Research On The Properties Of CsPbX₃ Perovskite And Its Application In Solar Cells

Perovskite solar cells have attracted a research boom in the field of photovoltaics due to their high photoelectric conversion efficiency,simple process,and abundant raw materials.However,the inherent instability of organic-inorganic hybrid perovskite(ABX3)limits its long-term development and large-scale commercial applications in the field of solar cells.At present,in order to improve thermal stability,the organic cation at the A site is replaced with an inorganic metal ruthenium(Cs)to constitute an all-inorganic CsPbX3 perovskite material.CsPbI3 has a wider band gap and a larger bandwidth,especially compared with organic cation-based perovskites,and is an important direction for the future development of perovskite solar cells.However,there are some problems in the preparation process of CsPbI3 material.It is urgent to solve the problem that the pure phase CsPbI3 black cubic phase(a-phase)needs to be formed at high temperature of 335-350?,and is sensitive to air and cannot exist stably at room temperature.In order to find a way to prepare more stable CsPbI3 at low temperature,this paper optimizes the preparation process of CsPbI3 materials by HBr treatment and pre-preparation of HPbI3 compounds,and improves the film quality to make all inorganic CsPbI3 perovskite solar cells.Performance is optimized.The specific research is as follows:1.Using a one-step spin coating method,a small amount of hydrobromic acid was added to the pure CsPbI3 precursor solution to prepare an all-inorganic perovskite at a low temperature,and the results were compared by direct preparation with hydriodic acid treated CsPbI3 and pure CsPbI3.In this work,the effects of the preparation process of HBr on CsPb13 on the light absorption properties of the film,the surface morphology of the perovskite layer,the quality of the perovskite crystal,the photoelectric properties and other related aspects were studied.After HBr treatment,the relatively small Br moiety replaces I to shrink the lattice and stabilize its structure,so that Cs+will stabilize the PbI6 octahedral structure and the perovskite phase will be more stable.The addition of HBr promotes rapid crystallization,and the formation of smaller sized grains can stabilize the perovskite phase at room temperature.At the same time,the incorporation of Br changes the work function,and the forbidden band width becomes wider,which greatly increases the open circuit voltage.The photoelectric conversion efficiency of the all-inorganic perovskite solar cell produced by this method was increased from 4.43%to 10.28%.2.This study proposes a method for preparing an all-inorganic perovskite solar cell by pre-synthesizing HPbI3 compounds in air.In this paper,the HPbI3 compound powder was synthesized and its characteristics were studied.The HPbI3 compound powder treated with all inorganic CsPbI3 perovskite and hydriodic acid(57 wt%HI aqueous solution)was compared to obtain two different morphologies of perovskite.film.We performed SEM,UV-visible absorption,and X-ray diffraction(XRD)characterization on the surface of two perovskite films.The results show that the PbI2 layer spacing increases and the lattice expands in the pre-synthesized HPbI3 structure,forming an H bond coordination.The formation of the coordination facilitates the entry of CsI into the crystal lattice and slows down the rate of cation exchange,resulting in a high-quality film,thereby obtaining a solar cell with higher efficiency and better performance,and the photoelectric efficiency is increased from 3.88%to 9.89%.In summary,HBr treatment and preparation of HPbI3 compounds in advance can optimize CsPbI3 materials,improve the stability of perovskite phase,and significantly improve the photoelectric conversion efficiency of CsPbI3 perovskite batteries.The research in this paper provides a new reference for the subsequent research of CsPbX3 perovskite materials and its application in solar cells.