Preparation Of Silica-based CH₃NH₃PbBr₃ Quantum Dot Phosphors And Research On Their Luminescence Properties

Perovskite quantum dots have broad applications in the fields of solar cells,lighting and display due to their high quantum yields,color-tunable,narrow-band emissions,and simple preparation methods.However,perovskite QDs have poorer stability compared to traditional III-V and II-VI semiconductor quantum dots,which greatly limits their applications in optoelectronics.In order to solve the problem of thermal stability and photostability of perovskite quantum dots,this paper first synthesized silica-coated perovskite quantum dots,and then embedded them in sol-gel glass to prepare quantum dots phosphor with hight stability.The specific research results obtained are as follows:(1)Using the aminosilicone as a ligand,we prepared the CH3NH3PbBr3 perovskite quantum dots(PLQY 78.3%)with good luminescence properties by reprecipitation methods,and studied their thermal stability and photostability properties.(2)Silica sols based on ethyl orthosilicate were prepared under acid-catalyzed conditions,and they gradually lost their luminescent properties by monitoring the luminescence of perovskite QDs during the coating process.However,partial luminescence properties can be restored after soaking with methyl ammonium bromide.The mechanism was analyzed to obtain the key factor of the sol-gel glass coated perovskite quantum dots,namely the methyl ammonium bromide was added to the sol.(3)By coating the perovskite quantum dots with silica sol added with methyl ammonium bromide,the prepared CH3NH3PbBr3/SiO2 quantum dots phosphor has good optical performance(PLQY 60.3%,FWHM at 25 nm).In particular,the phosphor showed great stability,and its fluorescence intensity was less than 4%when it was heated at 100℃ for 150 hours in air,and only 5%was attenuated at 450 nm(60mW)for 30 hours,and its stability was far away higher than the perovskite quantum dots reported in other literatures.