Synthesis Of CdZnSe Based Thick Shell Quantum Dots And Thrir Applications In White Light-Emitting Diodes

In recent years,quantum dots(QDs)have become the research focus of the next generation of lighting and display fields due to their excellent optical characteristics such as narrow emission line width,pure color,and adjustable wavelength.However,in practical applications,most quantum dots are prone to severe fluorescence quenching after film formation,resulting in a sharp decrease in the performance of optoelectronic devices.Studies have shown that thick-shell quantum dots can effectively inhibit the energy transmission between quantum dots and ensure the optical performance of quantum dots after film formation.However,so far,during the growth of the traditional binary thick shell core/shell quantum dots,the larger lattice mismatch between the core and shell will generate additional lattice stress near the growth interface,which in turn Lattice defects are generated,which eventually lead to fluorescence quenching of quantum dots.To solve this problem,this paper uses ternary CdZnSe alloy quantum dots as the luminescent core,and ZnSe and ZnS quantum dots as the shell material to construct thick shell CdZnSe/ZnSe/ZnS quantum dots.In this paper,the nucleation characteristics,growth rule of thick shell CdZnSe/ZnSe/ZnS quantum dots and the effect of shell thickness on the luminescence performance of quantum dots are studied.The effect of quantum dots on the performance of white LED devices.The main research contents are as follows:First,the ternary CdZnSe alloy quantum dot light-emitting core was synthesized by the organometallic method.By changing the reaction conditions,the CdZnSe core quantum dot light-emitting band can be effectively controlled in the range of 500-650 nm.When Cd/Zn=1:10,the nucleation temperature is 260 ?,and the reaction time is 6min,the synthesized CdZnSe nuclear quantum dots have the best luminescence performance.Secondly,the shell materials of different thicknesses were coated on the surface of the synthesized ternary CdZnSe alloy quantum dot light-emitting core.The study found that after coating 10 monolayer(monolayer,ML)ZnSe shell materials on the surface of the CdZnSe core,the fluorescence quantum yield of the solution was increased to about 95%,and the shell was continued to grow epitaxially on the ZnSe shell The fluorescence quantum yield of ZnS with a layer thickness of 3 ML is increased to 97%.In addition,the transient fluorescence spectra of CdZnSe/ZnSe(10 ML)and CdZnSe/ZnSe(10 ML)/ZnS(3 ML)quantum dots show single Eexponential decay fluorescence.The coating of the ZnS shell layer further restricts the area of electrons and holes,enhances the overlapping integration of electrons and holes,and enhances the single exciton recombination rate.Finally,we explored the effect of quantum dots with different shell thicknesses on white LED devices,and the prepared thick shell quantum dot white LED devices generally have a color rendering index Ra=91.48,a luminous efficiency of 68.51 lm/W,and a color temperature of 4138 K warm white LED device.In addition,the special color rendering index R9=93 provides a new way to solve the problem of insufficient or missing red light components in existing commercial white LED devices.