electrode layer with a thickness of 100 nm, and a perovskite solar cell is formed at the same time.

[0112] Example 5

[0113] The other conditions of this embodiment are the same as those of embodiment 4, except that the organic compound YZ-1 is replaced by the organic compound YZ-2 in this embodiment.

[0114] Example 6

[0115] The other conditions of this embodiment are the same as those of embodiment 4, except that the organic compound YZ-1 is replaced by the organic compound YZ-3 in this embodiment.

[0116] Comparative Example 1

[0117] The other conditions of this comparative example are the same as those of Example 4, except that the organic compound YZ-1 is replaced by 2PACz in this comparative example.

[0118] Test Case

[0119] Device performance test of perovskite solar cells: Under the AM 1.5G standard solar spectrum, a solar simulator was used to set the voltage range to -0.1-1.25V, and the current output of the perovskite solar cells prepared in Examples 4-6 and Comparative Example 1 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted, where the cell surface area was 0.0049m 2 , the incident light power (Pin) is 100mW / cm 2 The open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 4-6 and Comparative Example 1 were obtained according to the characteristic curves.

[0120] (1) Open circuit voltage (Voc): The voltage value corresponding to when the current is equal to zero.

[0121] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current per unit battery surface area is the short-circuit current density.

[0122] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the battery to the product of the open circuit voltage and the short circuit current. The calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0123] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0124] The test results of the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 4-6 and Comparative Example 1 are shown in Table 1.

[0125] Table 1: Open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of perovskite solar cells prepared in Examples 4-6 and Comparative Example 1

[0126] <![CDATA[Jsc(mA / cm 2 )]]> Voc(V) FF(%) PCE(%) Comparative Example 1 23.35 1.01 78.98 18.62 Example 4 24.12 1.07 80.31 20.72 Example 5 24.87 1.12 84.15 23.43 Example 6 24.66 1.03 83.34 21.16

Claims

1. An organic compound, characterized in that The structure of the organic compound is shown in Formula I-1 or Formula I-2; In formula I-1 and formula I-2, R1, R2, R3, R4, and R5 are each independently selected from a halogen atom, a C1-C6 straight-chain or branched alkoxy group, a C1-C6 straight-chain or branched alkylthio group, a C1-C10 straight-chain or branched alkyl group, a cyano group, and a hydrogen atom; R6 is a benzene ring or a C1-C10 straight-chain or branched alkylene group; R7 is -SO3H, -COOH, or -PO(OH)2.

2. The organic compound according to claim 1, characterized in that R1 is selected from hydrogen atom, methyl, ethyl, methoxy, ethoxy, cyano, R2, R3, R4, R5 are each independently selected from halogen atoms and hydrogen atoms, R6 is a C1-C4 straight-chain alkylene group, and R7 is -PO(OH)2.

3. A method for preparing the organic compound according to claim 1 or 2, characterized in that: The method comprises the following steps: (1) placing compound A, compound B and NaH in a first solvent for reaction to obtain compound C; (2) hydrolyzing compound C to obtain an organic compound represented by formula I-1 or formula I-2; Among them, the structure of compound A is The structure of compound B is The structure of compound C is In compound A, compound B and compound C, R1, R2, R3, R4, R5 and R6 are as defined in claim 1 or 2; R7 ’ It is -SO3R8, -COOR8 or -PO(OR8)2, wherein R8 is a C1-C10 straight-chain or branched alkyl group.

4. The method according to claim 3, characterized in that The method has one or more of the following features: In step (1), the first solvent is selected from one or more of N,N-dimethylformamide, tetrahydrofuran and 1,4-dioxane; In step (1), the molar ratio of compound A to compound B is 1:1.1-1.5 In step (1), the ratio of compound A to NaH is 1:1.1-1.5; In step (1), the reaction is carried out in a protective atmosphere; In step (1), the reaction temperature is -5-5°C; In step (2), the hydrolysis reaction comprises: placing compound C and trimethylsilyl bromide in a second solvent for a first-stage reaction to obtain a compound intermediate, and mixing the compound intermediate, methanol and water for a second-stage reaction to obtain an organic compound of formula I-1 or formula I-2.

5. The method according to claim 4, characterized in that The method has one or more of the following features: In step (2), the second solvent is 1,4-dioxane and / or dichloromethane; In step (2), the molar ratio of compound C to trimethylsilyl bromide is 1:10-20; In step (2), the first stage reaction is carried out in a protective atmosphere; In step (2), the first stage reaction temperature is 10-30°C; In step (2), the second stage reaction temperature is 10-30°C.

6. A hole transport layer, characterized in that: The hole transport layer comprises the organic compound according to claim 1 or 2.

7. The hole transport layer according to claim 6, characterized in that The thickness of the hole transport layer is 1-3 nm.

8. A method for preparing the hole transport layer according to claim 6 or 7, characterized in that: The method comprises mixing an organic compound and a third solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare a hole transport layer.

9. The method according to claim 8, characterized in that The method has one or more of the following features: The third solvent is selected from one or more of methanol, isopropanol, ethanol, N,N-dimethylformamide and chlorobenzene; In the hole transport layer precursor solution, the concentration of the organic compound is 0.1-1 mg / mL; The coating method is spin coating, blade coating or slit coating; Annealing temperature is 100-150°C; The annealing time is 10-20 minutes.

10. A perovskite solar cell comprising the hole transport layer according to claim 6 or 7.

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