Perovskite solar cell based on trimethylsilyl methanesulfonate modification and preparation method thereof

Abstract

The application discloses a perovskite solar cell based on trimethylsilyl methanesulfonate modification and a preparation method thereof. The cell comprises an anode substrate, an electron transport layer, a buried bottom interface modification layer, a perovskite light absorption layer, a top interface modification layer, a hole transport layer and a cathode layer. The electron transport layer is SnO2 modified by ammonium tartrate (AT) and nitric acid (HNO3), and the perovskite light absorption layer is CsPbI2Br. Trimethylsilyl methanesulfonate (TMSEs) is used as the buried bottom interface modification layer to modify the interface between the SnO2 electron transport layer and the CsPbI2Br perovskite light absorption layer, to construct a molecular bridge on the interface, to passivate the defects of the SnO2 / CsPbI2Br interface, to inhibit the non-radiative recombination of the interface, and to improve the room-temperature black-phase stability of the CsPbI2Br perovskite film, thereby improving the performance of the perovskite solar cell device. The method has low cost, is simple and easy to operate, is suitable for the preparation of large-scale perovskite solar cells, and has important research and application values.

Description

Technical Field

[0001] This invention belongs to the field of organic compound modified solar cell technology, and relates to a perovskite solar cell based on organic compounds and its preparation method, particularly to a perovskite solar cell based on trimethylsilyl methanesulfonate modification and its preparation method. Background Technology

[0002] CsPbI₂Br perovskite solar cells are considered a promising next-generation photovoltaic device due to their excellent thermal stability and appropriate trade-off between light absorption and phase stability, making them an ideal choice for perovskite solar cells. However, CsPbI₂Br perovskite solar cells suffer from interfacial nonradiative recombination (NRR) losses, which lead to a decline in cell stability and efficiency, thus limiting their industrial application.

[0003] Interface defects are a major source of interfacial nonradiative recombination, increasing the likelihood of moisture intrusion into layer-by-layer CsPbI₂Br PSCs. At the interface where the electron transport layer (ETL) or hole transport layer (HTL) contacts the perovskite phase, phenomena such as band bending, carrier recombination, charge accumulation, and ion migration easily occur, leading to severe interfacial nonradiative recombination losses. This reduces the open-circuit voltage of CsPbI₂Br perovskite solar cells, ultimately causing a decline in perovskite solar cell performance. Therefore, this invention provides a perovskite solar cell modified with trimethylsilyl methanesulfonate and its preparation method. By modifying the interface between the SnO₂ electron transport layer and the CsPbI₂Br perovskite light-absorbing layer with trimethylsilyl methanesulfonate, interface defects are passivated, interfacial energy level matching is optimized, and ion migration is suppressed, thereby inhibiting interfacial nonradiative recombination losses and improving the black phase stability of the perovskite film at room temperature, thus enhancing the efficiency and stability of the perovskite solar cell. Summary of the Invention

[0004] To address the above problems, this invention provides a perovskite solar cell based on trimethylsilyl methanesulfonate modification and its preparation method.

[0005] The technical solution adopted in this invention is as follows: A perovskite solar cell based on trimethylsilyl methanesulfonate modification includes an anode substrate, an electron transport layer, a buried interface modification layer, a perovskite light-absorbing layer, a top interface modification layer, a hole transport layer, and a cathode layer. The electron transport layer is an ammonium tartrate / nitric acid synergistic modified SnO2 film, the buried interface modification layer is trimethylsilyl methanesulfonate (hereinafter referred to as TMSEs), and the perovskite light-absorbing layer is CsPbI2Br.

[0006] Furthermore, the anode substrate is conductive glass FTO, the top interface modification layer is 2-amino-5-bromoacetophenone (hereinafter referred to as 2A5B), the hole transport layer is Spiro-OMeTAD, and the cathode layer is Ag.

[0007] The above-mentioned method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification includes the following steps: after surface treatment of the anode substrate, an electron transport layer, a buried interface modification layer, a perovskite light-absorbing layer, a top interface modification layer, and a hole transport layer are sequentially spin-coated, and then a cathode layer is prepared to obtain a perovskite solar cell modified with trimethylsilyl methanesulfonate; wherein, the buried interface modification layer is prepared by spin-coating a solution containing trimethylsilyl methanesulfonate onto the electron transport layer.

[0008] Further, the surface treatment steps of the anode substrate are as follows: ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water for at least 30 minutes each, followed by vacuum drying, and then cleaning with ultraviolet ozone for at least 30 minutes. Preferably, the anode substrate is made of conductive glass FTO with dimensions of 20 mm * 20 mm, sheet resistance of 14 Ω, and light transmittance ≥90%.

[0009] Furthermore, the fabrication steps of the electron transport layer are as follows: A certain mass of ammonium tartrate was dissolved in deionized water and stirred until homogeneous. A SnO2 aqueous colloidal dispersion mixed with deionized water in a certain proportion was added and stirred until homogeneous to obtain an ammonium tartrate-modified SnO2 aqueous colloidal dispersion. Nitric acid was then added to adjust the pH of the system. After stirring and filtration, an ammonium tartrate / nitric acid synergistic modified SnO2 precursor solution was obtained. This precursor solution was spin-coated onto an anode substrate and annealed to obtain an ammonium tartrate / nitric acid synergistic modified SnO2 electron transport layer. According to a specific embodiment of the present invention, the obtained FTO / ammonium tartrate / nitric acid synergistic modified SnO2 film has a planar structure and exhibits good chemical stability and electrical properties.

[0010] Furthermore, the stirring time after mixing the ammonium tartrate and deionized water is 10-60 min; the stirring time of the SnO2 aqueous colloidal dispersion and the ammonium tartrate aqueous solution is 1-5 h, and the mass concentration of ammonium tartrate and the mass percentage of SnO2 in the resulting system are both controlled within a suitable range; the stirring time until clarification after adjusting the pH value to 11.50-7.30 is 20-60 min; the spin coating speed of the modified SnO2 precursor solution is 1500-5500 rpm, and the spin coating time is 15-60 s; the annealing temperature is 70-200℃, and the annealing time is 10-90 min.

[0011] Furthermore, the preparation steps of the buried interface modification layer are as follows: Trimethylsilyl methanesulfonate was added to isopropanol and stirred until completely dissolved. The solution was then filtered through a 0.2 μm PTFE filter to obtain a trimethylsilyl methanesulfonate / isopropanol solution. This solution was spin-coated onto an ammonium tartrate / nitric acid synergistic modified SnO2 film and annealed to obtain a buried interface modification layer. According to a specific embodiment of the present invention, the sample obtained in this step is designated as an FTO / ammonium tartrate / nitric acid synergistic modified SnO2 / TMSEs film. The trimethylsilyl methanesulfonate interface modification layer is located between the ammonium tartrate / nitric acid synergistic modified SnO2 electron transport layer and the CsPbI2Br perovskite layer, which can improve interfacial contact, reduce interfacial defects, improve interfacial energy level matching, regulate perovskite crystallization, and improve the stability of the perovskite film. Specifically, TMSEs are spin-coated as modifiers onto the buried interface to improve the interfacial contact between the SnO2 electron transport layer and the CsPbI2Br perovskite light absorption layer, thereby passivating interfacial defects, effectively controlling the growth rate and crystal structure of perovskite grains, improving the quality and performance of the thin film, and thus enhancing the performance of perovskite solar cells.

[0012] The concentration of the trimethylsilyl methanesulfonate / isopropanol solution is not more than 5 mg / mL but not 0, preferably 1 mg / mL to 5 mg / mL. The spin-coating speed is 2000 to 4500 rpm, the spin-coating time is 20 to 60 seconds, the annealing temperature is 60 to 110°C, and the annealing time is 1 to 10 minutes. During interface modification, the spin-coating volume of the modifier solution needs to be controlled. Too small a spin-coating volume will increase grain boundary defects, resulting in a rough and uneven film surface; too large a spin-coating volume will affect the film surface morphology, thus affecting its optical properties. Therefore, only by spin-coating an appropriate amount of trimethylsilyl methanesulfonate / isopropanol solution for buried interface modification can the best-performing CsPbI2Br perovskite film be obtained. The perovskite film prepared in this way has a larger grain size, fewer grain boundary defects, a smoother and denser morphology, and higher crystallinity, while also possessing optimal phase stability, optical stability, and optical properties at room temperature. Therefore, in the fabrication process of the perovskite solar cell, spin-coating an appropriate amount of trimethylsilyl methanesulfonate solution (typically 100-175 μL) to modify the buried interface can improve the room temperature phase stability of the thin film, thereby enhancing the performance of the perovskite solar cell. This invention opens up a feasible path for the fabrication of high-performance CsPbI₂Br perovskite solar cells and has significant implications for the research and application of optoelectronic devices.

[0013] Furthermore, the preparation steps of the perovskite light-absorbing layer are as follows: A CsPbI₂Br precursor solution was spin-coated onto an electron transport layer and a modification layer. The spin-coating process consisted of two stages: the first stage involved a spin-coating speed of 700–1200 rpm for 6–15 seconds; the second stage involved a spin-coating speed of 1000–3000 rpm for 90–170 seconds. The film was then annealed at 40–100°C for 2–10 minutes, followed by annealing at 130–180°C for 1–6 minutes to obtain a CsPbI₂Br perovskite film, i.e., a perovskite light-absorbing layer. According to a specific embodiment of the present invention, the sample obtained in this step is designated as an FTO / ammonium tartrate / nitric acid synergistic modified SnO₂ / TMSEs / CsPbI₂Br film. Using a multi-stage spin-coating and temperature gradient annealing method is beneficial for improving the quality of the CsPbI₂Br perovskite film, enhancing its crystallinity, coverage, grain size, and uniformity of distribution, while reducing defect density.

[0014] Furthermore, the preparation steps of the top interface modification layer are as follows: A certain mass of 2-amino-5-bromoacetophenone (2A5B) modifier was dissolved in 1 mL of isopropanol to prepare a modifier / isopropanol solution of 1 mg / mL to 5 mg / mL. 80 to 140 μL of the modifier / isopropanol solution was spin-coated onto the CsPbI2Br perovskite light-absorbing layer at a spin-coating speed of 1500 to 4500 rpm for 10 to 40 s. Subsequently, annealing was performed at a temperature of 30 to 110 °C for 1 to 5 min.

[0015] Furthermore, the fabrication steps of the hole transport layer and the cathode layer are as follows: 10 μL to 130 μL of Spiro-OMeTAD solution was spin-coated onto the top interface modification layer at a spin-coating speed of 2500–4500 rpm for 20–60 seconds to obtain the hole transport layer. 0.1 g to 1 g of Ag was then vapor-deposited onto the hole transport layer at a vacuum degree of 1 × 10⁻⁶ for 3–6 minutes. -4 Pa ~10×10 -4 Pa.

[0016] The beneficial effects of this invention are as follows: This invention employs trimethylsilyl methanesulfonate (TMSEs) to modify the buried interface of (AT+HNO3)-SnO2 and CsPbI2Br. The S=O in the sulfonic acid group can simultaneously passivate the surface-undercoordinated Sn after AT / HNO3 synergistic modification of SnO2. 4+ And oxygen vacancy defects, undercoordinated Pb at the CsPbI2Br buried interface 2+ With Cs +By combining top interface modification to form a dual-interface synergistic passivation system, the density of interface defects is effectively reduced, non-radiative recombination at the interface is suppressed, and carrier extraction efficiency is significantly improved. At the same time, TMSEs can regulate the crystallization kinetics of perovskite, induce the directional growth of large-sized grains and reduce grain boundaries, thereby improving the film compactness and reducing carrier recombination sites. The stable bonding structure formed by its molecules can optimize the interface energy level matching, reduce the charge transport barrier, and enhance the built-in electric field to promote efficient carrier transport. In addition, the hydrophobic groups of TMSEs can construct a hydrophobic layer at the interface, inhibiting water and oxygen penetration to improve the room temperature black phase stability of CsPbI2Br. Moreover, this method is simple to operate, low in cost, and suitable for large-scale production, possessing both research value and application prospects. Attached Figure Description

[0017] Figure 1 SEM images of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations of TMSEs in the embodiments of the present invention: (a) a1 mg / mL TMSEs; (b) a2 mg / mL TMSEs; (c) a3 mg / mL TMSEs; (d) a4 mg / mL TMSEs; (e) a5 mg / mL TMSEs; (f) a6 mg / mL TMSEs.

[0018] Figure 2 The particle size distribution of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations of TMSEs in the embodiments of the present invention is as follows: (a) a1 mg / mL TMSEs; (b) a2 mg / mL TMSEs; (c) a3 mg / mL TMSEs; (d) a4 mg / mL TMSEs; (e) a5 mg / mL TMSEs; (f) a6 mg / mL TMSEs.

[0019] Figure 3 SEM cross-sectional images of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films with and without TMSEs modification in the embodiments of the present invention: (a) unmodified; (b) modified with TMSEs.

[0020] Figure 4 The X-ray diffraction patterns of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention are shown.

[0021] Figure 5The PL curves are for FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention.

[0022] Figure 6 The TRPL curves of the FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with TMSEs at a1 mg / mL and a4 mg / mL in the embodiments of the present invention are shown.

[0023] Figure 7 The UV-Vis absorption spectra of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention are shown.

[0024] Figure 8 The UV-Vis absorption spectra of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations of TMSEs in the embodiments of the present invention vary in the range of 0~90 min: (a) a1 mg / mL TMSEs; (b) a2 mg / mL TMSEs; (c) a3 mg / mL TMSEs; (d) a4 mg / mL TMSEs; (e) a5 mg / mL TMSEs; (f) a6 mg / mL TMSEs.

[0025] Figure 9 These are optical photographs of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention within the range of 0~90 min.

[0026] Figure 10 The images show the FTIR results of pure TMSEs and TMSEs-modified SnO2 films in the embodiments of the present invention.

[0027] Figure 11 The images show the FTIR results of pure TMSEs and TMSEs-modified CsPbI2Br films in the embodiments of the present invention.

[0028] Figure 12 XPS results of SnO2 and TMSEs modified SnO2 films in the embodiments of the present invention: (a) Sn 3d; (b) O1s.

[0029] Figure 13XPS results of CsPbI2Br and TMSEs modified CsPbI2Br films in the embodiments of the present invention: (a) Cs3d; (b) Pb 4f; (c) I 3d; (d) Br 3d.

[0030] Figure 14 The embodiments of the present invention include (a) the molecular structure of TMSEs; (b) the hierarchical stacking structure of the device; and (c) the mechanism of action of TMSEs at the SnO2 / CsPbI2Br interface.

[0031] Figure 15 For the AT / HNO3 synergistic modification of the SnO2 electron transport layer modified at the buried interface of a1 mg / mL and a4 mg / mL TMSEs in the embodiments of the present invention: (a) UPS cut-off edge (E cutoff (a) Spectrum; (b) UPS starting edge (E) onset (c) Spectrum; (d) Schematic diagram of the energy level arrangement of CsPbI2Br perovskite solar cell.

[0032] Figure 16 The EIS curves of the FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with a1mg / mL and a4mg / mL TMSEs in the embodiments of the present invention are shown.

[0033] Figure 17 The light intensity V of the FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with TMSEs at concentrations of a1 mg / mL and a4 mg / mL in the embodiments of the present invention is shown. OC curve.

[0034] Figure 18 The EQE results are for the FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with a1mg / mL and a4mg / mL TMSEs in the embodiments of the present invention.

[0035] Figure 19 The JV curves are for FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention.

[0036] Figure 20The figures show the stability curves of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with different mass concentrations (a1~a6 mg / mL) in the embodiments of the present invention. Detailed Implementation

[0037] The technical solution of the present invention will be further described clearly and in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Example 1 (1) Use FTO conductive glass with specifications of 20 mm*20 mm, sheet resistance of 14 Ω and light transmittance of ≥90% as the anode substrate of the device. Then, the FTO conductive glass is ultrasonically treated with acetone, anhydrous ethanol and deionized water for 30 minutes in sequence, dried in a vacuum drying oven at 60°C for 1 hour, and then treated in an ultraviolet ozone cleaner for 30 minutes.

[0039] (2) Weigh 0.020 g of ammonium tartrate and add it to 4 mL of deionized water. Stir for 20 min until completely dissolved to obtain an ammonium tartrate aqueous solution. Add 2 mL of 12 wt% SnO2 aqueous colloidal dispersion to the ammonium tartrate aqueous solution and stir for 1 h to obtain an ammonium tartrate-modified SnO2 aqueous colloidal dispersion. Add 1 µL of concentrated nitric acid to adjust the pH of the colloidal solution to 9.50 and stir for 20 min until completely clear. Then filter the solution using a 0.2 μm PTFE filter to obtain the modified SnO2 precursor solution. Spin-coat 100 μL of the SnO2 precursor solution (2500 rpm, 55 s) onto an FTO conductive glass treated with UV ozone. Then anneal the spin-coated FTO at 140°C for 30 min on a heating stage to prepare an FTO / (AT+HNO3)-SnO2 film.

[0040] (3) Prepare a solution by dissolving trimethylsilyl methanesulfonate in isopropanol. i A trimethylsilyl methanesulfonate / isopropanol solution with a concentration of (i=1~6, 0=a1<a2<a3<a4<a5<a6=5) mg / mL was prepared. 120 μL of the trimethylsilyl methanesulfonate / isopropanol solution was spin-coated onto an FTO / (AT+HNO3)-SnO2 film at a spin-coating speed of 4000 rpm for 20 seconds. After spin-coating, the film was annealed at 70°C for 8.5 minutes to obtain an interface-modified layer, denoted as FTO / (AT+HNO3)-SnO2 / TMSEs film.

[0041] (4) CsI, PbI2, and PbBr2 were dissolved in DMSO and heated and stirred at 90℃ for 3 hours. The solution was then filtered through a 0.2 μm polytetrafluoroethylene filter to prepare a 1 mol / L CsPbI2Br precursor solution. 120 µL of the CsPbI2Br precursor solution was spin-coated onto an FTO / (AT+HNO3)-SnO2 / TMSEs film. The spin-coating was divided into two stages: the first stage was a spin-coating speed of 900 rpm for 12 s; the second stage was a spin-coating speed of 1600 rpm for 110 s. Then, the film was treated by temperature gradient annealing at 60℃ for 3.5 min, followed by annealing at 150℃ for 1.5 min to obtain a perovskite light-absorbing layer, denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br film.

[0042] (5) Dissolve 2-amino-5-bromoacetophenone in isopropanol to prepare a 2 mg / mL 2-amino-5-bromoacetophenone / isopropanol solution. Take 120 μL of the 2-amino-5-bromoacetophenone / isopropanol solution and spin-coat it onto the perovskite light-absorbing layer. The spin-coating speed is 3000 rpm and the spin-coating time is 30 seconds. Then anneal at 90 °C for 2 minutes to obtain the interface modified layer, which is denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B film.

[0043] (6) Take 40 μL of Spiro-OMeTAD solution and spin-coat it onto the interface modification layer. The spin-coating speed is 3000 rpm and the time is 30 seconds to obtain the hole transport layer, which is denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro-OMeTAD film.

[0044] (7) 0.2 g Ag was vapor-deposited onto the hole transport layer for 5 min at a vacuum degree of 4 × 10⁻⁶. -4 PaPa, resulting in a perovskite solar cell based on trimethylsilyl methanesulfonate interface modification.

[0045] Figure 1 Field emission scanning electron microscope (SEM) images of perovskite films modified by adding a1~a6 mg / mL TMSEs as passivating agents at the (AT+HNO3)-SnO2 / CsPbI2Br interface are shown. Figure 2The SEM particle size distribution of (AT+HNO3)-SnO2 / CsPbI2Br films modified with different concentrations of TMSEs (a1~a6 mg / mL) at the buried interface is shown. As shown in Figure 2(a), the unmodified sample (a1 mg / mL TMSEs) has the smallest average grain size (650.15 nm); as the TMSE concentration increases from a1 mg / mL to a4 mg / mL... Figure 2 (d) ), the average grain size continued to increase, reaching a peak (925.32 nm) at a4 mg / mL, combined with Figure 1 The SEM image in (d) shows that the CsPbI2Br perovskite film modified with a4 mg / mL substrate has the most uniform grain size distribution. However, when the concentration of TMSEs exceeds a4 mg / mL and increases to a5 mg / mL... Figure 2 (e) and a6 mg / mL ( Figure 2 (f) After this, the average grain size gradually decreased to 842.17 nm and 781.20 nm, respectively, and the uniformity also decreased. This result indicates that using TMSEs at a concentration not exceeding 5 mg / mL for the buried interface modification can effectively induce the growth of perovskite grains and improve their size distribution uniformity, while excessive TMSEs at the buried interface modification can interfere with the uniform growth of grains. The effect is best at a concentration of 4 mg / mL.

[0046] like Figure 3 The images shown are SEM cross-sectional views of (AT+HNO3)-SnO2 / CsPbI2Br perovskite films, one unmodified and the other modified with TMSEs (Transient Electron Sequencers) buried interface. Figure 3 (a) As can be seen, the interface flatness between the unmodified CsPbI2Br perovskite layer and the electron transport layer (ETL) is poor, the thickness uniformity of the perovskite layer is poor, and there are many tiny gaps at the junction of SnO2 and CsPbI2Br layers. However, after TMSEs buried interface modification, as shown in Figure 3(b), the interface between the ETL and the perovskite layer becomes smoother and more continuous, the thickness uniformity of the perovskite layer is significantly improved, the interlayer contact is tighter, and there are no obvious pores or defects. This indicates that TMSEs buried interface modification effectively improves the interlayer contact quality of SnO2 and CsPbI2Br and the morphology of the film. In summary, TMSEs buried interface modification can enable CsPbI2Br perovskite films to obtain better interlayer morphology and structural integrity.

[0047] Figure 4 XRD patterns of CsPbI₂Br perovskite films modified with different concentrations (a1~a6 mg / mL) of TMSEs at the buried interface. Figure 4It can be seen that the unmodified sample (the sample modified with a1 mg / mL TMSEs) has diffraction peaks at 15° and 29.5°, corresponding to the (100) and (200) crystal planes of the α-phase CsPbI2Br, but the overall diffraction peak intensity is low and there is no obvious single crystal plane dominance. As the concentration of TMSEs increases from a1 mg / mL to a4 mg / mL, the diffraction peaks corresponding to the (100) and (200) crystal planes of the α-phase CsPbI2Br shift slightly to smaller angles and their absolute intensities continue to increase. The angle shift may be due to the increase in the interplanar spacing of the perovskite after modification. The diffraction peak intensity of the (100) crystal plane is particularly significantly improved and gradually becomes the dominant peak in this system. This indicates that the order and crystal quality of the CsPbI2Br perovskite crystal are gradually optimized as the concentration of TMSEs increases from a1 mg / mL to a4 mg / mL. When the concentration of TMSEs gradually increased from a4 mg / mL to a5 and a6 mg / mL, the intensities of the diffraction peaks corresponding to the (100) and (200) crystal planes of the α-phase CsPbI2Br gradually and significantly decreased. The experimental results show that the interface regulation effect of a4 mg / mL TMSEs is optimal, resulting in the best crystal quality of perovskite. This is mainly due to the adsorption of an appropriate amount of TMSEs molecules on the SnO2 surface, which regulates the interfacial environment, induces the growth of CsPbI2Br perovskite crystals along the (100) and (200) crystal planes, and simultaneously inhibits the formation of grain boundary defects.

[0048] Figure 5 PL spectra of perovskite films with different concentrations (a1~a6 mg / mL) of TMSEs-modified (AT+HNO3)-SnO2 / CsPbI2Br at the buried interface. Figure 5As shown, all samples exhibited characteristic emission peaks of CsPbI₂Br perovskite at around 660 nm. The sample without buried interface modification (a₁ mg / mL TMSEs) showed the highest PL emission peak intensity. As the TMSE concentration increased from a₁ mg / mL to a₄ mg / mL, the PL emission peak intensity of the sample continuously decreased, and the fluorescence quenching degree gradually increased. When the concentration of the buried interface modifier TMSEs gradually increased from a₄ mg / mL to a₅ and a₆ mg / mL, the PL emission peak intensity of the sample significantly and gradually recovered, and the fluorescence quenching efficiency decreased, but the intensity was still lower than that of the unmodified sample. This indicates that the interface modification with TMSEs at a concentration not exceeding 5 mg / mL effectively improves the interfacial contact between the SnO2 electron transport layer and the CsPbI2Br perovskite layer, reduces nonradiative recombination of charge carriers at the interface, and thus enhances the interfacial carrier transport efficiency. Moreover, the (AT+HNO3)-SnO2 / a4 mg / mL TMSEs / CsPbI2Br film sample exhibits the lowest PL emission peak intensity, corresponding to the highest fluorescence quenching efficiency. This suggests that when the concentration of the TMSEs as the interface modifier is a4 mg / mL, the carrier transport efficiency between the SnO2 electron transport layer and the CsPbI2Br light absorption layer is maximized.

[0049] Figure 6 Table 1 shows the time-resolved photoluminescence (TRPL) spectra and corresponding parameters of the buried interface modified (AT+HNO3)-SnO2 / CsPbI2Br perovskite films with TMSEs concentrations of a1 mg / mL and a4 mg / mL, respectively. As shown in Table 1, τ1 and τ2 represent the fast carrier decay lifetime and slow carrier decay lifetime, respectively. The average carrier lifetime of the unmodified (a1 mg / mL TMSEs) (AT+HNO3)-SnO2 electron transport layer / CsPbI2Br light absorption layer is 24.73 ns; while the average carrier lifetime of the a4 mg / mL TMSEs buried interface modified (AT+HNO3)-SnO2 electron transport layer / TMSEs / CsPbI2Br light absorption layer decreases to 19.52 ns. The shortening of the average carrier lifetime indicates that the carrier transport efficiency at the interface is improved after the buried interface modification. This is consistent with the increased photoluminescence quenching efficiency observed in the steady-state PL spectrum, confirming that the buried interface modification with appropriate amounts of TMSEs passivates interface defects, suppresses nonradiative recombination at the interface, and promotes efficient carrier transport.

[0050] Table 1. TRPL performance indicators of FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films modified with TMSEs at a1 mg / mL and a4 mg / mL

[0051] Figure 7 Table 2 shows the UV-Vis absorption spectra and corresponding absorption edges and band gaps of (AT+HNO3)-SnO2 / CsPbI2Br perovskite films modified with TMSEs at different concentrations (a1~a6 mg / mL) at the buried interface. Figure 7 As shown in Table 2, within the 500 nm–800 nm range, as the concentration of TMSEs increased from a1 mg / mL to a4 mg / mL, the absorption edge of the sample red-shifted from 653.35 nm to 655.40 nm, and the band gap decreased from 1.8979 eV to 1.8920 eV. Simultaneously, the absorbance of the sample modified with the TMSEs at the buried interface gradually increased, indicating an enhanced light-harvesting ability. However, when the concentration of TMSEs continued to increase from a4 mg / mL to a6 mg / mL, the absorption edge of the sample gradually blue-shifted from 655.40 nm to 653.40 nm, and the band gap gradually increased from 1.8920 eV to 1.8978 eV; and the absorbance of the sample also gradually decreased. Experimental results show that modification with TMSEs at a concentration not exceeding 5 mg / mL can effectively optimize the light absorption performance of the film, and the light absorption performance of the (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br film is optimal when the concentration of the buried interface modifier TMSEs is 4 mg / mL.

[0052] Table 2 (a1~a6 mg / mL) Absorption edge and band gap data of UV-Vis absorption spectra of TMSEs-modified FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br films.

[0053] Figure 8 The UV-Vis absorption spectra of CsPbI2Br films modified with different concentrations of TMSEs (a1~a6 mg / mL) at the buried interface were measured at 25℃ and 50% RH in 10-minute intervals within the time range of 0~90 min. Figure 9 To and Figure 8 Optical photographs of the room-temperature black-phase stability of the sample. From Figure 8 (a) and Figure 9(a) As can be seen, the absorbance of the CsPbI2Br film modified with a1 mg / mL TMSEs at the buried interface decreases rapidly from 0 min to 90 min in the wavelength range of 500 nm to 800 nm, and the absorbance has decreased significantly at 70 min, corresponding to the severe decomposition of the perovskite layer in the optical image; for the CsPbI2Br film modified with a2 mg / mL TMSEs (Fig. 8(b) and Fig. 9(b)), the absorbance decreases significantly with time in the wavelength range of 500 nm to 800 nm, and a significant decrease occurs at 80 min, corresponding to the degradation of the perovskite layer in the optical image, and the stability is slightly better than that of the sample modified with a1 mg / mL; the film modified with a3 mg / mL (Fig. 8(c)) Figure 9 (c) The absorbance decay rate was slower, with significant decay only occurring at 90 min, coinciding with noticeable degradation of the perovskite film in the corresponding optical photograph, indicating further improved stability. The films modified with a5 mg / mL (Fig. 8(e), Fig. 9(e)) began to decay absorbance at 90 min, coinciding with the start of degradation of the perovskite film in the corresponding optical photograph. The films modified with a6 mg / mL (Fig. 8(f), Fig. 9(f)) began to decay absorbance at 80 min, coinciding with the start of degradation of the perovskite film in the corresponding optical photograph. In contrast, the CsPbI2Br film modified with a4 mg / mL TMSEs at the buried interface showed little change in absorbance over time from 0 min to 90 min in the 500 nm to 800 nm wavelength range, and the perovskite black phase in the corresponding optical photograph remained stable without significant decomposition. Figure 8 (d) Figure 9 (d) exhibits the best optical stability. This result further confirms that modification with TMSEs at concentrations not exceeding 5 mg / mL can improve the optical stability of the film, especially modification of the buried interface of the electron transport layer / light absorption layer with 4 mg / mL TMSEs, which effectively enhances the optical stability of the film, while also improving the stability of the perovskite structure, inhibiting perovskite degradation, and... Figure 9 The optical photographs echo the room-temperature black-phase stability of the a4 mg / mL TMSEs-modified film.

[0054] Figure 10 Infrared spectra of pure TMSEs and SnO2 / TMSEs thin films. Figure 14 (a) is the molecular structural formula of TMSEs. From Figure 10 It can be seen that pure TMSEs at 937.2 cm -1 The Si-O bond stretching vibration peak at 954.9 cm⁻¹ completely disappeared after TMSEs recombine with SnO₂, while the peak at 954.9 cm⁻¹ disappeared completely.-1 A new Si-OH bond stretching vibration peak appeared at the point, confirming that the Si-O bond in the TMSEs molecule broke during annealing, generating a positively charged -Si(CH3)3 bond. + The hydroxyl groups (-OH) adsorbed on the SnO2 surface undergo a nucleophilic reaction with the TMSEs, forming Si-OH bonds, thus achieving chemical anchoring of TMSEs on the SnO2 surface. Furthermore, in pure TMSEs, 1330.3 cm⁻¹ -1 The S=O asymmetric stretching vibration peak shifts to 1338.4 cm⁻¹ after the recombination of TMSEs and SnO₂. -1 The moderate shift amplitude and significant decrease in peak intensity indicate that the oxygen atom of the S=O bond at this site is bonded to the Sn on the SnO2 surface. 4+ Coordination interactions occur; simultaneously located at 1257.4 cm. -1 The S=O bond symmetric stretching vibration peak shifted to 1205.8 cm⁻¹ after recombination of TMSEs with SnO₂. -1 The largest displacement amplitude and almost constant peak intensity indicate that the symmetric stretching vibration S=O plays a major role in bonding. The oxygen atom in the S=O bond at this site reacts with the Sn atom during the symmetric stretching vibration. 4+ The formation of strong coordination is the core of constructing the Sn-OS bridging structure; furthermore, located at 1168.4 cm... -1 Another S=O symmetric stretching vibration peak shifts to 1175.0 cm⁻¹ after the recombination of TMSEs and SnO₂. -1 The peak intensity dropped significantly, indicating that it also participated in the interaction with Sn. 4+ Multi-site coordination further enhanced the bonding effect. The results show that the bonding between TMSEs and the SnO2 surface, together with the chemical anchoring of Si-OH, synergistically optimized the interfacial stability.

[0055] Figure 11 Infrared spectra of pure TMSEs and TMSEs / CsPbI2Br films. Figure 14 (a) is the molecular structural formula of TMSEs. Figure 11 Infrared spectral analysis of the TMSEs / CsPbI2Br composite film showed that pure TMSEs exhibited high spectral density at 937.2 cm⁻¹. -1 The stretching vibration peak of the Si-O bond at the TMSEs completely disappeared after recombination with CsPbI2Br, and no characteristic peak of the Si-OH bond appeared. This indicates that after the Si-O bond in the TMSEs molecule breaks, the generated -Si(CH3)3 +The hydroxyl groups on the surface of CsPbI2Br did not undergo a nucleophilic reaction, but only exhibited the breaking and dissociation of Si-O bonds; while in pure TMSEs, the hydroxyl groups located at 1330.3 cm⁻¹... -1 The S=O asymmetric stretching vibration peak at point S shifts to 1314.6 cm⁻¹ after recombination of TMSEs with CsPbI₂Br. -1 Furthermore, the peak intensity decreased significantly, indicating that the oxygen atom of the S=O bond in the asymmetric stretching vibration at this site interacts with the cation (Pb) in CsPbI2Br. 2+ / Cs + Coordination interactions occurred, and pure TMSEs were located at 1257.4 cm⁻¹. -1 The S=O symmetric stretching vibration peak at point S shifts to 1207.7 cm⁻¹ after recombination of TMSEs with CsPbI₂Br. -1 The large displacement amplitude and decreased peak intensity indicate that the symmetric stretching vibration S=O is the core site for bonding with CsPbI2Br. The oxygen atom in the S=O bond at this site undergoes symmetric stretching vibration and bonds with the Pb atom in CsPbI2Br. 2+ / Cs + This resulted in strong coordination; furthermore, pure TMSEs were located at 1168.4 cm⁻¹. -1 At the same time, another S=O symmetric stretching vibration peak also shifted to 1140.2 cm. -1 Furthermore, the significant decrease in peak intensity indicates that it also participated in multi-site coordination with CsPbI2Br. These multi-site coordination interactions of S=O bonds collectively formed a stable interfacial bonding structure, significantly enhancing the interfacial binding strength between TMSEs and the CsPbI2Br layer.

[0056] As shown in Figure 12(a) of the Sn 3d XPS spectrum, the characteristic peaks of Sn 3d5 / 2 and Sn 3d3 / 2 of pure SnO2 are located at 486.00 eV and 494.40 eV, respectively. After modification with TMSEs, these two peaks shift to 486.40 eV and 494.80 eV, respectively, indicating a positive shift in binding energy. This phenomenon suggests a significant electronic interaction between TMSEs and SnO2, presumably due to the interaction between the O atoms of the S=O group in the TMSEs molecule and the undercoordinated Sn atoms on the SnO2 surface. 4+ The formation of coordinate bonds leads to a decrease in the electron cloud density of Sn atoms, thereby shifting the binding energy of Sn 3d to a higher value, confirming the successful chemisorption and interfacial bonding of TMSEs on the SnO2 surface. The O 1s XPS spectra analysis in Figure 12(b) shows that peak fitting of the O 1s peaks of pure SnO2 and SnO2 / TMSEs reveals that they can be decomposed into lattice oxygen and oxygen vacancies / adsorbed hydroxyl groups (V 1s XPS).O / -OH). In pure SnO2, V O The proportions of -OH and lattice oxygen were 57.21%; after modification with TMSEs, V O The proportions of -OH and lattice oxygen decreased to 51.47%. This indicates that the interface modification of TMSEs effectively reduced the oxygen vacancy defects and adsorbed hydroxyl content on the SnO2 surface, which is beneficial for suppressing nonradiative recombination and improving interfacial charge transport performance.

[0057] Figure 13XPS photoelectron spectra of Cs 3d, Pb 4f, I 3d, and Br 3d for CsPbI2Br and TMSEs / CsPbI2Br films. In the Cs 3d spectrum of Figure 13(a), the characteristic peaks of Cs 3d3 / 2 and Cs 3d5 / 2 of pure CsPbI2Br are located at 737.68 eV and 723.70 eV, respectively. After modification with TMSEs as a substrate interface, the binding energies of the two characteristic peaks of Cs 3d3 / 2 and Cs 3d5 / 2 shift to 737.66 eV and 723.69 eV, respectively. The shift in binding energy is very small, confirming that there is no electronic interaction or coordination effect between TMSEs and Cs sites. The Pb 4f spectrum of Figure 13(b) shows that the characteristic peaks of Pb 4f5 / 2 and Pb 4f7 / 2 of pure CsPbI2Br are located at 142.30 eV and 137.40 eV, respectively. After modification with TMSEs as a substrate interface, they shift to 142.02 eV, respectively. The decrease in binding energy to 137.17 eV indicates an increase in the electron cloud density of the Pb atom, suggesting charge transfer or coordination bonding between the TMSE functional groups and the Pb sites. As shown in Figure 13(c), the I 3d spectrum of pure CsPbI₂Br has characteristic peaks at 629.70 eV and 618.20 eV for I 3d³ / 2 and I 3d₅ / 2, respectively. After modification with the TMSE buried interface, these peaks shift to 629.51 eV and 618.00 eV, respectively. This shift in binding energy to lower energies indicates a change in the electronic environment surrounding the I atom, suggesting charge transfer or coordination bonding between the TMSE functional groups and the I sites. Similarly, as shown in Figure 13(d), the characteristic peaks of pure CsPbI₂Br for Br 3d³ / 2 and Br 3d₅ / 2 are located at 74.60 eV and 67.50 eV, respectively. After modification with TMSEs at the buried interface, the binding energies shifted to 74.57 eV and 67.46 eV, respectively. The small shift in binding energy confirms the absence of electronic interactions or coordination effects between TMSEs and the Br sites. This systematic shift in peak positions indicates that TMSEs successfully modified the surface of CsPbI₂Br. By regulating the chemical states and electron cloud distribution of each element through the bonding of functional groups in TMSEs with Pb and I in CsPbI₂Br, the surface electronic structure of the perovskite material is effectively optimized, thus improving its photoelectric properties and stability.

[0058] Figure 14 shows the molecular structure of TMSEs, the device hierarchy of perovskite solar cells, and the mechanism of action of TMSEs at the buried interface. Figure 14(a) shows the molecular structure of TMSEs. Its molecular skeleton includes breakable Si-O bonds, S=O bonds in sulfonic acid groups with strong coordination ability, and trimethylsilyl (-Si(CH3)3) functional groups, which provide the core structural basis for chemical bonding and defect passivation during the interface modification process. Figure 14(b) shows the complete device stack structure of the fabricated CsPbI2Br perovskite solar cell. From bottom to top, it consists of an FTO conductive glass substrate, an AT and HNO3 synergistically modified SnO2 electron transport layer, a TMSE buried interface modification layer, a CsPbI2Br perovskite light-absorbing layer, a 2A5B interface modification layer, a Spiro-OMeTAD hole transport layer, and a top Ag metal electrode, clearly showing the spatial arrangement of each functional layer and the structural design of the device. Figure 14(c) reveals the molecular interaction mechanism of TMSEs at the SnO2 / CsPbI2Br interface. During spin coating, the Si-O bonds of the TMSE molecules break, generating CH3-SO3 containing sulfonic acid groups. - With -Si(CH3)3 + Two types of active fragments; among them, the two S=O double bonds of the sulfonic acid group can respectively react with Pb in the upper CsPbI2Br perovskite. 2+ Undercoordinated Sn on the surface of the lower SnO2 layer 4+ Stable coordination bonds are formed, achieving bidirectional anchoring at the interface and effectively enhancing the interfacial bonding between SnO2 and the perovskite layer; simultaneously, the fracture generates -Si(CH3)3 + The active fragment can undergo a coordination reaction with the -OH groups on the SnO2 surface to form Si-OH bonds, passivating the hydroxyl defects on the SnO2 surface. Additionally, some -Si(CH3)3... + Fragments can interact with I at perovskite grain boundaries - Coordination occurs, further passivating halogen defects in the perovskite. This synergistic effect of bidirectional coordination anchoring and multi-site defect passivation effectively suppresses nonradiative recombination at the interface, improving the performance of photovoltaic devices.

[0059] Figure 15 Table 3 and the modified interface of 4 mg / mL TMSEs were used to investigate the regulatory effect of the (AT+HNO3)-SnO2 electron transport layer energy level, and photoelectron spectroscopy (UPS) characterization was performed. Figure 15 (a) Shows the cutoff edge (E) of 0 mg / mL TMSEs modified (AT+HNO3)-SnO2. cutoff The value was 16.91 eV, and after modification with 4 mg / mL TMSEs, E cutoff Increased to 16.98 eV; Figure 15 In (b), the sample starting edge (E) modified with 0 mg / mL TMSEs onset The valence band peak energy (E0) of SnO2 under different modification conditions was 3.56 eV, which slightly increased to 3.60 eV after modification with 4 mg / mL TMSEs. Based on UPS spectral analysis, the valence band peak energy (E0) of SnO2 under different modification conditions was... VBM The calculated result for the E sample modified with 0 mg / mL TMSEs was... VBM The value was -7.87 eV, which shifted upward to -7.84 eV after modification with 4 mg / mL TMSEs. Figure 15 (c) The device energy level diagram shows that, compared to the sample modified with 0 mg / mL TMSEs, the conduction band bottom energy (E0) after modification with 4 mg / mL TMSEs is significantly lower. CBM The value was finely adjusted from -4.09 eV to -4.07 eV, and the value was adjusted to match CsPbI2BrE. CBM The energy level difference (-4.03 eV) was further reduced from 0.06 eV to 0.04 eV. This favorable energy level modulation indicates that the interface modification of TMSEs can effectively adjust the energy level mismatch between the electron transport layer and the perovskite layer, promoting the transport and extraction of photogenerated electrons.

[0060] Table 3. UPS band structure parameters of AT / HNO3 synergistically modified SnO2 electron transport layers with a1 mg / mL and a4 mg / mL TMSEs at the buried interface.

[0061] To investigate the effect of TMSEs at concentrations of a1 mg / mL and a4 mg / mL on charge transport in the device, we performed electrochemical impedance spectroscopy (EIS) measurements. Figure 16 Tables 1 and 4 show the electrochemical impedance spectroscopy and corresponding charge transport impedance values ​​of TMSEs modified at buried interfaces with concentrations of a1 mg / mL and a4 mg / mL, respectively. Figure 16 As shown in Table 4, the charge transport impedance R of the unsubstantiated interface modified device (a1 mg / mL) trans The Ω value is 312.18 Ω. After modification with a 4 mg / mL TMSEs at the substrate interface, R... transThe impedance decreased to 280.57 Ω. This is because the buried interface modification of TMSEs improved the interfacial contact between the (AT+HNO3)-SnO2 electron transport layer and the CsPbI2Br perovskite layer, reducing the charge transport impedance at the electron transport layer / perovskite light-absorbing layer interface, thereby improving the interfacial charge transfer efficiency. This result confirms that the buried interface modification of TMSEs can effectively optimize the interfacial charge transport dynamics between the SnO2 electron transport layer and the perovskite light-absorbing layer, reduce carrier transport impedance, and thus improve device performance.

[0062] Table 4. R-values ​​of EIS curves for FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with a1 mg / mL and a4 mg / mL TMSEs. trans value

[0063] Figure 17 The open-circuit voltage (V) of CsPbI2Br perovskite devices with buried interface modification at a1 mg / mL and a4 mg / mL TMSEs. OC The curve showing the change in light intensity. From... Figure 17 It can be seen that the V1 of CsPbI2Br2 perovskite devices modified at the buried interface with a1 mg / mL and a4 mg / mL TMSEs is significantly higher than that of the TMSEs. OC All values ​​showed an increasing trend with increasing light intensity, but the ideal illumination factor n value of the device modified with a4 mg / mL TMSEs (k1=1.58kT / q, n=1.58) was smaller than that of the unmodified device (k1=1.83kT / q, n=1.83). n is closer to the ideal value of 1. The closer n is to 1, the weaker the nonradiative recombination loss caused by device defects, and the better the interface charge transport and energy level matching. Meanwhile, compared with the CsPbI2Br perovskite device without buried interface modification (a1 mg / mL TMSEs), under the same light intensity, the V1 of the device modified with a4 mg / mL TMSEs buried interface is lower. OC The value is significantly higher. The results show that the buried interface modification of TMSEs effectively passivates the interface defects of the SnO2 electron transport layer (ETL) / CsPbI2Br perovskite layer, suppresses nonradiative recombination at the interface, thereby reducing the n value and improving the photovoltaic performance of the device.

[0064] Figure 18Figure 18 shows the EQE curves of CsPbI₂Br perovskite devices fabricated under different concentrations of TMSEs at the buried interface. As can be seen from Figure 18, the device based on a₁ mg / mL TMSEs at the buried interface exhibits an EQE peak of 87.23%, corresponding to an integrated current density of 24.31 mA / cm². 2 J measured by the JV curve sc =24.48 mA / cm 2 Approximately; after modification with a 4 mg / mL TMSEs at the buried interface, the device's peak EQE increased to 88.75%, and the integrated current density increased to 24.91 mA / cm². 2 The Jsc measured by the JV curve is 25.01 mA / cm. 2 More closely. This enhancement in EQE indicates that the buried interface modification strategy of TMSEs effectively improves the quantum conversion efficiency of the device, and the obtained integrated current density is also improved, and it is closer to the JV curve. SC The test values ​​were close, which ultimately improved the photoelectric conversion efficiency.

[0065] Figure 19 and Table 5 show the JV curves and corresponding performance parameters of devices modified with buried interfaces at different TMSE concentrations a1~a6 mg / mL, respectively. As the TMSE concentration gradually increases from a1 mg / mL to a4 mg / mL, the open-circuit voltage V... OC Optimized from 1.12 V to 1.14 V, short-circuit current density J SC From 24.48 mA / cm 2 Increased to 25.01 mA / cm 2 As the fill factor (FF) increased from 0.50 to 0.53, the device's photoelectric conversion efficiency gradually increased from 13.71% to 15.11%; however, when the concentration of TMSEs was further increased to a5 and a6 mg / mL, J... SC They fell back to 24.95 mA / cm 2 and 24.90 mA / cm 2 The PCE also decreased accordingly to 14.79% and 14.63%. The above results indicate that TMSEs at a concentration not exceeding 5 mg / mL can effectively improve device performance, and a4 mg / mL TMSEs is the optimal concentration for TMSEs at the TMSE interface.

[0066] Table 5. Parameters of JV curves for FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro / Ag devices modified with different mass concentrations (a1~a6 mg / mL)

[0067] Figure 20 shows the PCE stability of CsPbI2Br perovskite solar cells modified with different concentrations of TMSEs at the buried interface. The results show that TMSE modification at the buried interface significantly affects device stability. Devices modified with a1 mg / mL TMSEs retain only about 70% of the initial PCE after 60 days, while devices modified with a4 mg / mL TMSEs exhibit the best stability, maintaining approximately 83% of the initial normalized PCE after 60 days. At other concentrations, devices modified with a2, a3, a5, and a6 mg / mL TMSEs have normalized PCEs of 75%, 76%, 80%, and 77% after 60 days, respectively, all lower than the device modified with a4 mg / mL TMSEs but better than the unmodified device. When the TMSE concentration deviates from a4 mg / mL, the device stability decreases to varying degrees. This indicates that using no more than 5 mg / mL TMSEs for subsurface interface modification can effectively improve the PCE stability of CsPbI2Br perovskite solar cells, which is closely related to its role in optimizing interface bonding and suppressing nonradiative recombination and defect formation.

[0068] In summary, this invention successfully improved the performance of CsPbI2Br perovskite solar cells by introducing TMSEs (Transmission Transformer Electron Sequencers) as interface modifiers at the interface between the electron transport layer and the CsPbI2Br perovskite light-absorbing layer. This method provides a new approach for fabricating high-efficiency and stable CsPbI2Br perovskite solar cells, promotes the commercialization of perovskite solar cells, and has significant application potential and research value.

[0069] Example 2 (1) Use FTO conductive glass with specifications of 20 mm*20 mm, sheet resistance of 14 Ω and light transmittance of ≥90% as the anode substrate of the device. Then, the FTO conductive glass is ultrasonically treated with acetone, anhydrous ethanol and deionized water for 30 minutes in sequence, dried in a vacuum drying oven at 60°C for 1 hour, and then treated in an ultraviolet ozone cleaner for 30 minutes.

[0070] (2) Weigh 0.050 g of ammonium tartrate and add it to 8 mL of deionized water. Dissolve it completely for 40 min to obtain an ammonium tartrate aqueous solution. Add 3 mL of 12 wt% SnO2 hydrocolloid dispersion to the ammonium tartrate aqueous solution and stir for 3 h to obtain an ammonium tartrate-modified SnO2 hydrocolloid dispersion. Add 4 µL of concentrated nitric acid to adjust the pH of the colloidal solution to 7.5 and stir for 40 min until completely clear. Then filter the solution using a 0.2 μm PTFE filter to obtain the modified SnO2 precursor solution. Spin-coat 110 μL of the SnO2 precursor solution (3500 rpm, 35 s) onto an FTO conductive glass treated with UV ozone. Then anneal the spin-coated FTO at 150°C for 25 min on a heating stage to prepare an FTO / (AT+HNO3)-SnO2 film.

[0071] (3) Dissolve trimethylsilyl methanesulfonate in isopropanol to prepare a 4 mg / mL trimethylsilyl methanesulfonate / isopropanol solution. Take 115 μL of the trimethylsilyl methanesulfonate / isopropanol solution and spin-coat it onto an FTO / (AT+HNO3)-SnO2 film. The spin-coating speed is 2000 rpm and the spin-coating time is 60 seconds. Then anneal at 100 °C for 3 minutes to obtain an interface modified layer, which is denoted as FTO / (AT+HNO3)-SnO2 / TMSEs film.

[0072] (4) CsI, PbI2, and PbBr2 were dissolved in DMSO and heated and stirred at 110℃ for 1 h to prepare a 1 mol / L CsPbI2Br precursor solution. 110 µL of the CsPbI2Br precursor solution was spin-coated onto an FTO / (AT+HNO3)-SnO2 / TMSEs film. The spin-coating was divided into two stages: the first stage spin-coating speed was 800 rpm and the spin-coating time was 13 s; the second stage spin-coating speed was 1300 rpm and the spin-coating time was 140 s. Then, the film was treated by temperature gradient annealing, annealing at 70℃ for 3 min and then at 130℃ for 4 min to obtain a perovskite light-absorbing layer, denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br film.

[0073] (5) Dissolve 2-amino-5-bromoacetophenone in isopropanol to prepare a 5 mg / mL 2-amino-5-bromoacetophenone / isopropanol solution. Take 130 μL of the 2-amino-5-bromoacetophenone / isopropanol solution and spin-coat it onto the perovskite light-absorbing layer. The spin-coating speed is 2500 rpm and the spin-coating time is 35 seconds. Then anneal at 70 °C for 3 minutes to obtain the interface modified layer, which is denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B film.

[0074] (6) Take 35 μL of Spiro-OMeTAD solution and spin-coat it onto the interface modification layer. The spin-coating speed is 3000 rpm and the time is 30 seconds to obtain the hole transport layer, which is denoted as FTO / (AT+HNO3)-SnO2 / TMSEs / CsPbI2Br / 2A5B / Spiro-OMeTAD film.

[0075] (7) 0.5g Ag was vapor-deposited onto the hole transport layer for 3 minutes at a vacuum degree of 6×10⁻⁶. -4 PaPa, resulting in a perovskite solar cell based on trimethylsilyl methanesulfonate interface modification.

[0076] The above description is merely a preferred embodiment of the present invention. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. A perovskite solar cell based on trimethylsilyl methanesulfonate modification, characterized in that, It includes an anode substrate, an electron transport layer, a buried interface modification layer, a perovskite light-absorbing layer, a top interface modification layer, a hole transport layer, and a cathode layer. The electron transport layer is ammonium tartrate / nitric acid synergistic modified SnO2, the buried interface modification layer is trimethylsilyl methanesulfonate, and the perovskite light-absorbing layer is CsPbI2Br.

2. The perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 1, characterized in that, The anode substrate is conductive glass FTO, the top interface modification layer is 2-amino-5-bromoacetophenone 2A5B, the hole transport layer is Spiro-OMeTAD, and the cathode layer is Ag.

3. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification as described in claim 1, characterized in that, Includes the following steps: After surface treatment, an electron transport layer, a buried interface modification layer, a perovskite light-absorbing layer, a top interface modification layer, and a hole transport layer are sequentially spin-coated onto the anode substrate. Then, a cathode layer is prepared to obtain a perovskite solar cell modified with trimethylsilyl methanesulfonate. The buried interface modification layer is prepared by spin-coating a solution containing trimethylsilyl methanesulfonate onto the electron transport layer.

4. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 3, characterized in that, The surface treatment steps for the anode substrate are as follows: ultrasonic cleaning with acetone, anhydrous ethanol, and deionized water for at least 30 minutes each, followed by vacuum drying, and then cleaning with ultraviolet ozone for at least 30 minutes.

5. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 3, characterized in that, The preparation steps of the electron transport layer are as follows: Ammonium tartrate was dissolved in deionized water and stirred until homogeneous to obtain an ammonium tartrate aqueous solution. A SnO2 aqueous colloidal dispersion mixed in a certain proportion and deionized water were added and stirred until homogeneous to obtain an ammonium tartrate-modified SnO2 aqueous colloidal dispersion. Concentrated nitric acid was then added to adjust the pH value of the system. The mixture was stirred until clear and then filtered to obtain an ammonium tartrate / nitric acid synergistic modified SnO2 precursor solution. The precursor solution was spin-coated onto an anode substrate and annealed to obtain an ammonium tartrate / nitric acid synergistic modified SnO2 electron transport layer. Finally, ultraviolet ozone cleaning was performed.

6. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 5, characterized in that, The concentration of ammonium tartrate (AT) in the aqueous tartrate solution is 1-5 mg / mL, the volume ratio of SnO2 aqueous colloidal dispersion to deionized water is 1:1-1:5, and the pH value of the system is 11.50-7.

30. The spin coating speed of the SnO2 precursor solution is 1500-5500 rpm, the spin coating time is 15s-60s, the annealing temperature is 70-200℃, and the annealing time is 10-90 min.

7. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 3, characterized in that, The preparation steps of the buried interface modification layer are as follows: Trimethylsilyl methanesulfonate was added to isopropanol and stirred. The solution was then filtered through a polytetrafluoroethylene filter with a pore size of 0.2 μm to obtain a trimethylsilyl methanesulfonate / isopropanol solution. The trimethylsilyl methanesulfonate / isopropanol solution was spin-coated onto an annealed ammonium tartrate / nitric acid synergistic modified SnO2 film and then annealed to obtain an interface modification layer. Then clean with ultraviolet ozone for at least 30 minutes.

8. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 7, characterized in that, The concentration of the trimethylsilyl methanesulfonate / isopropanol solution is 1 mg / mL to 5 mg / mL, the spin coating speed is 2000 to 4500 rpm, the spin coating time is 20 to 60 seconds, the annealing temperature is 60 to 110℃, and the annealing time is 1 to 10 minutes.

9. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 3, characterized in that, The preparation steps of the perovskite light-absorbing layer are as follows: The CsPbI2Br precursor solution was spin-coated onto the interface modification layer. The spin-coating was divided into two stages: the first stage spin-coating speed was 700~1200 rpm and the spin-coating time was 6~15 seconds; the second stage spin-coating speed was 1000~3000 rpm and the spin-coating time was 90~170 seconds; then annealing was carried out at 40~100℃ for 2~10 minutes, and then annealing was carried out at 130~180℃ for 1~6 minutes to obtain the perovskite light-absorbing layer.

10. The method for preparing a perovskite solar cell based on trimethylsilyl methanesulfonate modification according to claim 2, characterized in that, The top interface modification layer is 2-amino-5-bromoacetophenone 2A5B, and its preparation steps are as follows: The 2-amino-5-bromoacetophenone (2A5B) modifier was dissolved in isopropanol to prepare a modifier / isopropanol solution of 1 mg / mL to 5 mg / mL. The modifier / isopropanol solution was then spin-coated onto CsPbI2Br at a spin speed of 1500 to 4500 rpm for 10 to 40 s. The solution was then annealed at a temperature of 30 to 110 °C for 1 to 5 min.

Images