Perovskite precursor solution additives, solutions, solar cells and preparation methods

Abstract

This invention relates to the field of perovskite solar cell fabrication technology, specifically to perovskite precursor solution additives, solutions, solar cells, and fabrication methods. The structural formula of the perovskite precursor solution additive is: [Formula omitted for brevity], where X is selected from halogen atoms, m is an integer from 0 to 3, and n is an integer from 0 to 3. The perovskite precursor solution additive provided by this invention exhibits excellent compatibility and stability, effectively controlling the crystallization process of perovskite thin films and improving the microstructure and photoelectric properties of the films. Furthermore, the perovskite solar cells fabricated based on the perovskite precursor solution provided by this invention overcome the shortcomings of existing technologies, such as insufficient crystallization quality, limited photoelectric performance, and instability.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell fabrication technology, specifically to perovskite precursor solution additives, solutions, solar cells, and fabrication methods. Background Technology

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

[0003] Traditional perovskite precursor solutions are mainly formed by dissolving the constituent elements of perovskite materials, such as lead, iodine, or methylamine, in organic solvents. However, this basic formulation often fails to meet the high requirements of high-performance perovskite solar cells for thin-film crystal quality, photoelectric performance, and stability.

[0004] In recent years, researchers have modified perovskite precursor solutions by introducing various inorganic salts, organic substances, or interface modifiers as additives to obtain better perovskite thin films and battery performance. These perovskite precursor solution additives significantly improve the photoelectric conversion efficiency and stability of perovskite solar cells by influencing the growth kinetics of perovskite crystals, regulating solvent evaporation rates, optimizing film microstructure, and improving interfacial contact quality. However, existing perovskite precursor solution additives suffer from poor compatibility with perovskite precursor solutions, unstable battery performance after introduction, and high fabrication costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a perovskite precursor solution additive, a solution, a solar cell, and a preparation method. The perovskite precursor solution additive provided by this invention exhibits excellent solution compatibility and chemical stability. Its application in the perovskite precursor solution not only improves the compatibility and stability of the solution but also effectively regulates the crystallization process of the perovskite thin film, improving its microstructure and photoelectric properties. This overcomes the problems of poor compatibility, unstable battery performance, and high preparation costs associated with existing perovskite precursor solution additives. Based on the perovskite precursor solution of this invention, a perovskite solar cell was fabricated, overcoming the deficiencies in the crystal quality, limited photoelectric performance, and stability of the perovskite thin film in existing technologies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first objective of this invention is to provide a perovskite precursor solution additive, the structural formula of which is: , where X is selected from halogen atoms, m is an integer from 0 to 3; n is an integer from 0 to 3.

[0008] Preferably, the perovskite precursor solution additive is selected from... , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , or .

[0009] A second objective of this invention is to provide a perovskite precursor solution, which is prepared from the above-mentioned perovskite precursor solution additives, lead iodide, methylamine hydrobromide, lead bromide, formamidinium hydroiodide, cesium iodide, and lead chloride, wherein the molar ratio of lead iodide, methylamine hydrobromide, lead bromide, formamidinium 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, lead iodide, methylamine hydrobromide, lead bromide, formamidinium hydroiodide, cesium iodide, and lead chloride are dissolved together in a mixed solvent composed 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, formamidinium 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.

[0011] Preferably, in the mixed solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3.8~4.2:0.8~1.2.

[0012] Preferably, the volume ratio of the mixed solution to the perovskite precursor solution additive is 60~200:1.

[0013] The third objective of this invention is to provide a perovskite solar cell, which comprises a substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a top electrode layer stacked sequentially from bottom to top; wherein, the perovskite precursor solution is spin-coated onto the surface of the hole transport layer to form the perovskite light-absorbing layer.

[0014] A fourth objective of this invention is to provide a method for preparing the above-mentioned perovskite solar cell, characterized by comprising the following steps:

[0015] S1. Substrate pretreatment: Clean the indium tin oxide substrate and dry it to obtain the substrate.

[0016] S2. Hole transport layer preparation: An alcoholic solution of MeO-2PACz is spin-coated onto the substrate surface and annealed to form a hole transport layer on the substrate.

[0017] S3. Preparation of perovskite light-absorbing layer: The above perovskite precursor solution is spin-coated onto the hole transport layer, and chlorobenzene is used as the anti-solvent and deposited onto the hole transport layer. After annealing, the perovskite light-absorbing layer is obtained.

[0018] S4. Electron transport layer preparation: C is sequentially deposited onto the perovskite light-absorbing layer. 60 An electron transport layer was obtained by reacting 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline.

[0019] S6. Preparation of the top electrode layer: An Ag electrode is deposited on the electron transport layer to obtain a perovskite solar cell.

[0020] Preferably, during the formation of the hole transport layer, the annealing conditions are: annealing at 100℃~120℃ for 10min~20min.

[0021] Preferably, during the formation of the perovskite light-absorbing layer, the annealing conditions are: annealing at 100℃~300℃ for 10min~60min.

[0022] Preferably, the thickness of the C60 coating is 120nm~150nm.

[0023] Preferably, the thickness of the 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline coating is 60 nm to 80 nm.

[0024] Preferably, the thickness of the Ag electrode is 1000nm~1200nm.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. This invention provides a perovskite precursor solution additive, the structural formula of which is: Where X is selected from halogen atoms, m is an integer from 0 to 3, and n is an integer from 0 to 3. The perovskite precursor solution additive provided by this invention has excellent compatibility and stability, can effectively regulate the crystallization process of perovskite thin films, improve the microstructure and photoelectric properties of the films, and successfully overcomes the problems of poor compatibility of existing additives in perovskite precursor treatment, unstable performance of perovskite solar cells after introduction, and high preparation cost.

[0027] Specifically, firstly, the perovskite precursor solution additive provided by this invention exhibits excellent solution compatibility and chemical stability, attributed to its molecular structural features: halogen functional groups, capable of participating in nucleophilic substitution and elimination reactions to generate unsaturated bonds or introduce new functional groups; bromine atoms also function as directing groups, promoting electrophilic substitution reactions of the benzene ring, and their strong leaving ability facilitates subsequent functional group transformations; trifluoromethyl groups, as strong electron-withdrawing groups, significantly reduce the electron cloud density of the benzene ring through inductive effects, enhancing molecular electronegativity; strengthening ortho- or para-positional directing effects, guiding electrophilic reagents to attack in a directional manner; simultaneously, the introduction of trifluoromethyl groups can improve molecular thermal stability, chemical stability, and lipophilic solubility, thereby regulating intermolecular forces and endowing the perovskite precursor solution additive with excellent compatibility and stability.

[0028] Secondly, the perovskite precursor solution additive molecules of this invention can serve as heterogeneous nucleation sites in the perovskite precursor solution. Due to the specific interactions 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. Furthermore, the perovskite precursor solution additive can alter the physical properties of the perovskite precursor solution, such as viscosity and surface tension, thereby affecting the mass and heat transfer processes during crystallization. This effectively controls the crystallization process of the perovskite thin film, improves the microstructure and photoelectric properties of the film, and simultaneously reduces the preparation cost.

[0029] Finally, by adding the perovskite precursor solution additive provided by this invention to the perovskite precursor solution in a certain proportion, the perovskite light-absorbing layer prepared using the perovskite precursor solution can effectively reduce 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, thereby changing the diffusion rate of perovskite precursor ions. Increasing the solution viscosity can slow down the diffusion rate of perovskite precursor ions, avoiding grain coarsening and inhomogeneity caused by excessively rapid crystal growth; on the other hand, the perovskite precursor solution additive can change the surface tension of the perovskite precursor solution, affecting 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 adhesion and growth of crystal nuclei on the substrate. By comprehensively regulating these physical properties, perovskite precursor solution additives can control the crystallization rate and process of perovskite crystals, allowing the crystals to grow slowly under relatively mild conditions, forming perovskite films with high crystallinity and few defects, thereby enhancing the crystallinity of the perovskite film and thus improving charge transport efficiency.

[0030] 2. The perovskite precursor solution additive provided by this 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 lead, iodine and methylamine perovskite material components in organic solvents, which is difficult to meet the stringent requirements of high-performance perovskite solar cells for thin film crystallization quality, photoelectric performance and stability.

[0031] 3. When the perovskite precursor solution prepared using the perovskite precursor solution additive of this invention is applied to perovskite solar cells, the photoelectric conversion efficiency of the resulting perovskite solar cells is significantly improved. This is because the halogen atoms in the perovskite precursor solution additive molecules form hydrogen bonds with formamidinium ions. The strong interaction between them inhibits the formation of formamidinium ion vacancies, ultimately improving the photoelectric conversion capability of the perovskite solar cells. Attached Figure Description

[0032] Figure 1 The diagram shows the current density of Embodiments 1 to 3 and Comparative Example 1 under different voltages.

[0033] Figure 2 These are schematic diagrams of the perovskite solar cells of Examples 1 to 5 of the present invention, wherein... Figure 2 Explanation of reference numerals in the attached figures:

[0034] 1. Substrate; 2. Hole transport layer; 3. Perovskite light-absorbing layer; 4. Electron transport layer; 5. Top electrode layer. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that the technical terms used in this invention are only for describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased commercially 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; formamidinium iodide is abbreviated as FAI; cesium iodide is abbreviated as CsI; and lead chloride is abbreviated as PbCl2.

[0037] Existing perovskite precursor solution additives have problems such as poor compatibility with perovskite precursor solutions, unstable battery performance after introduction, and high preparation costs.

[0038] To address the aforementioned compatibility issues, this invention utilizes aromatic compounds containing halogens and trifluoromethyl groups as additives. By leveraging their excellent solubility and chemical affinity with perovskite components, such as halogen-lead coordination and hydrogen bonding, the precursor solution is uniformly dispersed and stabilized, thus overcoming the problem.

[0039] To address the aforementioned performance instability issue, this invention overcomes the problem by allowing additive molecules to be directionally adsorbed onto grain boundaries and surfaces during crystallization, passivating lead and halogen vacancies, and simultaneously optimizing crystal growth kinetics to obtain low-defect, high-crystallinity thin films.

[0040] To address the aforementioned high cost issue, this invention simplifies the additive synthesis route, such as through a one-step halogenation or trifluoromethylation reaction, using inexpensive raw materials such as halogenated benzenes and trifluoromethylation reagents, and employing a process that does not require precious metal catalysts, thereby significantly reducing production costs and overcoming this problem.

[0041] To enable those skilled in the art to more clearly understand the technical solution of the present invention, a detailed description will be provided below in conjunction with specific embodiments. Since the perovskite precursor solution additives provided by the present invention have similar structures and performance, only C8H5Br2F3 is used as an example here, and it is applied to the perovskite precursor solutions of Examples 1 to 3 to prepare perovskite solar cells. The structural formula of C8H5Br2F3 is... .

[0042] The structural schematic diagrams of the perovskite solar cells prepared in Examples 1 to 5 of this invention are shown below. Figure 2 As shown, 1 represents the substrate layer, 2 represents the hole transport layer, 3 represents the perovskite light-absorbing layer, 4 represents the electron transport layer, and 5 represents the top electrode layer.

[0043] Example 1

[0044] A method for fabricating a perovskite solar cell, the schematic diagram of which is shown below. Figure 2 As shown, it includes the following steps:

[0045] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0046] S2. Hole transport layer preparation: MeO-2PACz is mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution is spin-coated onto the hole transport layer on the surface of the prepared pretreated ITO substrate and annealed at 100℃ for 10 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0047] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in 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; then, a hole-conducting... The ITO substrate with the hole transport layer was subjected to ozone treatment for 30 min, then transferred to a spin coater, and 40 μL of perovskite precursor solution was dropped onto the surface of the hole transport layer. After standing, it was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene antisolvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 100 °C for annealing for 10 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0048] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4 At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0049] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4 At Pa, an Ag electrode is deposited on the electron transport layer of an ITO substrate containing an electron transport layer at an evaporation rate of 2 A / s to obtain a perovskite solar cell, wherein the thickness of the Ag electrode is 1200 nm.

[0050] Example 2

[0051] A method for fabricating a perovskite solar cell, the schematic diagram of which is shown below. Figure 2 As shown, the preparation steps are the same as in Example 1, except that the amount of C8H5Br2F3 added in S3 is replaced from 5 μL to 10 μL, including the following steps:

[0052] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0053] S2. Hole transport layer preparation: MeO-2PACz is mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution is spin-coated onto the hole transport layer on the surface of the prepared pretreated ITO substrate and annealed at 100℃ for 10 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0054] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in 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; then, a perovskite precursor solution containing holes was prepared. The ITO substrate with the hole transport layer was treated with ozone for 30 min, then transferred to a spin coater, and 40 μL of perovskite precursor solution was dropped onto the surface of the hole transport layer. After standing, it was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene antisolvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 100 °C for annealing for 10 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0055] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4 At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0056] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4 At Pa, Ag electrodes are deposited on the electron transport layer of an ITO substrate containing an electron transport layer by evaporation at an evaporation rate of 2 A / s to obtain a perovskite solar cell.

[0057] Example 3

[0058] A method for fabricating a perovskite solar cell, the schematic diagram of which is shown below. Figure 2As shown, the preparation steps are the same as in Example 1, except that the amount of C8H5Br2F3 added in S3 is replaced from 5 μL to 15 μL, including the following steps:

[0059] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0060] S2. Hole transport layer preparation: MeO-2PACz is mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution is spin-coated onto the hole transport layer on the surface of the prepared pretreated ITO substrate and annealed at 100℃ for 10 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0061] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in 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; then, a perovskite precursor solution containing holes was prepared. The ITO substrate with the hole transport layer was treated with ozone for 30 min, then transferred to a spin coater, and 40 μL of perovskite precursor solution was dropped onto the surface of the hole transport layer. After standing, it was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene antisolvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 100 °C for annealing for 10 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0062] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4 At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0063] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4 At Pa, Ag electrodes are deposited on the electron transport layer of an ITO substrate containing an electron transport layer by evaporation at an evaporation rate of 2 A / s to obtain a perovskite solar cell.

[0064] Example 4

[0065] A method for fabricating a perovskite solar cell, the schematic diagram of which is shown below. Figure 2 As shown, it includes the following steps:

[0066] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0067] S2. Hole transport layer preparation: 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 onto the hole transport layer on the surface of the pretreated ITO substrate and annealed at 120℃ for 20 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0068] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in 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; then... An ITO substrate with a hole transport layer was subjected to ozone treatment for 30 min, then transferred to a spin coater, and 40 μL of perovskite precursor solution was dropped onto the surface of the hole transport layer. After standing, the substrate was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene antisolvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 300 °C for annealing for 60 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0069] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4 At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0070] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4At Pa, an Ag electrode is deposited on the electron transport layer of an ITO substrate containing an electron transport layer at an evaporation rate of 2 A / s to obtain a perovskite solar cell, wherein the thickness of the Ag electrode is 1200 nm.

[0071] Example 5

[0072] A method for fabricating a perovskite solar cell, the schematic diagram of which is shown below. Figure 2 As shown, it includes the following steps:

[0073] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0074] S2. Hole transport layer preparation: MeO-2PACz is mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution is spin-coated onto the hole transport layer on the surface of the prepared pretreated ITO substrate and annealed at 100℃ for 10 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0075] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in 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; then... The ITO substrate with the hole transport layer was subjected to ozone treatment for 30 min, then transferred to a spin coater, and 40 μL of perovskite precursor solution was dropped onto the surface of the hole transport layer. After standing, it was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene antisolvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 100 °C for annealing for 10 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0076] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4 At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0077] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4 At Pa, an Ag electrode is deposited on the electron transport layer of an ITO substrate containing an electron transport layer at an evaporation rate of 2 A / s to obtain a perovskite solar cell, wherein the thickness of the Ag electrode is 1200 nm.

[0078] Comparative Example 1

[0079] A method for preparing a perovskite solar cell is the same as that in Example 1, except that the amount of C8H5Br2F3 added in S3 is replaced from 5 μL to 0 μL, and includes the following steps:

[0080] A method for fabricating a perovskite solar cell includes the following steps:

[0081] S1. Substrate preparation: The ITO substrate was placed in a solution of ultrapure water and a glass cleaner mixed at a ratio of 100:1 and ultrasonicated for 25 minutes. Then, it was ultrasonically cleaned twice with ultrapure water for 20 minutes each time. The cleaned ITO substrate was placed in a 100°C oven and dried for 20 minutes. Then, the dried ITO substrate was placed in an ultraviolet ozone generator for 25 minutes to obtain a pretreated ITO substrate for later use.

[0082] S2. Hole transport layer preparation: MeO-2PACz is mixed with anhydrous ethanol to obtain a mixed solution with a concentration of 1 mmol / L. The mixed solution is spin-coated onto the hole transport layer on the surface of the prepared pretreated ITO substrate and annealed at 100℃ for 10 min to form a hole transport layer on the pretreated ITO substrate, thus obtaining an ITO substrate containing a hole transport layer.

[0083] S3. Preparation of the perovskite light-absorbing layer: PbI2, MABr, PbBr2, FAI, CsI, and PbCl2 were dissolved together in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide 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 was subjected to ozone treatment for 30 min, then transferred to a spin coater, and 40 μL of the mixed solution was dropped onto the surface of the hole transport layer. After standing, it was spin-coated at 6000 rpm for 40 s. 20 s before the end of the spin coating, 100 μL of chlorobenzene anti-solvent was dropped. After the spin coating was completed, the substrate was quickly placed on a hot stage at 100℃ and annealed for 10 min to form a perovskite light-absorbing layer on the hole transport layer, thus obtaining an ITO substrate containing a perovskite light-absorbing layer.

[0084] S4. Electron transport layer fabrication: On an ITO substrate containing a perovskite light-absorbing layer, under a vacuum of 5 × 10⁻⁶... -4At Pa, C60 and BCP were deposited sequentially at an evaporation rate of 0.2 A / s, with coating thicknesses of 150 nm and 80 nm, respectively, to obtain an ITO substrate containing an electron transport layer.

[0085] S5. Top electrode layer fabrication: under a vacuum of 5×10⁻⁶ -4 At Pa, Ag electrodes are deposited on the electron transport layer of an ITO substrate containing an electron transport layer by evaporation at an evaporation rate of 2 A / s to obtain a perovskite solar cell.

[0086] Perovskite solar cells were fabricated in Examples 1-3 and Comparative Example 1 of this invention, and their photoelectric performance was tested using the following methods:

[0087] Measurements were performed using a solar energy simulation testing system. The light source was a 500W xenon lamp solar spectrum simulator, calibrated with standard silicon cells at a solar intensity of AM1.5G: 100mW / cm². 2 Measurements were performed under the following conditions. A continuously varying voltage from -0.1V to 1.2V was applied across the perovskite solar cell to measure its output current. A Keithley 2450 power supply was used for the test. The product of the voltage and current yielded the JV test curve, which displays the photoelectric conversion efficiency of the device under different conditions.

[0088] Table 1 Performance parameters of perovskite solar cells in Examples 1-3 and Comparative Example 1

[0089]

[0090] The results in Table 1 show that the photoelectric conversion efficiency of the perovskite solar cell prepared by adding C8H5Br2F3 was significantly improved, with the highest conversion efficiency achieved by adding 5 μL of the additive. This is because the F in the C8H5Br2F3 molecule forms hydrogen bonds with formamidinium ions, and the strong interaction between them inhibits the formation of FA vacancies, ultimately improving the photoelectric conversion capability of the perovskite solar cell.

[0091] Figure 1 The results demonstrate that the perovskite solar cells of Examples 1-3 outperform Comparative Example 1. In the low voltage range of 0V to 0.9V, Examples 1-3 exhibit higher and more stable current densities, indicating higher efficiency. Furthermore, the decrease in current density as the voltage approaches 1.2V also demonstrates better stability at higher voltages. In summary, these results indicate that the perovskite solar cells of Examples 1-3 outperform Comparative Example 1.

[0092] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A perovskite precursor solution, characterized in that, The perovskite precursor solution is prepared from perovskite precursor solution additives, lead iodide, methylamine hydrobromide, lead bromide, formamidinium hydroiodide, cesium iodide, and lead chloride, wherein the molar ratio of lead iodide, methylamine hydrobromide, lead bromide, formamidinium 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; The perovskite precursor solution additives are selected from... , or .

2. The method for preparing the perovskite precursor solution according to claim 1, characterized in that, Lead iodide, methylamine hydrobromide, lead bromide, formamidinium hydroiodide, cesium iodide, and lead chloride were dissolved together in a mixed solvent composed of N,N-dimethylformamide and dimethyl sulfoxide in 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. Add perovskite precursor solution additive to the mixed solution to obtain perovskite precursor solution.

3. The method for preparing the perovskite precursor solution according to claim 2, characterized in that, In the mixed solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3.8~4:0.8~1.

2.

4. The method for preparing the perovskite precursor solution according to claim 2, characterized in that, The volume ratio of the mixed solution to the perovskite precursor solution additive is 60~200:

1.

5. A perovskite solar cell, characterized in that, The perovskite solar cell consists of a substrate (1), a hole transport layer (2), a perovskite light-absorbing layer (3), an electron transport layer (4), and a top electrode layer (5) stacked sequentially from bottom to top. The perovskite precursor solution of claim 1 is spin-coated onto the surface of the hole transport layer (2) to form the perovskite light-absorbing layer (3).

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, Includes the following steps: An alcoholic solution of MeO-2PACz was spin-coated onto the substrate surface and then annealed to form a hole transport layer on the substrate. The perovskite precursor solution was spin-coated onto the hole transport layer, and chlorobenzene was used as the anti-solvent and deposited onto the hole transport layer. After annealing, the perovskite light-absorbing layer was obtained. C is sequentially deposited on the perovskite light-absorbing layer. 60 And 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, to obtain an electron transport layer; Ag electrodes are deposited on the electron transport layer to obtain perovskite solar cells.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that, During the formation of the hole transport layer, the annealing conditions are: annealing at 100℃~120℃ for 10min~20min.

8. The method for preparing a perovskite solar cell according to claim 6, characterized in that, During the formation of the perovskite light-absorbing layer, the annealing conditions are: annealing at 100℃~300℃ for 10min~60min.

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