The Interaction Mechanism Between Pulse Laser And Metal Halide Perovskite And The Patterned Laser Printing

More than 70%of human information retrieval comes from vision.Information technology,which is closely linked to vision,has become an indispensable part of modernization.As the core of display and detection technology,the research of photoelectric semiconductor materials and devices has received unprecedented attention in the world.All inorganic metal halide perovskite materials have the advantages of high photoluminescence efficiency(>90%),narrow emission spectrum(<30 nm),have become the most competitive"Star materials"in photoelectric semiconductor materials.Most of the LED and detector based on the halide perovskite are single devices,and the key technology of constructing display and detection imaging is to patternize and array the active layer materials.Compared with the synthesis and devices of halide perovskite,the research of patterning technology is relatively backward.Laser process in liquid has made remarkable achievements in the synthesis of nanocrystals,microstructure control and film patterning,and is expected to be applied to halide perovskite solution to overcome the difficulties of film patterning.However,there are few reports on the application of laser process to the halide perovskite materials,the main reason is that the mechanism of the interaction between laser and the halide perovskite is not clear.Therefore,it is necessary to study the micro process and mechanism of laser action on halide perovskite.In this paper,the mechanism of laser-induced synthesis and microstructure control and the mechanism of laser-induced anion exchange are explained by using laser irradiation and laser direct writing technology.The main research results are as follows:(1)The micro evolution of cesium lead bromine powders under the action of high energy laser pulse was observed by using high-speed imaging technology.The interaction between halide perovskite and laser is regulated by the relative position of laser wavelength and perovskite optical band gap:when the laser wavelength does not match the absorption band of perovskite,the laser cannot be absorbed by perovskite,only photon bombardment occurs;when the laser wavelength matches with the absorption band of perovskite,the laser is absorbed by halide perovskite,causing lattice fragmentation.The shape is remolded and the size is reduced.According to the optical properties of perovskite and the properties of laser irradiation products,the modulation relationship between the laser wavelength and the intrinsic absorption of perovskite nanocrystals is revealed,and the optical adaptive mechanism of halide perovskite is proposed(2)Based on the interaction mechanism between laser and halide perovskite,uniformed Cs Pb Br₃ nanocrystals were synthesized by laser fragmentation in liquid(LFL)using cesium lead bromide powder as raw material.The size of nanocrystals can be controlled by laser wavelength.The LFL method is suitable for the precursor materials.Cs Pb Br₃ powders with different morphology and characteristics can be used as raw materials.Cs Pb Br₃ nanocrystals were synthesized by laser reshaping and ligand induced growth.The morphology of Cs Pb Br₃powders were reshaped by laser irradiation in liquid process and the Cs Pb Br₃ micro sphere and micro rod were obtained.A narrow-band detector based on the Cs Pb Br₃ micro sphere was assembled.The peak response of the detector was in the range of 525-550 nm.(3)The mechanism of laser-induced anion exchange of halide perovskite nanocrystals is described.Under the direct action of laser,the halide ions released by haloalkanes.There is a dependence between the photolysis of haloalkanes and laser energy.By controlling the laser switch,the opening and ending of the anion exchange process are controlled;by controlling the laser intensity,the reaction rate of anion exchange is controlled;by controlling the time of laser irradiation,the degree of anion exchange is controlled.Chloroform and Iodoethane were used as the source of chlorine and iodine respectively,and the wavelength of 400-650 nm was precisely and continuously regulated.(4)Based on the mechanism of laser-induced anion exchange,the laser printing system was used to realize the patterning of halide perovskite films.There are laser action area and laser influence area in laser printing line.The laser influence area is caused by the flow and ion diffusion of the solution.The laser influence area can be effectively reduced by reducing the laser power,increasing the viscosity of the liquid and increasing the laser scanning rate.The influence of laser parameters on the printing line is systematically studied.The blue shift degree of laser action area is related to the scanning rate of laser power.With the laser power density of 1?10³ W/cm² and scanning rate of 50?m/s.The width of the line was 200?m,and the central fluorescence peak was located at 450 nm.The patterned halide perovskite fluorescent film was obtained by programming control.The array of Cs Pb Br₃ detector is constructed.The response band of each independent detector is changed,and the narrow-band detection of 465 nm,544nm and 620 nm response is realized.