Preparation And Photoelectric Properties Of Ultra-stable Cesium Lead Bromine Perovskite NCs Composite Materials

All-inorganic cesium lead halide perovskite?Cs Pb X₃,X=Cl,Br,I and Cs Pb₂X₅,X=Cl,Br,I?nanocrystals?NCs?materials have received a lot of attention owing to their outstanding properties,such as excellent luminescence performance,narrow spectral bandwidth,high photoluminescence quantum yields?PLQY?,tunable band gap and wide color gamut.Based on their excellent optical and semiconducting properties,all-inorganic cesium lead halide perovskite materials have been widely used in solar cells,lasers,LEDs,photodetectors and even upconversion emission materials.Nevertheless,their inherent poor stability causes great challenges for practical applications,in addition,exposure of NCs to ambient atmospheric conditions?such as moisture,light and heat?would cause a sharp drop of PLQY as well as phase transformation.Therefore,these issues need to be addressed urgently to acquire the high stability and performance perovskite NCs.In this paper,a series of potassium doped Cs Pb Br₃NCs in borosilicate glass and Cs Pb₂Br₅NCs nanocomposite were successfully fabricated by conventional melt-quenching with a subsequent heat-treatment way and traditional hot-injection method.The structure,morphology,stability and related optical properties were analyzed in detail through a series of tests and other characterization methods.The research contents of this paper are as follows:1.We have successfully synthesized a series of K_xCs_1-xPb Br₃NCs and KPb Br₃NCs in borosilicate glass for the first time by means of partial and entire substitution of Cs⁺ions via K⁺ions utilizing conventional melt-quenching with a subsequent heat-treatment method,and the composition and structure of K_0.6Cs_0.4Pb Br₃NCs glass were inspected in detail.K_0.6Cs_0.4Pb Br₃NCs glass has a PLQY of 62%and presents better water resistance and thermal stability;in addition,K_0.6Cs_0.4Pb Br₃NCs glass has excellent optical third-order nonlinear properties.Ultimately,WLEDs achieved by K_0.6Cs_0.4Pb Br₃NCs glass and Cs Pb Br_1.2I_1.8NCs glass has outstanding optical parameters,and it will be widely used in the next generation of solid state lighting and display devices.2.A nanocomposite material of Cs Pb₂Br₅NCs coated in mesoporous silica?NCs-MS?with high PL intensity and bright emission has been successfully fabricated by optimizing the components and synthesis conditions.The as-prepared NCs-MS nanocomposite presents improved thermal and water stability,photostability and moisture resistance.In addition,the components and structure of the NCs-MS nanocomposite were investigated in detail.Owing to its outstanding stability and optical property,a WLED constructed by coating the NCs-MS nanocomposite and commercial red Ca Al Si N₃:Eu²⁺phosphor powders on an In Ga N blue chip exhibited CIE chromaticity coordinates of?0.3377,0.3309?and super optical parameters,such as higher CRI and LE,so it opens up a new direction for the stability and application of all inorganic perovskite nanocrystals.