Synthesis Of Water-Soluble Cesium-Lead Bromide Perovskite Nanocrystals And Its Application In Analysis And Detection

Due to their excellent photoelectric properties,perovskite nanocrystals have set off a research boom in recent years.Compared with the organic-inorganic hybrid perovskite,the all-inorganic cesium-lead perovskite with better stability has become more and more popular.Since the initial development of the thermal injection method,many ways have been discovered to obtain products with a perovskite structure,and they are widely used in photovoltaic cells,solid-state lasers,light-emitting diodes,photodetectors and other fields.However,the perovskite nanocrystals are extremely unstable in aqueous solutions,which hinders their application and development in the field of analysis and detection.In order to solve the water stability problem of perovskite and apply it to the detection of analytes in water,this thesis takes the all-inorganic cesium bromide lead perovskite(Cs Pb Br₃/Cs4Pb Br₆)as the research object,studied the improvement of synthesis method and the analytical applications of the perovskites.The detail of the thesis is as follows:1.The method of solid phase synthesis of cesium bromide lead perovskite is studied.By using lysine as a ligand,in the presence of Cs Br and Pb Br₂,three methods of grinding,magnetic agitation,and vortex oscillation are directly used to obtain the perovskite mixed product of different dimensions with green photoluminescence Cs Pb Br₃/Cs₄Pb Br₆.Under the same reaction raw material ratio,the mechanical stress in the reaction process was changed to study the influence of lysine on the perovskite crystal under different forces.Finaly,by increasing the amount of lysine and using grinding method,we obtained a luminescence perovskite product with certain stability.2.Studied the synthesis method of water-stable perovskite and applied it to the detection of mercury ion(Hg²⁺).By using trifluoroacetyl lysine as the coating agent,the perovskite nanocrystals could be stable at the water-oil phase interface,thereby the improved the water stability of the cesium-lead perovskite.We also proved that the addition of Hg²⁺could selectively quench the luminescece of perovskite.The quenching mechanism is that Hg²⁺directly reacts with the perovskite and change its structure.The ligand can promote the stable presence of the perovskite in water,but it will not hinder other aspects of performance.This study established a selective detection method for Hg²⁺,and pave the way for the further analysis and application of perovskite in aqueous solution.3.Established an analytical method for penicillamine detection by using perovskite as a luminescence probe.In this study,by using lysine hydrochloride was used as the ligand and the previously used synthesis method,a highly water-stable perovskite aqueous solution was also obtained.The perovskite obtained by this method undergoes an anion exchange reaction to achieve its luminescence redshift.After studying the fluorescence property of the perovskite with different anion ratios,a specific ratio that can be clearly perceived by the naked eye was selected,and the perovskite under this condition was used as a probe to detect penicillamine.Under optimized conditions,the fluorescence of the perovskite probe would blue shift and increase with the addition of penicillamine.By using these phenomena,a quantitative analysis and a visual detection under ultraviolet light of penicillamine were established.The study also proved that the probe not only responds to penicillamine but also has specific response signals to most sulfur-containing substances that can be used for the detection of a wide range of sulfur-containing compounds.