Hole transport material and preparation method thereof, and perovskite solar cell

Abstract

The present invention provides a hole transport material and a preparation method thereof, and a perovskite solar cell. The chemical structural formula of the hole transport material is wherein each A is independently a heteroatom. The present application introduces a thiophene-methoxytriphenylamine group and a thiophene-methylthiotriphenylamine group into an acridine phosphate side chain to provide a series of novel hole transport materials. Such hole transport materials have a high decomposition temperature, good thermal stability, and high hole mobility, thereby facilitating the extraction and transmission of holes. Such hole transport materials have a deep HOMO energy level that matches that of perovskite, and can be used in perovskite solar cells without the need for doping with any additives, so that the perovskite solar cell has higher photoelectric conversion efficiency, photovoltaic performance, and stability, and the material has repeatability.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a hole transport material and a preparation method thereof, and a perovskite solar cell. Background Art

[0002] Perovskite solar cells (PSCs) utilize perovskite-type organometallic halide semiconductors as light-absorbing materials to directly convert light energy into electricity through the photovoltaic effect. Among them, trans-structured PSCs show great potential for commercial applications. The continuous development of new hole transport materials (HTMs) is a key factor in the preparation of efficient and stable perovskite solar cells. Polymer hole transport materials, due to their excellent film-forming properties and solvent resistance, have great potential in the realization of large-area trans-perovskite solar cells.

[0003] In inverse perovskite solar cells, hole transport materials, as important transport layer materials between the perovskite layer and the transparent electrode, are not only responsible for the extraction and transport of holes and blocking the flow of electrons, but also directly affect the crystallization and film formation of perovskite, playing a decisive role in improving battery performance and realizing large-scale commercial applications. Summary of the Invention

[0004] The main purpose of the present invention is to provide a hole transport material and a preparation method thereof, and a perovskite solar cell, so as to solve the problems of high raw material cost, low decomposition temperature and low hole mobility of hole transport materials in the prior art.

[0005] In order to achieve the above object, according to one aspect of the present invention, a hole transport material is provided, the chemical structure of which is wherein each A is independently a heteroatom.

[0006] Furthermore, each of the above A is independently O or S.

[0007] Furthermore, the decomposition temperature of the hole transport material is 298 to 345° C.; and / or the HOMO energy level of the hole transport material is -5.39 to -5.32 eV; and / or the hole mobility of the hole transport material is 3.67×10 -4 ~6.35×10 -4 cm 2 ·V -1 ·S -1 .

[0008] According to another aspect of the present invention, a method for preparing the aforementioned hole transport material is provided, the method comprising: step S1, under the protection of an inert gas, The raw materials are mixed and subjected to the first substitution reaction to generate Step S2, under the protection of inert gas, includes The raw materials of trimethylsilyl bromide and 1,4-dioxane are mixed and subjected to a first reaction to obtain an intermediate; step S3, under the protection of an inert gas, the raw materials including the intermediate, methanol and water are mixed and subjected to a second reaction to obtain Wherein, A is a heteroatom.

[0009] Furthermore, in the above step S1, Each A in is independently O or S.

[0010] Furthermore, the raw materials in the above step S1 further include tetrakis(triphenylphosphine)palladium, potassium carbonate, toluene, ethanol and water; and / or, The molar ratio of potassium carbonate to tetrakis(triphenylphosphine)palladium is 1:2.2-2.5:4-6:0.05-0.1; and / or the temperature of the first substitution reaction is 85-90° C.; and / or the time of the first substitution reaction is 6-12 hours.

[0011] Furthermore, the temperature of the first reaction is 25-30° C.; and / or, the time of the first reaction is 12-16 hours; and / or, the temperature of the second reaction is 25-30° C.; and / or, the time of the second reaction is 12-16 hours; and / or, The molar ratio of trimethylsilyl bromide to trimethylsilyl bromide is 1:10-20.

[0012] Furthermore, the above The preparation method includes: step S11, comprising After mixing with the raw material of N-bromosuccinimide, bromination reaction is carried out to obtain Step S12 includes The raw materials of tetrabutylammonium bromide, dibromobutane and potassium hydroxide are mixed and subjected to a second substitution reaction to obtain Step S13 includes After mixing with the raw material of triethyl phosphite, a third substitution reaction is carried out to obtain

[0013]

[0014] Furthermore, the raw materials in the above step S11 also include tetrahydrofuran, The amount ratio of the substance of N-bromosuccinimide is 1:2.5-3; and / or, the temperature of the bromination reaction is 0-5°C; and / or, the time of the bromination reaction is 12-18h; and / or, in step S12, The molar ratio of tetrabutylammonium bromide to potassium hydroxide is 1:0.1-0.2:7-10; and / or, the temperature of the second substitution reaction is 65-85° C.; and / or, the time of the second substitution reaction is 12-24 hours; and / or, in step S13, The molar ratio of the third substitution reaction to triethyl phosphite is 1:25-50; and / or the temperature of the third substitution reaction is 140-150° C.; and / or the time of the third substitution reaction is 12-24 hours.

[0015] According to another aspect of the present invention, a perovskite solar cell is provided, comprising a transparent conductive layer, a hole transport layer, a perovskite layer, an electron transport layer and an electrode layer, wherein the hole transport layer is composed of the aforementioned hole transport material.

[0016] By applying the technical solution of the present invention, the present application introduces thiophene-methoxytriphenylamine groups and thiophene-methylthiotriphenylamine groups into the acridine phosphate side chain to provide a series of novel hole transport materials. These materials have good solubility in solvents such as dimethyl sulfoxide, N,N' dimethylformamide, toluene, chlorobenzene and dichloromethane. The materials have good film-forming properties and good wettability with perovskite precursor solvents, thereby helping to improve the crystallinity and film-forming properties of perovskite. In addition, these hole transport materials have a high decomposition temperature, good thermal stability and high hole mobility, which are conducive to the extraction and transport of holes. These hole transport materials have a deep HOMO energy level that matches that of perovskite and can be used in perovskite solar cells without the need for doping with any additives, resulting in perovskite solar cells with higher photoelectric conversion efficiency, photovoltaic performance and stability, and the materials are reproducible. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0018] Figure 1 shows the hydrogen nuclear magnetic resonance spectrum of the hole transport material in Example 1 of the present application;

[0019] Figure 2 shows the hydrogen nuclear magnetic resonance spectrum of the hole transport material in Example 2 of the present application;

[0020] Figure 3 A schematic structural diagram of a perovskite solar cell of the present application is shown.

[0021] The above drawings include the following reference numerals:

[0022] 1. Transparent conductive layer; 2. Hole transport layer; 3. Perovskite layer; 4. Electron transport layer; 5. Electrode layer. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] Currently, some of the most promising inverted perovskite solar cells are prepared using self-assembled monolayers (SAMs) containing carbazolyl phosphate (PA), such as [2-(9H-carbazol-9-yl)ethyl]phosphate (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphate (MeO-2PACz), and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphate (Me-4PACz). They have the ability to coat uniformly on rough surfaces, high hole extraction selectivity, and low interfacial electron trap density, making them suitable for use as excellent hole-selective contact layers. At the same time, HTMs containing triphenylamine (TPA) have good thermal and morphological stability, as well as good charge transport and ionization potential. Currently, the most effective common method for constructing HTMs is still methoxy-substituted diphenylamine or triphenylamine. Currently, HTMs in perovskite solar cells are primarily classified into three categories: inorganic hole transport materials, organic small molecule hole transport materials, and organic polymer hole transport materials. Small molecule HTMs have well-defined structures and molecular weights. They can be broadly categorized based on their spatial structure: linear, spirocyclic, and star-shaped. They can also be classified based on the presence of different groups within their molecular structure, such as dithienopyrrole, triphenylamine, carbazole, bifluorene, and thiophene. Small molecule HTMs are the most common type of HTM in perovskite solar cells due to their diverse synthesis options, tunable properties, high purity, and ease of solution processing. However, due to their rigid structure, they exhibit low tolerance to perovskite precursor solutions. Thin films produced from small molecule HTMs often exhibit pinhole morphology defects and exhibit morphological instability under external stimuli. Furthermore, many small molecule HTMs require the addition of dopants, which poses significant obstacles to the large-scale commercialization of PSCs. As analyzed in the background technology of this application, hole transport materials in the prior art have problems such as high raw material cost, low decomposition temperature and low hole mobility. In order to solve the above problems, this application provides a hole transport material and a preparation method thereof, and a perovskite solar cell.

[0025] In a typical embodiment of the present application, a hole transport material is provided, the chemical structure of which is wherein each A is independently a heteroatom.

[0026] This application introduces thiophene-methoxytriphenylamine groups and thiophene-methylthiotriphenylamine groups into acridine phosphate side chains to provide a series of novel hole transport materials. These materials have good solubility in solvents such as dimethyl sulfoxide, N,N'dimethylformamide, toluene, chlorobenzene and dichloromethane. The material has good film-forming properties and has good wettability with perovskite precursor solvents, which helps to improve the crystallinity and film-forming properties of perovskite. In addition, this type of hole transport material has a high decomposition temperature, good thermal stability and high hole mobility, which is conducive to the extraction and transmission of holes. This type of hole transport material has a deep HOMO energy level that matches the perovskite, and it can be used in perovskite solar cells without doping with any additives, so that the perovskite solar cell has higher photoelectric conversion efficiency, photovoltaic performance and stability, and the material is reproducible.

[0027] In order to further improve the solubility, film-forming property and hole mobility of the hole transport material, in one embodiment of the present application, each of the above A is independently O or S, and optionally all A are O or all A are S.

[0028] In one embodiment of the present application, the decomposition temperature of the hole transport material is 298 to 345° C.; and / or the HOMO energy level of the hole transport material is -5.39 to -5.32 eV; and / or the hole mobility of the hole transport material is 3.67×10 -4 ~6.35×10 -4 cm 2 ·V -1 ·S -1 .

[0029] Applying hole transport materials with the above-mentioned decomposition temperature, HOMO energy level and hole mobility range to perovskite solar cells will help further improve the photoelectric conversion efficiency, photovoltaic performance and stability of perovskite solar cells.

[0030] In another typical embodiment of the present application, a method for preparing the aforementioned hole transport material is provided, the method comprising: step S1, under the protection of an inert gas, The raw materials are mixed and subjected to the first substitution reaction to generate Step S2, under the protection of inert gas, includes The raw materials of trimethylsilyl bromide and 1,4-dioxane are mixed and subjected to a first reaction to obtain an intermediate; step S3, under the protection of an inert gas, the raw materials including the intermediate, methanol and water are mixed and subjected to a second reaction to obtain Wherein, A is a heteroatom.

[0031] The raw materials used to prepare the hole transport material are low in cost, the process for preparing the hole transport material is simple, and it is suitable for industrial production. The hole transport material prepared by the above preparation method has good solubility, film-forming properties, and hole mobility. This type of hole transport material has a deep HOMO energy level that matches that of perovskite, and can be used in perovskite solar cells without the need for any additives, resulting in perovskite solar cells with higher photoelectric conversion efficiency, photovoltaic performance, and stability.

[0032] In order to further improve the solubility, film forming properties and hole mobility of the hole transport material, in one embodiment of the present application, in the above step S1, Each A in is independently O or S, optionally, for

[0033] In order to improve the reaction efficiency of the first substitution reaction and the yield of the product in step S1, in one embodiment of the present application, the raw materials in step S1 further include tetrakis(triphenylphosphine)palladium, potassium carbonate, toluene, ethanol and water; and / or, The molar ratio of potassium carbonate to tetrakis(triphenylphosphine)palladium is 1:2.2-2.5:4-6:0.05-0.1; and / or the temperature of the first substitution reaction is 85-90° C.; and / or the time of the first substitution reaction is 6-12 hours.

[0034] In one embodiment of the present application, the temperature of the first reaction is 25-30° C.; and / or, the time of the first reaction is 12-16 hours; and / or, the temperature of the second reaction is 25-30° C.; and / or, the time of the second reaction is 12-16 hours; and / or, The molar ratio of trimethylsilyl bromide to trimethylsilyl bromide is 1:10-20.

[0035] Controlling the temperature and time of the first reaction and the temperature and time of the second reaction helps to improve the reaction efficiency of the first reaction and the second reaction. The ratio of the amount of trimethylsilyl bromide to the amount of trimethylsilyl bromide is within the above range, which helps to further improve the yield of the final product.

[0036] In order to further reduce the cost of raw materials, in one embodiment of the present application, the above The preparation method includes: step S11, comprising After mixing with the raw material of N-bromosuccinimide, bromination reaction is carried out to obtain Step S12 includes The raw materials of tetrabutylammonium bromide, dibromobutane and potassium hydroxide are mixed and subjected to a second substitution reaction to obtain Step S13 includes After mixing with the raw material of triethyl phosphite, a third substitution reaction is carried out to obtain

[0037] To improve In one embodiment of the present application, the raw material in step S11 further comprises tetrahydrofuran, The amount ratio of the substance of N-bromosuccinimide is 1:2.5-3; and / or, the temperature of the bromination reaction is 0-5°C; and / or, the time of the bromination reaction is 12-18h; and / or, in step S12, The molar ratio of tetrabutylammonium bromide to potassium hydroxide is 1:0.1-0.2:7-10; and / or, the temperature of the second substitution reaction is 65-85° C.; and / or, the time of the second substitution reaction is 12-24 hours; and / or, in step S13, The molar ratio of the third substitution reaction to triethyl phosphite is 1:25-50; and / or the temperature of the third substitution reaction is 140-150° C.; and / or the time of the third substitution reaction is 12-24 hours.

[0038] In another typical embodiment of the present application, a perovskite solar cell is provided, such as Figure 3 As shown, it includes a transparent conductive layer 1, a hole transport layer 2, a perovskite layer 3, an electron transport layer 4 and an electrode layer 5, wherein the hole transport layer is composed of the aforementioned hole transport material.

[0039] Since the above-mentioned perovskite solar cell contains the hole transport material of the present application, the perovskite solar cell has high photoelectric conversion efficiency, photovoltaic performance and stability.

[0040] Including but not limited to, the transparent conductive layer 1 is an ITO glass sheet, the perovskite layer 3 is (3FBA)2(MA)3Pb4I 13 composition (3FBA=3-fluorobenzylammonium, MA=methylammonium), the electron transport layer 4 is PC61BM, and the electrode layer 5 is a Cr / Au electrode.

[0041] The method for preparing the above-mentioned perovskite solar cell comprises the following steps:

[0042] (1) Cleaning of the transparent conductive layer 1: The ITO glass sheet was ultrasonically cleaned with deionized water, acetone, and ethanol for 15 to 20 minutes, and then the residual solvent on the ITO surface was blown dry with an N2 air gun. The ITO glass sheet was then treated with oxygen plasma for 10 to 15 minutes, and then the ITO glass sheet was transferred to a nitrogen glove box.

[0043] (2) Preparation of hole transport layer 2: Weigh 3-15 mg of the hole transport material of the present application and completely dissolve it in 1 mL of chlorobenzene solution. Take an appropriate amount of the solution and evenly drop it onto the ITO glass substrate. Spin coat at 4000-5000 rpm for 20-30 seconds, and then anneal at 90-110°C for 10 minutes.

[0044] (3) Preparation of perovskite layer 3: The ITO / hole transport layer substrate obtained above was cooled to room temperature, preheated at 130-140°C for 3-5 minutes, 50 μL of perovskite solution was taken and spread all over the ITO / hole transport layer substrate, spin-coated at 3000-5000 rpm for 20-30 seconds, and then annealed at 90-100°C for 10 minutes to prepare a perovskite layer. The perovskite solution is prepared by mixing 3-bromo-benzyl-ammonium iodide or 3-chlorobenzyl ammonium iodide, methylammonium chloride, and lead iodide in a certain molar ratio in N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO);

[0045] (4) Preparation of electron transport layer 4: The ITO / hole transport layer / perovskite substrate obtained above was cooled to room temperature, PC61BM was prepared into a 15 mg / mL solution, and then 40 μL of PC61BM solution was taken to cover the ITO / hole transport layer / perovskite substrate and spin-coated at 1000 rpm for 30 to 50 seconds;

[0046] (5) Preparation of electrode layer 5: The above substrate is placed in a vacuum evaporation chamber, and Cr (6 nm) and Au (80 nm) are evaporated on the PC61BM layer respectively to obtain a perovskite solar cell.

[0047] The beneficial effects of the present application will be further illustrated below with reference to examples.

[0048] Example 1

[0049] Synthesis of compound of formula (2)

[0050]

[0051] In a 100 mL round-bottom flask, the compound of formula (1) (0.89 g, 4.24 mmol) and tetrahydrofuran (10 mL) were added, followed by the addition of N-bromosuccinimide (1.89 g, 10.6 mmol) for a substitution reaction at 0° C. for 12 h. After completion of the reaction, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The product was further purified by flash column chromatography using a main component and eluent having a volume ratio of petroleum ether / dichloromethane = 10 / 1 to obtain the compound of formula (2) as a white solid (1.40 g, 90% yield).

[0052] Synthesis of compound of formula (3)

[0053]

[0054] In a 100 mL double-necked flask, the compound of formula (2) (1.00 g, 2.72 mmol) was added, and tetrabutylammonium bromide (0.32 g, 0.27 mmol) was dissolved in dibromobutane (15 mL). The mixture was then added dropwise to 5 mL of a potassium hydroxide aqueous solution, wherein the amount of potassium hydroxide was 24 mmol. The substitution reaction was carried out at a temperature of 65° C. for 12 h. After the reaction was completed, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The product was further purified by flash column chromatography using a main component and an eluent having a volume ratio of petroleum ether / dichloromethane = 10 / 1 to obtain the compound of formula (3) as a colorless oil (1.20 g, 89% yield).

[0055] Synthesis of compound of formula (4)

[0056]

[0057] In a 100 mL double-necked flask, the compound of formula (3) (1.20 g, 2.39 mmol) and triethyl phosphite (60 mmol, 10 mL) were added and mixed. The mixture was reacted under a nitrogen atmosphere at a temperature of 140° C. for 12 h. After the reaction, the organic solvent was removed using a rotary evaporator to obtain a crude product of the compound of formula (4) (1.30 g, 2.27 mmol).

[0058] Synthesis of compound of formula (6)

[0059]

[0060] The compound of formula (5) (1.15 g, 3 mmol), 2-thiophene borate (0.46 g, 3.6 mmol), tetrakis(triphenylphosphine)palladium (0.092 g, 0.08 mmol), and potassium carbonate (1.2 g, 9 mmol) were weighed and added to a 100 mL two-necked reaction flask. DMF (40 mL) was used as the solvent and the reaction was carried out at 85° C. under N2 atmosphere for 8 hours. The mixture was cooled to 25° C. and extracted with dimethyl carbonate (DCM). The organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, it was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate in a volume ratio of 12:1 to obtain 0.84 g of green solid powder of the compound of formula (6) with a yield of 71%.

[0061] Synthesis of compound of formula (7)

[0062]

[0063] The compound of formula (6) (10 mmol) was weighed and added to a 500 mL three-necked flask. 30 mL of dry THF was then added. The mixture was cooled to -78°C under N2 and stirred for 10 min. Then, n-butyl lithium (3.75 mL, 1.00 equiv, 1.6 Min-hexane) was slowly added dropwise. The reaction was continued at -78°C for 1 hour. Tert-butyl alcohol pinacol borate (2.75 mL, 15 mmol) was then added. The reaction was continued at -78°C for 1 hour. Finally, the mixture was transferred to 25°C and allowed to react for 12 hours. The reaction was quenched with 50 mL of deionized water, extracted with saturated NaCl solution and DCM, and the organic phase was dried over anhydrous Mg2SO4, filtered, and finally purified by column chromatography using a volume ratio of petroleum ether (PE) to dimethyl carbonate of 15:1 to obtain the compound of formula (7).

[0064] Synthesis of compound of formula (8)

[0065]

[0066]

[0067] To a 100 mL double-necked flask, the compound of formula (4) (0.58 g, 1 mmol), the compound of formula (7) (2.2 mmol), tetrakis(triphenylphosphine)palladium (57 mg, 0.05 mmol), and potassium carbonate (0.83 g, 6 mmol) were added. The solvent was toluene, ethanol, and water (volume ratio of 2:1:1). The reaction was carried out at 85° C. for 6 hours. The mixture was cooled to 25° C. and extracted with DCM. The organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, it was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate (volume ratio of 4:1) to obtain the compound of formula (7) (0.75 g, 0.74 mmol) with a yield of 75%.

[0068] Synthesis of 4PAAc-OMe

[0069]

[0070] In a 100mL double-necked flask, compound (8) (2mmol) was added to anhydrous 1,4-1,4-dioxane (10mL) at 25°C, and trimethylsilane bromide (3.06g, 20mmol) was added dropwise, and then stirred for 12h. 1,4-dioxane was removed by rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol (10mL) at 25°C, and then deionized water was added dropwise until the mixture became opaque, and then stirred for 12 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in tetrahydrofuran (THF) (5mL), reprecipitated in acetone (20mL), and filtered to obtain the final product 4PAAc-OMe (1.2g, yield 75%). The nuclear magnetic resonance hydrogen spectrum of 4PAAc-OMe is shown as follows Figure 1 shown.

[0071] Example 2

[0072] Synthesis of compound of formula (2)

[0073]

[0074] In a 100 mL round-bottom flask, the compound of formula (1) (0.89 g, 4.24 mmol) and tetrahydrofuran (10 mL) were added, followed by the addition of N-bromosuccinimide (1.89 g, 10.6 mmol) for a substitution reaction at 0° C. for 12 h. After completion of the reaction, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The product was further purified by flash column chromatography using a main component and eluent having a volume ratio of petroleum ether / dichloromethane = 10 / 1 to obtain the compound of formula (2) as a white solid (1.40 g, 90% yield).

[0075] Synthesis of compound of formula (3)

[0076]

[0077] In a 100 mL double-necked flask, the compound of formula (2) (1.00 g, 2.72 mmol) was added, tetrabutylammonium bromide (0.32 g, 0.27 mmol) was dissolved in dibromobutane (15 mL), and then added dropwise to 5 mL of potassium hydroxide aqueous solution, wherein the amount of potassium hydroxide was 24 mmol, to carry out a substitution reaction at 65° C. for 12 h. After completion of the reaction, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined and dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The main component and eluent were petroleum ether / dichloromethane = 10 / 1 by volume, and further purified by flash column chromatography to obtain the compound of formula (3) as a colorless oil (1.20 g, yield 89%).

[0078] Synthesis of compound of formula (4)

[0079]

[0080] In a 100 mL double-necked flask, the compound of formula (3) (1.20 g, 2.39 mmol) and triethyl phosphite (60 mmol, 10 mL) were added and mixed. The mixture was reacted under a nitrogen atmosphere at a temperature of 140° C. for 12 h. After the reaction, the organic solvent was removed using a rotary evaporator to obtain a crude product of the compound of formula (4) (1.30 g, 2.27 mmol).

[0081] Synthesis of compound of formula (11)

[0082]

[0083] The compound of formula (10) (1.15 g, 3 mmol), 2-thiophene borate (0.46 g, 3.6 mmol), tetrakis(triphenylphosphine)palladium (0.092 g, 0.08 mmol), and potassium carbonate (1.2 g, 9 mmol) were weighed and added to a 100 mL two-necked reaction flask. DMF (40 mL) was used as the solvent and the reaction was carried out at 85° C. under N2 atmosphere for 8 hours. The mixture was cooled to 25° C. and extracted with DCM. The organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, it was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate in a volume ratio of 12:1 to obtain 0.87 g of solid powder of compound (11) with a yield of 71%.

[0084] Synthesis of compound of formula (12)

[0085]

[0086] The compound of formula (11) (10 mmol) was weighed and added to a 500 mL three-necked flask. 30 mL of dry THF was then added. The mixture was cooled to -78°C under N2 and stirred for 10 min. Then, n-butyl lithium (3.75 mL, 1.00 equiv, 1.6 Min-hexane) was slowly added dropwise. The reaction was continued at -78°C for 1 hour. Tert-butyl alcohol pinacol borate (2.75 mL, 15 mmol) was then added. The reaction was continued at -78°C for 1 hour. Finally, the mixture was transferred to 25°C and allowed to react for 12 hours. The reaction was quenched with 50 mL of deionized water. The mixture was extracted with saturated NaCl solution and DCM. The organic phase was dried over anhydrous Mg2SO4, filtered, and finally purified by column chromatography using a volume ratio of petroleum ether (PE) to dimethyl carbonate of 15:1 to obtain the compound of formula (12).

[0087] Synthesis of compound of formula (13)

[0088]

[0089]

[0090] To a 100 mL double-necked flask, the compound of formula (4) (0.58 g, 1 mmol), the compound of formula (7) (2.2 mmol), tetrakis(triphenylphosphine)palladium (57 mg, 0.05 mmol), and potassium carbonate (0.83 g, 6 mmol) were added. The solvent was toluene, ethanol, and water (volume ratio of 2:1:1). The reaction was carried out at 85° C. for 6 hours. The mixture was cooled to 25° C. and extracted with DCM. The organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, the mixture was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate (volume ratio of 4:1) to obtain the compound of formula (13) (0.75 g, 0.71 mmol) with a yield of 70%.

[0091] Synthesis of 4PAAc-SMe

[0092]

[0093] In a 100mL double-necked flask, compound (13) (g, 2mmol) was added to anhydrous 1,4-1,4-dioxane (10mL) at 25°C, and trimethylsilane bromide (3.06g, 20mmol) was added dropwise, and then stirred overnight. 1,4-dioxane was removed with a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol (10mL) at 25°C, and then deionized water was added dropwise until the mixture became opaque, and then stirred for 12 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in THF (5mL), reprecipitated in acetone (20mL), and filtered to obtain the final product 4PAAc-SMe (1.2g, yield 75%). The nuclear magnetic resonance hydrogen spectrum of 4PAAc-SMe is shown as follows Figure 2 shown.

[0094] Example 3

[0095] The difference from Example 1 is that, in a 100mL round-bottom flask, the compound of formula (1) (3.53mmol) and tetrahydrofuran (10mL) were added, and then N-bromosuccinimide (1.89g, 10.6mmol) was added to carry out a substitution reaction. The temperature of the substitution reaction was 5°C and the substitution reaction time was 18h. After the reaction was completed, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The main component and eluent were petroleum ether / dichloromethane = 10 / 1 by volume, and further purified by flash column chromatography to obtain the compound of formula (2) as a white solid (1.16g, 89% yield).

[0096] Example 4

[0097] The difference from Example 1 is that, in a 100mL round-bottom flask, the compound of formula (1) (2.65mmol) and tetrahydrofuran (10mL) were added, and then N-bromosuccinimide (1.89g, 10.6mmol) was added to carry out a substitution reaction. The temperature of the substitution reaction was 6°C and the substitution reaction time was 20h. After the reaction was completed, the reaction was quenched with water and extracted with dichloromethane. The organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The main component and eluent were petroleum ether / dichloromethane = 10 / 1 by volume, and further purified by flash column chromatography to obtain the compound of formula (2) as a white solid (0.78g, 81% yield).

[0098] Example 5

[0099] The difference from Example 1 is that the compound of formula (2) (1.00 g, 2.72 mmol) was added to a 100 mL double-necked flask, tetrabutylammonium bromide (0.54 mmol) was dissolved in dibromobutane (15 mL), and then added dropwise to 5 mL of potassium hydroxide aqueous solution, wherein the amount of potassium hydroxide was 19.04 mmol, to carry out a substitution reaction, the reaction temperature was 85 ° C, and the reaction time was 24 h. After the reaction was completed, the reaction was quenched with water, extracted with dichloromethane, and the organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The main component and eluent were petroleum ether / dichloromethane = 10 / 1, and further purified by flash column chromatography to obtain the compound of formula (3) as a colorless oil (1.18 g, 87% yield).

[0100] Example 6

[0101] The difference from Example 1 is that the compound of formula (2) (1.00 g, 2.72 mmol) was added to a 100 mL double-necked flask, tetrabutylammonium bromide (0.14 mmol) was dissolved in dibromobutane (15 mL), and then added dropwise to 5 mL of potassium hydroxide aqueous solution, wherein the amount of potassium hydroxide was 16.32 mmol, to carry out a substitution reaction, the reaction temperature was 90° C., and the reaction time was 25 h. After the reaction was completed, the reaction was quenched with water, extracted with dichloromethane, the organic layers were combined, dried over anhydrous magnesium sulfate, and then the organic solvent was removed on a rotary evaporator to obtain a crude product. The main component and eluent were petroleum ether / dichloromethane = 10 / 1, and further purified by flash column chromatography to obtain the compound of formula (3) as a colorless oil (0.68 g, 50% yield).

[0102] Example 7

[0103] The difference from Example 1 is that the compound of formula (3) (1.20 g, 2.39 mmol) and triethyl phosphite (119.5 mmol) were added to a 100 mL two-necked flask, mixed, and reacted under a nitrogen atmosphere at a temperature of 150° C. for 24 h. After the reaction, the organic solvent was removed using a rotary evaporator to obtain a crude product of the compound of formula (4) (1.28 g, 2.24 mmol).

[0104] Example 8

[0105] The difference from Example 1 is that the compound of formula (3) (1.20 g, 2.39 mmol) and triethyl phosphite (47.8 mmol) were added to a 100 mL two-necked flask, mixed, and reacted under a nitrogen atmosphere at a temperature of 130° C. for 10 h. After the reaction, the organic solvent was removed using a rotary evaporator to obtain a crude product of the compound of formula (4) (0.93 g, 1.62 mmol).

[0106] Example 9

[0107] The difference from Example 1 is that the compound of formula (4) (1 mmol), the compound of formula (7) (2.5 mmol), tetrakis(triphenylphosphine)palladium (0.1 mmol), and potassium carbonate (4 mmol) were added to a 100 mL double-necked flask. The solvent was toluene, ethanol, and water (volume ratio of 2:1:1), and the reaction was carried out at 90° C. for 12 hours. The mixture was cooled to 25° C., extracted with DCM, and the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, it was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate (volume ratio of 4:1) to obtain the compound of formula (7) (0.86 g, yield 74%).

[0108] Example 10

[0109] The difference from Example 1 is that the compound of formula (4) (1 mmol), the compound of formula (7) (2 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), and potassium carbonate (3 mmol) were added to a 100 mL double-necked flask. The solvent was toluene, ethanol, and water (volume ratio of 2:1:1), and the reaction was carried out at 80° C. for 5 hours. The mixture was cooled to 25° C., extracted with DCM, and the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. Finally, it was purified by column chromatography using petroleum ether (PE) and dimethyl carbonate (volume ratio of 4:1) to obtain the compound of formula (7) (0.53 g, yield 45%).

[0110] Example 11

[0111] The difference from Example 1 is that the compound of formula (8) (1 mmol) was added to anhydrous 1,4-1,4-dioxane (10 mL) at 30°C in a 100 mL two-necked flask, trimethylsilyl bromide (3.06 g, 20 mmol) was added dropwise, and then stirred for 16 hours. 1,4-dioxane was removed using a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol (10 mL) at 30°C, and deionized water was then added dropwise until the mixture became opaque, and then stirred for another 16 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in tetrahydrofuran (THF) (5 mL), reprecipitated in acetone (20 mL), and filtered to obtain the final product 4PAAc-OMe (0.83 g, 73% yield).

[0112] Example 12

[0113] The difference from Example 1 is that the compound of formula (8) (0.9 mmol) was added to anhydrous 1,4-1,4-dioxane (10 mL) at 40°C in a 100 mL two-necked flask, trimethylsilyl bromide (3.06 g, 20 mmol) was added dropwise, and then stirred for 10 hours. 1,4-dioxane was removed using a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol (10 mL) at 40°C, and deionized water was then added dropwise until the mixture became opaque, and then stirred for another 10 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in tetrahydrofuran (THF) (5 mL), reprecipitated in acetone (20 mL), and filtered to obtain the final product 4PAAc-OMe (0.7 g, 62% yield).

[0114] Example 13

[0115] The 4PAAc-OMe prepared in Example 1 is used as the hole transport layer of the perovskite solar cell. The structure of the perovskite solar cell is as follows: Figure 3 As shown, from bottom to top are the transparent conductive layer 1 (ITO glass), the hole transport layer 2 (4PAAc-OMe), the perovskite layer 3, the electron transport layer 4 (PC61BM) and the electrode 5 (Cr / Au). The preparation method of the perovskite solar cell includes the following steps:

[0116] (1) Cleaning of the transparent conductive layer 1: The ITO glass sheet was ultrasonically cleaned with deionized water, acetone, and ethanol for 15 minutes in sequence. The residual solvent on the ITO surface was then blown dry with an N2 air gun. The ITO glass sheet was then treated with oxygen plasma for 10 minutes. The ITO glass sheet was then transferred to a nitrogen glove box.

[0117] (2) Preparation of hole transport layer 2: 15 mg of 4PAAc-OMe was weighed and completely dissolved in 1 mL of chlorobenzene solution. The solution was evenly added dropwise onto the ITO glass substrate and spin-coated at 4000 rpm for 20 seconds, followed by annealing at 110°C for 10 minutes.

[0118] (3) Preparation of perovskite layer 3: The ITO / hole transport layer substrate obtained above was cooled to room temperature, preheated at 130°C for 3 minutes, 50 μL of perovskite solution was taken and spread all over the ITO / hole transport layer substrate, spin-coated at 3000 rpm for 20 seconds, and then annealed at 100°C for 10 minutes to prepare a perovskite layer. The perovskite solution was prepared by mixing 3-fluorobenzylammonium, methylammonium, and lead iodide in a molar ratio of 2.2:3.5:4 in a solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1;

[0119] (4) Preparation of electron transport layer 4: The ITO / hole transport layer / perovskite substrate obtained above was cooled to room temperature, PC61BM was prepared into a 15 mg / mL solution, and then 40 μL of PC61BM solution was taken to cover the ITO / hole transport layer / perovskite substrate and spin-coated at 1000 rpm for 30 seconds;

[0120] (5) Preparation of electrode layer 5: The above substrate is placed in a vacuum evaporation chamber, and Cr (6 nm) and Au (80 nm) are evaporated on the PC61BM layer respectively to obtain a perovskite solar cell.

[0121] Example 14

[0122] The difference from Example 13 is that 4PAAc-SMe is used instead of 4PAAc-OMe, and a perovskite solar cell is finally obtained.

[0123] Comparative Example 1

[0124] The difference from Example 13 is that 2BrDMAcPA prepared in Example 1 of the Chinese patent application with patent application publication number CN116178430A is used to replace 4PAAc-OMe, and finally a perovskite solar cell is obtained.

[0125] The decomposition temperature, HOMO energy level and hole mobility of 4PAAc-OMe prepared in Example 1 and 4PAAc-SMe prepared in Example 2 were tested. The test results are shown in Table 1.

[0126] The perovskite solar cells prepared in Example 13, Example 14 and Comparative Example 1 were tested for photoelectric conversion efficiency, open circuit voltage, short circuit current and fill factor. The test results are shown in Table 2.

[0127] Table 1

[0128]

[0129] Table 2

[0130]

[0131] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0132] This application introduces thiophene-methoxytriphenylamine groups and thiophene-methylthiotriphenylamine groups into acridine phosphate side chains to provide a series of novel hole transport materials. These materials have good solubility in solvents such as dimethyl sulfoxide, N,N'dimethylformamide, toluene, chlorobenzene and dichloromethane. The material has good film-forming properties and has good wettability with perovskite precursor solvents, which helps to improve the crystallinity and film-forming properties of perovskite. In addition, this type of hole transport material has a high decomposition temperature, good thermal stability and high hole mobility, which is conducive to the extraction and transmission of holes. This type of hole transport material has a deep HOMO energy level that matches the perovskite, and it can be used in perovskite solar cells without doping with any additives, so that the perovskite solar cell has higher photoelectric conversion efficiency, photovoltaic performance and stability, and the material is reproducible.

[0133] The above are merely embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A hole transport material, characterized in that The chemical structure of the hole transport material is wherein each A is independently O or S.

2. The hole transport material according to claim 1, characterized in that The decomposition temperature of the hole transport material is 298 to 345° C.; and / or the HOMO energy level of the hole transport material is -5.39 to -5.32 eV; and / or the hole mobility of the hole transport material is 3.67×10 -4 ~6.35×10 -4 cm 2 ·V -1 ·S -1 .

3. A method for preparing a hole transport material according to claim 1 or 2, characterized in that: The preparation method comprises: Step S1, under the protection of inert gas, includes and The raw materials are mixed and subjected to the first substitution reaction to generate Step S2, under the protection of inert gas, includes The raw materials of trimethylsilyl bromide and 1,4-dioxane are mixed and subjected to a first reaction to obtain an intermediate; Step S3, under the protection of inert gas, mixing the raw materials including the intermediate, methanol and water and performing a second reaction to obtain wherein each A is independently O or S.

4. The preparation method according to claim 3, characterized in that The raw materials in step S1 further include tetrakis(triphenylphosphine)palladium, potassium carbonate, toluene, ethanol and water; and / or, described The molar ratio of the potassium carbonate to the tetrakis(triphenylphosphine)palladium is 1:2.2-2.5:4-6:0.05-0.1; and / or the temperature of the first substitution reaction is 85-90° C.; and / or the time of the first substitution reaction is 6-12 hours.

5. The preparation method according to claim 3, characterized in that The temperature of the first reaction is 25 to 30°C; and / or, the time of the first reaction is 12 to 16 hours; and / or, the temperature of the second reaction is 25 to 30°C; and / or, the time of the second reaction is 12 to 16 hours; and / or, The molar ratio of the trimethylsilyl bromide to the trimethylsilyl bromide is 1:10-20.

6. The preparation method according to any one of claims 3 to 5, characterized in that described The preparation method comprises: Step S11 includes After mixing with the raw material of N-bromosuccinimide, bromination reaction is carried out to obtain Step S12 includes the The raw materials of tetrabutylammonium bromide, dibromobutane and potassium hydroxide are mixed and subjected to a second substitution reaction to obtain Step S13 includes the After mixing with the raw material of triethyl phosphite, a third substitution reaction is carried out to obtain the 7. The preparation method according to claim 6, characterized in that The raw materials in step S11 also include tetrahydrofuran, The molar ratio of the bromination reaction to the N-bromosuccinimide is 1:2.5-3; and / or the temperature of the bromination reaction is 0-5° C.; and / or the time of the bromination reaction is 12-18 hours; And / or, in step S12, the The molar ratio of the tetrabutylammonium bromide to the potassium hydroxide is 1:0.1-0.2:7-10; and / or the temperature of the second substitution reaction is 65-85° C.; and / or the time of the second substitution reaction is 12-24 hours; And / or, in step S13, the The molar ratio of the triethyl phosphite to the triethyl phosphite is 1:25-50; and / or the temperature of the third substitution reaction is 140-150° C.; and / or the time of the third substitution reaction is 12-24 hours.

8. A perovskite solar cell comprising a transparent conductive layer, a hole transport layer, a perovskite layer, an electron transport layer and an electrode layer, characterized in that: The hole transport layer is composed of the hole transport material according to claim 1 or 2.

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