Co-deposition preparation method of self-assembly molecular layer / perovskite light absorption layer and solar cell

Abstract

The invention belongs to the technical field of optoelectronic materials and devices, and discloses a co-deposition preparation method of a self-assembly molecular layer / perovskite light absorption layer and a solar cell. According to the method, self-assembly molecules are added into a lead halide solution, a charge transport layer is formed on a transparent conductive substrate in a self-assembly mode, and the self-assembly molecular layer / perovskite light absorption layer is prepared. And preparing the perovskite light absorption layer through chemical reaction of ammonium halide salt and lead halide. Based on the method, an organic-inorganic hybrid perovskite solar cell and a photoelectric device which are high in efficiency and good in long-term stability can be prepared. According to the co-deposition preparation method of the self-assembled molecular charge transport layer and the perovskite light absorption layer disclosed by the invention, the preparation process flow of the device is simplified, the problem of substrate wettability caused by self-assembled molecular hydrophobicity can be solved, the uniformity and the crystallization quality of the perovskite light absorption layer are improved, and the performance of the device is improved. And a technical path is provided for realizing an efficient and stable large-area perovskite solar cell.

Description

Technical Field

[0001] This application belongs to the field of optoelectronic materials and devices technology, specifically relating to a method for co-deposition of a self-assembled molecular layer / perovskite light-absorbing layer and a solar cell. Background Technology

[0002] Energy is the foundation of human society's survival and development. With the continuous growth of the world's population and the advancement of science and technology, human demand for energy is increasing. The large-scale extraction of fossil fuels not only causes environmental pollution, but their non-renewable nature also threatens humanity with an energy crisis. Among many renewable energy sources, solar energy is considered the most promising energy form due to its wide distribution and clean, pollution-free characteristics. Perovskite solar cells (PSCs) have stood out among new solar cell technologies due to the advantages of perovskite light-absorbing materials, such as tunable band gap, high absorption coefficient, and high carrier mobility. In just over a decade, their photoelectric conversion efficiency (PCE) has increased to 27%, and device stability is also continuously improving, making them a potential replacement for traditional solar cells in the future.

[0003] In recent years, self-assembled molecules (SAMs) that can be anchored on a transparent conductive substrate to form a transport layer have greatly improved the performance of perovskite solar cells due to their unique advantages in high transparency, high charge selectivity, and interface passivation. However, commonly used SAM molecules suffer from problems such as weak binding to the substrate, uneven substrate coverage, and poor surface wettability, which limit the fabrication of high-efficiency, large-area devices.

[0004] To address the aforementioned issues, researchers have conducted extensive studies and achieved certain results. Zhu Zonglong's research group (2023, Nature Energy) proposed a one-step solution coating process. By adding (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz) to the perovskite precursor solution, a hole-selective contact layer and a perovskite light-absorbing layer are spontaneously formed, solving the wettability problem, simplifying the device fabrication process, and ultimately obtaining high-efficiency perovskite solar cells. He Zhubing's research group (2023, Nature) designed a SAM molecule, [4-(2,7-dibromo-9,9-dimethylacridin-10(9-hydrogen)-yl)butyl]phosphoric acid (DMAcPA). Adding it as a molecular dopant to the perovskite precursor solution optimizes the energy level matching between the perovskite layer and the ITO substrate, thereby improving the extraction and transport of interfacial charges and comprehensively passivating the grain boundaries. Zhang Lijun's research group (2024, Advanced Materials) developed an in-situ passivation strategy. By adding (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz) to the precursor solution, well-oriented perovskite grains are induced, while grain boundaries and interface defects are passivated, thereby significantly improving the efficiency and stability of perovskite solar cell devices.

[0005] The aforementioned methods can effectively improve the photoelectric efficiency and stability of perovskite solar cells, but all of them employ a one-step method to prepare the perovskite layer. Compared to the two-step method, the one-step method suffers from difficulties in controlling crystallization, making it challenging to precisely control the growth process and orientation of perovskite crystals; the process flow is more complex, increasing the operational difficulty and uncertainty during preparation; and reproducibility is poor, with significant performance fluctuations between different batches of cells. Furthermore, the one-step method is not suitable for the preparation of large-area perovskite solar cell modules, limiting the widespread adoption of perovskite solar cells in large-scale commercial applications. Summary of the Invention

[0006] This application aims to provide a method for co-deposition of a self-assembled molecular layer / perovskite light-absorbing layer, as well as solar cells and optoelectronic devices. This method involves adding SAM molecules to a lead halide solution for co-deposition, which not only improves the wettability of the conductive substrate and enhances the bonding between the perovskite layer and the conductive substrate, but also simplifies the process. Furthermore, it can regulate the crystallization of the lead halide film and the perovskite film, improve the crystal quality, and passivate defects.

[0007] To achieve the above technical objectives, this application specifically adopts the following technical solution: In one aspect of this application, a method for co-deposition of a self-assembled molecular layer / perovskite light-absorbing layer is provided, comprising the following steps: S1. Dissolve the self-assembled molecules and lead halide in an organic solvent to obtain a lead halide precursor solution; S2. The lead halide precursor solution is coated onto a transparent conductive substrate and then annealed to form a lead halide thin film. S3. Dissolve the ammonium halide salt in isopropanol to obtain an ammonium halide salt solution; S4. The ammonium halide salt solution is coated on the surface of the lead halide film, and after annealing, a self-assembled molecular charge transport layer / perovskite light-absorbing layer is obtained.

[0008] In one embodiment, the self-assembled molecule is selected from one or a mixture of two or more of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz).

[0009] In one embodiment, the organic solvent is selected from one or a mixture of two or more of N,N-dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF).

[0010] In one embodiment, the concentration of the self-assembled molecules in the lead halide precursor solution is 0.25~1.5 mg / mL, and the concentration of the lead halide is 0.5~2 mol / L.

[0011] In one embodiment, the transparent conductive substrate is selected from indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), or fluorine-doped tin oxide (FTO).

[0012] In one implementation, the annealing conditions in step S2 are: annealing temperature 50°C~70°C, annealing time 50~60 s.

[0013] In one embodiment, the ammonium halide salt is selected from one or a mixture of two or more of formamidinium hydroiodide, methyl ammonium iodide, methyl ammonium chloride, methyl ammonium bromide, and cesium iodide.

[0014] In one embodiment, the concentration of the ammonium halide salt solution is 60-90 mg / mL.

[0015] In one embodiment, the annealing conditions in step S4 are: annealing temperature 100℃~180℃, annealing time 10~30min.

[0016] In another aspect of this application, a self-assembled molecular layer / perovskite light-absorbing layer composite structure is provided, comprising a transparent conductive substrate, and a self-assembled molecular charge transport layer and a perovskite light-absorbing layer sequentially disposed on the transparent conductive substrate. The self-assembled molecular charge transport layer contains the self-assembled molecules.

[0017] In another aspect of this application, a perovskite solar cell is provided, the perovskite solar cell comprising a self-assembled molecular layer / perovskite light-absorbing layer prepared by the above method.

[0018] The beneficial effects of this application are as follows: 1) Simplify processing and improve the wettability of transparent conductive substrates This application employs a two-step co-deposition method for self-assembled molecular charge transport layers. During fabrication, only the perovskite light-absorbing layer needs to be co-deposited, eliminating the need for a separate charge transport layer and simplifying the processing. Furthermore, this method improves the wettability of transparent conductive substrates. Moreover, the co-deposition method for the self-assembled molecular layer and perovskite light-absorbing layer provided in this application offers advantages such as simple process, good repeatability, and strong scalability, making it suitable for large-scale production and significantly contributing to the commercial application of perovskite solar cells.

[0019] (2) Reduce the density of interface defect states and improve the crystallinity of perovskite films. This application utilizes a co-deposition method to prepare a self-assembled molecular charge transport layer, which exhibits a more uniform distribution on the conductive substrate surface, resulting in tighter interfacial bonding and effectively reducing interfacial carrier losses. Simultaneously, it improves the energy level matching between the conductive substrate and the perovskite absorber layer. The co-deposition method causes the energy bands of the perovskite absorber layer to bend upwards, promoting charge extraction, lowering the energy barrier for charge extraction, reducing carrier accumulation at the interface, and improving the charge extraction efficiency at the interface. Furthermore, this method improves the crystallinity of the perovskite absorber layer, slows down the crystallization rate, and helps to form a perovskite absorber layer with higher crystal quality and larger grains, thereby significantly improving the photoelectric conversion efficiency of perovskite solar cells.

[0020] (3) Improve the stability of perovskite solar cells The phosphate groups in the SAM molecule can coordinate with uncoordinated lead ions and form hydrogen bonds with uncoordinated iodide ions, thereby passivating defects in the perovskite layer, reducing non-radiative recombination, and significantly improving the stability of perovskite solar cells. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the inverted perovskite solar cell structure prepared by co-deposition of a self-assembled molecular charge transport layer and a perovskite light-absorbing layer in a two-step method according to an embodiment of this application. Figure 2 This is a schematic diagram comparing the JV curves of the perovskite solar cells in Comparative Example 1 and Example 2 of this application under AM 1.5G test conditions; Figure 3 This is the JV curve of the perovskite solar cell prepared by co-deposition of a self-assembled molecular charge transport layer and a perovskite light-absorbing layer in Example 1 of this application under AM 1.5G test conditions; Figure 4 This is the JV curve of the perovskite solar cell prepared by co-deposition of a self-assembled molecular charge transport layer and a perovskite light-absorbing layer in Example 3 of this application under AM 1.5G test conditions; Figure 5 This is the JV curve of the perovskite solar cell prepared by co-deposition of a self-assembled molecular charge transport layer and a perovskite light-absorbing layer in Example 4 of this application under AM 1.5G test conditions. Figure 6 This is the JV curve of the perovskite solar cell prepared by co-deposition of a self-assembled molecular charge transport layer and a perovskite light-absorbing layer in Example 5 of this application under AM 1.5G test conditions. Figure 7 These are contact angle diagrams of the conductive substrates in Comparative Example 1 and Example 2 of this application; wherein, Figure 7 (a) in the diagram is the contact angle diagram of Comparative Example 1. Figure 7 (b) in the diagram is the contact angle diagram of Example 2; Figure 8 These are SEM images of the perovskite light-absorbing layers prepared in Comparative Example 1 and Example 2 of this application; wherein, Figure 8 Image (a) in the diagram is the SEM image of Comparative Example 1, with a scale bar of 500 nm. Figure 8 (b) is the SEM image of Example 2, with a scale bar of 500 nm; Figure 9 This is a schematic diagram comparing the defect state density of the perovskite light-absorbing layer prepared in Comparative Example 1 and Example 2 of this application; wherein, Figure 9 In Figure (a), the defect state density plot of Comparative Example 1 is shown. Figure 9 (b) in the figure is the defect state density diagram of Example 2; Figure 10 This is a schematic diagram comparing the stability of the perovskite solar cells prepared in Comparative Example 1 and Example 2 of this application. Detailed Implementation

[0022] The technical solution of this application will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this application, not all embodiments, and are only used to illustrate this application, and should not be regarded as limiting the scope of this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] In one specific embodiment of this application, a method for co-deposition of a self-assembled molecular layer / perovskite light-absorbing layer is provided, comprising the following steps: S1. Dissolve the self-assembled molecules and lead halide in an organic solvent to obtain a lead halide precursor solution.

[0024] The self-assembled molecules are selected from one or a mixture of two or more of the following: (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz). All self-assembled molecules contain phosphate groups, which can coordinate with uncoordinated lead ions, passivating defects in the perovskite layer and thus improving the performance and stability of the perovskite solar cell.

[0025] In some embodiments, the self-assembled molecule is selected from a mixture of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), wherein the mass ratio of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) to (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) is 3:2.

[0026] In some embodiments, the lead halide is selected from one or more of lead chloride (PbCl2), lead bromide (PbBr2), and lead iodide (PbI2). Preferably, the lead halide is selected from lead iodide (PbI2).

[0027] The organic solvent is selected from one or a mixture of two or more of N,N-dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF).

[0028] In some embodiments, the organic solvent is selected from N,N-dimethylformamide (DMF) and N,N-dimethyl sulfoxide (DMSO), and the volume ratio of N,N-dimethylformamide to N,N-dimethyl sulfoxide is 4 to 14:1. Specifically, the volume ratio of N,N-dimethylformamide to N,N-dimethyl sulfoxide can be 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, or 14:1.

[0029] The concentration of the self-assembled molecules in the lead halide precursor solution is 0.25~1.5 mg / mL, and the concentration of the lead halide is 0.5~2 mol / L. Specifically, the concentration of the self-assembled molecules can be 0.25 mg / mL, 0.5 mg / mL, 0.75 mg / mL, 1.0 mg / mL, 1.25 mg / mL, or 1.5 mg / mL, and the concentration of the lead halide can be 0.5 mol / L, 0.75 mol / L, 1.0 mol / L, 1.25 mol / L, 1.5 mol / L, 1.75 mol / L, or 2 mol / L.

[0030] S2. The lead halide precursor solution is coated onto a transparent conductive substrate and then annealed to form a lead halide thin film.

[0031] It is understood that the transparent conductive substrate has undergone cleaning and drying treatment before use. Specifically, the surface of the transparent conductive substrate is subjected to ultraviolet-ozone treatment for 5-20 minutes or plasma cleaning for 1-5 minutes. Ultraviolet-ozone treatment helps improve the properties of the substrate surface, such as cleanliness, activity, and hydrophilicity, and can enhance the bonding effect between the precursor solution and the substrate. Plasma cleaning can effectively remove contaminants from the substrate surface and also activate the substrate surface.

[0032] The transparent conductive substrate is selected from indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), or fluorine-doped tin oxide (FTO).

[0033] The annealing conditions are: annealing temperature 50℃~70℃, annealing time 50~60 s. Specifically, the annealing temperature can be 50℃, 55℃, 60℃, 65℃, or 70℃, and the annealing time can be 50s, 52s, 54s, 56s, 58s, or 60s.

[0034] S3. Dissolve the ammonium halide salt in isopropanol to obtain an ammonium halide salt solution.

[0035] The ammonium halide salt is selected from one or a mixture of two or more of formamidinium hydroiodide, methyl ammonium iodide, methyl ammonium chloride, methyl ammonium bromide, and cesium iodide.

[0036] In some embodiments, the ammonium halide salt is selected from a mixture of formamidinium iodide, methylammonium bromide and methylammonium chloride, wherein the mass ratio of formamidinium iodide, methylammonium bromide and methylammonium chloride is 10:1:1.

[0037] In some embodiments, the concentration of the ammonium halide solution is 60-90 mg / mL. Specifically, the concentration of the ammonium halide solution is the concentration of the ammonium halide in the solution, which can be 60 mg / mL, 65 mg / mL, 70 mg / mL, 75 mg / mL, 80 mg / mL, 85 mg / mL, or 90 mg / mL.

[0038] S4. The ammonium halide salt solution is coated on the surface of the lead halide film, and after annealing, a self-assembled molecular charge transport layer / perovskite light-absorbing layer is obtained.

[0039] The annealing conditions are as follows: annealing temperature 100℃~180℃, annealing time 10~30 min. Specifically, the annealing temperature can be 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, or 180℃, and the annealing time can be 10 min, 15 min, 20 min, 25 min, or 30 min.

[0040] The perovskite light-absorbing layer has the structure APbX3, where A is one or more of methylamine, formamidinium, cesium ions, and potassium ions, and X is one or more of I, Br, and Cl.

[0041] This application employs a two-step co-deposition method by incorporating SAM molecules into a lead halide solution. During the crystallization of the perovskite light-absorbing layer, self-assembled molecules are extruded and anchored on the surface of a transparent conductive substrate, forming a charge transport layer. This optimizes the energy level arrangement between the conductive substrate and the perovskite layer, lowers the charge extraction barrier, improves substrate wettability, and enhances the bonding between the substrate and the perovskite layer. Furthermore, the phosphate groups in the SAM molecules can coordinate with uncoordinated lead ions, passivating defects in the perovskite layer and thus improving the performance and stability of the perovskite solar cell. Simultaneously, SAM molecules can effectively regulate the crystallization of lead halide and perovskite, slowing down the crystallization rate to obtain a perovskite light-absorbing layer with larger grain size and fewer defects. This helps enhance the light absorption capacity of the perovskite light-absorbing layer, reduces carrier accumulation and non-radiative recombination at the interface, and thus significantly improves the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0042] In another specific embodiment of this application, a self-assembled molecular layer / perovskite light-absorbing layer composite structure is provided. The composite structure is prepared by the above-described co-deposition method of the self-assembled molecular layer / perovskite light-absorbing layer and includes a transparent conductive substrate, a self-assembled molecular charge transport layer and a perovskite light-absorbing layer. The self-assembled molecular charge transport layer is anchored on the surface of the transparent conductive substrate, and the perovskite light-absorbing layer covers the self-assembled molecular charge transport layer.

[0043] Specifically, the composite structure is generated simultaneously through the following steps: coating an organic solvent solution containing self-assembled molecules and lead halide onto the transparent conductive substrate, followed by annealing to form a lead halide film; coating an isopropanol solution of ammonium halide salt onto the surface of the lead halide film, followed by secondary annealing to induce the self-assembled molecules to migrate to the substrate to form a charge transport layer, while ammonium halide reacts with lead halide to form a perovskite light-absorbing layer.

[0044] The transparent conductive substrate is selected from indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), or fluorine-doped tin oxide (FTO).

[0045] The self-assembled molecule is selected from one or a mixture of two or more of the following: (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz).

[0046] The organic solvent is selected from one or a mixture of two or more of N,N-dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF).

[0047] The ammonium halide salt is selected from one or a mixture of two or more of formamidinium hydroiodide, methyl ammonium iodide, methyl ammonium chloride, methyl ammonium bromide, and cesium iodide.

[0048] The perovskite light-absorbing layer has the structure APbX3, wherein A is one or more of methylamine, formamidinium, cesium ions, and potassium ions, and X is one or more of I, Br, and Cl.

[0049] In another specific embodiment of this application, a perovskite solar cell is provided, the perovskite solar cell comprising a self-assembled molecular layer / perovskite light-absorbing layer prepared by the above-described co-deposition method of the self-assembled molecular layer / perovskite light-absorbing layer.

[0050] Specifically, the perovskite solar cell has a layered structure, in which a self-assembled molecular charge transport layer, a perovskite light-absorbing layer, a charge transport layer and a metal electrode layer are sequentially stacked from the transparent conductive substrate in a direction away from the transparent conductive substrate.

[0051] The charge transport layer is made of fullerene (C60 ... 60 ), (6,6)-phenyl-C61-butyrate methyl ester (PCBM) or tin oxide (SnO2).

[0052] The material of the metal electrode layer is selected from one or more of gold, silver, copper, indium tin oxide, and aluminum-doped zinc oxide.

[0053] In some embodiments, the thickness of the metal electrode layer is 50~200 nm, specifically, it can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, or 200 nm.

[0054] In some embodiments, the method for fabricating the perovskite solar cell includes the following steps: T1. A co-deposited self-assembled molecular charge transport layer and an APbX3 structured perovskite light-absorbing layer are prepared on the surface of an ITO substrate, wherein A is one or more of methylamine, formamidinium, cesium ions, and potassium ions, and X is one or more of I, Br, and Cl. T2. A charge transport layer is prepared on the surface of the perovskite light-absorbing layer by spin coating or thermal evaporation. T3. Electrode layers are prepared on the surface of the charge transport layer using thermal evaporation or magnetron sputtering processes.

[0055] Example 1 This embodiment provides a self-assembled molecular charge transport layer and FA. 1-x MA x The method for co-deposition of a PbI3 structured perovskite light-absorbing layer includes the following steps: S1. Cleaning the ITO substrate: The substrate was ultrasonically cleaned sequentially with detergent, deionized water, acetone, isopropanol, and anhydrous ethanol, each for 20 minutes. After cleaning and drying, it underwent UV-ozone treatment for 15 minutes or plasma treatment for 3 minutes to improve the hydrophilicity of the substrate surface. The ITO substrate dimensions were 15 mm × 15 mm × 1.1 mm.

[0056] S2. Dissolve 691.5 mg of lead iodide and 1 mg of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and N,N-dimethyl sulfoxide (DMSO). Stir on a magnetic stirrer until completely dissolved to obtain a lead iodide precursor solution; wherein the volume ratio of DMF to DMSO solvent is 9:1. S3. Under a nitrogen atmosphere, 50 μL of the lead iodide precursor solution obtained in step S2 was spin-coated onto the surface of a transparent conductive substrate. The spin-coating speed was 1500 rpm, the spin-coating acceleration was 750 rpm / s, and the spin-coating time was 30s. The substrate was then annealed on a hot plate at 70℃ for 1 min to obtain a lead iodide film. S4. Dissolve 90 mg formammonium iodide (FAI), 9 mg methylammonium bromide (MABr), and 9 mg methylammonium chloride (MACl) in 1 mL of isopropanol (IPA) solvent and stir at room temperature until completely dissolved to obtain a mixed ammonium halide salt solution of FAI, MABr, and MACl. S5. Under a nitrogen atmosphere, 80 μL of the mixed ammonium halide salt solution obtained in step S4 was spin-coated onto a lead iodide film. The spin-coating speed was 2000 rpm, the spin-coating acceleration was 1000 rpm / s, and the spin-coating time was 35s. Then, the film was quickly transferred to an environment with a relative humidity of 30-40% and annealed on a hot stage at 150℃ for 15 min to prepare a self-assembled molecular charge transport layer and a perovskite light-absorbing layer with a thickness of 700 nm.

[0057] Inverted perovskite solar cells were fabricated using the two-step co-deposition method described above to create a self-assembled molecular charge transport layer and a perovskite light-absorbing layer. The structure of the inverted perovskite solar cell is as follows: Figure 1 As shown, the specific preparation method is as follows: T1. Preparation of passivation layer: Weigh 2 mg of 2-phenylethylamine hydroiodide (PEAI) and dissolve it in 1 mL of isopropanol (IPA) solvent. Stir at room temperature until completely dissolved to obtain passivation layer solution. Then spin-coat the passivation layer solution onto the surface of the perovskite light-absorbing layer obtained in S5. The spin-coating speed is 3000 rpm, the spin-coating acceleration is 1500 rpm / s, and the spin-coating time is 20s. Then anneal on a hot stage at 100℃ for 5 min.

[0058] T2. Preparation of the charge transport layer: In a high vacuum (below 10°C) -4 In an environment of Pa), fullerenes (C) are sequentially deposited by thermal evaporation. 60 ) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP); wherein C 60 The thickness of the is 35 nm, and the thickness of the BCP is 5 nm.

[0059] T3. Electrode layer preparation: Under high vacuum (below 10°C) -4 In an environment of Pa, a silver electrode is deposited onto the charge transport layer by thermal evaporation. The electrode layer has a thickness of 100 nm.

[0060] Example 2 Based on Example 1, the difference from Example 1 is that the amount of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) added in step S2 is 0.5 mg.

[0061] Example 3 Based on Example 1, the difference from Example 1 is that the SAM molecule added in step S2 is (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphate (Me-4PACz), and the amount is 0.5 mg.

[0062] Example 4 Based on Example 1, the difference from Example 1 is that the SAM molecule added in step S2 is (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphate (Me-2PACz), and the amount is 0.5 mg.

[0063] Example 5 Based on Example 1, the difference from Example 1 is that the SAM molecules added in step S2 are (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), wherein the amount of Ph-4PACz is 0.3 mg and the amount of 2PACz is 0.2 mg.

[0064] Comparative Example Based on Example 1, the difference from Example 1 lies in step S2: 0.5 mg of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphoric acid (Ph-4PACz) was dissolved in 1 mL of N,N-dimethylformamide solvent, stirred and mixed evenly to obtain a charge transport layer solution, and then the obtained charge transport layer solution was spin-coated onto the surface of the ITO substrate obtained in S1; wherein the spin-coating speed was 3000 rpm, the spin-coating acceleration was 1500 rpm / s, the spin-coating time was 20 s, and then annealed on a hot plate at 100°C for 10 min.

[0065] Experimental Example The perovskite solar cells prepared in Comparative Example 1 and Example 2 were tested at AM 1.5G and 100 mW cm⁻¹, respectively. -2The test was conducted under illumination conditions. The results are as follows: Figure 2 As shown, the photoelectric conversion efficiency of Comparative Example 1 is 24.14%, and that of Example 2 is 25.38%, indicating that the co-deposition preparation strategy of the self-assembled molecular charge transport layer and the perovskite light-absorbing layer provided in this application can significantly improve the photoelectric conversion efficiency of the inverted perovskite solar cell.

[0066] The perovskite solar cell prepared in Example 1 was placed in an AM 1.5G, 100 mW cm⁻¹ solar cell. -2 Tested under illumination conditions. For example... Figure 3 As shown, the reverse-scan photoelectric conversion efficiency of the perovskite solar cell is 24.29%, with an open-circuit voltage of 1.13 V and a short-circuit current density of 25.34 mA cm⁻¹. -2 The fill factor is 84.68%.

[0067] The perovskite solar cell prepared in Example 3 was placed in an AM 1.5G, 100 mW cm⁻¹ solar cell. -2 Tested under illumination conditions. For example... Figure 4 As shown, the reverse-scan photoelectric conversion efficiency of the perovskite solar cell is 24.03%, with an open-circuit voltage of 1.14 V and a short-circuit current density of 25.38 mA cm⁻¹. -2 The fill factor is 82.37%.

[0068] The perovskite solar cell prepared in Example 4 was placed in an AM 1.5G, 100 mW cm⁻¹ solar cell. -2 Tested under illumination conditions. For example... Figure 5 As shown, the reverse-scan photoelectric conversion efficiency of the perovskite solar cell is 23.91%, with an open-circuit voltage of 1.14 V and a short-circuit current density of 24.99 mA cm⁻¹. -2 The fill factor is 83.48%.

[0069] The perovskite solar cell prepared in Example 5 was placed in an AM 1.5G, 100 mW cm⁻¹ solar cell. -2 Tested under illumination conditions. For example... Figure 6 As shown, the reverse-scan photoelectric conversion efficiency of the perovskite solar cell is 24.07%, with an open-circuit voltage of 1.15 V and a short-circuit current density of 25.14 mA cm⁻¹. -2 The fill factor is 83.20%.

[0070] Contact angle tests were performed on the conductive substrates in Comparative Example 1 and Example 2, such as... Figure 7 (a) and Figure 7As shown in (b), the wetting contact angle of the conductive substrate in Comparative Example 1 is 57.8°, and the wetting contact angle of the conductive substrate in Example 2 is 27.4°. This indicates that the co-deposition preparation method further improves the wettability of the conductive substrate surface, which is beneficial to the epitaxial growth of the perovskite light-absorbing layer on the conductive substrate surface.

[0071] The perovskite light-absorbing layers prepared in Comparative Example 1 and Example 2 were analyzed by surface scanning electron microscopy (SEM), and their morphologies are as follows: Figure 8 (a) and Figure 8 As shown in (b), the perovskite light-absorbing layer of Example 2 has a larger average grain size and fewer pores, indicating that the perovskite light-absorbing layer has higher crystal quality, which is beneficial to improving the photoelectric performance of perovskite solar cells.

[0072] The perovskite light-absorbing layers prepared in Comparative Example 1 and Example 2 were subjected to space charge confinement current (SCLC) tests, and the results are as follows: Figure 9 (a) and Figure 9 As shown in (b), the perovskite light-absorbing layer of Example 2 has a lower space charge confinement voltage (0.33 V), indicating that the perovskite light-absorbing layer prepared therein has fewer defects, thereby improving the stability of the perovskite solar cell.

[0073] The perovskite solar cells prepared in Comparative Example 1 and Example 2 were tested at AM 1.5G and 100 mW cm⁻¹. -2 Maximum power point tracking (MPP) tests were performed under illumination conditions, such as... Figure 10 As shown, after 500 h of illumination, Example 2 maintained 95% of its initial efficiency, while Comparative Example 1 only maintained 65% of its initial efficiency. This indicates that the co-deposition preparation strategy of the self-assembled molecular charge transport layer and the perovskite light-absorbing layer provided in this application can significantly improve the long-term stability of perovskite solar cells.

[0074] Although the embodiments of this application have been described above in conjunction with the accompanying drawings, this application is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of this application, and these are all within the scope of protection of this application.

Claims

1. A method for co-deposition of a self-assembled molecular layer / perovskite light-absorbing layer, characterized in that, include: S1. Dissolve the self-assembled molecules and lead halide in an organic solvent to obtain a lead halide precursor solution; S2. The lead halide precursor solution is coated onto a transparent conductive substrate and then annealed to form a lead halide thin film. S3. Dissolve the ammonium halide salt in isopropanol to obtain an ammonium halide salt solution; S4. The ammonium halide salt solution is coated on the surface of the lead halide film, and after annealing, a self-assembled molecular charge transport layer / perovskite light-absorbing layer is obtained.

2. The co-deposition preparation method according to claim 1, characterized in that, The self-assembled molecule is selected from one or more of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz).

3. The co-deposition preparation method according to claim 1, characterized in that, The organic solvent is selected from one or more of N,N-dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF).

4. The co-deposition preparation method according to claim 1, characterized in that, The concentration of the self-assembled molecules in the lead halide precursor solution is 0.25~1.5 mg / mL, and the concentration of the lead halide is 0.5~2 mol / L.

5. The co-deposition preparation method according to claim 1, characterized in that, The annealing conditions in step S2 are: annealing temperature 50℃~70℃, annealing time 50~60 s.

6. The co-deposition preparation method according to claim 1, characterized in that, The annealing conditions in step S2 are as follows: the ammonium halide salt is selected from one or more of formamidinium hydroiodate, methyl ammonium iodide, methyl ammonium chloride, methyl ammonium bromide, and cesium iodide.

7. The co-deposition preparation method according to claim 1, characterized in that, The concentration of the ammonium halide salt solution is 60~90 mg / mL.

8. The co-deposition preparation method according to claim 1, characterized in that, The annealing conditions in step S4 are: annealing temperature 100℃~180℃, annealing time 10~30 min.

9. A self-assembled molecular layer / perovskite light-absorbing layer composite structure, characterized in that, It includes a transparent conductive substrate, and a self-assembled molecular charge transport layer and a perovskite light-absorbing layer sequentially disposed on the transparent conductive substrate; The self-assembled molecular charge transport layer contains self-assembled molecules; the self-assembled molecules are selected from one or more of (4-(3,6-diphenyl-9H-carbazole-9-yl)butyl)phosphonic acid (Ph-4PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), and (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz).

10. A perovskite solar cell, characterized in that, The perovskite solar cell includes a self-assembled molecular layer / perovskite light-absorbing layer prepared by the co-deposition method according to claims 1 to 8, or a self-assembled molecular layer / perovskite light-absorbing layer composite structure according to claim 9.

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