Perovskite precursor solution additive, solution, solar cell and preparation method

Abstract

The invention relates to the technical field of perovskite solar cell preparation, in particular to a perovskite precursor solution additive, a solution, a solar cell and a preparation method. The structural formula of the perovskite precursor solution additive is shown in the specification, X is selected from halogen atoms, and m is an integer from 0 to 3; and n is an integer of 0-3. The perovskite precursor solution additive provided by the invention has excellent compatibility and stability, can effectively regulate and control the crystallization process of the perovskite film, and improves the microstructure and photoelectric properties of the film. Besides, the perovskite solar cell prepared on the basis of the perovskite precursor solution provided by the invention overcomes the defects of insufficient perovskite film crystal quality, limited photoelectric property and stability in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite solar cell preparation, and in particular to a perovskite precursor solution additive, a solution, a solar cell and a preparation method. Background Art

[0002] Perovskite solar cells, an emerging solar cell technology, show great potential in the photovoltaic field due to their high photoelectric conversion efficiency, low-cost fabrication process, and tunable photoelectric properties. However, their commercial application is limited by the stability of perovskite materials, the optimization of photoelectric properties, and the quality control of thin films during the fabrication process. The composition and formulation of the perovskite precursor solution, the basic material for preparing perovskite thin films, have a decisive influence on the performance of the final cell.

[0003] Conventional perovskite precursor solutions consist primarily of perovskite material components, such as lead, iodine, or methylamine, dissolved in an organic solvent. However, this basic formula often fails to meet the stringent requirements for thin film crystallization quality, optoelectronic properties, and stability required for high-performance perovskite solar cells.

[0004] In recent years, researchers have modified perovskite precursor solutions by introducing various inorganic salts, organic compounds, or interface modifiers as perovskite precursor solution additives in an effort to achieve better perovskite film and cell performance. These perovskite precursor solution additives have significantly improved the photoelectric conversion efficiency and stability of perovskite solar cells by influencing the growth kinetics of perovskite crystals, regulating the solvent evaporation rate, optimizing the film microstructure, and improving the interface contact quality. However, existing perovskite precursor solution additives have poor compatibility with the perovskite precursor solution, resulting in unstable cell performance after introduction, and high preparation costs. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present invention provides a perovskite precursor solution additive, a solution, a solar cell, and a preparation method. The perovskite precursor solution additive provided by the present invention has excellent solution compatibility and chemical stability. When applied to a perovskite precursor solution, it can not only improve the compatibility and stability of the perovskite precursor solution, but also effectively regulate the crystallization process of the perovskite film, improve the microstructure and photoelectric properties of the film, and overcome the problems in the prior art of poor compatibility of the perovskite precursor solution additive, unstable battery performance after introduction, and high preparation cost. Based on the perovskite precursor solution of the present invention, a perovskite solar cell is prepared, which overcomes the problems of insufficient perovskite film crystallization quality, limited photoelectric performance, and stability defects in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The first object of the present invention is to provide a perovskite precursor solution additive, the structural formula of the perovskite precursor solution additive is: , wherein X is selected from a halogen atom, m is an integer of 0 to 3; and n is an integer of 0 to 3.

[0007] Preferably, the perovskite precursor solution additive is selected from 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 or .

[0008] A second object of the present invention is to provide a perovskite precursor solution, which is prepared from the above-mentioned perovskite precursor solution additive, lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride, and the molar ratio of the lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride is 1.0~1.1:0.1~0.12:0.07~0.1:1~1.2:0.18~0.2:0.16~0.2.

[0009] Preferably, lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride are dissolved together in a mixed solvent consisting of N,N-dimethylformamide and dimethyl sulfoxide to obtain a mixed solution; a perovskite precursor solution additive is added to the mixed solution to obtain a perovskite precursor solution; wherein the molar ratio of lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride is 1.0~1.1:0.1~0.12:0.07~0.1:1~1.2:0.18~0.2:0.16~0.2.

[0010] Preferably, in the mixed solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3.8-4.2:0.8-1.2.

[0011] Preferably, the volume ratio of the mixed solution to the perovskite precursor solution additive is 60-200:1.

[0012] The third object of the present invention is to provide a perovskite solar cell, which is composed of a substrate, a hole transport layer, a perovskite light absorbing layer, an electron transport layer and a top electrode layer stacked in sequence from bottom to top; wherein the above-mentioned perovskite precursor solution is spin-coated on the surface of the hole transport layer to form the perovskite light absorbing layer.

[0013] A fourth object of the present invention is to provide a method for preparing the above-mentioned perovskite solar cell, characterized in that it comprises the following steps: S1. Substrate pretreatment: clean the indium tin oxide substrate and dry it to obtain a substrate.

[0014] S2. Preparation of hole transport layer: spin-coating the alcohol solution of MeO-2PACz on the surface of the substrate, and annealing the substrate to form a hole transport layer on the substrate.

[0015] S3. Preparation of perovskite light absorbing layer: spin-coating the above perovskite precursor solution on the hole transport layer, using chlorobenzene as an anti-solvent, and depositing it on the hole transport layer, followed by annealing to obtain the perovskite light absorbing layer.

[0016] S4, preparation of electron transport layer: evaporate C on the perovskite light absorbing layer in sequence 60 and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline to obtain an electron transport layer.

[0017] S6. Preparation of the top electrode layer: vapor-depositing an Ag electrode on the electron transport layer to obtain a perovskite solar cell.

[0018] Preferably, during the formation of the hole transport layer, the annealing treatment is performed at 100° C. to 120° C. for 10 min to 20 min.

[0019] Preferably, during the formation of the perovskite light-absorbing layer, the annealing treatment conditions are: annealing at 100° C. to 300° C. for 10 min to 60 min.

[0020] Preferably, the thickness of the C60 coating is 120 nm to 150 nm.

[0021] Preferably, the thickness of the 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline coating is 60 nm to 80 nm.

[0022] Preferably, the thickness of the Ag electrode is 1000 nm to 1200 nm.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a perovskite precursor solution additive, the structural formula of the perovskite precursor solution additive is: , wherein X is selected from a halogen atom, m is an integer from 0 to 3, and n is an integer from 0 to 3. The perovskite precursor solution additive provided by the present invention has excellent compatibility and stability, can effectively regulate the crystallization process of perovskite thin films, and improve the microstructure and photoelectric properties of the films. This successfully overcomes the problems of existing additives in perovskite precursor processing, such as poor compatibility, unstable performance of perovskite solar cells after introduction, and high preparation costs.

[0024] Specifically, first, the perovskite precursor solution additive provided by the present invention has excellent solution compatibility and chemical stability, which is attributed to its molecular structure characteristics: the halogen functional group can participate in nucleophilic substitution reactions and elimination reactions to generate unsaturated bonds or introduce new functional groups; the bromine atom also has the function of a directing group, promoting the electrophilic substitution reaction of the benzene ring, and its strong leaving ability is beneficial to the subsequent functional group transformation; the trifluoromethyl group, as a strong electron-withdrawing group, significantly reduces the electron cloud density of the benzene ring through the inductive effect, thereby enhancing the electronegativity of the molecule; strengthens the ortho or para positioning effect, and guides the directional attack of the electrophilic reagent; at the same time, the introduction of the trifluoromethyl group can improve the thermal stability, chemical stability and fat solubility of the molecule, thereby regulating the intermolecular force, giving the perovskite precursor solution additive excellent compatibility and stability.

[0025] Secondly, the perovskite precursor solution additive molecules of the present invention can serve as heterogeneous nucleation sites in the perovskite precursor solution. Due to the specific interaction between the perovskite precursor solution additive molecules and the perovskite precursor ions, they can attract the perovskite precursor ions to aggregate around them, thereby reducing the energy barrier required for nucleation. In addition, the perovskite precursor solution additive can change the physical properties of the perovskite precursor solution, such as viscosity and surface tension, thereby affecting the mass and heat transfer processes during the crystallization process, thereby effectively regulating the crystallization process of the perovskite film, improving the microstructure and optoelectronic properties of the film, and reducing the preparation cost.

[0026] Finally, the perovskite precursor solution additive provided by the present invention is added to the perovskite precursor solution in proportion, and the perovskite light-absorbing layer prepared using the perovskite precursor solution can effectively reduce the defect states on the perovskite surface. Under continuous heating conditions, on the one hand, the perovskite precursor solution additive can adjust the viscosity of the perovskite precursor solution and change the diffusion rate of the perovskite precursor ions. Increasing the viscosity of the solution can slow down the diffusion rate of the perovskite precursor ions and avoid coarse and uneven grains caused by rapid crystal growth; on the other hand, the perovskite precursor solution additive can change the surface tension of the perovskite precursor solution and affect the wettability and spreadability of the perovskite precursor solution on the substrate. The perovskite precursor solution additive can diffuse to the surface and grain boundaries of the perovskite film, thereby affecting the attachment and growth of the crystal nuclei on the substrate. By comprehensively regulating these physical properties, perovskite precursor solution additives can control the crystallization rate and crystallization process of perovskite crystals, allowing the crystals to grow slowly under relatively mild conditions, forming a perovskite film with high crystallinity and few defects, thereby enhancing the crystallinity of the perovskite film and thus enhancing the charge transfer efficiency.

[0027] 2. The perovskite precursor solution additive provided by the present invention is applied to the perovskite precursor solution, which successfully overcomes the limitations of traditional perovskite precursor solutions in the prior art. Such traditional solutions are formed by dissolving the constituent elements of lead, iodine and methylamine perovskite materials in an organic solvent, which is difficult to meet the stringent requirements of high-performance perovskite solar cells on thin film crystallization quality, photoelectric performance and stability.

[0028] 3. When the perovskite precursor solution prepared using the perovskite precursor solution additive of the present invention is applied to a perovskite solar cell, the photoelectric conversion efficiency of the resulting perovskite solar cell is significantly improved. This is because the halogen atoms in the perovskite precursor solution additive molecules form hydrogen bonds with the formamidinium ions. The strong interaction between them suppresses the formation of formamidinium ion vacancies and ultimately improves the photoelectric conversion capacity of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Graphs of current density at different voltages for Examples 1 to 3 of the present invention and Comparative Example 1.

[0030] Figure 2 Schematic diagram of the structure of the perovskite solar cell according to Examples 1 to 5 of the present invention, wherein: Figure 2 Description of the reference numerals: 1. Substrate; 2. Hole transport layer; 3. Perovskite light absorption layer; 4. Electron transport layer; 5. Top electrode layer. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solution of the present invention in conjunction with the data in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. Among them, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is abbreviated as BCP; indium tin oxide is abbreviated as ITO; lead iodide is abbreviated as PbI2; methylammonium bromide is abbreviated as MABr; lead bromide is abbreviated as PbBr2; formamidine iodide is abbreviated as FAI; cesium iodide is abbreviated as CsI; lead chloride is abbreviated as PbCl2.

[0033] Existing perovskite precursor solution additives have poor compatibility with the perovskite precursor solution, lead to unstable battery performance after introduction, and have high preparation costs.

[0034] To address the above-mentioned compatibility issue, the present invention overcomes this problem by using halogen- and trifluoromethyl-containing aromatic compounds as additives, utilizing their excellent solubility and chemical affinity with perovskite components, such as halogen-lead coordination and hydrogen bonding, to achieve uniform dispersion and stabilize the precursor solution.

[0035] To address the above-mentioned performance instability problem, the present invention overcomes this problem by directionally adsorbing additive molecules on grain boundaries and surfaces during the crystallization process, passivating lead vacancy and halogen vacancy defects, and optimizing crystal growth kinetics to obtain a low-defect, high-crystallinity film.

[0036] To address the above-mentioned high cost problem, the present invention overcomes this problem by simplifying the additive synthesis route, such as a one-step halogenation or trifluoromethylation reaction, using inexpensive raw materials such as halogenated benzenes and trifluoromethylation reagents, and a process that does not require precious metal catalysts, thereby significantly reducing production costs.

[0037] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will be described in detail with reference to specific embodiments. Since the perovskite precursor solution additives provided by the present invention have similar structures and similar performances, only C8H5Br2F3 is taken as an example and applied to the perovskite precursor solutions of Examples 1 to 3 to prepare perovskite solar cells. The structural formula of C8H5Br2F3 is .

[0038] The structural diagram of the perovskite solar cell prepared in Examples 1 to 5 of the present invention is as follows: Figure 2 As shown, 1 represents the substrate layer, 2 represents the hole transport layer, 3 represents the perovskite light absorption layer, 4 represents the electron transport layer, and 5 represents the top electrode layer.

[0039] Example 1 A method for preparing a perovskite solar cell, the structural diagram of which is shown in FIG. Figure 2 As shown, the following steps are included: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0040] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 100°C for 10 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0041] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1 according to a molar ratio of 1.1:0.1:0.1:1:0.2:0.2 to obtain a mixed solution; 5 μL of C8H5Br2F3 was added to 1200 μL of the mixed solution to form a perovskite precursor solution; and the hole-transmitting The ITO substrate of the hole transport layer was treated with ozone for 30 minutes, and then transferred to a spin coater, and 40 μL of perovskite precursor solution was added to the surface of the hole transport layer. After standing, it was spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent was added 20 seconds before the end of spin coating. After the spin coating was completed, the substrate was quickly placed on a hot plate at 100°C for annealing for 10 minutes to form a perovskite absorption layer on the hole transport layer, thereby obtaining an ITO substrate containing a perovskite absorption layer.

[0042] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0043] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell, wherein the Ag electrode had a thickness of 1200 nm.

[0044] Example 2 A method for preparing a perovskite solar cell, the structural diagram of which is shown in FIG. Figure 2 As shown, the preparation steps are the same as those in Example 1, except that the amount of C8H5Br2F3 added in S3 is replaced from 5 μL to 10 μL, comprising the following steps: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0045] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 100°C for 10 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0046] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1 according to a molar ratio of 1.1:0.1:0.1:1:0.2:0.2 to obtain a mixed solution; 10 μL of C8H5Br2F3 was added to 1200 μL of the mixed solution to form a perovskite precursor solution; and the solution containing holes was added to the mixed solvent. The ITO substrate of the transport layer was treated with ozone for 30 minutes, and then transferred to a spin coater, and 40 μL of perovskite precursor solution was added to the surface of the hole transport layer. After standing, it was spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent was added 20 seconds before the end of spin coating. After the spin coating was completed, the substrate was quickly placed on a hot plate at 100°C for annealing for 10 minutes to form a perovskite absorption layer on the hole transport layer, thereby obtaining an ITO substrate containing a perovskite absorption layer.

[0047] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0048] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell.

[0049] Example 3 A method for preparing a perovskite solar cell, the structural diagram of which is shown in FIG. Figure 2As shown, the preparation steps are the same as those in Example 1, except that the amount of C8H5Br2F3 added in S3 is replaced from 5 μL to 15 μL, comprising the following steps: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0050] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 100°C for 10 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0051] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1 according to a molar ratio of 1.1:0.1:0.1:1:0.2:0.2 to obtain a mixed solution; 15 μL of C8H5Br2F3 was added to 1200 μL of the mixed solution to form a perovskite precursor solution; and the solution containing holes was added to the mixture. The ITO substrate of the transport layer was treated with ozone for 30 minutes, and then transferred to a spin coater, and 40 μL of perovskite precursor solution was added to the surface of the hole transport layer. After standing, it was spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent was added 20 seconds before the end of spin coating. After the spin coating was completed, the substrate was quickly placed on a hot plate at 100°C for annealing for 10 minutes to form a perovskite absorption layer on the hole transport layer, thereby obtaining an ITO substrate containing a perovskite absorption layer.

[0052] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0053] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell.

[0054] Example 4 A method for preparing a perovskite solar cell, the structural diagram of which is shown in FIG. Figure 2 As shown, the following steps are included: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0055] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 120°C for 20 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0056] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1.2 according to a molar ratio of 1.0:0.12:0.07:1.2:0.18:0.16 to obtain a mixed solution; 6 μL of C8H5Br2F3 was added to 1200 μL of the mixed solution to form a perovskite precursor solution; and the perovskite precursor solution containing The ITO substrate with a hole transport layer was treated with ozone for 30 minutes, then transferred to a spin coater, and 40 μL of perovskite precursor solution was added to the surface of the hole transport layer. After standing, it was spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent was added 20 seconds before the end of spin coating. After the spin coating was completed, the substrate was quickly placed on a hot plate at 300°C for annealing for 60 minutes to form a perovskite absorption layer on the hole transport layer, thereby obtaining an ITO substrate containing a perovskite absorption layer.

[0057] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0058] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell, wherein the Ag electrode had a thickness of 1200 nm.

[0059] Example 5 A method for preparing a perovskite solar cell, the structural diagram of which is shown in FIG. Figure 2 As shown, the following steps are included: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0060] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 100°C for 10 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0061] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 were dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 3.8:0.8 according to a molar ratio of 1.1:0.1:0.1:1:0.2:0.2 to obtain a mixed solution; 20 μL of C8H5Br2F3 was added to 1200 μL of the mixed solution to form a perovskite precursor solution; and the solution containing The ITO substrate of the hole transport layer was treated with ozone for 30 minutes, and then transferred to a spin coater, and 40 μL of perovskite precursor solution was added to the surface of the hole transport layer. After standing, it was spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent was added 20 seconds before the end of spin coating. After the spin coating was completed, the substrate was quickly placed on a hot plate at 100°C for annealing for 10 minutes to form a perovskite absorption layer on the hole transport layer, thereby obtaining an ITO substrate containing a perovskite absorption layer.

[0062] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0063] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell, wherein the thickness of the Ag electrode was 1200 nm.

[0064] Comparative Example 1 A method for preparing a perovskite solar cell is the same as the preparation steps of Example 1, except that the amount of C8H5Br2F3 added to S3 is replaced from 5 μL to 0 μL, comprising the following steps: A method for preparing a perovskite solar cell comprises the following steps: S1. Preparation of substrate layer: The ITO substrate was placed in a solution of ultrapure water and de-glassing washing machine mixed at a ratio of 100:1 and ultrasonically cleaned for 25 minutes, followed by ultrasonic cleaning with ultrapure water twice, each time for 20 minutes; the cleaned ITO substrate was placed in a 100°C oven to dry for 20 minutes, and then the dried ITO substrate was placed in a UV ozone machine for treatment for 25 minutes to obtain a pretreated ITO substrate for use.

[0065] S2. Preparation of hole transport layer: MeO-2PACz was mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution was spin-coated on the hole transport layer on the surface of a spare pretreated ITO substrate, and annealed at 100°C for 10 min to form a hole transport layer on the pretreated ITO substrate, thereby obtaining an ITO substrate containing a hole transport layer.

[0066] S3. Preparation of perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI and PbCl2 are dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1 in a molar ratio of 1.1:0.1:0.1:1:0.2:0.2 to obtain a mixed solution; the ITO substrate containing the hole transport layer is treated with ozone for 30 minutes, and then transferred to a spin coater, and 40 μL of the mixed solution is added to the surface of the hole transport layer. After standing, it is spin-coated at a speed of 6000 rpm for 40 seconds, and 100 μL of chlorobenzene antisolvent is added 20 seconds before the end of spin coating; after the spin coating is completed, the substrate is quickly placed on a hot plate at 100°C for annealing for 10 minutes to form a perovskite light-absorbing layer on the hole transport layer to obtain an ITO substrate containing a perovskite light-absorbing layer.

[0067] S4. Preparation of electron transport layer: On the ITO substrate containing the perovskite light absorbing layer, the electron transport layer was prepared under vacuum of 5×10 -4 Pa, at an evaporation rate of 0.2 A / s, C60 and BCP were sequentially evaporated to a thickness of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0068] S5. Preparation of top electrode layer: in vacuum degree 5×10 -4 Pa, at an evaporation rate of 2 A / s, an Ag electrode was evaporated on the electron transport layer of an ITO substrate containing an electron transport layer to obtain a perovskite solar cell.

[0069] Perovskite solar cells were prepared in Examples 1 to 3 of the present invention and Comparative Example 1, and their photoelectric performance was tested using the following test method: The measurement was performed using a solar simulation test system. The light source used was a 500W xenon lamp solar spectrum simulator, and a standard silicon cell was used to calibrate the light source. At a sunlight intensity of AM1.5G: 100mW / cm 2 The measurement was performed under the following conditions. A continuously varying voltage of -0.1V to 1.2V was applied to both ends of the perovskite solar cell to measure the output current of the perovskite solar cell. The test power supply used was Keithley 2450. The product of the voltage and current was used to obtain the JV test curve, which shows the photoelectric conversion efficiency of the device under different states.

[0070] Table 1 Performance parameters of perovskite solar cells of Examples 1 to 3 and Comparative Example 1 The results in Table 1 show that the photoelectric conversion efficiency of perovskite solar cells prepared by adding C8H5Br2F3 is significantly improved, with the highest conversion efficiency achieved when 5μL of the additive is added. This is because the F in the C8H5Br2F3 molecule forms hydrogen bonds with the formamidine ion. The strong interaction between them suppresses the formation of FA vacancies, ultimately improving the photoelectric conversion capacity of the perovskite solar cell.

[0071] Figure 1 The results show that the perovskite solar cells of Examples 1 to 3 outperformed Comparative Example 1. In the low voltage range of 0V to 0.9V, the current density of Examples 1 to 3 was high and stable, indicating higher efficiency. As the voltage approached 1.2V, the current density decreased, indicating better stability at high voltages. These results demonstrate that the perovskite solar cells of Examples 1 to 3 outperformed Comparative Example 1.

[0072] It should be noted that when the present invention involves numerical ranges, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. A perovskite precursor solution additive, characterized in that: The structural formula of the perovskite precursor solution additive is: , wherein X is selected from a halogen atom, m is an integer of 0 to 3; and n is an integer of 0 to 3.

2. The perovskite precursor solution additive according to claim 1, characterized in that The perovskite precursor solution additive is selected from 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 or .

3. A perovskite precursor solution, characterized in that The perovskite precursor solution is prepared from the perovskite precursor solution additive according to claim 1, lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride, and the molar ratio of the lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide and lead chloride is 1.0~1.1:0.1~0.12:0.07~0.1:1~1.2:0.18~0.2:0.16~0.

2.

4. The method for preparing a perovskite precursor solution according to claim 3, wherein: Dissolving lead iodide, methylamine hydrobromide, lead bromide, formamidine hydroiodide, cesium iodide, and lead chloride in a mixed solvent consisting of N,N-dimethylformamide and dimethyl sulfoxide at a molar ratio of 1.0-1.1:0.1-0.12:0.07-0.1:1-1.2:0.18-0.2:0.16-0.2 to obtain a mixed solution; A perovskite precursor solution additive is added to the mixed solution to obtain a perovskite precursor solution.

5. The method for preparing a perovskite precursor solution according to claim 4, wherein: In the mixed solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3.8~4:0.8~1.

2.

6. The method for preparing a perovskite precursor solution according to claim 4, wherein: The volume ratio of the mixed solution to the perovskite precursor solution additive is 60~200:

1.

7. A perovskite solar cell, characterized in that: The perovskite solar cell is composed of a substrate (1), a hole transport layer (2), a perovskite light absorption layer (3), an electron transport layer (4) and a top electrode layer (5) which are stacked in sequence from bottom to top; The perovskite precursor solution according to claim 3 is spin-coated on the surface of the hole transport layer (2) to form the perovskite light absorption layer (3).

8. The method for preparing a perovskite solar cell according to claim 7, wherein: The following steps are involved: The alcohol solution of MeO-2PACz was spin-coated on the substrate surface and annealed to form a hole transport layer on the substrate; The perovskite precursor solution is spin-coated on the hole transport layer, using chlorobenzene as an anti-solvent, and deposited on the hole transport layer, followed by annealing to obtain the perovskite light absorbing layer; C is sequentially evaporated on the perovskite light absorbing layer. 60 and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline to obtain an electron transport layer; An Ag electrode is evaporated on the electron transport layer to obtain a perovskite solar cell.

9. The method for preparing a perovskite solar cell according to claim 8, wherein: During the formation of the hole transport layer, the annealing conditions are: annealing at 100° C. to 120° C. for 10 min to 20 min.

10. The method for preparing a perovskite solar cell according to claim 8, wherein: During the formation of the perovskite light-absorbing layer, the annealing conditions are: annealing at 100°C~300°C for 10min~60min.

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