| All inorganic cesium lead halide Cs Pb X3(X=Cl,Br,I)perovskite quantum dots(IPQDs)has excellent performance such as emission tunability over the entire visible spectral region,narrow full width at half-maximum(FWHM),photoluminescent high quantum yield(PLQY)and liquid phase synthesis,has been widely used in various fields.The mainly development of cesium lead halide perovskite quantum dots are the applications in photovoltaic fields like solar cells,electronic display and luminescent LED devices.If lead elements in cesium lead halide perovskite quantum dots are replaced by other non-toxic metal elements,perovskite quantum dots will also be devoted to bioluminescent labeling and other fields.At present,there are three popular methods for synthesis of perovskite quantum dots:hot injection method,room-temperature supersaturation recrystallization method and anion exchange method.Via changing the ratio of reagents and regulating the synthesis temperature,the size of the quantum dots can be adjusted to control the emission wavelength.Via changing the type and ratio of the two ligands added as surfactants in synthesis process,the shape of the cesium lead halide nanocrystals can be controlled.At present,the synthetic methods used in the production and research of quantum dots is hot injection method,supersaturation recrystallization and anion exchange method.Due to some tough conditions and difficult to control kinetic factors,these two methods popularly used are still have certain restrictions and need further research or optimization.Although the all inorganic cesium lead halide perovskite quantum dot which is a potential new star in the field of luminescent devices,has many excellent properties of luminescent materials,the structure of the cesium lead halide perovskite quantum dots and surface traps lead to problems.It irreversible degradation in heat,light,water and air cause fluorescence quenching.Therefore,if the stability of the perovskite quantum dots can be solved,the commercialization of this material is to be realized.The following points are the main research contents of this article:1.Optimization of All Inorganic cesium Lead Halide Cs Pb X3(X=Cl,Br)Perovskite Quantum Dots Synthesis at Room TemperatureAll inorganic cesium lead halide Cs Pb X3(X=Cl,Br)perovskite quantum dots were prepared via recrystallization at room temperature.The crystal structure and fluorescence luminescence properties of a series of cesium lead halide perovskite quantum dots containing Cl/Br were characterized by transmission electron microscopy(TEM)and fluorescence spectrometry.Cs Pb X3(X=Cl,Br)quantum dots have a fluorescence emission region of 410-520 nm and narrow FWHM(13-20nm).The Cl/Br element quantum dots can be observed by ultraviolet lamp excited in 365 nm.The fluorescent color of the perovskite quantum dots gradually changes from purple,blue,indigo to green.When a series of quantum dots of Cs Pb Cl3-Cs Pb Br3were synthesized at room temperature,the injection volume of the precursor changed with the ratio of Cl/Br.At the same time,when test the quantum dot solution used the fluorometer,the concentration of the quantum dot solution has an influence on the fluorescence emission intensity,and the optimal concentration of the quantum dot solution during the test is determined through experiments.2.All Inorganic Cs Pb X3(X=Cl,Br,I)Quantum Dots Synthesis Via Hot Injection at High-temperature and Preparation of Silica from Rice Husk to Adsorb the Quantum Dots to Improve StabilityAll inorganic cesium lead halide Cs Pb X3(X=Cl,Br,I)perovskite quantum dots were prepared via hot injection at high temperature.In addition,the emission wavelength region is 410-710 nm and the fluorescence color gradually change from purple,blue,indigo,green,yellow,rose,and red,and the FWHM from 13 to 40 nm.Due to the poor stability of the Cs Pb X3(X=Cl,Br,I)quantum dots,fluorescence quenching is extremely occurred,and the researchers use different methods to improve the stability of the quantum dots.Firstly,rice husk powder is acidified by hydrochloric acid,and calcined at high temperature to obtain spherical amrphous silica,afterwards,prepared cesium lead halide Cs Pb X3(X=Cl,Br,I)perovskite quantum dots is absorbed by silica.Thus,reunification and fluorescence quenching due to the structure defects of the perovskite quantum dots itself in liquid phase are avoided,improving the stability of quantum dots,and the emission wavelength and he full width at half-maximum have not changed. |
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