Heteroatom-containing asymmetric self-assembly molecular interface material for perovskite solar cell, and synthesis method and application of heteroatom-containing asymmetric self-assembly molecular interface material

Abstract

The invention discloses a heteroatom-containing asymmetric self-assembly molecular interface material for a perovskite solar cell and a synthesis method and application thereof. According to the heteroatom conjugated asymmetric self-assembled molecular material, heteroatom-containing benzo-fused carbazole is used as a basic framework, and carbazole nitrogen atoms and phosphonic acid groups are connected through carbon chains. According to the asymmetric structure, the material has good substrate covering and polar solvent resisting performance, the large molecular dipole enhances the interface hole extraction capacity, the material serves as an additive of a perovskite precursor solution, heteroatoms and phosphate groups of the material strengthen passivation of interface defect sites, and the crystal growth process of a thin film is improved. A hole selection layer used for a perovskite solar cell is beneficial to formation of a uniform and compact molecular layer, interface contact is improved, and hole extraction and transmission are promoted; and meanwhile, the compound is used as a precursor solution additive, has a buried defect passivation function and an auxiliary perovskite crystallization function, enhances the stability of a cell device interface, and improves the photoelectric conversion efficiency and stability of a perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cells, and relates to a heteroatom-containing asymmetric self-assembled molecular interface material, its synthesis method, and its application in perovskite solar cells. Background Technology

[0002] Perovskite solar cells (PSCs) with inverted pin structures have shown broad application prospects in the photovoltaic field due to their low-temperature processing characteristics, compatibility with flexible substrates, excellent operational stability, and integration potential with tandem cells. Currently, through innovation in hole-selective layer materials and the development of interface passivation strategies, the photoelectric conversion efficiency of PSCs has exceeded 27%, and device stability has also been significantly improved. Among these, self-assembled molecules (SAMs), as key hole-selective layer materials for high-performance PSCs, directly affect the device's performance and stability through their interfacial properties. However, achieving uniform and dense monolayer coverage still faces significant challenges. First, the amphiphilic nature of SAMs makes them prone to self-aggregation in solution, forming clusters or micelles, hindering the formation of a stable monolayer. Furthermore, substrate roughness can lead to insufficient SAM coverage, introducing voids and defects into the hole-selective layer. These defects not only cause current leakage and energy loss at the buried interface but also adversely affect the crystallinity quality of the perovskite film.

[0003] To address the aforementioned interface issues, researchers have proposed several solutions. Song Yanlin's research group, through additive engineering, mixed perfluorotripropylamine (FC-3283) with self-assembled molecules (MeO-2PACz) to prepare a solution, which was then coated onto a substrate. This achieved uniform coverage of the self-assembled molecules, while simultaneously improving charge extraction efficiency and perovskite crystal quality, significantly enhancing battery performance (Xiwen Zhang, Yang Wang, Kun Zhang, Mingquan Tao, Haodan Guo, LutongGuo, Zhaofei Song, Jinxu Wen, Yongrui Yang, Yuqing Hou, Yanlin Song, Angewandte Chemie International Edition). 2025, 64 (13), e202423827.); Henry J. Snaith and Nam-Gyu Park employed a co-adsorption strategy to co-assemble the self-assembled molecule [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz) with the polyazolic acid 4,4',4"-nitrotribenzoic acid (NA), effectively improving interfacial properties. (Sanwan Liu, Jingbai Li, Wenshan Xiao, Rui Chen, Zhenxing Sun, Yong Zhang, Xia Lei, Shuaifeng Hu, Manuel Kober-Czerny, Jianan Wang, FumengRen, Qisen Zhou, Hasan Raza, You Gao, Yitong Ji, Sibo Li, Huan Li, LongbinQiu, Wenchao Huang, Yan Zhao, Baomin Xu, Zonghao Liu, Henry J. Snaith, Nam-Gyu Park&Wei Chen, Nature 2024, 632, 536–542.); Professor Baomin Xu's research group developed a self-assembly molecule, 4PADCB-V, which can be polymerized in situ. After being coated on a substrate, it can be rapidly polymerized into a self-assembled monolayer, crs-4PADCB-V, under ultraviolet light irradiation. This layer can maintain its structural integrity in polar solvents, which not only reduces interfacial defects but also enhances charge transport properties and the crystallinity of perovskite films (Lida Wang, Zhixin Liu, Jiasheng Zou, ShichuPeng, Deng Wang, Peide Zhu, Zhiwei Lei, Xia Lei, Wenxuan Yang, Fei Su, YuqiBao, Wenbo Peng, Siru He, Jie Zeng, Zonglong Song, Xingzhu Wang, Lei Yan, and Baomin Xu, Angewandte Chemie International Edition 2025, e17058).

[0004] Despite these advances, there is still room for improvement in the design and development of SAMs materials. The structure-property relationship between molecular configuration and multifunctionality needs further investigation, and defect passivation strategies for buried interfaces also require further refinement. Therefore, related research is of great guiding significance for developing higher-performance SAMs materials and constructing stable buried interfaces. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to develop a class of heteroatom-conjugated asymmetric self-assembled molecular materials for repairing the buried interface of inverted perovskite solar cells. The asymmetric configuration of these self-assembled molecular materials provides excellent substrate coverage and resistance to polar solvents, while the larger molecular dipoles enhance the interfacial hole-pulling capability. As an additive to perovskite precursor solutions, its heteroatoms and phosphate groups strengthen the passivation of interfacial defect sites, improving the crystallization and growth process of the thin film. The aforementioned heteroatom-conjugated asymmetric self-assembled molecular material uses heteroatom-containing benzo[a]-fused carbazole as its basic framework, connecting carbazole nitrogen atoms and phosphonic acid groups via carbon chains to form self-assembled molecules.

[0006] This invention provides a method for synthesizing the aforementioned heteroatom-containing benzo[a]-fused carbazole self-assembled molecular material. This method has advantages such as simple reaction steps, high yield, and easy purification. Applying it as a hole-selective layer in perovskite solar cells helps form a uniform and dense molecular layer, improves interfacial contact, and promotes hole extraction and transport. Furthermore, using this material as an additive in perovskite precursor solutions also provides good passivation of buried defects and assists in perovskite crystallization, thereby enhancing the stability of the cell device interface and ultimately improving the photoelectric conversion efficiency and stability of perovskite solar cells. The successful development of this heteroatom-containing asymmetric self-assembled material provides a new approach for the fabrication of high-efficiency and stable inverted perovskite solar cells.

[0007] The technical solution adopted in this invention is as follows: A heteroatom-containing asymmetric self-assembled molecular interface material is characterized by: using heteroatom-fused benzoxyl carbazole as the starting material, introducing a 4-bromobutyl chain through an alkylation reaction, and then introducing phosphonic acid groups through an Albuzov reaction and a hydrolysis reaction to obtain the target molecule. The self-assembled molecular material has the following general chemical structural formula (I): ; In formula (I), X is one of oxygen, sulfur, or selenium atoms, specifically one of the following structures: .

[0008] The synthesis method of the above-mentioned heteroatom-containing asymmetric self-assembled molecular interface materials is as follows: Compound 1 was alkylated with 1,4-dibromobutane to give compound 2; compound 2 was then Suzuki coupled with triethyl phosphate to give compound 3, abbreviated as O-AS, S-AS, or Se-AS, respectively. The specific reaction steps are as follows: (i) In a dry reaction vessel, compound 1 and tetrabutylammonium bromide were added, along with solvent 1,4-dibromobutane. After stirring until homogeneous, 50 wt.% potassium hydroxide aqueous solution was added dropwise. The mixture was heated to 60-70°C and stirred for 9-15 hours. After the reaction was completed, the reaction was quenched with deionized water and extracted with dichloromethane. The organic phases were combined, dried with anhydrous sodium sulfate, and concentrated under reduced pressure to remove the solvent, yielding a crude product. The crude product was purified by silica gel column chromatography to obtain compound 2, which was an off-white solid. (ii) Compound 2 was dissolved in triethyl phosphite and heated to 160–175 °C under nitrogen protection with stirring overnight. After the reaction was complete, excess triethyl phosphite was removed by vacuum distillation to obtain a pale yellow oily crude product (no further purification required). This crude product was dissolved in anhydrous 1,4-dioxane, and trimethylbromosilane was added dropwise at room temperature with stirring continued overnight at room temperature. After the reaction was complete, 1,4-dioxane was removed by vacuum distillation to obtain a liquid residue. This liquid product was redissolved in methanol, and then distilled water was added dropwise until the solution became turbid. The solid was collected by filtration and washed with water to obtain a white solid, target compound 3.

[0009] The synthesis process is as follows: ; In step (i), the molar ratio of compound 1, tetrabutylammonium bromide and potassium hydroxide is 1.00:0.15:5.00; the reaction concentration of compound 1 is 0.3 ~ 0.5 mol / L.

[0010] In step (ii), the molar ratio of compound 2 to bromotrimethylsilane is 1.00:10.00; the reaction concentration of compound 2 is 0.1 ~ 0.2 mol / L.

[0011] The heteroatom-containing asymmetric self-assembled molecular interface material synthesized in this invention is used as a passivation material in perovskite solar cells. The perovskite solar cell comprises a transparent conductive substrate, a hole selection layer or a hole transport layer + hole selection layer, a perovskite absorber layer, an electron transport layer, and a metal electrode. The specific steps of the perovskite solar cell are as follows: (1) Cut the transparent conductive substrate into a fixed size and clean it with cleaning agent, deionized water, acetone and isopropanol in sequence for 15-20 minutes each. After drying, treat it with ultraviolet ozone for 20-30 minutes. (2) On the transparent conductive substrate after step (1), a hole selection layer is deposited by spin coating, or a hole transport layer and a hole selection layer are deposited sequentially. Among them, nickel oxide (NiO) is used when depositing the hole transport layer. x The aqueous solution was spin-coated at 3000-4000 rpm for 25-35 seconds, and then dried on a heated plate at 135-145 °C for 20-30 minutes to form a dense NiO. x film; In the deposition of the hole-selective layer, the solute is the heteroatom-containing asymmetric self-assembled molecular interface material prepared in this invention, and the solvent is ethanol, tetrahydrofuran, or... N, N- One of dimethylformamide (DMF); control the rotation speed at 3000~4000 rpm for 25~35 seconds, and then anneal at 90~105 ℃ for 10~15 minutes; (3) The perovskite precursor solution containing the heteroatom-containing asymmetric self-assembled molecular interface material prepared in this invention is spin-coated onto the hole selection layer by a two-step spin-coating method to form a perovskite absorption layer; 5-8 seconds before the end of spin-coating, chlorobenzene antisolvent is added dropwise; then, the perovskite film is annealed at 100-110 °C for 20-30 minutes. (4) After cooling, a solution of isopropanol containing passivating agent is dynamically spin-coated onto the perovskite absorber layer, and then annealed at 90~105℃ for 5~10 minutes. (5) The electron transport layer and the electrode buffer layer are deposited sequentially by spin coating or vacuum evaporation. (6) Finally, a metal electrode is deposited under vacuum conditions by thermal evaporation.

[0012] In step (1), the transparent conductive substrate is FTO conductive glass, ITO conductive glass, transparent flexible conductive substrate, or spin-coated nickel oxide (NiO). x It is one of FTO conductive glass, ITO conductive glass or transparent flexible conductive substrate.

[0013] In step (2), nickel oxide (NiO) x The concentration of the aqueous solution is 10~20 mg / mL.

[0014] In step (2), when the hole-selective layer is deposited by spin coating, the concentration of the heteroatom-containing asymmetric self-assembled molecular interface material is 0.50~1.00 mg / mL; In step (3), the perovskite absorber layer is FAPbI3 or Cs. x FA 1-x-y MA y Pb(I 1-z Br z)3、CH3NH3PbI3、CH3NH3PbI 3-x Br x CH3NH3PbI 3-x Cl x (0≤x≤3) or one of the all-inorganic perovskites CsPbI3 and CsPbBr3; wherein FA is CH2=CHNH3; in the perovskite precursor solution, the concentration of the heteroatom-containing asymmetric self-assembled molecular interface material is 0.50~4.00 mg / mL. In step (4), the passivating agent is one of phenylethylamine hydroiodate (PEAI), ethylenediamine dihydroiodate (EDAI2) or propylenediamine dihydroiodate (PDAI2), with a concentration range of 0.50~1.00 mg / mL.

[0015] In step (5), the electron transport material is methyl [6,6]-phenyl-C61-butyrate (PCBM) or fullerene (C60); the electrode buffer layer material is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), polyethyleneimine (PEIE), or tin oxide (SnO). x One of them.

[0016] In step (6), the metal electrode is one of gold, silver or copper, and has a thickness of 100~120 nm.

[0017] The beneficial effects of this invention are as follows: The asymmetric heteroatom benzo[a]-fused carbazole self-assembled molecular material provided by this invention has a simple synthetic route, excellent substrate coverage and resistance to polar solvents, and its large molecular dipole enhances interfacial hole-pulling capability. As an additive to perovskite precursor solutions, it improves the crystallization and growth process of thin films, and its heteroatoms and phosphate groups effectively passivate buried defects in perovskite. These advantages enable this type of material to be used as a hole-selective layer and perovskite precursor additive in perovskite solar cells, optimizing the interfacial energy level arrangement of the device, improving hole-pulling capability, reducing buried interface defects, suppressing nonradiative recombination losses, thereby improving the photoelectric conversion efficiency of the cell and also contributing to enhanced device stability. The successful development of this type of heteroatom conjugated asymmetric self-assembled molecular material provides technical support for the commercialization of perovskite solar cells.

[0018] Figure 1 This is a schematic diagram of the molecular structure of O-AS, S-AS and Se-AS heteroatom conjugated asymmetric self-assembled molecular materials synthesized based on Examples 1, 2 and 3 of the present invention.

[0019] Figure 2a) The NMR spectrum of the O-AS synthesized in Example 1 of the present invention as a heteroatom conjugated asymmetric self-assembled molecular material; b) The NMR spectrum of the S-AS synthesized in Example 2 of the present invention as a heteroatom conjugated asymmetric self-assembled molecular material.

[0020] Figure 3 a) Scanning electron microscope (SEM) bottom view of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite thin film prepared in Comparative Example 1 (Control); b) Scanning electron microscope (SEM) cross-sectional view of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control).

[0021] Figure 4 a) PL spectra of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite thin film prepared in Comparative Example 1 (Control); b) TRPL spectra of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite thin film prepared in Comparative Example 1 (Control); c) Transient photocurrent decay diagram of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control); d) Light intensity dependence test diagram of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control).

[0022] Figure 5 a) Based on the O-AS and S-AS synthesized in Examples 1 and 2 of this invention as heteroatom conjugated asymmetric self-assembled molecular materials, and the perovskite solar cell prepared in Comparative Example 1 (Control), forward and reverse scans were performed. JV a) Curve graph; b) The O-AS and S-AS synthesized in Examples 1 and 2 of this invention are heteroatom conjugated asymmetric self-assembled molecular materials, and the perovskite solar cell prepared in Comparative Example 1 (Control) is tested for maximum power output at 65 °C. Detailed Implementation

[0023] The present invention will be further described below with reference to specific implementation examples to enable those skilled in the art to better understand the present invention. However, the scope of protection of the present invention is not limited to the following embodiments, and the scope of the present invention should be determined by the claims.

[0024] Example 1: Synthesis of self-assembled material O-AS: ; (i) In a dry reaction vessel, compound 1 (3.000 g, 11.66 mmol) and tetrabutylammonium bromide (0.560 g, 1.75 mmol) were added, along with 1,4-dibromobutane (25 mL) as solvent. After stirring until homogeneous, a 50% potassium hydroxide aqueous solution (6.600 g) was added dropwise. The mixture was heated to 65 °C and stirred for 12 hours. After the reaction was complete, the reaction was quenched with deionized water and extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 10:1, v / v), and dried under vacuum to obtain compound 2 as a white solid (3.499 g, yield: 76.5%). 1 H NMR (400 MHz, DMSO- d 6) δ 8.89 – 8.83(m, 1H), 8.30 – 8.11 (m, 2H), 7.97 – 7.84 (m, 1H), 7.72 – 7.61 (m, 2H), 7.53– 7.34 (m, 3H), 7.33 – 7.19 (m, 1H), 4.50 (t, J = 6.6 Hz, 2H), 3.55 (t, J =6.3 Hz, 2H), 1.90 (dddd, J = 15.9, 8.8, 7.2, 4.5 Hz, 4H). (ii) Compound 2 (1.000 g, 2.55 mmol) was dissolved in triethyl phosphite (20 mL), heated to 165 °C under nitrogen protection, and stirred overnight. After the reaction was complete, excess triethyl phosphite was removed by vacuum distillation to give a pale yellow oily crude product (no further purification required). This crude product was dissolved in anhydrous 1,4-dioxane (20 mL), and trimethylbromosilane (3.900 g, 25.5 mmol, 10 equivalents) was added dropwise at room temperature, while stirring was continued overnight at room temperature. After the reaction was complete, 1,4-dioxane was removed by vacuum distillation to give a liquid residue. This liquid product was redissolved in methanol (5–10 mL), and then distilled water was added dropwise until the solution became turbid. The solid was collected by filtration, washed with water, and dried under vacuum to give the target compound O-AS as a grayish-white solid (0.866 g, yield: 86.6%). 1 H NMR (400 MHz, DMSO- d6) δ 8.85(s, 1H), 8.27 – 8.07 (m, 2H), 7.90 (s, 1H), 7.64 (dd, J = 12.8, 8.1 Hz, 2H),7.49 – 7.32 (m, 3H), 7.23 (t, J = 7.4 Hz, 1H), 4.45 (t, J = 7.2 Hz, 2H), 1.88(t, J = 6.0 Hz, 2H), 1.71 – 1.41 (m, 4H). HRMS [M−H] − (ESI) m / z: C22H19NO4P, calculated value 392.1130; measured value 392.1054.

[0025] The self-assembled molecular material O-AS synthesized above was applied to perovskite solar cells. The preparation process is as follows: (1) Cut the ITO (indium doped tin dioxide) conductive glass into glass substrates of 25 mm × 25 mm and etch them with a laser. Clean the etched glass substrates with deionized water, acetone and ethanol for 20 min each, then dry them and treat them in an ultraviolet ozone generator for 30 min.

[0026] (2) Hole transport layer fabricated using solution spin coating: Nickel oxide (NiO) x An aqueous solution (10 mg / mL) was spin-coated onto an ITO glass substrate at 3000 rpm for 30 s. The substrate was then dried on a heated plate at 140 °C for 20 min to form a dense NiO layer. x film.

[0027] All the following operations (except for the vacuum evaporation step) are performed in the glove box.

[0028] Hole-selective layers are created using solution spin coating: An ethanol solution of self-assembled molecular material (0.5 mg / mL) was deposited on NiO using a spin-coating method. x The film was spin-coated at 4000 rpm for 30 s, and then annealed and calcined on a hot plate at 100 ℃ for 10 min.

[0029] (3) Spin-coated perovskite absorber layer: Cesium iodide (CsI), formamidinium hydroiodate (FAI), methylamine hydroiodate (MAI), lead bromide (PbBr2), methylammonium chloride (MACl), and lead iodide (PbI2) were dissolved in water at a stoichiometric ratio of 0.05:0.90:0.05:0.02:0.10:1.00. N, N- A 1.5 M solution was prepared by mixing dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio 4:1), and stirred at 60 °C for 1 hour. O-AS (concentration 0.50–4.00 mg / mL) was then added and the mixture was shaken well before use. Using a spin coater, 60 μL of the prepared perovskite solution was spin-coated onto NiO. x On the film, the rotation speed was controlled at 1000 rpm and the spin coating time was 10 s. Then the rotation speed was controlled at 4000 rpm and the spin coating time was 30 s. During this process, 150 μL of chlorobenzene antisolvent was dropped onto the film. The perovskite film was then annealed and calcined on a hot stage at 100 ℃ for 30 min.

[0030] (4) An isopropanol solution of the passivating agent ethylenediamine dihydroiodate (EDAI2, 1.00 mg / mL) was spin-coated onto the surface of the perovskite film by spin coating at a speed of 4000 rpm for 30 s. The film was then annealed and calcined on a hot plate at 100 °C for 5 min.

[0031] (5) Subsequently, a chlorobenzene solution of electron transport material PCBM (20 mg / mL) was spin-coated onto the perovskite film surface using a solution spin-coating method, with a spin speed controlled at 1500 rpm and a spin-coating time of 35 s. The film was then annealed and calcined on a hot plate at 100 ℃ for 10 min. After the film cooled, a saturated isopropanol solution of BCP was spin-coated onto the PCBM film, with a spin speed controlled at 4500 rpm and a spin-coating time of 30 s.

[0032] (6) Finally, 100 nm Ag was deposited onto the device film by vacuum evaporation.

[0033] Example 2: Synthesis of passivation material S-AS: ; (i) In a dry reaction vessel, compound 1 (2.500 g, 9.15 mmol) and tetrabutylammonium bromide (0.442 g, 1.37 mmol) were added, along with 1,4-dibromobutane (20 mL) as solvent. After stirring until homogeneous, a 50% potassium hydroxide aqueous solution (5.130 g) was added dropwise. The mixture was heated to 70 °C and stirred for 10 hours. After the reaction was complete, the reaction was quenched with deionized water and extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 10:2, v / v), and dried under vacuum to obtain compound 2 as an off-white solid (2.573 g, yield: 68.9%). 1 H NMR (400 MHz, Chloroform- d ) δ 8.82 (d, J = 0.8 Hz, 1H), 8.31 – 8.19 (m, 2H), 7.84 (dt, J = 7.8, 0.9 Hz, 1H), 7.76(d, J = 0.8 Hz, 1H), 7.55 – 7.39 (m, 4H), 7.30 (ddd, J = 8.0, 7.2, 1.0 Hz,1H), 4.39 (t, J = 7.0 Hz, 2H), 3.41 (t, J = 6.5 Hz, 2H), 2.18 – 2.07 (m, 2H), 2.02 – 1.92 (m, 2H). (ii) Compound 2 (0.500 g, 1.22 mmol) was dissolved in triethyl phosphite (10 mL), heated to 170 °C under nitrogen protection, and stirred overnight. After the reaction was complete, excess triethyl phosphite was removed by vacuum distillation to obtain a pale yellow oily crude product (no further purification required). This crude product was dissolved in anhydrous 1,4-dioxane (10 mL), and trimethylbromosilane (1.874 g, 12.2 mmol, 10 equivalents) was added dropwise at room temperature, while stirring was continued overnight at room temperature. After the reaction was complete, 1,4-dioxane was removed by vacuum distillation to obtain a liquid residue. This liquid product was redissolved in methanol (5–10 mL), and then distilled water was added dropwise until the solution became turbid. The solid was collected by filtration, washed with water, and dried under vacuum to obtain the target compound S-AS as a grayish-white solid (0.450 g, yield: 90.1%). 1 H NMR (400 MHz, DMSO-d 6) δ 9.16 (s, 1H), 8.42 (d, J = 7.8 Hz, 1H), 8.30 (d, J = 7.4 Hz, 1H), 8.24 (d, J = 2.4Hz, 1H), 7.98 (d, J = 7.5 Hz, 1H), 7.66 (d, J = 8.2 Hz, 1H), 7.56 – 7.41 (m,3H), 7.27 (t, J = 7.4 Hz, 1H), 4.45 (t, J = 7.1 Hz, 2H), 1.91 (t, J = 5.3 Hz, 2H), 1.56 (d, J = 18.7 Hz, 4H). HRMS [M−H] − (ESI) m / z: C22H19NO3PS, calculated value 408.0826; measured value 408.0902.

[0034] The above-synthesized passivation material S-AS is applied to perovskite solar cells, and its preparation process is as follows: (1) FTO (fluorine-doped tin dioxide) conductive glass was cut into glass substrates of 25 mm × 25 mm and etched using a laser. The etched glass substrates were ultrasonically cleaned in deionized water, acetone and ethanol for 15 min respectively, then dried and treated in an ultraviolet ozone generator for 25 min.

[0035] (2) Hole transport layer fabricated using solution spin coating: Nickel oxide (NiO) x An aqueous solution (20 mg / mL) was spin-coated onto an FTO glass substrate at a speed of 4000 rpm for 35 s. The substrate was then dried on a heated plate at 145 °C for 30 min to form a dense NiO layer. x film.

[0036] All the following operations (except for the vacuum evaporation step) are performed in the glove box.

[0037] Hole-selective layer fabricated using solution spin-coating: A DMF solution of self-assembled molecular material (0.6 mg / mL) was spin-coated onto NiO. xThe film was spin-coated at 3000 rpm for 25 s, and then annealed and calcined on a hot plate at 105 ℃ for 15 min.

[0038] (3) Cesium iodide (CsI), formamidinium hydroiodate (FAI), methylamine hydroiodate (MAI), lead bromide (PbBr2), methylammonium chloride (MACl), and lead iodide (PbI2) were dissolved in water at a stoichiometric ratio of 0.05:0.90:0.05:0.02:0.10:1.00. N, N- A 1.5 M solution was prepared by mixing dimethylformamide and dimethyl sulfoxide (4:1 volume ratio) and stirring at 60 °C for 1 hour. S-AS (0.50–4.00 mg / mL) was then added and the mixture was shaken well before use. Using a spin coater, 60 μL of the prepared perovskite solution was spin-coated onto NiO. x On the film, the rotation speed was controlled at 1000 rpm and the spin coating time was 10 s. Then the rotation speed was controlled at 4000 rpm and the spin coating time was 30 s. During this process, 200 μL of chlorobenzene antisolvent was dropped onto the film. The perovskite film was then annealed and calcined on a hot stage at 110 ℃ for 20 min.

[0039] (4) Then, the isopropanol solution of the passivating agent propylene diamine dihydroiodate (PDAI2, 0.50 mg / mL) was spin-coated onto the surface of the perovskite film by spin coating, with the rotation speed controlled at 4000 rpm and the spin coating time at 30 s. The film was annealed and calcined on a hot plate at 105 °C for 10 min.

[0040] (5) Subsequently, electron transport material C60 was thermally deposited on the surface of the perovskite thin film by vacuum evaporation, with the film thickness controlled at 25 nm. Electrode buffer layer BCP was thermally deposited on the C60 thin film, with the film thickness controlled at 8 nm.

[0041] (6) Finally, 100 nm Cu was deposited onto the device film by vacuum evaporation.

[0042] Example 3: Synthesis of self-assembled material Se-AS: ;

[0043] (i) In a dry reaction vessel, compound 1 (3.500 g, 10.93 mmol) and tetrabutylammonium bromide (0.528 g, 1.64 mmol) were added, along with 1,4-dibromobutane (30 mL) as solvent. After stirring until homogeneous, 50% potassium hydroxide aqueous solution (6.100 g) was added dropwise. The mixture was heated to 70 °C and stirred for 12.5 h. After the reaction was complete, the reaction was quenched with deionized water and extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether / dichloromethane = 9:1, v / v), and dried under vacuum to obtain compound 2 as an off-white solid (4.129 g, yield: 82.97%).

[0044] (ii) Compound 2 (1.500 g, 3.29 mmol) was dissolved in triethyl phosphite (22 mL), heated to 170 °C and stirred overnight under nitrogen protection. After the reaction was complete, excess triethyl phosphite was removed by vacuum distillation to give a pale yellow oily crude product (no further purification required). The crude product was dissolved in anhydrous 1,4-dioxane (25 mL), and trimethylbromosilane (5.044 g, 32.9 mmol, 10 equivalents) was added dropwise at room temperature, while stirring was continued overnight at room temperature. After the reaction was complete, 1,4-dioxane was removed by vacuum distillation to give a liquid residue. The liquid product was redissolved in methanol (5–10 mL), and then distilled water was added dropwise until the solution became turbid. The solid was collected by filtration, washed with water, and dried under vacuum to give the target compound Se-AS as a grayish-white solid (1.045 g, yield: 69.60%).

[0045] The above-synthesized self-assembled molecular material Se-AS was applied to perovskite solar cells, and its preparation process is as follows: (1) Cut the ITO (indium doped tin dioxide) conductive glass into glass substrates of 25 mm × 25 mm and etch them with a laser. Clean the etched glass substrates with deionized water, acetone and ethanol for 20 min each, then dry them and treat them in an ultraviolet ozone generator for 30 min.

[0046] All the following operations (except for the vacuum evaporation step) are performed in the glove box.

[0047] (2) Using solution spin coating to create a cavity selective layer A tetrahydrofuran solution of self-assembled molecular material (0.5 mg / mL) was deposited on an ITO substrate by spin coating at a speed of 4000 rpm for 30 s. The film was then annealed and calcined on a hot plate at 100 °C for 10 min.

[0048] (3) Spin-coated perovskite absorber layer: Cesium iodide (CsI), formamidine hydroiodate (FAI), methylammonium chloride (MACl), and lead iodide (PbI2) were dissolved in water at a stoichiometric ratio of 0.05:0.95:0.10:1.00. N, N- A 1.5 M solution was prepared by mixing dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (volume ratio 4:1), and stirred at 60 °C for 1 hour. Se-AS (concentration 0.50–4.00 mg / mL) was then added and the mixture was shaken well before use. Using a spin coater, 60 μL of the prepared perovskite solution was spin-coated onto NiO. x On the film, the rotation speed was controlled at 1000 rpm and the spin coating time was 10 s. Then the rotation speed was controlled at 4000 rpm and the spin coating time was 30 s. During this process, 150 μL of chlorobenzene antisolvent was dropped onto the film. The perovskite film was then annealed and calcined on a hot stage at 100 ℃ for 30 min.

[0049] (4) A solution of phenethylamine hydroiodide (PEAI, 1.00 mg / mL) in isopropanol was spin-coated onto the surface of the perovskite film by spin coating at a speed of 3500 rpm for 35 s. The film was then annealed and calcined on a hot plate at 105 °C for 15 min.

[0050] (5) Subsequently, a chlorobenzene solution of electron transport material PCBM (25 mg / mL) was spin-coated onto the perovskite film surface using a solution spin-coating method, with a spin speed controlled at 2000 rpm and a spin-coating time of 35 s. The film was then annealed and calcined on a hot plate at 70 ℃ for 10 min. After the film cooled, an isopropanol solution of BCP (1.00 mg / mL) was spin-coated onto the PCBM film, with a spin speed controlled at 5000 rpm and a spin-coating time of 30 s.

[0051] (6) Finally, 100 nm Ag was deposited onto the device film by vacuum evaporation.

[0052] Comparative Example 1: ; [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz)

[0053] Comparative Example 1 (Control) used the commonly used [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz) as the charge selectivity layer material and additive. The specific perovskite solar cell fabrication method is as follows: ITO (indium-doped tin dioxide) conductive glass was cut into 25 mm × 25 mm glass substrates and etched using a laser. The etched glass substrates were ultrasonically cleaned in deionized water, acetone, and ethanol for 20 min each, then dried and treated in a UV ozone generator for 30 min.

[0054] Using solution spin coating, nickel oxide (NiO) is coated onto the substrate. x An aqueous solution (10 mg / mL) was spin-coated onto an ITO glass substrate at 3000 rpm for 30 s. The substrate was then dried on a heated plate at 140 °C for 20 min to form a dense NiO layer. x film.

[0055] All the following operations (except for the vacuum evaporation step) are performed in the glove box.

[0056] An ethanol solution of self-assembled molecular material (0.5 mg / mL) was deposited on NiO using a spin-coating method. x The film was spin-coated at 4000 rpm for 30 s, and then annealed and calcined on a hot plate at 100 ℃ for 10 min.

[0057] Cesium iodide (CsI), formamidinium hydroiodate (FAI), methylamine hydroiodate (MAI), lead bromide (PbBr2), methylammonium chloride (MACl), and lead iodide (PbI2) were dissolved in water at a stoichiometric ratio of 0.05:0.90:0.05:0.02:0.10:1.00. N, N- A 1.5 M solution was prepared by mixing dimethylformamide and dimethyl sulfoxide (4:1 volume ratio) and stirring at 60 °C for 1 hour. Then, 4 PACz (0.50–4.00 mg / mL) was added and the mixture was shaken well before use. Using a spin coater, 60 μL of the prepared perovskite solution was spin-coated onto NiO. x On the film, the rotation speed was controlled at 1000 rpm and the spin coating time was 10 s. Then the rotation speed was controlled at 4000 rpm and the spin coating time was 30 s. During this process, 150 μL of chlorobenzene antisolvent was dropped onto the film. The perovskite film was then annealed and calcined on a hot stage at 100 ℃ for 30 min.

[0058] Then, an isopropanol solution of the passivating agent ethylenediamine dihydroiodate (EDAI2, 1.00 mg / mL) was spin-coated onto the surface of the perovskite film using a spin-coating method, with the spin speed controlled at 4000 rpm and the spin-coating time at 30 s. The film was then annealed and calcined on a hot plate at 100 ℃ for 5 min.

[0059] Subsequently, electron transport material C60 was thermally deposited on the surface of the perovskite thin film using vacuum evaporation, with the film thickness controlled at 25 nm. Electrode buffer layer BCP was thermally deposited on the PCBM thin film, with the film thickness controlled at 8 nm.

[0060] Finally, 100 nm Cu was deposited onto the device film using vacuum evaporation.

[0061] Figure 1 The diagram shows the molecular structures of O-AS, S-AS, and Se-AS synthesized based on Examples 1, 2, and 3 of this invention, which are heteroatom conjugated asymmetric self-assembled molecular materials. The molecular structures of O-AS and S-AS are shown in the diagram.

[0062] Figure 2 a) NMR spectrum of the O-AS synthesized in Example 1 of this invention as a heteroatom conjugated asymmetric self-assembled molecular material; b) NMR spectrum of the S-AS synthesized in Example 2 of this invention as a heteroatom conjugated asymmetric self-assembled molecular material. The figures demonstrate that the synthesized materials of the examples conform to the structural formulas of O-AS and S-AS.

[0063] Figure 3 a) Scanning electron microscope (SEM) bottom view of the O-AS and S-AS synthesized in Examples 1 and 2 of this invention as heteroatom conjugated asymmetric self-assembled molecular materials, and the perovskite thin film prepared in Comparative Example 1 (Control); b) Scanning electron microscope (SEM) cross-sectional view of the O-AS and S-AS synthesized in Examples 1 and 2 of this invention as heteroatom conjugated asymmetric self-assembled molecular materials, and the perovskite solar cell prepared in Comparative Example 1 (Control). As can be seen from the figures, thanks to the synergistic effect of the heteroatoms, asymmetric configuration, and functional groups of O-AS and S-AS, the morphological defects at the perovskite surface and interface are significantly reduced.

[0064] Figure 4a) PL spectra of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite thin film prepared in Comparative Example 1 (Control); b) TRPL spectra of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite thin film prepared in Comparative Example 1 (Control); c) Transient photocurrent decay diagram of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control); d) Light intensity dependence test diagram of the O-AS and S-AS synthesized in Examples 1 and 2 of the present invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control). As shown in the figure, thanks to the synergistic effect of heteroatoms, asymmetric configurations, and functional groups in O-AS and S-AS, defects at the hole transport interface and the perovskite buried interface are effectively passivated, the defect density is significantly reduced, and nonradiative recombination is effectively suppressed. Among these, S atoms exhibit strong electron-donating properties, and S-AS shows a stronger passivation effect. Simultaneously, the rapid photocurrent decay indicates enhanced charge transport at the interface.

[0065] Figure 5 a) Based on the O-AS and S-AS synthesized in Examples 1 and 2 of this invention as heteroatom conjugated asymmetric self-assembled molecular materials, and the perovskite solar cell prepared in Comparative Example 1 (Control), forward and reverse scans were performed. JV (a) Curve graph; (b) Stability test graph of the maximum power output point of the O-AS and S-AS synthesized in Examples 1 and 2 of this invention as heteroatom conjugated asymmetric self-assembled molecular materials and the perovskite solar cell prepared in Comparative Example 1 (Control) at 65 °C. As shown in the graph, thanks to the synergistic effect of heteroatoms, asymmetric configuration, and functional groups of O-AS and S-AS, the perovskite solar cell based on S-AS achieved the highest photoelectric conversion efficiency (PCE) of 26.49% and the open-circuit voltage (…). V oc The voltage is 1.186 V, and the short-circuit current density is ( J sc The value was 25.93 mA / cm². 2 Fill factor ( FF The PCE rate was 86.16%, higher than the 23.92% of the control group. V oc 、J sc and FF The values ​​are 1.155 V and 25.76 mA / cm, respectively. 2And 80.38%. The PCE of O-AS-based devices is 25.83%. V oc It is 1.172 V. J sc 25.82 mA / cm 2 , FF The success rate was 85.39%. Compared to Comparative Example 1 (Control), the hole transport interface and perovskite buried interface constructed by O-AS and S-AS were more stable, and the corresponding perovskite solar cell devices had better stability. S-AS benefited from the superior passivation effect of S atoms, and the corresponding device was more stable than O-AS.

Claims

1. A heteroatom-containing asymmetric self-assembled molecular interface material, characterized in that, It is obtained by using heteroatom benzofused carbazole as the starting material, introducing a 4-bromobutyl chain through alkylation, and then introducing a phosphonic acid group through Albuzov reaction and hydrolysis reaction. Its chemical structure is of general formula (I): ； In formula (I), X is one of oxygen, sulfur, or selenium atoms.

2. The method for synthesizing heteroatom-containing asymmetric self-assembled molecular interface materials as described in claim 1, characterized in that, The steps are as follows: (i) In a dry reaction vessel, add compound 1 and tetrabutylammonium bromide, add solvent 1,4-dibromobutane, stir until homogeneous, add potassium hydroxide aqueous solution dropwise, heat the mixture to 60-70°C and stir for 9-15 hours. After the reaction is complete, quench the reaction with deionized water and extract with dichloromethane; combine the organic phases, dry with anhydrous sodium sulfate, concentrate under reduced pressure to remove the solvent, and obtain crude product. The crude product is purified by silica gel column chromatography to obtain compound 2, which is an off-white solid. (ii) Compound 2 was dissolved in triethyl phosphite and heated to 160-175 °C under nitrogen protection and stirred overnight. After the reaction was complete, excess triethyl phosphite was removed by vacuum distillation to obtain a pale yellow oily crude product. The crude product was dissolved in anhydrous 1,4-dioxane, and bromotrimethylsilane was added dropwise at room temperature. The mixture was stirred overnight at room temperature. After the reaction was complete, 1,4-dioxane was removed by vacuum distillation to obtain a liquid residue. The liquid product was redissolved in methanol, and then distilled water was added dropwise until the solution became turbid. The solid was collected by filtration and washed with water to obtain a white solid, target compound 3. The synthesis process is as follows: 。 3. The method for synthesizing heteroatom-containing asymmetric self-assembled molecular interface materials as described in claim 2, characterized in that, In step (i), the molar ratio of compound 1, tetrabutylammonium bromide and potassium hydroxide is 1.00:0.15:5.00; the reaction concentration of compound 1 is 0.3 ~ 0.5 mol / L, and the mass percentage concentration of the potassium hydroxide aqueous solution is 50 wt%.

4. The method for synthesizing heteroatom-containing asymmetric self-assembled molecular interface materials as described in claim 2, characterized in that, In step (ii), the molar ratio of compound 2 to trimethylbromosilane is 1.00:10.00; the reaction concentration of compound 2 is 0.1 ~ 0.2 mol / L.

5. The use of the heteroatom-containing asymmetric self-assembled molecular interface material of claim 1 in perovskite solar cells.

6. The use as described in claim 5, characterized in that, The perovskite solar cell comprises a transparent conductive substrate, a hole selection layer or a hole transport layer + hole selection layer, a perovskite absorber layer, an electron transport layer, and a metal electrode. The fabrication steps are as follows: (1) Cut the transparent conductive substrate into fixed sizes and clean it with cleaning agent, deionized water, acetone and isopropanol in sequence by ultrasonic cleaning. After drying, perform ultraviolet ozone treatment. (2) On the transparent conductive substrate after step (1), a hole selection layer is deposited by spin coating, or a hole transport layer and a hole selection layer are deposited sequentially. (3) The perovskite precursor solution containing heteroatom-containing asymmetric self-assembled molecular interface material is spin-coated onto the hole selection layer by a two-step spin-coating method to form a perovskite absorption layer; 5-8 seconds before the end of spin-coating, chlorobenzene antisolvent is added dropwise; then the perovskite film is annealed at 100-110 °C for 20-30 minutes. (4) After cooling, a solution of isopropanol containing passivating agent is dynamically spin-coated onto the perovskite absorber layer, and then annealed at 90~105 °C for 5~10 minutes; (5) The electron transport layer and the electrode buffer layer are deposited sequentially by spin coating or vacuum evaporation. (6) Finally, a metal electrode is deposited under vacuum conditions by thermal evaporation.

7. The use as described in claim 6, characterized in that, In step (1), the transparent conductive substrate is FTO conductive glass, ITO conductive glass, transparent flexible conductive substrate, or spin-coated nickel oxide (NiO). x The cleaning time is 15-20 minutes for each of the following: FTO conductive glass, ITO conductive glass, or transparent flexible conductive substrate; UV ozone treatment time is 20-30 minutes.

8. The use as described in claim 6, characterized in that, In step (2), when depositing the hole transport layer, nickel oxide (NiO) with a concentration of 10~20 mg / mL is used. x The aqueous solution was spin-coated at 3000-4000 rpm for 25-35 seconds, and then dried on a heated plate at 135-145 °C for 20-30 minutes to form a dense NiO. x film; In step (2), when depositing the hole-selective layer, the solute is an asymmetric self-assembled molecular interface material containing heteroatoms, and the solvent is ethanol, tetrahydrofuran, or... N, N- One of the dimethylformamides (DMF); concentration of 0.50~1.00 mg / mL; control the rotation speed at 3000~4000 rpm for 25~35 seconds, and then anneal at 90~105 °C for 10~15 minutes.

9. The use as described in claim 6, characterized in that, In step (3), the perovskite absorber layer is FAPbI3 or Cs. x FA 1-x-y MA y Pb(I 1-z Br z )3、CH3NH3PbI3、CH3NH3PbI 3-x Br x CH3NH3PbI 3-x Cl x (0≤x≤3) or one of the all-inorganic perovskites CsPbI3 and CsPbBr3; wherein FA is CH2=CHNH3; in the perovskite precursor solution, the concentration of the heteroatom-containing asymmetric self-assembled molecular interface material is 0.50~4.00 mg / mL.

10. The use as described in claim 6, characterized in that, In step (4), the passivating agent is one of phenylethylamine hydroiodate (PEAI), ethylenediamine dihydroiodate (EDAI2), or propylenediamine dihydroiodate (PDAI2), with a concentration range of 0.50~1.00 mg / mL. In step (5), the electron transport material is methyl [6,6]-phenyl-C61-butyrate PCBM or fullerene C60; the electrode buffer layer material is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline BCP, polyethyleneimine PEIE, or tin oxide SnO. x One of them; In step (6), the metal electrode is one of gold, silver or copper, and has a thickness of 100~120 nm.

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