Research On Preparation And Photoelectric Performance Of Inorganic Perovskite Materials CsPbBr₃ And Cs₂SnI₆

New clean energy has always been a research hotspot for scientists from all over the world.As semiconductor devices that can convert renewable solar energy into electrical energy directly,solar cells have attracted a lot of attention in the field of new energy material.Perovskite solar cells are currently the most promising third-generation solar cells owing to advantages of low material cost,simple preparation and excellent photoelectric performance.The highest power conversion efficiency of organic-inorganic hybrid perovskite solar cells is already close to commercial silicon solar cells.However,the stability and toxicity of hybrid perovskite hinders the their large-scale commercial production and application.In response to the above problems,this paper focuses on the stability and toxicity of the organic-inorganic perovskite light absorption layer,and studies the preparation process and photoelectric properties of inorganic perovskite CsPbBr₃and lead-free double perovskite Cs₂SnI₆,and discusses their application in photovoltaics devices.The main research contents and conclusions are summarized as follows:1.High-quality semi-transparent CsPbBr₃film was prepared by continuous vacuum evaporation deposition method without high temperature annealing,and it was successfully used as the active layer of flexible perovskite solar cell for the first time,realizing a power conversion efficiency of 5.00%.In addition,by introducing an energy level buffer layer of Cu₂O between CsPbBr₃and Spiro-OMe TAD,reducing electron-hole recombination and enhancing charge extraction,the champion efficiency was further increased to 5.67%.The optimized device presented higher stability and can maintain an initial efficiency of more than 95%even after 240 hours of continuous heating at 85?;After being aged under ambient conditions(25?,relative humidity 50%)for 60 days,the efficiency only drops by around 10%.In addition,flexible devices also have excellent mechanical durability,and can retain 90%of the original efficiency after 1000 bending cycles under a radius of curvature of 3 mm.We prepared high-purity,dense and uniform Cs₂SnI₆film using a two-step method.XRD,SEM and other characterization methods were used to explore the Cs I coating thickness and annealing temperature and other process parameters.Through comparison,we found that the film quality is better than that obtained by others preparation method.Then,we studied the optical performance and stability of Cs₂SnI₆.The ultraviolet-visible light absorption spectrum shows that Cs₂SnI₆has a strong light absorption capacity,and the limit absorption wavelength is about 850 nm,which is consistent with the photoluminescence results,and the energy band gap can be calculated to be about 1.45e V.In terms of stability,after 60 days of aging under environmental conditions(25?,relative humidity 50%),the XRD of Cs₂SnI₆did not change much,indicating no obvious decomposition.At the same time,the thermogravimetric results of the powder show that the decomposition temperature of Cs₂SnI₆is higher than 200?,which meets the demand for photovoltaic materials.