Regulation Of Luminescence Properties Of Perovskite Quantum Dots By Rare Earth Ions And Its Application

CsPbX₃（X=Cl,Br,I）quantum dots have become a research hotspot in the fields of quantum dot displays,solar cells,lasers,and so on because of their unique physical and optoelectronic properties.At present,the luminescence color is unstable due to the easy anion exchange reaction between different halide perovskite quantum dots,and the perovskite quantum dots have poor stability under the influence of environmental stability,and there is a problem of Pb toxicity,which restricts their practical application.The preparation process of common perovskite quantum dots is cumbersome and needs inert gas protection.Due to the rich energy levels of rare earth luminescent materials,the unique optical properties are produced.In this paper,firstly,the luminescence properties of perovskite quantum dots can be controlled by doping rare earth elements,and single-component white light emitting quantum dots were obtained.Secondly,synthesize rare earth ions and transition metal ions co-doping perovskite quantum dots（Mn,Ce）:CsPbCl₃ fluorescent powders were used to prepare white light emitting LED.Finally,the fluorescent ink of rare earth ion doped perovskite quantum dots were synthesized by core-shell double-encapsulation method to explore the possibility of information protection.The following work has been carried out in detail:（1）Double-doped rare-earth ion perovskite quantum dots were prepared by thermal implantation at atmospheric pressure,By adjusting the doping ratio of rare earth ions Tb³⁺and Eu³⁺,and adjusting the energy transfer from the main lattice of perovskite quantum dots to Tb³⁺,Eu³⁺,CsPbCl₃ with single component white light emission was synthesized.The results show that under the excitation of 365nm laser,the color coordinates corresponding to the emission spectra of perovskite quantum dots（Tb,Eu）:CsPbCl₃ co-doped with different contents of Tb³⁺/Eu³⁺ions are located in the white light region in the 1931 chromaticity diagram.Compared with pure CsPbCl₃ quantum dots,the luminescence efficiency of rare earth double-doped CsPbCl₃ quantum dots is increased by 6 times,and it maintains good stability in air.In addition,the luminescence properties of Tb³⁺/Eu³⁺co-doped perovskite quantum dots synthesized in different solvents were studied.（2）Aiming at the problem of low luminous efficiency and lead toxicity in Mn²⁺ion-doped CsPbCl₃ quantum dots,（Mn,Ce）:CsPbCl₃ quantum dots were prepared by an improved thermal injection method.The Mn²⁺emission enhancement is achieved by utilizing the energy transfer from the host lattice to the Mn²⁺emission caused by the 4f-5d intrinsic transition of Ce³⁺ions.The results show that the introduction of rare earth ion Ce³⁺helps to improve the energy transfer efficiency from exciton to Mn²⁺,so as to improve the photoluminescence quantum efficiency of quantum dots.When the feed ratio of PbCl₂:MnCl₂:CeCl₃is 1:1:0.5,the quantum yield is 19%,which is 33 times higher than that of pure CsPbCl₃ quantum dots.Moreover,a white light-emitting diode based on（Mn,Ce）:CsPbCl₃ quantum dot composite phosphors was prepared.The changes of electroluminescence intensity,color rendering index（CRI）and color temperature with driving current were studied.When the driving current was 20mA,the color temperature was 3000K,and the CRI was 81.9.（3）Combined with the multi-color luminescence properties of rare earth luminescent materials,PVP/PS double layer was used to coat perovskite quantum dots to prepare rare earth ion-doped quantum dots M:CsPbCl₃（M=Eu,Tb,（Tb,Eu））luminescent ink material with a core-shell structure,and explored the possibility of using this ink for information protection.