Preparation Of All-inorganic Metal Halide Perovskite Materials And Their Luminescence Kinetics Under High Pressure

In recent years,all-inorganic metal halide perovskite materials have attracted extensive attention in materials,chemistry,physics,and energy due to their excellent photoelectric properties and good chemical stability.However,heavy metal lead and synthesized under neutral gas are brutal to achieve large-scale production and seriously restrict its commercial development.This thesis aims to prepare all-inorganic lead halide perovskite materials of rare-earth ions replacing partial lead ions under air conditions and lead-free all-inorganic tin halide perovskite materials independently forming a simple experimental device and optimizing synthesis conditions.In situ high-pressure spectroscopic measurement system is an effective way to tune the luminescence kinetics and expand applications in the field of radiation detection of perovskite quantum dots.The main research contents and results of this paper are as follows:(1)Breaking the limitations of the synthesis of perovskite quantum dots under the nitrogen conditions of the original heat injection method,the stable inorganic lead-based halide perovskite quantum dots of rare earth ions are synthesized under environmental conditions by vacuum heating furnace,and the operation method is simple and convenient,which is suitable for actual large-scale production.Under environmental conditions,after 30 days of Cs Pb Br₃:Ce quantum dots in n-hexane,their luminous peak intensity remains 50%of the original intensity.(2)The pressure dependence and luminescence dynamics of Ce³⁺doped Cs Pb Br₃ quantum dots were further studied by in situ high-pressure and time-resolved spectroscopy.The luminescence kinetics of lattice changes caused by the pressure of perovskite quantum dots doped with inorganic lead-based halides of rare-earth ions were revealed through the study of the changes in the band exciton state,surface defects and radiation,and non-radiative life changes in the steady-state spectrum of materials under high pressure.Ce³⁺doping improved the luminous persistence of Cs Pb Br₃ quantum dots at high pressure,and the luminous peak intensity and peak energy pressure coefficient of Cs Pb Br₃:Ce decreased by 0.08 a.u/GPa and 0.012 e V/GPa,respectively,compared with Cs Pb Br₃ quantum dots.Ce³⁺-doped all-inorganic lead-based halide perovskite quantum dots have a minimum fluorescence lifetime of 2.56 ns at high pressure,which is much smaller than the fluorescence lifetime of Ce³⁺-doped perovskite quanta at atmospheric pressure(8.41 ns),and Cs Pb Br₃:Ce life decreases linearly with increasing pressure.Ce³⁺doping significantly adjusts the luminous dynamics of Cs Pb Br₃ quantum dots,enhances the luminous persistence of Cs Pb Br₃ quantum dots,improves the quenching pressure of perovskite quantum dots,expands the pressure application range of perovskite quantum dots,optimizes the performance of photoluminescence ultra-fast response of perovskite quantum dots,and provides a basis for the application of perovskite quantum dots in the field of radiation detection under extreme conditions.(3)Through the independent assembly of the reaction device,the magnetic stirrer is used as the heating device,and the silicone oil is used as the heat transfer medium to control the dissolution temperature of the precursor accurately.CuI was added to the original DMF solution by solution method to form a Cu⁺-DMF passivation layer covering the surface of the particles,and a CsSnI₃material with high crystallinity and good dispersibility was prepared.When the molar ratio of CuI was added to 5%,the doped CuI and the original DMF in solution combined to inhibit the production of the secondary phase Cs₂Sn I₆ in the CsSnI₃ product.(4)The doping of 5%CuI causes the blue shift of the luminescence wavelength of CsSnI₃particles,the intensity of the luminous wavelength increases,and the luminous peak becomes narrower.The doping of Cu⁺changes the optical properties of the perovskite material.