Preparation Of Highlyphoto-stable CsPbBr₃ Nanocrystals Improved With Metal Sulfide

All inorganic cesium lead halide?CsPbX₃,X=Cl,Br,and I? perovskite nanocrystals?NCs?are promising materials because of their advantages such as optically tunable bandgap and excellent photoluminescence quantum yield?PLQY?,which are expected to meet the needs for quantum dots backlight applications,and become a new generation of display materials.At the same time,they also have application potentiality in electroluminescence,laser,optical detection and other fields.However,they are very sensitive to water and oxygen,and thus they are quite vulnerable to be quenched due to the influence of surrounding environment.High stability of quantum dots is the basis of physical properties research and device application.Therefore,how to improve the stability of perovskite nanocrystals is an important problem in its popularization and application.In order to improve the stability of CsPbBr₃ NCs,we treated their surface with vulcanizing agent and metal salt.The effects of preparation conditions such as metal salts species and amount of reactants added on the composition and morphology were investigated in detail,and the photostability,thermal stability and solution stability of were also compared.The experimental products was characterized by transmission electron microscope?TEM?and X-ray powder diffraction?XRD?.Besides,Optimum preparation reaction precursor and reaction parameters were selected by the result of the characterization and photostability and thermal stability experiments.Under 25°C,100?L S^2--DDA⁺?0.05 mol/L?was added into 1 mL of CsPbBr₃ NCs solution.Then the mixture was stirred for 1 h.After that,the salt powders of indium acetate?In?Ac?₃?were added directly into the mixture solution and stirred for another 2 h.Based on the principle of self-assembled adsorption surface treatment in solution,the"S-In"layer was loaded on the surface of CsPbBr₃ NCs,which could greatly improve the photostability.The photoluminescence quantum yield increases from 57%to 80%.The resultant CsPbBr₃·S-In NCs remained stable for 188 h under strong LED light illumination?450 nm,175mW/cm²?,while pristine CsPbBr₃ NCs totally quenched in 2 h.The corresponding metal sulfide loaded CsPbBr₃ NCs were prepared by adding different kinds of metal salt powder into the vulcanized CsPbBr₃·S NCs.The relative photostability of the various product CsPbBr₃·S-X NCs was compared through photostability test.Through further comprehensive analysis,rough rule of the photostability between metal salts species.By comparing the photostability of the obtained CsPbBr₃·S-In NCs with those of the two commercial CdSe NCs,we found that the photostability of the obtained CsPbBr₃·S-In QDs was also stronger than that of them.This paper provided a new method for improving the stability and application potentiality of perovskite NCs.