Preparation And Luminescence Mechanism Of BACsPbBr Quasi-two-dimensional Perovskite Films And Microcavitys

Quasi-two-dimensional（2D）perovskite semiconductor materials have the characteristics of strong stability,multi-band structure,high luminescence efficiency and easy preparation,and have high development potential in the fields of light-emitting diodes,solar cells and lasers.The micro-nano laser structures made of perovskite as gain materials have the characteristics of tunable wavelength,high coherence and small size,and have great potential in the field of optical chip and communication.It is of great significance to study the preparation technology of high quality quasi-two-dimensional perovskite micro-nano structure laser,realize short wavelength laser maser,and explore the luminescence mechanism and energy transmission mechanism in quasi-two-dimensional perovskite.In this paper,the preparation process of quasi-2D perovskite film and micro-nano structure was studied,and the BA₂C_sn-1Pb_nBr_3n+1quasi-2D perovskite films and quasi-2D perovskite micron lines were prepared.Based on the experimental analysis of photoemission spectrum,time-resolved fluorescence spectrum and transient absorption spectrum,the internal luminescence mechanism and energy transport mechanism were studied.The main research contents are as follows:（1）Based on femtosecond laser parameter amplifier,microscope,high-resolution grating spectrometer and stripe camera,the photoluminescence microzone test optical path and time-resolved microzone test optical path were established and adjusted.（2）BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskite precursor solution was prepared by solution method.The precursor solution was spin-coated and annealed in air atmosphere.By adjusting the n value of BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskite precursor solution,the BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskite micron lines wire prepared,and the laser emission was realized.The excitation threshold was 7.87μJ/cm²,and the laser wavelength was about 538 nm.The size of the micron lines were2μm×4μm.（3）BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskite precursor solution was prepared by solution method.The precursor solution was spin-coated and annealed in nitrogen atmosphere.BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskite precursors with different n values have been used to prepare quasi-two-dimensional perovskite films with different characteristics.When n of the presursor solution was 4,the relative smooth BA₂Cs_n-1Pb_nBr_3n+1quasi-2D perovskites was fabricated.The film showed a multi spontaneous radiation,whose peaks were around 440 nm,470 nm and 518 nm.The Phase structure,elemental composition,luminescence mechanism and energy transport mechanism of quasi-2D perovskite films were deeply researched.