All Inorganic Perovskite Quantum Dot Glass:in Situ Crystallization,stability,optical Properties And Solid-state Lighting Applications

All-inorganic cesium lead halides perovskite quantum dot has become a hot material for research in recent years owing to excellent photoelectric properties.It is widely considered that it can be used in solar cells,LED lighting and laser fields.However,because of the characteristics of its ionic crystals,the perovskite quantum dots are easily decomposed and destroyed under wet and high temperature conditions,and thus have poor stability.As a result,the application of perovskite quantum dots is very limited.In this work,the solid-state sintering and heat treatment process were used to crystallize the perovskite quantum dots in inorganic glass matrix with different components.Under the protection of the glass matrix,the stability of cesium lead halides perovskite quantum dots was greatly improved compared with that of colloidal perovskite quantum dots.Importantly,through modifying the molar ratio of halide sources in glass,multi-color tunable emissions in the entire visible spectral range of 400-750 nm are achieved.As a result,light-emitting diode(LED)devices can be constructed by coupling perovskite quantum dot glass powders with a commercial chip,to explore the optoelectronic performance of LED devices.The main content and research results are as follows:(1)In situ crystallized CsPbBr3 perovskite quantum dot-embedded tellurite glasses were successfully achieved by controlling glass composition,perovskite composition,sintering temperature and heat treatment conditions.The as-prepared glass shows bright green emission and series of characterization methods such as XRD and TEM have proved that the precipitated CsPbBr3 quantum dots have cubic phase grains.The influences of the changes of raw materials and experimental conditions on crystallization were investigated,and the optimum composition and reaction conditions were determined.The CsPbBr3 quantum dot glass is characterized by typical perovskite luminescence characteristics,as well as excellent optical stability,moisture resistance and thermal stability.As a consequence,CsPbBr3 quantum dot glass was demonstrated to be applicable as color converter on the InGaN chip for solid-state lighting,and the prepared white LED device has excellent photoelectric performance.(2)The compositions of phosphosilicate CsPbBr3 quantum dot glasses are optimized by controlling glass composition and perovskite composition.The as-prepared quantum dot glass has cubic CsPbBr3 structure and excellent thermal stability.Impressively,the crystallization of CsPbBr3-xIx(x=0-3)quantum dots in phosphosilicate glass matrix was achieved by replacing all or part of Br-ions with I-ions.XRD and fluorescence lifetime show that the CsPbBr3-xIx(x=0-3)quantum dot glass conforms to the characteristics of colloidal quantum dots,and multi-color tunable emissions in the spectral range of 500-750 nm were achieved by modifying the molar ratio of halide sources in the glass.Finally,a light-emitting diode device was constructed by coupling the green-emitting CsPbBr3 quantum dot glass and red-emitting CsPbBr2I quantum dot glass with a commercial InGaN blue chip,yielding a bright white light emission with excellent optoelectronic performance.(3)CsPbX3(X=C1,Br,I and their mixture)perovskite QD have been successfully embedded in Zn-P-B-Sb based oxide glasses via an in situ nanocrystallization strategy.The as-prepared CsPbX3 quantum dot glass nanocomposites exhibit typical excitonic recombination emissions and superior chemical stability benefited from the protection of the robust inorganic glass matrix.Through modifying the molar ratio of halide sources in glass,multi-color tunable emissions in the entire visible spectral range of 400-750nm are achieved.As a result,light-emitting diode devices can be constructed by coupling blue-missive CsPbBrCl2,green-emissive CsPbBr3 and red-emissive CsPbBr0.5I2.5 quantum dot glass powders with a commercial ultraviolet chip,yielding bright white light luminescence with excellent optoelectronic performance.