A perovskite solar cell based on an organically modified lithium salt-doped hole transport layer

Abstract

This invention discloses a perovskite solar cell based on an organically modified lithium salt-doped hole transport layer. Organic molecules containing at least two electron-donating groups are directly introduced into the lithium salt-doped hole transport layer and spin-coated onto the perovskite film surface in a one-step deposition process. By strictly controlling the amount of organic molecules added, the spin-coating speed, and the spin-coating time in the lithium salt-doped hole transport layer, the overall modification and optimization of the perovskite solar cell device is achieved. This results in a dual effect of reducing film defects and improving the water stability of the lithium salt-doped hole transport layer, thereby enhancing the photoelectric conversion efficiency and stability of the perovskite solar cell. Furthermore, this invention combines the deposition of the passivation layer and the hole transport layer, significantly reducing the construction steps of the perovskite solar cell, lowering manufacturing costs, and offering a simple, effective, and reproducible fabrication process.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials technology, specifically relating to a perovskite solar cell based on an organic molecule-modified lithium salt-doped hole transport layer. Background Technology

[0002] In recent years, the global energy crisis and environmental pollution have spurred the development of new renewable and clean energy sources. Among various clean energy sources, solar energy, as an inexhaustible green energy source, has become a focus of global energy development and research due to its advantages such as large reserves, no pollution, and wide distribution. After decades of research, solar cells based on the photovoltaic effect can directly convert solar energy into electrical energy, and have been rapidly developed and put into use. Meanwhile, novel solar cells based on lead halide perovskite materials have become a research hotspot in recent years due to their advantages such as tunable bandgap, excellent photoelectric properties, simple fabrication methods, and flexible devices.

[0003] Over the past decade, perovskite-based solar cells have experienced rapid development, achieving power conversion efficiencies (PCE) exceeding 25%, comparable to traditional silicon cells, and their commercialization is progressing steadily. However, while obtaining high-efficiency perovskite solar cell devices, improving long-term stability remains the most challenging issue in the commercialization of this photovoltaic technology. Currently, most of the best-performing devices place the perovskite absorber layer between the electron transport layer and the hole transport layer. Since the electron transport layer is mostly made of relatively stable materials, such as TiO2, ZnO, SnO2, and Nb2O5, it is not easily affected by environmental factors. Therefore, under environmental conditions, especially when exposed to atmospheres with high relative humidity, moisture, oxygen, etc., mainly damage perovskite solar cells through the perovskite absorber layer, hole transport layer, and the interface between the two, affecting device performance and commercial development.

[0004] On the one hand, one of the main reasons for the poor performance of perovskite solar cells is the defects on the surface and at the grain boundaries of the perovskite film. These defect sites become recombination centers for photogenerated carriers, causing severe nonradiative recombination, leading to a loss of open-circuit voltage and a reduction in photoelectric conversion efficiency. In addition, water and oxygen from the external environment easily adsorb onto these defect sites, causing decomposition or phase transition reactions in the perovskite and accelerating the degradation of the perovskite film. On the other hand, commonly used hole transport materials, such as 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and poly(3-hexylthiophene) (P3HT), require the introduction of lithium bis(trifluoroethanesulfonylimide) (LiTFSI) to improve their hole conductivity. However, LiTFSI is extremely hygroscopic, easily absorbing moisture from the air and causing degradation of the underlying perovskite film, further affecting device stability. Therefore, reducing defects in perovskite thin films while minimizing the negative impact of lithium salt doping on perovskite is crucial for improving the photovoltaic performance and stability of perovskite solar cells. To date, most strategies for improving device stability have focused on suppressing defects at the perovskite surface and grain boundaries, while methods to simultaneously address both issues have been rarely reported. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a perovskite solar cell based on an organic molecule-modified lithium salt-doped hole transport layer. This reduces the surface defect density of the perovskite film while improving the moisture resistance of the lithium salt-doped hole transport layer, thus solving the problems of low photoelectric conversion efficiency and poor stability of perovskite solar cells. Importantly, this invention introduces organic molecules into the lithium salt-doped hole transport layer precursor solution and deposits them directly onto the already formed perovskite film, combining the deposition of the perovskite surface passivator with the deposition of the hole transport layer. This simplifies the preparation process, reduces the number of construction steps for perovskite solar cells, lowers manufacturing costs, and facilitates industrialization.

[0006] To achieve the above objectives, the perovskite solar cell used in this invention comprises, from bottom to top, a transparent conductive glass, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal electrode; the material of the perovskite absorber layer is APbX3, wherein A is a methylamine cation (MA). + ), formamidinium cation (FA) + ), cesium cation (Cs) + ), rubidium cations (Rb + Any one or more of the following, where X is a halide anion (I2). - ,Br -The hole transport layer is an organic molecule-modified lithium salt-doped hole transport layer, wherein the organic molecule is an organic compound containing at least two electron-donating groups and having a molecular weight of less than 500.

[0007] Furthermore, the electron-donating group is any one or more of -NH2, -NH, -SH, -OH, -CN, -C=O, and -OR, wherein R is an alkyl group. Specifically, examples include: tryptamine, 5-methoxytryptamine, 1,4-diaminobutane, mercaptosuccinic acid, 4-aminothiophenol, 2,2′-(ethylenedioxy)bis(ethylamine), 3-(2-aminoacetic acid)indole, 3-(1H-indole-3-yl)propyl-1-amine, indole-3-methylamine, 1-acetylguanidine, 1-(tert-butoxycarbonyl)guanidine, guanidine acetate, 2-mercaptoimidazole, 2-mercaptobenzimidazole, 5-amino-2-mercaptobenzimidazole, α-[2-(methylamino)ethyl]benzyl alcohol, indole-3-acetamide, cyanoacetamide, etc.

[0008] The method for preparing the perovskite solar cell of the present invention includes the following steps:

[0009] Step 1: Clean the transparent conductive glass and prepare an electron transport layer on the transparent conductive glass;

[0010] Step 2: Spin-coat the perovskite precursor solution onto the electron transport layer, and then anneal to obtain the perovskite absorber layer;

[0011] Step 3: Spin-coat the organic molecule-modified lithium salt-doped hole transport layer precursor solution onto the perovskite absorber layer to prepare the hole transport layer.

[0012] Step 4: Fabricate a metal electrode on the hole transport layer.

[0013] Furthermore, in step 1 above, the material of the electron transport layer is any one of TiO2, ZnO, SnO2, Nb2O5, etc.

[0014] Furthermore, in step 2 above, the spin coating of the perovskite precursor solution on the electron transport layer is divided into two stages: the first stage has a rotation speed of 500-1500 rpm / min and a spin coating time of 5-20 s; the second stage has a rotation speed of 2000-5000 rpm / min and a spin coating time of 30-50 s; the annealing temperature after spin coating is 100-220℃ and the annealing time is 5-30 min.

[0015] Furthermore, in step 2 above, the solute of the perovskite precursor solution is APbX3, the concentration of APbX3 is 0.6 to 1.2 mol / L, and the solvent is any one or a mixture of dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

[0016] Furthermore, in step 3 above, the hole transport layer is prepared by directly adding organic molecules to a lithium salt-doped hole transport layer precursor solution and then spin-coating the resulting solution directly onto a perovskite absorber layer. In the lithium salt-doped hole transport layer precursor solution, the molar ratio of the added organic molecules to the lithium salt is 0.5:1 to 2:1; the material of the lithium salt-doped hole transport layer is any one of the following: bis(trifluoroethanesulfonylimide)lithium (LiTFSI) doped structures: Spiro-OMeTAD, PTAA, X55, X60, P3HT, etc.

[0017]

[0018]

[0019] Furthermore, in step 3 above, the spin coating speed is 2000-5000 rpm / min, and the spin coating time is 20-40 s.

[0020] Furthermore, in step 4 above, the material of the metal electrode is any one of Au, Ag, Cu, etc.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention directly incorporates organic molecules into a lithium salt-doped hole transport layer precursor solution, and prepares the hole transport layer by spin-coating the resulting solution directly onto a perovskite absorber layer. Some organic molecules directly deposit on the perovskite film surface, creating an interaction between the two and passivating defects at the film surface and grain boundaries, reducing non-radiative recombination, extending carrier lifetime, and reducing open-circuit voltage loss. Therefore, the organically modified CsPbI 3-x Br x Perovskite solar cell devices can convert V OC The voltage was increased from 1.192V to 1.251V, which is equivalent to an energy loss of only 0.48V, and the corresponding PCE increased from 19.5% to 21.8%.

[0023] 2. Because organic molecules containing two or more electron-donating groups have low formation energies with lithium ions in the hole transport layer, they are more likely to coordinate with lithium salts, delaying the reaction between lithium cations and water molecules, reducing the hygroscopicity of lithium salts, and improving the water stability of the hole transport layer, thereby further improving the stability of perovskite solar cells. The perovskite film beneath the hole transport layer modified with organic molecules exhibits excellent stability, and the corresponding CsPbI... 3-x Br x Perovskite solar cell devices can maintain 90% of their initial efficiency within 800 hours (at a humidity of 55%–65%).

[0024] 3. Compared to traditional perovskite solar cells that sequentially deposit the passivation layer and hole transport layer onto the surface of a pre-formed perovskite thin film using conventional passivation methods, this invention introduces organic molecules into a lithium salt-doped hole transport layer precursor solution and directly deposits it onto the pre-formed perovskite thin film in one step. This combines surface passivation agent deposition with hole transport layer deposition, significantly reducing manufacturing costs. Therefore, modifying the lithium salt-doped hole transport layer with organic molecules improves the photoelectric conversion efficiency and stability of perovskite solar cells while simultaneously reducing manufacturing costs. Attached Figure Description

[0025] Figure 1 It is the CsPbI of the tryptophan-modified lithium salt-doped hole transport layer in Example 2. 3-x Br x Cross-sectional field emission scanning electron microscope image of a perovskite solar cell device;

[0026] Figure 2 The CsPbI prepared in Examples 1-3 and Comparative Example 1 3-x Br x Comparison of JV curves for perovskite solar cells.

[0027] Figure 3 The CsPbI prepared in Examples 1-3 and Comparative Example 1 3-x Br x JV parameter statistics for perovskite solar cells.

[0028] Figure 4 The CsPbI prepared in Example 2 and Comparative Example 1 3-x Br x Comparison of humidity stability between perovskite thin films and hole transport layers.

[0029] Figure 5 The CsPbI prepared in Example 2 and Comparative Example 1 3-x Br x A comparison chart of the humidity stability of perovskite solar cell devices.

[0030] Figure 6 The CsPbI prepared in Example 4 and Comparative Example 1 3-x Br x Comparison of JV curves for perovskite solar cells. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0032] This invention provides a perovskite solar cell based on an organically modified lithium salt-doped hole transport layer. The modification and optimization of the lithium salt-doped hole transport layer using organic molecules effectively improves the efficiency and stability of the perovskite solar cell. The cell structure, from bottom to top, consists of a transparent conductive glass, an electron transport layer, a perovskite absorber layer, a hole transport layer, and a metal electrode. The entire fabrication method includes the following steps:

[0033] Step 1: Fabrication of the electron transport layer

[0034] The conductive glass was ultrasonically cleaned sequentially in acetone, isopropanol, and ethanol for 10–30 minutes each. After cleaning, it was dried with compressed air to obtain clean, transparent conductive glass. The conductive glass was either indium tin oxide (ITO) conductive glass or fluorine-doped tin oxide (FTO) conductive glass. An electron transport layer was prepared on the clean, transparent conductive glass using water bath deposition, spin coating, blade coating, atomic layer deposition, or physical vapor deposition. The electron transport layer material was any one of TiO2, ZnO, SnO2, or Nb2O5.

[0035] Step 2: Preparation of the perovskite absorber layer

[0036] The APbX3 precursor was dissolved in a solvent by molar ratio and stirred at room temperature for more than 6 hours to prepare a perovskite precursor solution with a concentration of 0.6–1.2 mol / L; wherein, A is a methylamine cation (MA). + ), formamidinium cation (FA) + ), cesium cation (Cs) + ), rubidium cations (Rb + Any one or more of the following, where X is a halide anion (I-, Br-). - The perovskite precursor solution is prepared by spin-coating the electron transport layer obtained in step 1 with a solvent of any one or more of dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone. The spin-coating process consists of two stages: the first stage has a spin speed of 500–1500 rpm / min and a spin-coating time of 5–20 s; the second stage has a spin speed of 2000–5000 rpm / min and a spin-coating time of 30–50 s. After spin-coating, the perovskite absorber layer is obtained by annealing at a temperature of 180–220 °C for 5–30 min.

[0037] Step 3: Fabrication of the hole transport layer

[0038] Hole transport layer material, 4-tert-butylpyridine, and lithium bis(trifluoroethanesulfonylimide) were dissolved in their respective solvents and stirred at room temperature for more than 6 hours to prepare a lithium salt-doped hole transport layer precursor solution with a concentration of 40–100 mg / mL. Then, organic molecules were added to the solution, with a molar ratio of organic molecules to lithium salt of 0.5:1–2:1. The lithium salt-doped hole transport layer precursor solution containing organic molecules was then spin-coated onto the perovskite absorber layer prepared in step 2 using a spin-coating method. The spin-coating speed was 3000–5000 rpm / min, and the spin-coating time was 20–40 s to prepare the hole transport layer. The hole transport layer material is any one of Spiro-OMeTAD, PTAA, X55, X60, P3TH, etc.; the organic molecule is an organic compound containing at least two electron-donating groups and having a molecular weight of less than 500, wherein the electron-donating groups are any one or more of -NH2, -NH, -SH, -OH, -CN, -C=O, -OR (R is alkyl), etc., specifically such as tryptamine, 5-methoxytryptamine, 1,4-diaminobutane. The following are all of the following: mercaptosuccinic acid, 4-aminothiophenol, 2,2′-(ethylenedioxy)bis(ethylamine), 3-(2-aminoacetic acid)indole, 3-(1H-indole-3-yl)propyl-1-amine, indole-3-methylamine, 1-acetylguanidine, 1-(tert-butoxycarbonyl)guanidine, guanidine acetate, 2-mercaptoimidazole, 2-mercaptobenzimidazole, 5-amino-2-mercaptobenzimidazole, α-[2-(methylamino)ethyl]benzyl alcohol, indole-3-acetamide, and cyanoacetamide.

[0039] Step 4: Deposit metal electrodes

[0040] A perovskite solar cell is obtained by depositing a metal electrode on a hole transport layer using a metal thermal evaporation method, wherein the metal electrode material is any one of Au, Ag, or Cu.

[0041] Comparative Example 1

[0042] Step 1: The FTO conductive glass was ultrasonically cleaned sequentially in acetone, isopropanol, and ethanol for 30 minutes each, and then dried with compressed air to obtain clean FTO conductive glass. 4.5 mL of TiCl4 solution was slowly dropped into ice made from 200 mL of ultrapure water. When the ice was about to melt completely, the ice-water mixture was poured into a petri dish containing the FTO conductive glass and placed in an oven at 70°C for 50-60 minutes to deposit a TiO2 film of about 50 nm thickness, thus preparing an electron transport layer.

[0043] Step 2: Dissolve CsI, HPbI3, and PbBr2 in a molar ratio of 3.00:2.85:0.15 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15. Stir the solution on a stirring table for at least 6 hours to obtain a CsPbI3 solution with a concentration of 0.6 mol / L. 3-x Br x Perovskite precursor solution; the prepared CsPbI 3-x Br x The perovskite precursor solution was spin-coated onto the electron transport layer in step 1. The spin-coating process consisted of two stages: the first stage had a spin speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage had a spin speed of 4000 rpm / min and a spin-coating time of 30 s; after spin-coating, the perovskite absorber layer was obtained by hot-setting at 210℃ for 5 min.

[0044] Step 3: Add 90 mg Spiro-OMeTAD, 22 μL (0.04 mol) LiTFSI solution (520 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 36 μL 4-tert-butylpyridine to 1 mL chlorobenzene, stir for 12 h and filter to obtain a lithium salt-doped hole transport layer precursor solution; spin-coat the lithium salt-doped hole transport layer precursor solution onto the perovskite absorber layer prepared in Step 2 using a spin-coating method at a speed of 5000 rpm / min and a spin-coating time of 30 s to prepare a hole transport layer.

[0045] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 CsPbI 3-x Br x Perovskite solar cells.

[0046] Example 1

[0047] Step 1: The FTO conductive glass was ultrasonically cleaned sequentially in acetone, isopropanol, and ethanol for 30 minutes each, and then dried with compressed air to obtain clean FTO conductive glass. 4.5 mL of TiCl4 solution was slowly dropped into ice made from 200 mL of ultrapure water. When the ice was about to melt completely, the ice-water mixture was poured into a petri dish containing the FTO conductive glass and placed in an oven at 70°C for 50-60 minutes to deposit a TiO2 film of about 50 nm thickness, thus preparing an electron transport layer.

[0048] Step 2: Dissolve CsI, HPbI3, and PbBr2 in a molar ratio of 3.00:2.85:0.15 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15. Stir the solution on a stirring table for at least 6 hours to obtain a CsPbI3 solution with a concentration of 0.6 mol / L. 3-xBr x Perovskite precursor solution; the prepared CsPbI 3-x Br x The perovskite precursor solution was spin-coated onto the electron transport layer in step 1. The spin-coating process consisted of two stages: the first stage had a spin speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage had a spin speed of 4000 rpm / min and a spin-coating time of 30 s; after spin-coating, the perovskite absorber layer was obtained by hot-setting at 210℃ for 5 min.

[0049] Step 3: Add 90 mg Spiro-OMeTAD, 22 μL (0.04 mol) LiTFSI solution (520 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 36 μL 4-tert-butylpyridine to 1 mL chlorobenzene, and add 3.0 mg (0.02 mol) tryptamine. After stirring for 12 h, filter to obtain a tryptamine-modified lithium salt-doped hole transport layer solution. Spin-coat the tryptamine-modified lithium salt-doped hole transport layer precursor solution onto the perovskite absorber layer prepared in Step 2. The spin-coating speed is 5000 rpm / min and the spin-coating time is 30 s to prepare the tryptamine-modified lithium salt-doped hole transport layer.

[0050] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 CsPbI 3-x Br x Perovskite solar cells.

[0051] Example 2

[0052] In step 3 of this embodiment, 6.0 mg (0.04 mol) of tryptophan was added, and the other steps were the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0053] Example 3

[0054] In step 3 of this embodiment, 12.0 mg (0.08 mol) of tryptophan was added, and the other steps were the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0055] Example 4

[0056] In step 3 of this embodiment, the tryptophan is replaced with 4.0 mg (0.04 mol) of 1-acetylguanidine, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0057] Example 5

[0058] Step 1: The FTO conductive glass was ultrasonically cleaned in acetone, isopropanol and ethanol for 30 min each, and then dried with compressed air to obtain a clean FTO conductive glass. SnO2 colloidal nanoparticles were coated in air at 3000 rpm / min for 40 s, and then annealed in air at 150℃ for 20 min to prepare an electron transport layer.

[0059] Step 2: Dissolve FAI and PbI2 in a molar ratio of 1:1 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15, and stir on a stirring table for more than 6 hours to obtain a 1.0 mol / L FAPbI3 perovskite precursor solution. Spin-coat the obtained FAPbI3 perovskite precursor solution onto the electron transport layer of Step 1. The spin-coating process is divided into two stages: the first stage has a rotation speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage has a rotation speed of 4000 rpm / min and a spin-coating time of 30 s. After spin-coating, anneal at 150℃ for 15 min to obtain the perovskite absorber layer.

[0060] Step 3: Add 90 mg Spiro-OMeTAD, 22 μL (0.04 mol) LiTFSI solution (520 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 36 μL 4-tert-butylpyridine to 1 mL chlorobenzene, and add 3.5 mg (0.04 mol) 1,4-diaminobutane. Stir for 12 h and filter to obtain a lithium salt-doped hole transport layer solution containing 1,4-diaminobutane. Spin-coat the lithium salt-doped hole transport layer precursor solution containing 1,4-diaminobutane onto the perovskite absorber layer prepared in Step 2 using a spin-coating method. The spin-coating speed is 5000 rpm / min and the spin-coating time is 30 s to prepare a 1,4-diaminobutane-modified lithium salt-doped hole transport layer.

[0061] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 FAPbI3 perovskite solar cells were obtained.

[0062] Example 6

[0063] Step 1: The FTO conductive glass was ultrasonically cleaned in acetone, isopropanol and ethanol for 30 min each, and then dried with compressed air to obtain a clean FTO conductive glass. SnO2 colloidal nanoparticles were coated in air at 3000 rpm / min for 40 s, and then annealed in air at 150℃ for 20 min to prepare an electron transport layer.

[0064] Step 2: Dissolve MAI and PbI2 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a molar ratio of 1:1 and a volume ratio of 85:15. Stir the solution on a stirring table for more than 6 hours to obtain a MAPbI3 perovskite precursor solution with a concentration of 1.0 mol / L. Spin-coat the obtained MAPbI3 perovskite precursor solution onto the electron transport layer in Step 1. The spin-coating process is divided into two stages: the first stage has a rotation speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage has a rotation speed of 4000 rpm / min and a spin-coating time of 30 s. After spin-coating, anneal at 150℃ for 15 min to obtain the perovskite absorber layer.

[0065] Step 3: Add 90 mg Spiro-OMeTAD, 22 μL (0.04 mol) LiTFSI solution (520 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 36 μL 4-tert-butylpyridine to 1 mL chlorobenzene, and add 6.0 mg (0.04 mol) mercaptosuccinic acid. Stir for 12 h and then filter to obtain a lithium salt-doped hole transport layer solution containing mercaptosuccinic acid. Spin-coat the lithium salt-doped hole transport layer precursor solution containing mercaptosuccinic acid onto the perovskite absorber layer prepared in Step 2. The spin-coating speed is 5000 rpm / min and the spin-coating time is 30 s to prepare a mercaptosuccinic acid-modified lithium salt-doped hole transport layer.

[0066] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 MAPbI3 perovskite solar cells were obtained.

[0067] Example 7

[0068] Step 1: The FTO conductive glass was ultrasonically cleaned sequentially in acetone, isopropanol, and ethanol for 30 minutes each, and then dried with compressed air to obtain clean FTO conductive glass. 4.5 mL of TiCl4 solution was slowly dropped into ice made from 200 mL of ultrapure water. When the ice was about to melt completely, the ice-water mixture was poured into a petri dish containing the FTO conductive glass and placed in an oven at 70°C for 50-60 minutes to deposit a TiO2 film of about 50 nm thickness, thus preparing an electron transport layer.

[0069] Step 2: Dissolve FAI, CsI, and PbI2 in a molar ratio of 0.9:0.1:1.0 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15. Stir the solution on a stirring table for at least 6 hours to obtain a FA solution with a concentration of 1.0 mol / L. 0.9 Cs 0.1 PbI3 perovskite precursor solution; the prepared FA 0.9 Cs 0.1The PbI3 perovskite precursor solution was spin-coated onto the electron transport layer in step 1. The spin-coating process consisted of two stages: the first stage had a spin speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage had a spin speed of 4000 rpm / min and a spin-coating time of 30 s; after spin-coating, the perovskite absorber layer was obtained by hot-setting at 150°C for 20 min.

[0070] Step 3: Add 90 mg Spiro-OMeTAD, 22 μL (0.04 mol) LiTFSI solution (520 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 36 μL 4-tert-butylpyridine to 1 mL chlorobenzene, and add 5.0 mg (0.04 mol) 4-aminothiophenol. Stir for 12 h and filter to obtain a lithium salt-doped hole transport layer solution containing 4-aminothiophenol. Spin-coat the lithium salt-doped hole transport layer precursor solution containing 4-aminothiophenol onto the perovskite absorber layer prepared in Step 2. The spin-coating speed is 5000 rpm / min and the spin-coating time is 30 s to prepare a 4-aminothiophenol-modified lithium salt-doped hole transport layer.

[0071] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 , obtain FA 0.9 Cs 0.1 PbI3 perovskite solar cells.

[0072] Example 8

[0073] Step 1: The FTO conductive glass was ultrasonically cleaned in acetone, isopropanol and ethanol for 30 min each, and then dried with compressed air to obtain a clean FTO conductive glass. SnO2 colloidal nanoparticles were coated in air at 3000 rpm / min for 40 s, and then annealed in air at 150℃ for 20 min to prepare an electron transport layer.

[0074] Step 2: Dissolve FAI, MAI, and PbI2 in a molar ratio of 0.9:0.1:1.0 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15. Stir the solution on a stirring table for at least 6 hours to obtain a 1.0 mol / L FAI solution. 0.9 MA 0.1 PbI3 perovskite precursor solution; the prepared FA 0.9 MA 0.1The PbI3 perovskite precursor solution was spin-coated onto the electron transport layer in step 1. The spin-coating process consisted of two stages: the first stage had a spin speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage had a spin speed of 4000 rpm / min and a spin-coating time of 30 s; after spin-coating, the perovskite absorber layer was obtained by hot-setting at 150°C for 20 min.

[0075] Step 3: Add 20 mg PTAA, 15 μL (0.008 mol) LiTFSI solution (170 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 10 μL 4-tert-butylpyridine to 1 mL toluene, and add 2.5 mg (0.016 mol) 2,2′-(ethylenedioxy)bis(ethylamine). Stir for 12 h and filter to obtain a lithium salt-doped hole transport layer solution containing 2,2′-(ethylenedioxy)bis(ethylamine). Spin-coat the lithium salt-doped hole transport layer precursor solution containing 2,2′-(ethylenedioxy)bis(ethylamine) onto the perovskite absorber layer prepared in Step 2. The spin-coating speed is 3000 rpm / min and the spin-coating time is 30 s to prepare a 2,2′-(ethylenedioxy)bis(ethylamine) modified lithium salt-doped hole transport layer.

[0076] Step 4: Deposit an 80nm thick Au film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 , obtain FA 0.9 MA 0.1 PbI3 perovskite solar cells.

[0077] Example 9

[0078] Step 1: The FTO conductive glass was ultrasonically cleaned sequentially in acetone, isopropanol, and ethanol for 30 minutes each, and then dried with compressed air to obtain clean FTO conductive glass. 4.5 mL of TiCl4 solution was slowly dropped into ice made from 200 mL of ultrapure water. When the ice was about to melt completely, the ice-water mixture was poured into a petri dish containing the FTO conductive glass and placed in an oven at 70°C for 50-60 minutes to deposit a TiO2 film of about 50 nm thickness, thus preparing an electron transport layer.

[0079] Step 2: Dissolve CsI, HPbI3, and PbBr2 in a molar ratio of 3.00:2.85:0.15 in a mixed solution of dimethylformamide and dimethyl sulfoxide in a volume ratio of 85:15. Stir the solution on a stirring table for at least 6 hours to obtain a CsPbI3 solution with a concentration of 0.6 mol / L. 3-x Br x Perovskite precursor solution; the prepared CsPbI 3-x Br xThe perovskite precursor solution was spin-coated onto the electron transport layer in step 1. The spin-coating process consisted of two stages: the first stage had a spin speed of 1000 rpm / min and a spin-coating time of 10 s; the second stage had a spin speed of 4000 rpm / min and a spin-coating time of 30 s; after spin-coating, the perovskite absorber layer was obtained by hot-setting at 210℃ for 5 min.

[0080] Step 3: Add 20 mg PTAA, 15 μL (0.008 mol) LiTFSI solution (170 mg LiTFSI powder dissolved in 1 mL acetonitrile) and 10 μL 4-tert-butylpyridine to 1 mL toluene, and add 3.0 mg (0.016 mol) 5-methoxytryptamine. Stir for 12 h and filter to obtain a lithium salt-doped hole transport layer solution containing 5-methoxytryptamine. Spin-coat the lithium salt-doped hole transport layer precursor solution containing 5-methoxytryptamine onto the perovskite absorber layer prepared in Step 2 using a spin-coating method. The spin-coating speed is 3000 rpm / min and the spin-coating time is 30 s to prepare a 5-methoxytryptamine-modified lithium salt-doped hole transport layer.

[0081] Step 4: Deposit an 80nm thick Ag film on the hole transport layer from Step 3. The cell area is 0.09cm². 2 CsPbI 3-x Br x Perovskite solar cells.

[0082] Example 10

[0083] In step 3 of this embodiment, the tryptophan is replaced with 3.5 mg (0.04 mol) cyanoacetamide, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0084] Example 11

[0085] In step 3 of this embodiment, the tryptamine is replaced with 7.0 mg (0.04 mol) of 3-(2-aminoacetic acid) indole. The other steps are the same as in Example 1, yielding CsPbI. 3-x Br x Perovskite solar cells.

[0086] Example 12

[0087] In step 3 of this embodiment, the tryptophan is replaced with 11.0 mg (0.04 mol) 3-(1H-indol-3-yl)propyl-1-amine. The other steps are the same as in Example 1, yielding CsPbI. 3-x Br x Perovskite solar cells.

[0088] Example 13

[0089] In step 3 of this embodiment, the tryptamine is replaced with 7.0 mg (0.04 mol) indole-3-methylamine, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0090] Example 14

[0091] In step 3 of this embodiment, the tryptophan is replaced with 14.0 mg (0.04 mol) 1-(tert-butyloxycarbonyl)guanidine, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0092] Example 15

[0093] In step 3 of this embodiment, the tryptophan is replaced with 4.5 mg (0.04 mol) guanidine acetate, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0094] Example 16

[0095] In step 3 of this embodiment, the tryptophan is replaced with 4.0 mg (0.04 mol) of 2-mercaptoimidazole. The other steps are the same as in Example 1, yielding CsPbI. 3-x Br x Perovskite solar cells.

[0096] Example 17

[0097] In step 3 of this embodiment, the tryptophan is replaced with 6.0 mg (0.04 mol) of 2-mercaptobenzimidazole, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0098] Example 18

[0099] In step 3 of this embodiment, the tryptophan is replaced with 6.5 mg (0.04 mol) of 5-amino-2-mercaptobenzimidazole. The other steps are the same as in Example 1, yielding CsPbI. 3-x Br x Perovskite solar cells.

[0100] Example 19

[0101] In step 3 of this embodiment, the tryptamine is replaced with 6.5 mg (0.04 mol) α-[2-(methylamino)ethyl]benzyl alcohol, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0102] Example 20

[0103] In step 3 of this embodiment, the tryptophan is replaced with 7.0 mg (0.04 mol) of indole-3-acetamide, and the other steps are the same as in Example 1, to obtain CsPbI. 3-x Br x Perovskite solar cells.

[0104] The CsPbI prepared in Examples 1-4 and Comparative Example 1 above 3-x Br x The perovskite solar cells were characterized, and the results are shown in the figure. Figures 1-6 And Tables 1-2.

[0105] Figure 1 The CsPbI2 of the tryptophan-modified lithium salt-doped hole transport layer in Example 2 3-x Br x Cross-sectional field emission scanning electron microscope (FESEM) image of a perovskite solar cell device. The image shows the basic structure of the all-inorganic perovskite solar cell, from bottom to top: transparent FTO conductive glass, electron transport layer TiO2, and perovskite absorber layer CsPbI. 3-x Br x The figure shows a hole transport layer (Spiro-OMeTAD(+TA)) and a metal electrode (Au). As shown in the figure, there is a clear delamination and good contact between the perovskite absorber layer and the hole transport layer, indicating that the addition of tryptamine does not affect the interfacial charge transfer between the perovskite absorber layer and the hole transport layer.

[0106] Figure 2 Table 1 shows the CsPbI prepared in Examples 1-3 and Comparative Example 1. 3-x Br x A comparison of the JV curves of perovskite solar cells. As shown in the figure, compared with Comparative Example 1, the addition of tryptamine to the hole transport layer in Examples 1-3 all improved the efficiency. In particular, the device prepared in Example 2 achieved the highest efficiency, and V... OC The voltage was increased from 1.192V to 1.251V, which is equivalent to an energy loss of 0.48V. The corresponding PCE increased from 19.5% to 21.8%, which is also the highest efficiency among all inorganic perovskite solar cells to date.

[0107] Table 1. Detailed parameters of the JV curves for Examples 1-3 and Comparative Example 1.

[0108]

[0109] Figure 3 CsPbI prepared in Examples 1-3 and Comparative Example 1 3-x Br x Statistical graph of JV parameters for perovskite solar cells. As shown in the figure, compared with Comparative Example 1, the efficiency of perovskite solar cell devices obtained using Examples 1-3 is improved, which is attributed to V. OC FF and J SC The performance is improved and the reproducibility is good.

[0110] Figure 4 CsPbI prepared for Example 2 and Comparative Example 1 3-x Br x A comparison of the humidity stability of the perovskite film and the hole transport layer. As shown in the figure, compared with Comparative Example 1, the perovskite film prepared in Example 2 remains black for more than 14 hours, and its stability is improved. This is because the addition of tryptamine can not only suppress surface defects, but also reduce the water absorption of the hole transport layer, thereby significantly stabilizing the black phase of the perovskite.

[0111] Figure 5 CsPbI prepared for Example 2 and Comparative Example 1 3-x Br x A comparison of the humidity stability of perovskite solar cell devices. As shown in the figure, during the 800-hour test period, the efficiency of the device prepared in Example 2 decreased to 90% of its initial value, compared to the efficiency of the device in Comparative Example 1, which decreased to 72%. This is because the addition of tryptamine not only enhances the water resistance of the hole transport layer but also passivates surface defects in the perovskite film, thereby reducing the defect density. This result strongly demonstrates the superior stability of inorganic perovskite solar cells with tryptamine added to the hole transport layer.

[0112] Figure 6 CsPbI prepared for Example 4 and Comparative Example 1 3-x Br x A comparison of the JV curves of perovskite solar cells. As shown in the figure, compared with Comparative Example 1, the efficiency of Example 4 is improved by adding 1-acetylguanidine to the hole transport layer, indicating that the method has strong applicability.

Claims

1. A perovskite solar cell based on modification of lithium salt doped hole transport layer with organic molecules, comprising transparent conductive glass, electron transport layer, perovskite absorber layer, hole transport layer and metal electrode stacked in order from bottom to top; characterized in that, The perovskite absorber layer is made of APbX3, wherein A is any one or more of methylamine cation, formamidinium cation, cesium cation, and rubidium cation, and X is a halide anion; the hole transport layer is an organic molecule-modified lithium salt-doped hole transport layer, wherein the organic molecule is tryptamine; The hole transport layer is prepared by directly adding organic molecules to a lithium salt-doped hole transport layer precursor solution and then spin-coating the resulting solution onto a perovskite absorber layer. The molar ratio of the added organic molecules to the lithium salt in the lithium salt-doped hole transport layer precursor solution is 0.5:1 to 2:

1.

2. The perovskite solar cell based on organic molecule-modified lithium salt-doped hole transport layer according to claim 1, characterized in that, The material of the lithium salt-doped hole transport layer is any one of the following: Spiro-OMeTAD, PTAA, X55, X60, and P3HT, which are bis(trifluoroethanesulfonylimide) lithium-doped structures. Spiro-OMeTAD PTAA X55 X60 P3HT.

3. The perovskite solar cell based on organic molecule-modified lithium salt-doped hole-transporting layer according to claim 1, characterized in that, The spin coating speed is 2000-5000 rpm / min, and the spin coating time is 20-40 s.

4. The perovskite solar cell based on organic molecule-modified lithium salt-doped hole-transporting layer according to claim 1, characterized in that, The perovskite absorber layer is prepared by spin coating a perovskite precursor solution followed by annealing. The spin coating consists of two stages: the first stage has a rotation speed of 500–1500 rpm / min and a spin coating time of 5–20 s. The second stage involves a spin coating speed of 2000–5000 rpm / min and a spin coating time of 30–50 s; the annealing temperature after spin coating is 100–220 ℃ and the annealing time is 5–30 min.

5. The perovskite solar cell based on an organically modified lithium salt-doped hole transport layer according to claim 4, characterized in that, The solute in the perovskite precursor solution is APbX3, with an APbX3 concentration of 0.6–1.2 mol / L, and the solvent is any one or a mixture of dimethylformamide, dimethyl sulfoxide, γ-butyrolactone, and N-methylpyrrolidone.

6. The perovskite solar cell based on an organically modified lithium salt-doped hole transport layer according to claim 1, characterized in that, The electron transport layer is made of any one of TiO2, ZnO, SnO2, or Nb2O5.

7. The perovskite solar cell based on an organically modified lithium salt-doped hole transport layer according to claim 1, characterized in that, The material of the metal electrode is any one of Au, Ag, and Cu.

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