Preparation Of CsPbBr₃ Nanocrystals And Study On Application Of LED And Stability

Bromine lead cesium（CsPbBr₃）nanocrystalline materials is a kind of good optical performance of the inorganic nano material,it has a high rate of quantity of fluorescent quantum yield（PLQY）,a narrow full width at half maximum（FWHM）and good stability,etc.,are thought to be an important part of the next generation of lighting material for preparation of CsPbBr₃ nanocrystalline material itself,by simple and feasible and can improve the performance of the method as the core.Through the research on the preparation method of CsPbBr₃ nanocrystalline materials,this paper successfully synthesized CsPbBr₃ nanocrystalline materials with good optical properties,controllable size and good stability by one-pot method and two-phase emulsion extraction,and applied them to light-emitting diodes（LEDs）.The researches are summarized as follow:（1）CsPbBr₃ nanocrystals were synthesized by one pot method.The CsPbBr₃nanocrystals have good fluorescence properties such as half peak width and narrow peak width.In addition,this preparation method does not involve precursor preparation or vacuum treatment,and CsPbBr₃ nanocrystalline materials can be synthesized on a large scale,with an effective excitation at 450 nm.Therefore,CsPbBr₃ NCs has been successfully used as phosphors for the preparation of green LEDs.（2）All-inorganic perovskite CsPbBr₃ QDs were prepared by two-phase（water and toluene）emulsion extraction method.By tuning the concentration of ligand,the size of QDs could be easily controlled in the range of 1-4.7 nm.The prepared CsPbBr₃QDs exhibited a broad absorption range from 325 to 500 nm,and a narrow full width at half maximum（FWHM）of photoluminescence（PL）emission down to 15nm.A quantum efficiency of about 69%and a PL lifetime of 40.85 ns were achieved at the optimized condition,demonstrating the great application potential in optoelectronics and energy storage.（3）The CsPbBr₃ nanocrystals synthesized by two-phase emulsion extraction and one-pot method were tested respectively,and it was found that the CsPbBr₃nanocrystals obtained by two-phase emulsion extraction and hot-injection method had similar thermal stability.Through the experiment on the water resistance of CsPbBr₃nanocrystals synthesized by these two methods,it was placed in water for 24 h and tested every hour.The experiment showed that the CsPbBr₃ quantum dot synthesized by two-phase emulsion extraction before 4 h had better water resistance.In a simple one-pot method,I-was proportionally doped into CsPbBr₃ nanocrystals to obtain the yellow-green light of CsPbBr_2.4I_0.6 nanocrystals,the orange light of CsPbBr_1.5I_1.5nanocrystals and the red light of CsPbBr_0.6I_2.4 nanocrystals.The doping of CsPbBr₃nanocrystal I-realized the material of near red light.