A hole transport layer and a preparation method of a perovskite solar cell

Abstract

The application belongs to the technical field of perovskite solar cells, and relates to a hole transport layer and a preparation method of a perovskite solar cell. The preparation method of the hole transport layer comprises the following steps: a nickel salt is added to an organic solvent, a ligand is added drop by drop while stirring, a thermal decomposition type additive is further added, the mixed solution is filtered to obtain a nickel oxide precursor filtrate, the obtained nickel oxide precursor filtrate is coated on the surface of a substrate with a prepared conductive layer, pre-annealing treatment is performed on the obtained nickel oxide wet film, high-temperature annealing treatment is performed on the nickel oxide film after the pre-annealing treatment at a temperature of 280-350 DEG C for 30-60 min, and a nickel oxide film with a porous structure is obtained, which is the required hole transport layer. In the application, the thermal decomposition type additive is added to the nickel oxide precursor solution, the nickel oxide film is obtained through coating and annealing, the additive is completely decomposed into gas in the annealing process, the porous structure of the nickel oxide film is promoted, and therefore the photoelectric conversion efficiency of the perovskite solar cell is improved.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, and specifically relates to a hole transport layer and a method for preparing perovskite solar cells. Background Technology

[0002] Nickel oxide (NiO) x Nickel oxide (NiO) is a wide-bandgap p-type semiconductor with a bandgap of approximately 3.6 eV, giving it excellent electrical properties in optoelectronic and electronic devices, making it particularly suitable for low-power, high-stability devices such as transparent thin-film transistors (TFTs). Nickel oxide is widely used as a hole transport layer material in perovskite solar cells and is the preferred material for the industrialization of perovskite solar cells. However, undoped nickel oxide films typically have low intrinsic conductivity, around 10⁻⁶ eV. -5 ~10 -4 The S / cm scale limitation greatly restricts its application in solar cells.

[0003] To address the low electrical conductivity of nickel oxide thin films, existing technologies fall into two categories: chemical doping, which enhances the conductivity of nickel oxide films by incorporating certain metal or non-metal elements, essentially introducing additional charge carriers to alter their conductive behavior; and fabrication processes, which obtain high-quality nickel oxide films through high-temperature sintering to achieve cubic nickel oxide with higher conductivity. The conductivity can also be adjusted by modifying the film's thickness, surface roughness, and microstructure (such as porosity and grain size). For undoped nickel oxide films, the low conductivity necessitates high quality requirements (such as thickness, roughness, and crystallinity) for applications in solar cells, especially for large-area nickel oxide films with poor uniformity, where film thickness is highly sensitive.

[0004] Therefore, the poor conductivity and uniformity of existing nickel oxide films lead to thickness sensitivity issues. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hole transport layer and a method for preparing a perovskite solar cell. A thermally decomposable additive is introduced into a nickel oxide precursor solution. During the annealing process, the thermally decomposable additive is completely decomposed into gas, which promotes the formation of a porous structure in the nickel oxide film. This porous structure can shorten the carrier transport distance and enhance the ability of nickel oxide to extract carriers, thereby making carrier transport insensitive to the thickness of the nickel oxide film, thus improving the photoelectric conversion efficiency of the perovskite solar cell.

[0006] This invention is achieved by providing a method for preparing a hole transport layer, comprising the following steps: Step 1: Prepare nickel oxide precursor solution. Add nickel salt to organic solvent and stir thoroughly for 0.5-2 hours. While stirring, add ligand dropwise and continue stirring for 2-10 hours. Then add thermally decomposable additive and stir thoroughly for 2-24 hours. Filter the mixed solution using a 0.22μm PTFE organic filter to obtain nickel oxide precursor filtrate. Step 2: Coat the obtained nickel oxide precursor filtrate onto the substrate surface of the prepared conductive layer, and pre-anneal the obtained nickel oxide wet film at 100~120℃ for 2~10 min. Step 3: The pre-annealed nickel oxide film is subjected to high-temperature annealing at 280~350℃ for 30~60 minutes to obtain a nickel oxide film with a porous structure, which is the desired hole transport layer; wherein, In step one, the nickel salt is at least one selected from nickel nitrate, nickel acetate, nickel carbonate, nickel chloride, and nickel acetylacetone, and the concentration of the nickel salt is 0.05~2 mol / L; the organic solvent is at least one selected from ethanol, ethylene glycol, ethylene glycol monomethyl ether, glycerol, methanol, and isopropanol; the ligand is at least one selected from ethylamine, ethylenediamine, triethylamine, ethanolamine, triethanolamine, urea, and ammonia water, and the concentration of the ligand is 0.5~2 mol / L; the thermally decomposable additive is at least one selected from ammonium bicarbonate, ammonium chloride, ammonium acetate, ammonium carbonate, ammonium bromide, ammonium iodide, and ammonium thiocyanate, and the concentration of the thermally decomposable additive is 0.001~0.05 mol / L.

[0007] This invention is implemented as follows, and also provides a method for fabricating a perovskite solar cell, comprising the following steps: Step 1: Using the hole transport layer preparation method described above, a hole transport layer is prepared on the substrate surface of the prepared conductive layer; Step 2: Prepare a perovskite wet film on the hole transport layer by spin coating in one step, and then anneal it to obtain a perovskite thin film layer; Step 3: Prepare an electron transport layer on the perovskite thin film; Step 4: Fabricate the back electrode on the electron transport layer to complete the fabrication of the perovskite solar cell.

[0008] Compared with the prior art, the hole transport layer and the fabrication method of the perovskite solar cell of the present invention have the following characteristics: (1) A thermally decomposable additive is introduced into the nickel oxide precursor solution to promote the formation of a porous structure in the nickel oxide film during the preparation process. The thermally decomposable additive can be completely decomposed into gas without any residue and will not affect the performance of the nickel oxide film.

[0009] (2) As a hole transport layer in perovskite solar cells, this porous structure increases the contact area between the nickel oxide film and the perovskite film layer and shortens the distance from the perovskite film layer to the electrode, which is beneficial to improving the performance of porous nickel oxide film in carrier extraction and transport, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0010] (3) The enhanced carrier extraction and transport performance due to the porous structure can effectively reduce the film thickness sensitivity problem caused by the poor uniformity of large-area nickel oxide films, increase the short-circuit current density and fill factor, and improve the photoelectric conversion efficiency of large-area perovskite solar cells. Attached Figure Description

[0011] Figure 1 This is a schematic diagram comparing the JV performance curves of the perovskite solar cells prepared in Examples 1-5 and Comparative Example 1 of the present invention. Detailed Implementation

[0012] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0013] A preferred embodiment of the method for preparing the hole transport layer of the present invention includes the following steps: Step 1: Prepare nickel oxide precursor solution. Add nickel salt to organic solvent and stir thoroughly for 0.5-2 hours. While stirring, add ligand dropwise and continue stirring for 2-10 hours. Then add thermally decomposable additive and stir thoroughly for 2-24 hours. Filter the mixed solution using a 0.22μm PTFE organic filter to obtain nickel oxide precursor filtrate.

[0014] Step 2: Coat the obtained nickel oxide precursor filtrate onto the substrate surface of the prepared conductive layer, and pre-anneal the obtained nickel oxide wet film at 100~120℃ for 2~10 min.

[0015] Step 3: Perform high-temperature annealing treatment on the pre-annealed nickel oxide film at 280~350℃ for 30~60 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer.

[0016] In step one, the nickel salt is at least one selected from nickel nitrate, nickel acetate, nickel carbonate, nickel chloride, and nickel acetylacetone, and the concentration of the nickel salt is 0.05~2 mol / L; the organic solvent is at least one selected from ethanol, ethylene glycol, ethylene glycol monomethyl ether, glycerol, methanol, and isopropanol; the ligand is at least one selected from ethylamine, ethylenediamine, triethylamine, ethanolamine, triethanolamine, urea, and ammonia water, and the concentration of the ligand is 0.5~2 mol / L; the thermally decomposable additive is at least one selected from ammonium bicarbonate, ammonium chloride, ammonium acetate, ammonium carbonate, ammonium bromide, ammonium iodide, and ammonium thiocyanate, and the concentration of the thermally decomposable additive is 0.001~0.05 mol / L.

[0017] This invention introduces a thermally decomposable additive into a nickel oxide precursor solution. This additive exhibits thermal decomposition properties and can completely decompose upon heating, with all decomposition products being gases. On one hand, the thermal decomposability of this additive ensures complete decomposition without residue during nickel oxide film preparation, thus not affecting the properties of nickel oxide itself. On the other hand, the gaseous nature of its decomposition products facilitates the formation of numerous porous structures in the nickel oxide film during annealing, resulting in a porous nickel oxide film. This porous nickel oxide film not only retains the photoelectric properties of nickel oxide itself but also enhances carrier extraction and transport performance, making the film thickness insensitive for large-area nickel oxide films. This increases short-circuit current density and fill factor, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0018] This invention also discloses a method for preparing a perovskite solar cell, comprising the following steps: Step 1: Using the hole transport layer preparation method described above, a hole transport layer is prepared on the substrate surface of the prepared conductive layer.

[0019] Step 2: Prepare a perovskite wet film on the hole transport layer by spin coating in one step, and then anneal it to obtain a perovskite thin film layer.

[0020] Step 3: Prepare an electron transport layer with a thickness of 20~50nm on the perovskite thin film.

[0021] Step 4: Fabricate the back electrode on the electron transport layer to complete the fabrication of the perovskite solar cell.

[0022] The following specific embodiments further illustrate the hole transport layer of the present invention and the fabrication method of the perovskite solar cell.

[0023] Example 1

[0024] The first embodiment of the hole transport layer and the method for fabricating perovskite solar cells of the present invention includes the following steps: Step 11: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0025] Step 12, Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 39.5 mg of 0.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use.

[0026] Step 13, Nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film.

[0027] Step 14, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0028] Step 15: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0029] Step 16: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0030] Step 17: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0031] Example 2

[0032] A second embodiment of the hole transport layer and the method for fabricating perovskite solar cells of the present invention includes the following steps: Step 21: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0033] Step 22: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 3.95 mg of 0.05 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use.

[0034] Step 23, Nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film.

[0035] Step 24, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0036] Step 25: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0037] Step 26: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0038] Step 27: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0039] Example 3

[0040] A third embodiment of the hole transport layer and the method for fabricating perovskite solar cells of the present invention includes the following steps: Step 31: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0041] Step 32: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 197.5 mg of 2.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use.

[0042] Step 33, Nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor solution to the ITO conductive layer to obtain an unannealed nickel oxide film.

[0043] Step 34, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0044] Step 35: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0045] Step 36: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0046] Step 37: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0047] Example 4

[0048] A fourth embodiment of the hole transport layer and the method for fabricating perovskite solar cells of the present invention includes the following steps: Step 41: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0049] Step 42, Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 38.5 mg of 0.5 mmol ammonium acetate powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use.

[0050] Step 43, Nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor solution to the ITO conductive layer to obtain an unannealed nickel oxide film.

[0051] Step 44, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0052] Step 45: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0053] Step 46: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0054] Step 47: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0055] Example 5

[0056] The fifth embodiment of the hole transport layer and the method for fabricating perovskite solar cells of the present invention includes the following steps: Step 51: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0057] Step 52: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 26.7 mg of 0.5 mmol ammonium chloride powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use.

[0058] Step 53, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film.

[0059] Step 54, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0060] Step 55: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0061] Step 56: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0062] Step 57: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0063] Comparative Example 1 The first comparative example of the perovskite solar cell of the present invention includes the following steps: Step D11: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes.

[0064] Step D12, Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 100 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 6.685 mL of 0.1 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 400 mL of ethylene glycol monomethyl ether to 100 mL of the above gel solution and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter and obtain the filtrate as the nickel oxide precursor solution, to be used later.

[0065] Step D13, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film.

[0066] Step D14, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use.

[0067] Step D15: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer.

[0068] Step D16: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm.

[0069] Step D17: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

[0070] The perovskite solar cells prepared in Examples 1-5 and Comparative Example 1 were subjected to JV performance tests, and the results were as follows: Figure 1 The diagram shows a comparison of JV performance curves, and Table 1 shows a comparison of performance test data.

[0071] Table 1. Comparison of performance test data of perovskite solar cells prepared in Examples 1-5 and Comparative Example 1

[0072] from Figure 1 From Table 1, we can find that: Example 1 is a perovskite solar cell with 0.01 mol / L ammonium bicarbonate added. Its power conversion efficiency is 20.32%, open circuit voltage is 1.13 V, short circuit current density is 22.61 mA / cm², and fill factor is 79.77%.

[0073] Example 2 is a perovskite solar cell with 0.001 mol / L ammonium bicarbonate added. Its power conversion efficiency is 20.14%, open circuit voltage is 1.13 V, short circuit current density is 22.63 mA / cm², and fill factor is 79.00%.

[0074] Example 3 is a perovskite solar cell with 0.05 mol / L ammonium bicarbonate added. Its power conversion efficiency is 19.51%, open circuit voltage is 1.13 V, short circuit current density is 22.56 mA / cm², and fill factor is 76.79%.

[0075] Example 4 is a perovskite solar cell with 0.01 mol / L ammonium acetate added. Its power conversion efficiency is 20.15%, open circuit voltage is 1.13 V, short circuit current density is 22.64 mA / cm², and fill factor is 79.00%.

[0076] Example 5 is a perovskite solar cell with 0.01 mol / L ammonium chloride added. Its power conversion efficiency is 20.23%, open circuit voltage is 1.13 V, short circuit current density is 22.77 mA / cm², and fill factor is 78.89%.

[0077] Comparative Example 1 is a perovskite solar cell without thermally decomposable additives, with a power conversion efficiency of 18.50%, an open-circuit voltage of 1.13 volts, a short-circuit current density of 22.47 mA / cm², and a fill factor of 73.10%.

[0078] Comparative analysis revealed that the perovskite solar cells with thermally decomposable additives of this invention exhibit higher energy conversion efficiency, primarily due to improvements in fill factor. A slight increase in short-circuit current density aligns with the beneficial effects described in this invention, namely, enhanced carrier extraction and transport capabilities. In Examples 1-3, the optimal concentration of ammonium bicarbonate was found to be 0.01 mol / L, with lower concentrations (0.001 mol / L) showing better efficiency improvements than higher concentrations (0.05 mol / L). Perovskite solar cells with ammonium acetate and ammonium chloride additives prepared at this optimal concentration achieved energy conversion efficiencies exceeding 20%, significantly higher than the efficiency of the perovskite solar cell in Comparative Example 1.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a hole transport layer, characterized in that, Includes the following steps: Step 1: Prepare nickel oxide precursor solution. Add nickel salt to organic solvent and stir thoroughly for 0.5-2 hours. While stirring, add ligand dropwise and continue stirring for 2-10 hours. Then add thermally decomposable additive and stir thoroughly for 2-24 hours. Filter the mixed solution using a 0.22μm PTFE organic filter to obtain nickel oxide precursor filtrate. Step 2: Coat the obtained nickel oxide precursor filtrate onto the substrate surface of the prepared conductive layer, and pre-anneal the obtained nickel oxide wet film at 100~120℃ for 2~10 min. Step 3: The pre-annealed nickel oxide film is subjected to high-temperature annealing at 280~350℃ for 30~60 minutes to obtain a nickel oxide film with a porous structure, which is the desired hole transport layer; wherein, In step one, the nickel salt is at least one selected from nickel nitrate, nickel acetate, nickel carbonate, nickel chloride, and nickel acetylacetone, and the concentration of the nickel salt is 0.05~2 mol / L; the organic solvent is at least one selected from ethanol, ethylene glycol, ethylene glycol monomethyl ether, glycerol, methanol, and isopropanol; the ligand is at least one selected from ethylamine, ethylenediamine, triethylamine, ethanolamine, triethanolamine, urea, and ammonia water, and the concentration of the ligand is 0.5~2 mol / L; the thermally decomposable additive is at least one selected from ammonium bicarbonate, ammonium chloride, ammonium acetate, ammonium carbonate, ammonium bromide, ammonium iodide, and ammonium thiocyanate, and the concentration of the thermally decomposable additive is 0.001~0.05 mol / L.

2. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: Step 1: Using the hole transport layer preparation method as described in claim 1, a hole transport layer is prepared on the surface of a substrate with a pre-prepared conductive layer; Step 2: Prepare a perovskite wet film on the hole transport layer by spin coating in one step, and then anneal it to obtain a perovskite thin film layer; Step 3: Prepare an electron transport layer on the perovskite thin film; Step 4: Fabricate the back electrode on the electron transport layer to complete the fabrication of the perovskite solar cell.

3. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, Includes the following steps: Step 11: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes. Step 12, Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 39.5 mg of 0.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter using a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use. Step 13, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film. Step 14, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use. Step 15: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer; Step 16: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm. Step 17: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

4. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, Includes the following steps: Step 21: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes. Step 22: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 3.95 mg of 0.05 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter using a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use. Step 23, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film. Step 24, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use. Step 25: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer; Step 26: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm. Step 27: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

5. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, Includes the following steps: Step 31: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes. Step 32: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 197.5 mg of 2.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter using a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use. Step 33, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film. Step 34, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use. Step 35: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer; Step 36: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm. Step 37: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

6. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, Includes the following steps: Step 41: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes. Step 42, Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 38.5 mg of 0.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter with a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use. Step 43, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film. Step 44, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use. Step 45: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer; Step 46: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm. Step 47: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

7. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, Includes the following steps: Step 51: The patterned ITO conductive layer glass substrate is sequentially cleaned with detergent, deionized water, acetone and isopropanol by ultrasonic cleaning for 30 minutes each, then dried with N2 and treated with UVO for 10 minutes. Step 52: Preparation of nickel oxide precursor solution: a) Dissolve 2.908 g of 0.01 mol nickel nitrate hexahydrate in 10 mL of ethylene glycol monomethyl ether and stir for 2 hours; b) Gradually add 0.669 mL of 0.01 mol ethylenediamine and stir for 5 hours to obtain a gel solution; c) Add 40 mL of ethylene glycol monomethyl ether to 10 mL of the above gel solution, then add 26.7 mg of 0.5 mmol ammonium bicarbonate powder and stir thoroughly for 12 hours; d) Filter using a 0.22 μm PTFE organic filter. The filtrate obtained is the nickel oxide precursor solution, which is ready for use. Step 53, nickel oxide film coating: Heat a 6cm×6cm ITO conductive layer glass substrate to 70°C, and apply the nickel oxide precursor liquid onto the ITO conductive layer to obtain an unannealed nickel oxide film. Step 54, High-temperature annealing process: The unannealed nickel oxide film is subjected to high-temperature annealing. The temperature control program is to hold at 110°C for 5 minutes, raise the temperature to 300°C within 15 minutes, hold at 300°C for 60 minutes, and lower the temperature to 70°C within 30 minutes to obtain a nickel oxide film with a porous structure, which is the required hole transport layer. Remove it and place it in a drying cabinet for later use. Step 55: Prepare a perovskite wet film on the hole transport layer by spin coating, and then anneal it to obtain a perovskite thin film layer; Step 56: Deposit fullerene material C on the perovskite thin film layer. 60 It serves as an electron transport layer with a thickness of 20 nm. Step 57: Vacuum-deposit silver metal as the back electrode on the electron transport layer with a thickness of 80 nm to obtain a perovskite solar cell.

Images