Hole transport layer, preparation method and application thereof, perovskite cell and preparation method thereof

Abstract

The invention provides a hole transport layer, a preparation method and application of the hole transport layer, a perovskite battery and a preparation method of the perovskite battery, and belongs to the technical field of perovskite batteries. The precursor solution is prepared by adopting the triethylene glycol-containing solvent, the competitive adsorption of the solvent and the self-assembled monomolecules can be reduced, the anchoring efficiency of the self-assembled monomolecules and the substrate can be enhanced, meanwhile, the precursor solution is molded to obtain a wet film, the wet film is washed or not washed with ethanol, and then the hole transport layer is prepared through natural volatilization drying or flash evaporation drying. The solvent can be effectively removed, the compact hole transport layer is prepared, the hole transport efficiency of the hole transport layer is improved, and the device performance is improved.

Description

Technical Field

[0001] This application relates to the field of perovskite solar cell technology, and in particular to a hole transport layer, its preparation method and application, and a perovskite solar cell and its preparation method. Background Technology

[0002] Perovskite solar cells (PSCs) have become a hot research topic in next-generation photovoltaic technology due to their high photoelectric conversion efficiency, low cost, and solution-processability.

[0003] In perovskite solar cells, the hole transport layer typically uses a precursor solution of SAM (self-assembled monolayer) molecules as the precursor solution. The solvent used in the precursor solution significantly impacts the performance of the hole transport layer. However, current solvents used in SAM precursor solutions suffer from drawbacks such as high volatility, high polarity, or competitive adsorption with SAM molecules. High solvent volatility limits the self-assembly time of SAM molecules in solution, affecting the quality of the hole transport layer. High solvent polarity leads to stronger intermolecular forces, increasing the risk of SAM molecule aggregation and reducing the stability and uniformity of the hole transport layer. Competitive adsorption between the solvent and SAM molecules reduces the density of the hole transport layer, even causing porosity and limiting its application performance. Furthermore, the method of solvent removal after coating with the SAM precursor solution also significantly affects the quality of the hole transport layer. Summary of the Invention

[0004] Based on this, the main objective of this application is to provide a hole transport layer and its preparation method and application, as well as a perovskite solar cell and its preparation method, to improve the density and hole transport efficiency of the hole transport layer.

[0005] The first aspect of this application provides a method for preparing a hole transport layer, comprising the following steps:

[0006] A hole transport layer precursor solution was prepared by mixing self-assembled monomolecules with a solvent.

[0007] A wet film was prepared using the hole transport layer precursor solution;

[0008] The wet film is dried, with or without post-treatment, to prepare the hole transport layer;

[0009] The mixed solvent includes triethylene glycol;

[0010] The post-treatment includes washing with one or more of ethanol, isopropanol, N,N-dimethylformamide and N-methylpyrrolidone;

[0011] The drying process includes either natural evaporation or flash drying.

[0012] In some embodiments, the solvent further includes a low-boiling-point solvent; the low-boiling-point solvent includes one or more of methanol, ethanol, isopropanol, and ethylene glycol butyl ether.

[0013] In some embodiments, the volume ratio of the triethylene glycol to the low-boiling solvent is 2-6:4-8.

[0014] In some embodiments, the concentration of the hole transport layer precursor solution is 0.1-1.0 mg / mL.

[0015] In some embodiments, the self-assembled monomolecule includes phosphate-based self-assembled monomolecules.

[0016] In some embodiments, the flash drying conditions include: a pressure of 0.01-2 Pa; a temperature of 0-50 °C; and a time of 1-10 min.

[0017] In a second aspect of this application, a hole transport layer prepared by the method described in the first aspect is provided.

[0018] The third aspect of this application provides the application of a hole transport layer prepared by the method described in the first aspect or the hole transport layer described in the second aspect in a perovskite solar cell.

[0019] In a fourth aspect of this application, a perovskite solar cell is provided, comprising a conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a barrier layer, and an electrode layer stacked sequentially.

[0020] The hole transport layer is either the hole transport layer prepared by the method described in the first aspect or the hole transport layer described in the second aspect.

[0021] The fifth aspect of this application provides a method for preparing the perovskite solar cell described in the fourth aspect, comprising the following steps:

[0022] A wet film is prepared by coating the hole transport layer precursor solution described in the first aspect onto a conductive substrate; the wet film is then dried, with or without post-treatment, to prepare the hole transport layer.

[0023] After coating the hole transport layer with a perovskite precursor solution, the perovskite layer is prepared by annealing.

[0024] An electron transport layer, a barrier layer, and an electrode layer are sequentially fabricated on the perovskite layer to prepare the perovskite solar cell.

[0025] Compared with traditional technologies, this application has at least the following beneficial effects:

[0026] This application uses a solvent containing triethylene glycol to prepare a precursor solution, which can reduce the competitive adsorption between the solvent and the self-assembled monomolecules and enhance the anchoring efficiency of the self-assembled monomolecules to the substrate. At the same time, the precursor solution is shaped into a wet film and washed with or without ethanol, and then naturally evaporated or flash dried to prepare a hole transport layer. This can effectively remove the solvent, prepare a dense hole transport layer, and improve the hole transport efficiency of the hole transport layer. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments and examples. These embodiments and examples are only for illustrating the present application and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the disclosure of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or alterations without departing from the spirit of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. In addition, numerous specific details are set forth in the following description to provide a fuller understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] To address the issues of high volatility, high polarity, or competitive adsorption between solvents used in current SAM molecule precursor solutions and SAM molecules, this application employs a solvent containing triethylene glycol to prepare the precursor solution. This reduces the competitive adsorption between the solvent and the self-assembled monomolecules, enhancing the anchoring efficiency between the self-assembled monomolecules and the substrate. Furthermore, by forming a wet film from the precursor solution and washing it with or without ethanol, followed by natural evaporation or flash drying to prepare the hole transport layer, effective solvent removal is achieved, resulting in a dense hole transport layer. This improves the hole transport efficiency of the hole transport layer and enhances device performance.

[0030] The first aspect of this application provides a method for preparing a hole transport layer, comprising the following steps:

[0031] A hole transport layer precursor solution was prepared by mixing self-assembled monomolecules with a solvent.

[0032] A wet film was prepared using the hole transport layer precursor solution;

[0033] The wet film is dried, with or without post-treatment, to prepare the hole transport layer;

[0034] The solvent includes triethylene glycol;

[0035] The post-treatment includes washing with one or more of ethanol, isopropanol, N,N-dimethylformamide (DMF), and N-methylpyrrolidone (NMP);

[0036] The drying process includes either natural evaporation or flash drying.

[0037] This application uses a solvent containing triethylene glycol to prepare the precursor solution, which reduces the competitive adsorption between the solvent and the self-assembled monomolecules, enhancing the anchoring efficiency between the self-assembled monomolecules and the substrate. Simultaneously, the precursor solution is molded into a wet film, which is washed with or without ethanol, and then naturally evaporated or flash-dried to prepare the hole transport layer. This effectively removes the solvent, resulting in a dense hole transport layer and improving its hole transport efficiency. In this application, the hole transport layer is not annealed separately; instead, it is annealed together with the perovskite layer, which significantly improves the photoelectric conversion efficiency of the perovskite solar cell and enhances device performance.

[0038] In some embodiments, the solvent further includes a low-boiling-point solvent; the low-boiling-point solvent includes one or more of methanol, ethanol, isopropanol, and ethylene glycol butyl ether.

[0039] In some embodiments, the volume ratio of the triethylene glycol to the low-boiling solvent is 2-6:4-8, which can be 2:8, 3:7, 4:6, 5:5, or 6:4.

[0040] In some embodiments, the low-boiling-point solvent is methanol, and the volume ratio of triethylene glycol to methanol is 2-6:4-8, which can be 2:8, 3:7, 4:6, 5:5, or 6:4.

[0041] In some embodiments, the concentration of the hole transport layer precursor solution is 0.1-1.0 mg / mL, and can be 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 or 1.0 mg / mL.

[0042] In some embodiments, the self-assembled monomolecule includes phosphate-based self-assembled monomolecules.

[0043] In some embodiments, the phosphate self-assembled monomers include one or more of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4pacz), [2-(3,6-diphenyl-9H-carbazole-9-yl)ethyl]phosphonic acid (Me-2pacz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), and [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz).

[0044] In some embodiments, the flash drying conditions include: a pressure of 0.01-2 Pa, which can be 0.01 Pa, 0.02 Pa, 0.03 Pa, 0.04 Pa, 0.05 Pa, 0.08 Pa, 0.1 Pa, 0.2 Pa, 0.5 Pa, 0.8 Pa, 1 Pa, 1.2 Pa, 1.5 Pa, 1.8 Pa, or 2 Pa; a temperature of 0-50°C, which can be 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, or 50°C; and a time of 1-10 min, which can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min.

[0045] In some embodiments, the coating conditions include: a coating gap of 20-220 μm, which can be 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm or 220 μm; and a coating speed of 3-30 mm / s, which can be 3 mm / s, 5 mm / s, 8 mm / s, 10 mm / s, 15 mm / s, 20 mm / s, 25 mm / s or 30 mm / s.

[0046] In some embodiments, the step of preparing a wet film using the hole transport layer precursor solution includes: coating or inkjet printing the hole transport layer precursor solution to prepare a wet film; the coating includes blade coating or spin coating.

[0047] In some embodiments, the method for preparing the hole transport layer includes the following steps:

[0048] A hole transport layer precursor solution was prepared by mixing self-assembled monomolecules with a solvent.

[0049] A wet film was prepared using the hole transport layer precursor solution;

[0050] The wet film is post-treated and then dried to prepare a hole transport layer;

[0051] The solvent is triethylene glycol;

[0052] The post-processing includes washing with ethanol;

[0053] The drying process includes natural evaporation.

[0054] In some embodiments, the method for preparing the hole transport layer includes the following steps:

[0055] A hole transport layer precursor solution was prepared by mixing self-assembled monomolecules with a solvent.

[0056] A wet film was prepared using the hole transport layer precursor solution;

[0057] The wet film is dried, with or without post-treatment, to prepare a hole transport layer;

[0058] The solvents include triethylene glycol and low-boiling-point solvents;

[0059] The post-processing includes washing with ethanol;

[0060] The drying process includes either natural evaporation or flash drying.

[0061] In some embodiments, the step of washing with ethanol includes: immersing the wet film in ethanol for washing; or rinsing the wet film with ethanol.

[0062] In some embodiments, the step of washing with ethanol includes: immersing the wet film in ethanol and stirring for 10-20 seconds; or rinsing the wet film with ethanol, wherein the rinsing flow rate is controlled within 2 mL / s and the rinsing time is 10-30 seconds.

[0063] In some embodiments, the conditions for natural drying include: placing the wet film in the air for 1 minute to allow it to dry naturally.

[0064] In a second aspect of this application, a hole transport layer prepared by the method described in the first aspect is provided.

[0065] The third aspect of this application provides the application of a hole transport layer prepared by the method described in the first aspect or the hole transport layer described in the second aspect in a perovskite solar cell.

[0066] In a fourth aspect of this application, a perovskite solar cell is provided, comprising a conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a barrier layer, and an electrode layer stacked sequentially.

[0067] The hole transport layer is either the hole transport layer prepared by the method described in the first aspect or the hole transport layer described in the second aspect.

[0068] In some embodiments, the conductive substrate comprises a metal oxide.

[0069] In some embodiments, the electron transport layer includes C60.

[0070] In some embodiments, the barrier layer comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0071] In some embodiments, the electrode layer comprises Ag or Cu.

[0072] The fifth aspect of this application provides a method for preparing the perovskite solar cell described in the fourth aspect, comprising the following steps:

[0073] A wet film is prepared by coating a hole transport layer precursor solution as described in the first aspect onto a conductive substrate; the wet film is then dried, with or without post-treatment, to prepare the hole transport layer.

[0074] After coating the hole transport layer with a perovskite precursor solution, the perovskite layer is prepared by annealing.

[0075] An electron transport layer, a barrier layer, and an electrode layer are sequentially fabricated on the perovskite layer to prepare the perovskite solar cell.

[0076] In some embodiments, the annealing conditions include: using an inert gas atmosphere; the inert gas including nitrogen; a temperature of 100-150°C, which can be 100°C, 110°C, 120°C, 130°C, 140°C or 150°C; and a time of 10-30 min, which can be 10 min, 15 min, 20 min, 25 min or 30 min.

[0077] After preparing the hole transport layer, this application coats the hole transport layer with a perovskite precursor solution and then performs annealing to achieve co-annealing of the perovskite layer and the hole transport layer, which can significantly improve the photoelectric conversion efficiency of the perovskite solar cell and enhance device performance.

[0078] The embodiments of this application will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of this application. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this application, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0079] Example 1

[0080] The fabrication method of perovskite solar cells is as follows:

[0081] (1) Preparation of hole transport layer:

[0082] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with triethylene glycol;

[0083] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 10 mm / s coating speed, and 300 μL injection volume to prepare a wet film.

[0084] The wet film was placed in air for 30 min, then washed with 60 mL of alcohol (75% volume fraction of ethanol solution), and then allowed to air dry naturally at 23°C for 1 min to prepare a hole transport layer (thickness of 1.5 nm).

[0085] (2) Preparation of perovskite layer:

[0086] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0087] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0088] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0089] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0090] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0091] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0092] Example 2

[0093] The fabrication method of perovskite solar cells is as follows:

[0094] (1) Preparation of hole transport layer:

[0095] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with triethylene glycol and methanol in a volume ratio of 1:9 as solvents.

[0096] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 20 mm / s coating speed, and 34 μL injection volume to prepare a wet film.

[0097] The wet film was left to air dry naturally for 1 minute (23°C) to prepare a hole transport layer (1.5 nm thick).

[0098] (2) Preparation of perovskite layer:

[0099] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0100] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0101] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0102] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0103] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0104] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0105] Example 3

[0106] The fabrication method of perovskite solar cells is as follows:

[0107] (1) Preparation of hole transport layer:

[0108] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with a solvent in a volume ratio of 1:1 of triethylene glycol and methanol.

[0109] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 4 mm / s coating speed and 34 μL injection volume to prepare a wet film.

[0110] The wet film was placed in a flash drying device for flash drying at a pressure of 2 Pa, a temperature of 23 °C, and a time of 5 min to prepare a hole transport layer (thickness of 1.5 nm).

[0111] (2) Preparation of perovskite layer:

[0112] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0113] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0114] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0115] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0116] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0117] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0118] Example 4

[0119] The fabrication method of perovskite solar cells is as follows:

[0120] (1) Preparation of hole transport layer:

[0121] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with a solvent using triethylene glycol and methanol in a volume ratio of 2:8.

[0122] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 20 mm / s coating speed, and 34 μL injection volume to prepare a wet film.

[0123] The wet film was placed in a flash drying device for flash drying at a pressure of 2 Pa, a temperature of 23 °C, and a time of 5 min to prepare a hole transport layer (thickness of 1.5 nm).

[0124] (2) Preparation of perovskite layer:

[0125] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0126] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0127] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0128] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0129] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0130] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0131] Example 5

[0132] The fabrication method of perovskite solar cells is as follows:

[0133] (1) Preparation of hole transport layer:

[0134] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with a solvent in a volume ratio of 4:6 of triethylene glycol and methanol.

[0135] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 20 mm / s coating speed, and 34 μL injection volume to prepare a wet film.

[0136] The wet film was placed in a flash drying device for flash drying at a pressure of 2 Pa, a temperature of 23 °C, and a time of 5 min to prepare a hole transport layer (thickness of 1.5 nm).

[0137] (2) Preparation of perovskite layer:

[0138] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0139] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0140] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0141] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0142] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0143] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0144] Example 6

[0145] The fabrication method of perovskite solar cells is as follows:

[0146] (1) Preparation of hole transport layer:

[0147] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with a solvent in a volume ratio of 6:4 of triethylene glycol and methanol.

[0148] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 20 mm / s coating speed, and 50 μL injection volume to prepare a wet film.

[0149] The wet film was placed in a flash drying device for flash drying at a pressure of 2 Pa, a temperature of 23 °C, and a time of 5 min. After flash drying, it was rinsed with 60 mL of anhydrous ethanol and left to air dry naturally for 1 min (23 °C) to prepare a hole transport layer (thickness of 1.5 nm).

[0150] (2) Preparation of perovskite layer:

[0151] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0152] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0153] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0154] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0155] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0156] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0157] Comparative Example 1

[0158] The preparation methods of Comparative Example 1 and Example 2 are basically the same, except that methanol is used as a solvent to prepare a 0.3 mg / mL hole transport layer precursor solution by mixing Me-4pacz with the solvent.

[0159] Hole transport layer and perovskite solar cell were prepared according to the method in Example 2.

[0160] Comparative Example 2

[0161] The preparation methods of Comparative Example 2 and Example 2 are basically the same, except that ethanol is used as a solvent to prepare a 0.3 mg / mL hole transport layer precursor solution by mixing Me-4pacz with the solvent.

[0162] Hole transport layer and perovskite solar cell were prepared according to the method in Example 2.

[0163] Comparative Example 3

[0164] The preparation methods of Comparative Example 3 and Example 2 are basically the same, except that: hexane and methanol with a volume ratio of 1:1 are used as solvents to prepare a 0.3 mg / mL hole transport layer precursor solution by mixing Me-4pacz with the solvent.

[0165] Hole transport layer and perovskite solar cell were prepared according to the method in Example 2.

[0166] Comparative Example 4

[0167] The preparation methods of Comparative Example 4 and Example 6 are basically the same, except that: after flash drying, the hole transport layer is prepared by annealing at 100°C for 5 minutes on a hot table.

[0168] Perovskite solar cells were prepared according to the method in Example 6.

[0169] Specifically, the fabrication method of perovskite solar cells is as follows:

[0170] (1) Preparation of hole transport layer:

[0171] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with a solvent in a volume ratio of 6:4 of triethylene glycol and methanol.

[0172] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 20 mm / s coating speed, and 50 μL injection volume to prepare a wet film.

[0173] The wet film was placed in a flash drying apparatus for flash drying at a pressure of 2 Pa, a temperature of 23 °C, and a time of 5 min. After flash drying, it was placed on a hot table for annealing at 100 °C for 5 min to prepare a hole transport layer (thickness of 1.5 nm).

[0174] (2) Preparation of perovskite layer:

[0175] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0176] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0177] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0178] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0179] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0180] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0181] Comparative Example 5

[0182] The preparation method of Comparative Example 5 is basically the same as that of Example 1, except that the wet film is annealed at 100°C for 10 minutes on a hot table to prepare the hole transport layer.

[0183] Perovskite solar cells were prepared according to the method in Example 1.

[0184] Specifically, the fabrication method of perovskite solar cells is as follows:

[0185] (1) Preparation of hole transport layer:

[0186] A 0.3 mg / mL hole transport layer precursor solution was prepared by mixing Me-4pacz with triethylene glycol;

[0187] The hole transport layer precursor solution was coated onto a conductive substrate (composition: the lower layer is a float glass substrate, and the upper layer is a fluorine-doped tin oxide transparent conductive layer). The coating parameters were set as follows: 80 μm coating gap, 10 mm / s coating speed, and 300 μL injection volume to prepare a wet film.

[0188] The wet film was annealed at 100°C for 10 minutes on a hot stage to prepare a hole transport layer (1.5 nm thick).

[0189] (2) Preparation of perovskite layer:

[0190] Using Cs 0.05 MA 0.95 PbI3 solution (solvent: NMP and DMF in a volume ratio of 1:9) was used as the perovskite precursor solution;

[0191] A perovskite precursor solution was coated onto the hole transport layer, and then annealed at 100°C for 30 min under nitrogen protection to prepare a perovskite layer (thickness 550 nm, band gap 1.5 eV).

[0192] (3) The electron transport layer, the barrier layer, and the electrode layer are prepared sequentially:

[0193] An electron transport layer (25 nm thick) was prepared on the perovskite layer by C60 vapor deposition.

[0194] A barrier layer (8 nm thick) was fabricated on the electron transport layer using BCP.

[0195] Perovskite solar cells were fabricated by using Cu to prepare an electrode layer (100 nm thick) on a barrier layer.

[0196] Experimental Example 1

[0197] The short-circuit current density (Jsc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) of the perovskite solar cells prepared in Examples 1-6 and Comparative Examples 1-5 were tested.

[0198] Test method:

[0199] Large-area IV testing was conducted, with the following standards: Illumination conditions: AM1.5G spectrum was used, with a light intensity of 100mW / cm², calibrated with a standard silicon cell, and the deviation did not exceed ±2%. Environmental conditions: The device was tested at 25±2℃, with a relative humidity not exceeding 50%.

[0200] The results are shown in Table 1.

[0201] Table 1. Performance of perovskite solar cells prepared in Examples 1-6 and Comparative Examples 1-5

[0202]

[0203] The results in Table 1 show that:

[0204] Compared to Comparative Examples 1-5, the photoelectric conversion efficiency of Examples 1-6 increased to 20.95-21.31%. This indicates that using a solvent containing triethylene glycol to prepare the hole transport layer precursor solution can reduce the competitive adsorption between the solvent and the self-assembled monomolecules, and enhance the anchoring efficiency between the self-assembled monomolecules and the substrate. At the same time, washing the wet film obtained by molding the precursor solution with or without ethanol, and then subjecting it to natural evaporation or flash drying to prepare the hole transport layer, can significantly improve the compactness of the hole transport layer and improve the hole transport efficiency of the perovskite solar cell.

[0205] Compared to Comparative Example 1, which used only methanol as the solvent for the hole transport layer precursor solution, Example 2 used a 1:9 volume ratio of triethylene glycol and methanol as the solvent for the hole transport layer precursor solution. The photoelectric conversion efficiency of the prepared perovskite solar cell increased from 20.1% to 20.95%. This indicates that, compared to using only methanol, using triethylene glycol and methanol as the solvent for the hole transport layer precursor solution in this application can significantly improve the hole transport efficiency of the perovskite solar cell.

[0206] Compared to Comparative Example 2, which used ethanol as the solvent for the hole transport layer precursor solution, Example 2 used a 1:9 volume ratio of triethylene glycol and methanol as the solvent for the hole transport layer precursor solution. The photoelectric conversion efficiency of the prepared perovskite solar cell increased from 19.97% to 20.95%. This indicates that, compared to using only ethanol, this application uses triethylene glycol and methanol as the solvent for the hole transport layer precursor solution. Triethylene glycol, as a harmonizing solvent, can prevent SAM molecule aggregation by improving polarity, prolong the self-assembly time in solution, and reduce competitive adsorption effects, thus significantly improving the hole transport efficiency of the perovskite solar cell.

[0207] Compared to Comparative Example 3, which used a 1:1 volume ratio of hexane and methanol as the solvent for the hole transport layer precursor solution, Example 2 used a 1:9 volume ratio of triethylene glycol and methanol as the solvent for the hole transport layer precursor solution. The photoelectric conversion efficiency of the prepared perovskite solar cell increased from 19.97% to 20.95%. This indicates that, compared to using a 1:1 volume ratio of hexane and methanol, using a 1:9 volume ratio of triethylene glycol and methanol as the solvent for the hole transport layer precursor solution in this application can significantly improve the hole transport efficiency of the perovskite solar cell.

[0208] Triethylene glycol has a boiling point of 288.0℃. As the proportion of triethylene glycol in the hole transport layer precursor solution increases, neither natural evaporation nor flash drying can effectively remove the solvent in a short time. Solvent residue affects the fabrication quality and performance of the perovskite solar cell. Therefore, post-treatment with one or more solvents selected from ethanol, isopropanol, N,N-dimethylformamide, and N-methylpyrrolidone is necessary before drying to remove the solvent, or annealing can be used to remove the solvent. Compared to Comparative Example 4, which used flash drying and annealing, Example 6, which used flash drying, ethanol rinsing, and natural evaporation, increased the photoelectric conversion efficiency of the prepared perovskite solar cell from 20.12% to 21.21%. This indicates that annealing has a significant impact on device efficiency, and compared to annealing, ethanol rinsing and drying can significantly improve the hole transport efficiency of the perovskite solar cell.

[0209] Compared to Comparative Example 5, which used a hot-plate annealing process at 100°C for 5 minutes to prepare the wet film, Example 1, which used alcohol washing and natural air drying, resulted in an increase in the photoelectric conversion efficiency of the prepared perovskite solar cell from 20.36% to 21.31%. This indicates that, compared to a two-step annealing process involving annealing to prepare the hole transport layer and simultaneously annealing to prepare the perovskite layer, this application's method of post-treatment with alcohol washing followed by natural drying, and subsequent co-annealing with the perovskite layer, can significantly improve the hole transport efficiency of the perovskite solar cell.

[0210] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0211] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a hole transport layer, characterized in that, Includes the following steps: A hole transport layer precursor solution was prepared by mixing self-assembled monomolecules with a solvent. A wet film was prepared using the hole transport layer precursor solution; The wet film is dried, with or without post-treatment, to prepare the hole transport layer; The solvent includes triethylene glycol; The post-treatment includes washing with one or more of ethanol, isopropanol, N,N-dimethylformamide and N-methylpyrrolidone; The drying process includes either natural evaporation or flash drying.

2. The method for preparing a hole transport layer according to claim 1, characterized in that, The solvent also includes low-boiling-point solvents; The low-boiling-point solvent includes one or more of methanol, ethanol, isopropanol, and ethylene glycol butyl ether.

3. The method for preparing a hole transport layer according to claim 2, characterized in that, The volume ratio of the triethylene glycol to the low-boiling solvent is 2-6:4-8.

4. The method for preparing the hole transport layer according to claim 1 or 2, characterized in that, The concentration of the hole transport layer precursor solution is 0.1-1.0 mg / mL.

5. The method for preparing a hole transport layer according to claim 1 or 2, characterized in that, The self-assembled monomolecules include phosphate-based self-assembled monomolecules.

6. The method for preparing a hole transport layer according to claim 1, characterized in that, The conditions for flash drying include: pressure of 0.01-2 Pa; temperature of 0-50℃; and time of 1-10 min.

7. A hole transport layer prepared by the method for preparing a hole transport layer according to any one of claims 1-6.

8. The application of a hole transport layer prepared by the method of any one of claims 1-6 or the hole transport layer of claim 7 in a perovskite solar cell.

9. A perovskite battery, characterized in that, It includes a conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer, a barrier layer, and an electrode layer stacked sequentially. The hole transport layer is a hole transport layer prepared by the method of any one of claims 1-6 or the hole transport layer of claim 7.

10. The method for preparing a perovskite solar cell as described in claim 9, characterized in that, Includes the following steps: A wet film is prepared by coating the hole transport layer precursor solution according to any one of claims 1-6 onto a conductive substrate; the wet film is then dried, with or without post-treatment, to prepare the hole transport layer. After coating the hole transport layer with a perovskite precursor solution, the perovskite layer is prepared by annealing. An electron transport layer, a barrier layer, and an electrode layer are sequentially fabricated on the perovskite layer to prepare the perovskite solar cell.

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