Perovskite Nanocrystals Stabilized With Polymerizable Ligand And Their Optical Applications

Lead halide perovskite nanocrystals(PNCs)have broad application prospects in light-emitting diodes and displays due to their excellent optoelectronic properties,including high absolute photoluminescence quantum yield,high defect tolerance,and wide color gamut.However,due to the inherent "soft" ion structure and highly dynamic binding surface of lead halide perovskite nanocrystals,they exhibit poor stability and are easily affected by various environmental factors,such as moisture,light,heat,oxygen,and so on,which may lead to the decline of fluorescence or photoelectric properties and even degradation.This factor of stability has seriously hindered the practical application of perovskite nanocrystals in commerce.Therefore,improving the stability of perovskite nanocrystals is of great significance to broaden the application field of this material.In this paper,the stability of perovskite nanocrystals was studied.A series of perovskite nanocrystalline complexes were successfully prepared by modification of polymerizable surfactant ligands and composite with polymers or inorganic materials,and their crystal structure,spectral properties,stability and application of perovskite nanocrystals were systematically studied,mainly including the following three aspects:(1)Preparation of NOSVC CsPbBr3 NCs:A polymerizable surfactant ligand Noleoyl-S-(4-vinylbenzyl)-L-cysteine(NOSVC)was designed and modified on the surface of perovskite nanocrystals to obtain a nanocrystalline material with high luminescent performance and high chemical stability.In addition,combining the styrene groups in the ligand,the crosslinking between perovskite nanocrystals was realized,which effectively improves the light,heat and humidity stability of perovskite nanocrystals in the film state,laying a foundation for the practical application of perovskite nanocrystals.(2)Preparation of NOSVC CsPbBr3 NCs@p(MMA/BA):On the basis of the first work,a new perovskite nanocrystalline-polymer composite was prepared by photopolymerization of NOSVC CsPbBr3 NCs,methyl methacrylate and butyl acrylate in one pot.The obtained composite has good self-healing,flexibility,transparency,and water resistance.This further demonstrates the application of this composite in lightemitting diodes,which lays a foundation for broadening the field of flexible lightemitting devices such as displays and lighting devices.(3)Preparation of NOSVC CsPbBr3 NCs@Nano-Al2O3:A highly stable nanoalumina composite material embedded with perovskite nanocrystals was prepared by using the ligand NOSVC to regulate the formation of perovskite nanocrystals in porous nano-alumina.Moreover,with the help of the stabilizing effect of nano-alumina on perovskite nanocrystals,the reversible conversion of CsPbBr3(with fluorescence)and CsPb2Br5(without fluorescence)in the humidification and dehumidification process of perovskite composites is realized,which provides an opportunity for the application of perovskite nanocrystals in the field of anti-counterfeiting.