Study On The Properties And Application Of Methylammonium Lead Bromide Crystal

Perovskites materials have become hotspots in new functional materials due to the advantages of being produced facilely and cheaply.They also have good performance in the field of catalytic,sensing and solar cells because of the unique structural characteristics and physical and chemical properties.Up to date,researches focused on the peroskites thin film are adequate,while the studies on the growth techniques to materials performance of crystals are relatively insufficient.In this article,the impact of precursor solution concentrations,kinds of anti-solvents and substrates on the growth of CH₃NH₃PbBr₃ crystals is considered,combined with the theory mode and simulation to explore the rules of the crystal coverage rate,thickness and fractal dimensions varied with time in the crystals'crystallization mechanism.Self-doping CH₃NH₃PbBr₃ crystals were fabricated by modulating the molar ratio of PbBr₂ to CH₃NH₃Br from 0.2,0.6,1.0 to 1.5 with making use of the intrinsic defect engineering.The structure of crystals fabricated under different precursor ratios were confirmed to be the same by X-ray diffraction,bandgap of the materials is 2.16 eV characterized with Uv-vis spectroscopy,the carrier concentrations and mobilities increased with the ratios variation and the carrier exhibit different characteristics to afford p and n-type CH₃NH₃PbBr₃ crystals showed by Hall-effect measurement.To determine the crystals'intrinsic charge transport parameters in devices,the normal-on field-effect transistors based on CH₃NH₃PbBr₃ crystals have been fabricated with carrier mobility over 1.5 cm²?v^-1?s^-1 at room temperature.The solar cells with 3.7%PCE were produced with precursor ratio of 1.5 by solution spin coating method.Because the stability and defects formation of materials is easily affected by the external environment,so to find the key impact factor on the stability of crystals,the stability of the crystals in oxygen and air is analyzed.Compared with pure oxygen,crystal surface is more susceptible to decompose in the air,according to X-ray photoelectron spectroscopy characterization.