Method for realizing efficient anti-ultraviolet perovskite photovoltaic device through mixed self-assembly monomolecular layer hole transport layer

Abstract

The invention provides a method for realizing a high-efficiency anti-ultraviolet perovskite photovoltaic device through a mixed self-assembly monomolecular layer hole transport layer, and the method is an effective way for solving the tradeoff between efficiency and stability by mixing two SAMs of 2-phenethyl phosphoric acid and (2-(pyrene-1-yl) ethyl) phosphonic acid to cooperatively modify an interface. Wherein the 2-phenethyl phosphoric acid has relatively high ultraviolet stability, so that the illumination stability of the device can be effectively improved; and (2-(pyrene-1-yl) ethyl) phosphonic acid has a good pi conjugated skeleton structure and vertical orientation capability, and can promote the improvement of perovskite crystal quality, inhibit the formation of crystal boundary halogen vacancies and reduce ion migration barriers, so that the open-circuit voltage (VOC) and fill factor (FF) of the device are significantly improved, and the strategy is expected to improve the performance of the device on the premise of not sacrificing the initial efficiency of the device. The service life and the ultraviolet stability of the perovskite device are remarkably improved, and further development of the perovskite device in practical application is promoted.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a method for realizing a high-efficiency UV-resistant perovskite photovoltaic device using a hybrid self-assembled monolayer hole transport layer. Background Technology

[0002] Perovskite solar cells (PSCs) have demonstrated immense application potential in emerging photovoltaic technologies due to their superior photoelectric properties and low-cost fabrication. Currently, perovskite materials, with their tunable bandgap, strong light absorption, high carrier mobility, and long carrier diffusion length, have become ideal active layer materials for achieving high-efficiency photoelectric conversion. In recent years, the efficiency of single-junction PSC devices has rapidly increased from an initial 3.8% to 27.0% in just over a decade, approaching the theoretical Shockley-Queisser limit, making it one of the most competitive next-generation photovoltaic technologies.

[0003] In terms of device structure, compared with the traditional "upright structure" (nip), the "inverted structure" (pin) PSC has attracted increasing attention due to its low-temperature fabrication process, flexibility and compatibility, and higher interface controllability. Furthermore, because self-assembled monolayers (SAMs) can form stable chemical bonds with electrode materials such as indium tin oxide (ITO) through their terminal groups such as phosphate or carboxylic acid, they can further regulate energy level arrangement, improve interface contact, suppress interface defects and non-radiative recombination, thereby significantly improving the open-circuit voltage, short-circuit current density and fill factor of the device. Using SAMs as hole-selective layers (HSLs) has become an important strategy for constructing high-performance inverted PSCs.

[0004] Existing technologies combine the two methods mentioned above, introducing SAM as a hole transport layer in inverted structure devices. While this has led to significant progress in the performance and structural optimization of perovskite solar cells, particularly in their photoelectric performance, two prominent problems remain:

[0005] (1) Long-term stability issues, especially the performance degradation under ultraviolet light irradiation, remain one of the key challenges restricting the practical application of PSCs: the perovskite active layer itself is easily induced to undergo degradation reactions under ultraviolet light (UV) excitation, such as halogen migration, phase separation or destruction of the surface passivation layer. In particular, wide-bandgap perovskites are more prone to UV-induced crystal structure destruction and phase instability. The interface region, especially the SAM / perovskite interface, is also prone to charge transport obstruction and interface recombination enhancement due to chemical bond breakage, interface energy level drift or molecular rearrangement under UV excitation, thereby aggravating the device performance degradation.

[0006] (2) Single SAM materials usually cannot simultaneously possess excellent performance in terms of energy level matching, interface passivation ability, chemical stability and light stability, that is, it is difficult to balance device efficiency and operational stability: some SAMs with strong interfacial bonding and good energy level matching (such as MeO-2PACz, Me-4PACz, etc.) may be unstable under ultraviolet light, easily generating decomposition products or even forming an interfacial insulating layer, affecting the carrier extraction efficiency; while some aromatic structure SAMs with good ultraviolet stability have weak adhesion to the electrode or cannot effectively control the band arrangement, resulting in limited initial device efficiency.

[0007] In summary, we consider developing a hybrid SAM strategy and propose a method for constructing a hole transport layer based on hybrid SAM. Summary of the Invention

[0008] This invention aims to address the aforementioned problems by proposing a method for achieving high-efficiency, UV-resistant perovskite photovoltaic devices using a hybrid self-assembled monolayer hole transport layer. This method synergistically modifies the interface with two or more SAM molecules possessing complementary properties, providing an effective way to balance efficiency and stability. The hybrid SAM not only combines the advantages of different molecules in interface energy level modulation, carrier selectivity, UV stability, and chemical binding forces, but also adjusts the molecular packing structure and surface polarity, thereby optimizing the interface microenvironment and enhancing interface stability. This strategy is expected to significantly improve the lifetime and UV stability of perovskite devices without sacrificing initial device efficiency, promoting their further development in practical applications.

[0009] The technical solution of this invention is:

[0010] This invention proposes an inverted perovskite solar cell based on a hybrid self-assembled monolayer, characterized in that it comprises a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an electron blocking layer, and a metal electrode layer stacked sequentially.

[0011] The hole transport layer material includes 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid;

[0012] The perovskite light-absorbing layer material, i.e., the perovskite precursor, has the following general formula: Where: A is FA + MA + Cs + One or more of them; B is Pb 2+ Sn 2+ One or more of them; X is Cl - ,Br - Or I -One or more of them.

[0013] This invention also proposes a method for fabricating perovskite solar cells based on the above, characterized in that the specific steps include:

[0014] Step 1: Prepare SAM solution;

[0015] Step 2: Substrate pretreatment;

[0016] Treating the conductive substrate with ultraviolet ozone increases its surface hydrophilicity and functional group activity, thereby improving the self-assembly efficiency of SAM molecules.

[0017] Step 3: Hole transport layer fabrication:

[0018] The SAM solution prepared in step 1 is spin-coated onto the substrate surface after the pretreatment in step 2, and then annealed to form a dense and uniform mixed SAM hole transport layer.

[0019] Step 4: Preparation of the perovskite light-absorbing layer:

[0020] The precursor solution was dropped onto the hole transport layer prepared in step 3, spin-coated, and then annealed to form a perovskite light-absorbing layer.

[0021] Step 5: Surface passivation layer construction:

[0022] A passivating agent solution is spin-coated onto the perovskite light-absorbing layer formed in step 4, followed by annealing to form a surface passivation layer;

[0023] Step 6: Fabrication of the electron transport layer:

[0024] An electron transport layer solution is spin-coated onto the surface passivation layer formed in step 5 to obtain an electron transport layer.

[0025] Step 7: Electron blocking layer preparation:

[0026] An electron blocking layer solution is spin-coated onto the electron transport layer formed in step 6, and then an electron blocking layer is obtained after annealing heat treatment.

[0027] Step 8: Metal electrode deposition:

[0028] The device is constructed by depositing a metal electrode on the electron blocking layer obtained in step 7 using thermal evaporation technology.

[0029] Furthermore, the preparation process of the SAM solution in step 1 includes: dissolving 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid in ethylene glycol monomethyl ether to prepare single SAM solutions with the same mass concentration, and then mixing the two in a volume ratio of 1:1 to form a mixed SAM solution.

[0030] Furthermore, the preparation process of the precursor solution in step 4 includes: dissolving the perovskite precursor in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1 in an anhydrous and oxygen-free nitrogen glove box to form a precursor solution with a concentration of 1.3-1.8M, and stirring at room temperature for 2-4 hours.

[0031] Furthermore, the preparation process of the passivating agent solution in step 5 includes: dissolving phenylethyl ammonium iodide (PEAI) in isopropanol (IPA) in an anhydrous and oxygen-free nitrogen glove box to form a passivating agent solution.

[0032] Furthermore, the preparation process of the electron transport layer solution in step 6 includes: dissolving isomethyl [6,6]-phenyl-C61-butyrate (PCBM) in chlorobenzene to prepare an electron transport layer solution.

[0033] Furthermore, the preparation process of the electron blocking layer solution in step 7 includes: dissolving 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in isopropanol to prepare an electron blocking layer solution.

[0034] Furthermore,

[0035] In step 2, the conductive substrate is treated with ultraviolet ozone for 15-30 minutes.

[0036] In step 3, the spin coating speed of the SAM solution is 2000-3000 rpm and the time is 20-30 s; the annealing temperature is 100-150℃ and the time is 10-30 min.

[0037] In step 4, 70-75 μL of precursor solution is added dropwise; the precursor solution is spin-coated at a speed of 3000-5000 rpm for 30-40 seconds; and the annealing treatment is performed at a temperature of 100-150℃ for 10-20 minutes.

[0038] In step 5, 70-75 μL of passivating agent solution is added dropwise; the passivating agent solution is spin-coated at a speed of 3000-4000 rpm for 20-25 seconds; the annealing temperature is 100-120℃ and the time is 5-10 minutes.

[0039] In step 6, 30-50 μL of electron transport layer solution is added dropwise; the electron transport layer solution is spin-coated at a speed of 1500-2000 rpm for 20-25 seconds.

[0040] In step 7, 200-250 μL of electron blocking layer solution is added dropwise; the electron blocking layer solution is spin-coated at a speed of 3000-4000 rpm for 20-25 seconds; the annealing temperature is 100-120℃ and the time is 10-20 minutes.

[0041] The thickness of the metal vapor-deposited in step 8 is 100-150 nm.

[0042] The beneficial effects of this invention are:

[0043] A method for achieving high-efficiency, UV-resistant perovskite photovoltaic devices using a hybrid self-assembled monolayer hole transport layer is disclosed. Based on the construction of a hole transport layer using hybrid SAMs, the method optimizes the perovskite crystal quality and interface properties through intermolecular synergistic effects, thereby significantly improving the photoelectric conversion efficiency and environmental stability of perovskite solar cells. Specifically:

[0044] 1. This invention obtains a hybrid SAM hole transport layer by mixing 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid, two types of SAMs. This fully combines the complementary advantages of the two molecules in terms of chemical stability and interface regulation. Specifically, 2-phenylethyl phosphoric acid exhibits high UV stability, effectively improving the device's light-induced stability; while (2-(pyrene-1-yl)ethyl)phosphonic acid possesses a good π-conjugated framework structure and vertical orientation capability, promoting the improvement of perovskite crystal quality, inhibiting the formation of grain boundary halogen vacancies, and reducing ion migration barriers, thereby significantly increasing the device's open-circuit voltage (V). OC ) and fill factor (FF);

[0045] 2. The hybrid SAM layer constructed in this invention can effectively control the interface energy level structure: by adjusting the ratio of the two SAMs, the HOMO energy level of the hole transport layer is better matched with the energy level of the perovskite light-absorbing layer, thereby improving the hole extraction efficiency and suppressing interface charge recombination and charge accumulation. This synergistic control mechanism further improves the short-circuit current density (J / L) of the device. SC This improves both the efficiency and stability of perovskite solar cells, ultimately achieving a dual improvement in both efficiency and stability. Attached Figure Description

[0046] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0047] Figure 1 This is a structural diagram of a perovskite solar cell with a hybrid self-assembled monolayer hole transport layer according to the present invention.

[0048] Figure 2 (a) is the molecular structure diagram of 2-phenylethyl phosphoric acid, and (b) is the molecular structure diagram of (2-(pyrene-1-yl)ethyl)phosphonic acid;

[0049] Figure 3 This is a current-voltage curve of a perovskite solar cell based on a 2-phenylethyl phosphate hole transport layer;

[0050] Figure 4 This is a current-voltage curve of a perovskite solar cell based on a (2-(pyrene-1-yl)ethyl)phosphonic acid hole transport layer;

[0051] Figure 5 This is a current-voltage curve of a perovskite solar cell based on a hybrid SAM hole transport layer;

[0052] Figure 6 (a) is the absorption curve of 2-phenylethyl phosphoric acid before and after ultraviolet light irradiation, and (b) is the absorption curve of (2-(pyrene-1-yl)ethyl)phosphonic acid before and after ultraviolet light irradiation.

[0053] Figure 7 (a) is the NMR spectrum of 2-phenylethyl phosphoric acid before and after UV irradiation, (b) is the NMR spectrum of (2-(pyrene-1-yl)ethyl)phosphonic acid before and after UV irradiation, and (c) is the NMR spectrum of mixed SAM group before and after UV irradiation.

[0054] Figure 8 (a) is a SEM image of a 2-phenylethyl phosphate perovskite film, (b) is a SEM image of a (2-(pyrene-1-yl)ethyl)phosphonate perovskite film, and (c) is a SEM image of a mixed SAM-based perovskite film.

[0055] Figure 9 (a) is the in-situ UV aging PL image of 2-phenylethyl phosphate perovskite film, (b) is the in-situ UV aging PL image of (2-(pyrene-1-yl)ethyl)phosphonate perovskite film, and (c) is the in-situ UV aging PL image of mixed SAM-based perovskite film. Detailed Implementation

[0056] See appendix Figure 1-2 This invention provides an inverted perovskite solar cell based on a mixed self-assembled monolayer (Mixed SAM). The device structure includes, in sequence, a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an electron blocking layer, and a metal electrode layer. The hole transport layer is composed of a mixed SAM consisting of 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid in different proportions.

[0057] This invention also provides a method for preparing the above-mentioned perovskite solar cell, the specific steps of which include:

[0058] Step 1: Prepare SAM solution:

[0059] 2-Phenylacetic acid and (2-(pyrene-1-yl)ethyl)phosphonic acid were dissolved in ethylene glycol monomethyl ether to prepare single SAM solutions with the same mass concentration. Then, the two were mixed in a volume ratio of 1:1 to form a mixed SAM solution.

[0060] Step 2: Substrate pretreatment:

[0061] Treating conductive substrates (such as ITO) with ultraviolet ozone (UV-O3) for 15-30 minutes increases surface hydrophilicity and functional group activity, thereby improving the self-assembly efficiency of SAM molecules.

[0062] Step 3: Hole transport layer fabrication:

[0063] The pretreated substrate surface was spin-coated with a mixed SAM solution at a spin speed of 2000-3000 rpm for 20-30 s. After spin-coating, the substrate was heat-annealed at 100-150℃ for 10-30 min to form a dense and uniform mixed SAM hole transport layer.

[0064] Step 4: Preparation of the perovskite light-absorbing layer:

[0065] In an anhydrous and oxygen-free nitrogen glove box, the perovskite precursor was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1 to form a precursor solution with a concentration of 1.3-1.8M, and stirred at room temperature for 2-4 hours.

[0066] The general formula of the perovskite precursor is: Where A is FA + MA + Cs + One or more of them, where B is Pb 2 + Sn 2+ One or more of them, where X is Cl - ,Br - Or I - One or more of the following;

[0067] Add 70-75 μL of the above precursor solution to the hole transport layer, spin coat at 3000-5000 rpm for 30-40 s, and then anneal at 100-150℃ for 10-20 min.

[0068] Step 5: Surface passivation layer construction:

[0069] In an anhydrous and oxygen-free nitrogen glove box, phenylethyl ammonium iodide (PEAI) is dissolved in isopropanol (IPA) to form a passivating agent solution. 70-75 μL of this solution is spin-coated onto the perovskite light-absorbing layer at a spin speed of 3000-4000 rpm for 20-25 s, followed by annealing at 100-120℃ for 5-10 min.

[0070] Step 6: Fabrication of the electron transport layer:

[0071] [6,6]-phenyl-C61-butyric acid isomethyl ester (PCBM) was dissolved in chlorobenzene to prepare an electron transport layer solution. 30-50 μL of the electron transport layer solution was spin-coated onto the surface passivation layer at a spin speed of 1500-2000 rpm for 20-25 s to obtain the electron transport layer.

[0072] Step 7: Electron blocking layer preparation:

[0073] 2,9-Dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was dissolved in isopropanol to prepare an electron blocking layer solution. 200-250 μL of the solution was spin-coated onto the electron transport layer at a spin speed of 3000-4000 rpm for 20-25 s, followed by annealing at 100-120 °C for 10-20 min.

[0074] Step 8: Metal electrode deposition:

[0075] The device is constructed by depositing metal electrodes (such as Ag or Au) on the electron blocking layer using thermal evaporation technology, with a evaporation thickness of 100-150 nm.

[0076] The principles and features of this invention are described in conjunction with the following experimental examples and accompanying drawings. The examples are only used to explain this invention and are not intended to limit the scope of this invention.

[0077] Experimental Example 1:

[0078] Fabrication of perovskite solar cells based on 2-phenylethyl phosphoric acid as a hole transport layer:

[0079] S1: Preparation of hole transport layer: ITO conductive glass was treated with ultraviolet ozone for 25 min, and then transferred to a dry nitrogen glove box. 2-phenylethyl phosphoric acid was dissolved in ethylene glycol monomethyl ether solvent to obtain a SAM solution with a concentration of 0.5 mg / mL. 70 μL of hole transport layer solution was taken and dropped onto the center of ITO glass. After spin coating for 30 s, the substrate of hole transport layer was obtained after heat treatment at 100 °C.

[0080] S2: Preparation of perovskite precursor solution: In a nitrogen glove box environment, first, N,N-dimethylformamide and dimethyl sulfoxide were mixed in a 4:1 volume ratio. Then, CsI, FAI, PbI2, and PbBr2 were dissolved in the mixture in a molar ratio of 0.22:0.78:0.60:0.40. The mixture was stirred at 30°C for 3 hours. Finally, it was passed through PTFE 13... After filtration through a 0.22µm filter, a 1.5M perovskite precursor solution (Cs) was obtained. 0.22 FA 0.78 Pb(I 0.6 Br 0.4 )3;

[0081] S3: Preparation of perovskite light-absorbing layer: 70 μL of perovskite precursor solution was dropped onto the center of the 2-phenylethyl phosphate hole transport layer substrate and rotated at 5000 rpm for 30 s. 10 s before the end of spin coating, 200 μL of ethyl acetate was added as an anti-solvent. After annealing at 150 °C for 10 min, a perovskite film was formed and placed in a dry place to cool.

[0082] S4: Preparation of surface passivation layer: Phenethyl ammonium iodide (PEAI) was dissolved in isopropanol (IPA) to form a passivating agent solution. 70 μL of the solution was spin-coated onto the perovskite light-absorbing layer at a spin speed of 4000 rpm for 20 s, followed by annealing at 100 °C for 5 min.

[0083] S5: Preparation of electron transport layer: Isomethyl [6,6]-phenyl-C61-butyrate (PCBM) was dissolved in chlorobenzene to prepare an electron transport layer solution. 40 μL of the electron transport layer solution was spin-coated onto the surface passivation layer to obtain the electron transport layer.

[0084] S6: Preparation of electron blocking layer: Dissolve 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in isopropanol to prepare an electron blocking layer solution, and spin-coat 200 μL onto the electron transport layer. After heat treatment, the electron blocking layer is obtained.

[0085] S7: Preparation of metal electrode layer: Using thermal evaporation, 100 nm of silver is deposited on top of the electron blocking layer.

[0086] like Figure 3 As shown, the photoelectric conversion efficiency of the 2-phenylethyl phosphate perovskite solar cell is 3.64%, the open-circuit voltage is 1.118V, and the effective area is 0.05cm². 2 .

[0087] Experiment Example 2

[0088] Perovskite solar cells were fabricated using (2-(pyrene-1-yl)ethyl)phosphonic acid as a hole transport layer.

[0089] S1: Preparation of hole transport layer: ITO conductive glass was treated with ultraviolet ozone for 25 min, and then transferred to a dry nitrogen glove box. (2-(pyrene-1-yl)ethyl)phosphonic acid was dissolved in ethylene glycol monomethyl ether solvent to obtain a SAM solution with a concentration of 0.5 mg / mL. 70 μL of hole transport layer solution was taken and dropped onto the center of ITO glass. After spin coating for 30 s, the substrate of hole transport layer was obtained after heat treatment at 100 °C.

[0090] S2: Preparation of perovskite precursor solution: In a nitrogen glove box environment, first, N,N-dimethylformamide and dimethyl sulfoxide were mixed in a 4:1 volume ratio. Then, CsI, FAI, PbI2, and PbBr2 were dissolved in the mixture in a molar ratio of 0.22:0.78:0.60:0.40. The mixture was stirred at 30°C for 3 hours. Finally, it was passed through PTFE 13... After filtration through a 0.22µm filter, a 1.5M perovskite precursor solution (Cs) was obtained. 0.22 FA 0.78 Pb(I 0.6 Br 0.4 )3;

[0091] S3: Preparation of perovskite light-absorbing layer: 70 μL of perovskite precursor solution was dropped onto the center of the (2-(pyrene-1-yl)ethyl)phosphonic acid hole transport layer substrate and rotated at 5000 rpm for 30 s. 10 s before the end of spin coating, 200 μL of ethyl acetate was added as an antisolvent. After annealing at 150 °C for 10 min, a perovskite film was formed and placed in a dry place to cool.

[0092] S4: Preparation of surface passivation layer: Phenethyl ammonium iodide (PEAI) was dissolved in isopropanol (IPA) to form a passivating agent solution. 70 μL of the solution was spin-coated onto the perovskite light-absorbing layer at a spin speed of 4000 rpm for 20 s, followed by annealing at 100 °C for 5 min.

[0093] S5: Preparation of electron transport layer: Isomethyl [6,6]-phenyl-C61-butyrate (PCBM) was dissolved in chlorobenzene to prepare an electron transport layer solution. 40 μL of the electron transport layer solution was spin-coated onto the surface passivation layer to obtain the electron transport layer.

[0094] S6: Preparation of electron blocking layer: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was dissolved in isopropanol to prepare an electron blocking layer solution, and 200 μL of the solution was spin-coated onto the electron transport layer. After heat treatment, the electron blocking layer was obtained.

[0095] S7: Preparation of metal electrode layer: Using thermal evaporation, 100 nm of silver is deposited on top of the electron blocking layer.

[0096] like Figure 4 As shown, the photoelectric conversion efficiency of the (2-(pyrene-1-yl)ethyl)phosphonate perovskite solar cell is 19.67%, the open-circuit voltage is 1.281V, and the effective area is 0.05cm². 2 .

[0097] Experimental Example 3

[0098] Perovskite solar cells were fabricated using a mixed SAM of 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid as a hole transport layer.

[0099] S1: Preparation of hole transport layer: ITO conductive glass was treated with ultraviolet ozone for 25 min, and then transferred to a dry nitrogen glove box. 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid were dissolved in ethylene glycol monomethyl ether solvent to obtain a SAM solution with a concentration of 0.5 mg / mL. The two were mixed in different volume ratios to obtain mixed SAM solutions with (2-(pyrene-1-yl)ethyl)phosphonic acid: 2-phenylethyl phosphoric acid ratios of 10%, 30%, and 50%, respectively. 70 μL of the mixed SAM solution was pipetted and dropped onto the center of the ITO glass. After spin coating for 30 s, the glass was heat-treated at 100 °C to obtain the hole transport layer substrate.

[0100] S2: Preparation of perovskite precursor solution: In a nitrogen glove box environment, first, N,N-dimethylformamide and dimethyl sulfoxide were mixed in a 4:1 volume ratio. Then, CsI, FAI, PbI2, and PbBr2 were dissolved in the mixture in a molar ratio of 0.22:0.78:0.60:0.40. The mixture was stirred at 30°C for 3 hours. Finally, it was passed through PTFE 13... After filtration through a 0.22µm filter, a 1.5M perovskite precursor solution (Cs) was obtained. 0.22 FA 0.78 Pb(I 0.6 Br 0.4 )3;

[0101] S3: Preparation of perovskite light-absorbing layer: 70 μL of perovskite precursor solution was dropped onto the center of the (2-(pyrene-1-yl)ethyl)phosphonic acid hole transport layer substrate and rotated at 5000 rpm for 30 s. 10 s before the end of spin coating, 200 μL of ethyl acetate was added as an antisolvent. After annealing at 150 °C for 10 min, a perovskite film was formed and placed in a dry place to cool.

[0102] S4: Preparation of surface passivation layer: Phenethyl ammonium iodide (PEAI) was dissolved in isopropanol (IPA) to form a passivating agent solution. 70 μL of the solution was spin-coated onto the perovskite light-absorbing layer at a spin speed of 4000 rpm for 20 s, followed by annealing at 100 °C for 5 min.

[0103] S5: Preparation of electron transport layer: Isomethyl [6,6]-phenyl-C61-butyrate (PCBM) was dissolved in chlorobenzene to prepare an electron transport layer solution. 40 μL of the electron transport layer solution was spin-coated onto the surface passivation layer to obtain the electron transport layer.

[0104] S6: Preparation of electron blocking layer: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was dissolved in isopropanol to prepare an electron blocking layer solution, and 200 μL of the solution was spin-coated onto the electron transport layer. After heat treatment, the electron blocking layer was obtained.

[0105] S7: Preparation of metal electrode layer: Using thermal evaporation, 100 nm of silver is deposited on top of the electron blocking layer.

[0106] like Figure 5 As shown, the perovskite solar cell based on hybrid SAM has a photoelectric conversion efficiency of 19.86%, an open-circuit voltage of 1.293V, and an effective area of ​​0.05cm². 2 .

[0107] like Figure 6 As shown, (a) is the absorption curve of 2-phenylethyl phosphoric acid before and after ultraviolet light irradiation, and (b) is the absorption curve of (2-(pyrene-1-yl)ethyl)phosphonic acid before and after ultraviolet light irradiation. It can be found that the absorption intensity of 2-phenylethyl phosphoric acid remains basically unchanged after 32h ultraviolet light irradiation, while the absorption intensity of (2-(pyrene-1-yl)ethyl)phosphonic acid decreases significantly after 32h ultraviolet light irradiation, indicating that 2-phenylethyl phosphoric acid has excellent anti-ultraviolet light performance.

[0108] like Figure 7 As shown, (a) is the NMR spectrum of 2-phenylethyl phosphoric acid before and after UV irradiation, and (b) is the NMR spectrum and a magnified view of (2-(pyrene-1-yl)ethyl)phosphonic acid before and after UV irradiation. It can be found that the NMR spectrum of 2-phenylethyl phosphoric acid before and after irradiation is almost unchanged, while (2-(pyrene-1-yl)ethyl)phosphonic acid shows impurity peaks in the aromatic region after UV irradiation, that is, the fragmentation of the aromatic ring.

[0109] like Figure 8As shown, (a) is a SEM image of the 2-phenylethyl phosphate perovskite film, (b) is a SEM image of the (2-(pyrene-1-yl)ethyl)phosphonate perovskite film, and (c) is a SEM image of the mixed SAM-based perovskite film. The 2-phenylethyl phosphate perovskite film has large grains but contains residual lead iodide. The (2-(pyrene-1-yl)ethyl)phosphonate perovskite film has smaller grains but is more uniform. The mixed SAM-based perovskite film has larger and more uniform grains and no residual lead iodide.

[0110] like Figure 9 As shown, (a) is the in-situ UV aging PL pattern of the 2-phenylethyl phosphate perovskite film, (b) is the in-situ UV aging PL pattern of the (2-(pyrene-1-yl)ethyl)phosphonic acid perovskite film, and (c) is the in-situ UV aging PL pattern of the mixed SAM-based perovskite film. The stability of the mixed SAM-based film under UV irradiation is significantly better than that of the control film using a single (2-(pyrene-1-yl)ethyl)phosphonic acid as the hole transport layer, showing a lower PL peak shift, indicating that it has a significant advantage in resisting UV aging.

[0111] The above research results indicate that the hybrid SAM strategy developed in this invention, through the synergistic effect of 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid, can significantly improve the crystallinity and surface morphology of perovskite films, and regulate the interfacial band structure, thereby effectively enhancing the photoelectric performance of the device. Simultaneously, the introduction of 2-phenylethyl phosphoric acid into the hybrid SAM structure enhances the chemical and photostability of the interface, enabling the device to maintain high performance output under ultraviolet light irradiation and significantly improving the device's lifetime. The hybrid SAM construction strategy provided by this invention offers a new approach to achieving efficient and stable perovskite solar cells, demonstrating good processability and promising prospects for industrial application.

[0112] The above description is merely a preferred experimental example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A perovskite solar cell with an inverted structure based on a hybrid self-assembled monolayer, characterized in that, It includes a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an electron blocking layer, and a metal electrode layer, which are stacked sequentially. The hole transport layer material includes 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid; The perovskite light-absorbing layer material, i.e., the perovskite precursor, has the following general formula: Where: A is FA + MA + Cs + One or more of them; B is Pb 2+ Sn 2+ One or more of them; X is Cl - ,Br - Or I - One or more of them.

2. A method for preparing a perovskite solar cell based on claim 1, characterized in that, The specific steps include: Step 1: Prepare SAM solution; Step 2: Substrate pretreatment; Treating the conductive substrate with ultraviolet ozone increases its surface hydrophilicity and functional group activity, thereby improving the self-assembly efficiency of SAM molecules. Step 3: Hole transport layer fabrication: The SAM solution prepared in step 1 is spin-coated onto the substrate surface after the pretreatment in step 2, and then annealed to form a dense and uniform mixed SAM hole transport layer. Step 4: Preparation of the perovskite light-absorbing layer: The precursor solution was dropped onto the hole transport layer prepared in step 3, spin-coated, and then annealed to form a perovskite light-absorbing layer. Step 5: Surface passivation layer construction: A passivating agent solution is spin-coated onto the perovskite light-absorbing layer formed in step 4, followed by annealing to form a surface passivation layer; Step 6: Fabrication of the electron transport layer: An electron transport layer solution is spin-coated onto the surface passivation layer formed in step 5 to obtain an electron transport layer. Step 7: Electron blocking layer preparation: An electron blocking layer solution is spin-coated onto the electron transport layer formed in step 6, and then an electron blocking layer is obtained after annealing heat treatment. Step 8: Metal electrode deposition: The device is constructed by depositing a metal electrode on the electron blocking layer obtained in step 7 using thermal evaporation technology.

3. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, The preparation process of the SAM solution in step 1 includes: dissolving 2-phenylethyl phosphoric acid and (2-(pyrene-1-yl)ethyl)phosphonic acid in ethylene glycol monomethyl ether to prepare single SAM solutions with the same mass concentration, and then mixing the two in a volume ratio of 1:1 to form a mixed SAM solution.

4. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, The preparation process of the precursor solution in step 4 includes: dissolving the perovskite precursor in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1 in an anhydrous and oxygen-free nitrogen glove box to form a precursor solution with a concentration of 1.3-1.8M, and stirring at room temperature for 2-4 hours.

5. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, The preparation process of the passivating agent solution in step 5 includes: dissolving phenylethyl ammonium iodide (PEAI) in isopropanol (IPA) in an anhydrous and oxygen-free nitrogen glove box to form a passivating agent solution.

6. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, The preparation process of the electron transport layer solution in step 6 includes: dissolving isomethyl [6,6]-phenyl-C61-butyrate (PCBM) in chlorobenzene to prepare an electron transport layer solution.

7. The method for preparing a perovskite solar cell as described in claim 2, characterized in that, The preparation process of the electron blocking layer solution in step 7 includes: dissolving 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in isopropanol to prepare an electron blocking layer solution.

8. The method for preparing a perovskite solar cell as described in claim 2, characterized in that: In step 2, the conductive substrate is treated with ultraviolet ozone for 15-30 minutes. In step 3, the spin coating speed of the SAM solution is 2000-3000 rpm and the time is 20-30 s; the annealing temperature is 100-150℃ and the time is 10-30 min. In step 4, 70-75 μL of precursor solution is added dropwise; the precursor solution is spin-coated at a speed of 3000-5000 rpm for 30-40 seconds; and the annealing treatment is performed at a temperature of 100-150℃ for 10-20 minutes. In step 5, 70-75 μL of passivating agent solution is added dropwise; the passivating agent solution is spin-coated at a speed of 3000-4000 rpm for 20-25 seconds; the annealing temperature is 100-120℃ and the time is 5-10 minutes. In step 6, 30-50 μL of electron transport layer solution is added dropwise; the electron transport layer solution is spin-coated at a speed of 1500-2000 rpm for 20-25 seconds. In step 7, 200-250 μL of electron blocking layer solution is added dropwise; the electron blocking layer solution is spin-coated at a speed of 3000-4000 rpm for 20-25 seconds; the annealing temperature is 100-120℃ and the time is 10-20 minutes. The thickness of the metal vapor-deposited in step 8 is 100-150 nm.

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