The Preparation,Property And Application Of Highly Stable Cesium Lead Halide Perovskite Material

In recent years,cesium lead halide perovskite nanocrystals（NCs）have attracted widespread attention and been used in many fields such as nano lasers,solar cells and light emitting diodes（LEDs）,due to the advantages of adjustable emission wavelength and high quantum yield.Despite its admirable properties,the structure of perovskite nanocrystals is easily destroyed by polar solvents,light or heat due to their ionic characteristics,which leads to severe fluorescence quenching,further results in a decrease in the photoelectric conversion efficiency of the device,seriously hindering its actual application process.At the same time,most of the reported research is mainly focused on green,red and near-infrared emission.On the contrary,the preparation of high-performance blue perovskite materials is one of the hot topics,but remains great challenge.By adjusting the size,CsPbBr₃ QDs can emit light in the blue region,however the high temperature and inert gas protection are still inevitable in the synthesis,which are not conducive to the batch synthesis.In this paper,CsPbBr₃/SiO₂composites with superior stability and high-quality blue emission were synthesized at room temperature by a facile recrystallization method.At the same time,a systematic research was conducted on the structure formation mechanism,controllable preparation parameters,fluorescence performance and stability of perovskite NCs.The main results include:（1）The CsPbBr₃/SiO₂ composites are prepared by a recrystallization method at room temperature,based on the fact that APTES could react with trace water to form SiO₂.The composite material is simple to synthesize,easy to collect and convenient to the mass production.The effects of the concentration of CsBr and PbBr₂ on the structure and fluorescence properties of the obtained sample are systematically studied.The prepared CsPbBr₃/SiO₂ composite material not only has excellent fluorescence properties,but also has high thermal stability and light stability.It provides a good foundation for the practical application.The white light LED modulation experiments show that the CsPbBr₃/SiO₂composite material has a good application prospect in the field of green solid-state lighting.（2）The blue emission CsPbBr₃ QDs are synthesized by a facile recrystallization method at room temperature using HBr as an additional bromine source.Blue emissive CsPbBr₃ QDs are characterized as high PLQY and narrow FWHM.The effects of the concentration of HBr and oleylamine on the morphology and fluorescence properties of the blue light-emitting CsPbBr3 QDs are systematically studied.By combining with colorless and transparent polymethyl methacrylate（PMMA）,a blue emission Cs PbBr₃/PMMA composite film was prepared,which has very high stability in water.