Research On The Design, Luminescence Mechanism And Application Of Rare Earth Phosphor/tungstate Luminescent Materials Based On The Principle Of Energy Transfer

Inorganic luminescent materials have been extensively studied for their superior properties such as high luminous efficiency and good stability.Among them,rare earth luminescent materials have various colors,high conversion rates,and stable properties.They are widely used in the field of white LEDs for lighting display and optical temperature measurement.As an important component,luminescent materials are a prerequisite for the success of white LEDs and optical thermometers.Therefore,the development of new light-emitting materials is one of the research hot spots in this field.In this paper,we synthesized a series of rare earth ions(Ce³⁺,Tb³⁺,Eu^2+/3+),Mn²⁺,and Bi³⁺doped phosphate and tungstate luminescence systems by high temperature solid-phase method,studied the luminescence mechanism in detail and discussed its potential applications value.Ca₉LiY_0.667?PO₄?₇:Eu²⁺,Mn²⁺phosphors were synthesized by high-temperature solid-phase method.Investigated its crystal structure and characterized its luminescence properties.The fluorescence spectrum showed that the Ca₉LiY_0.667?PO₄?₇:Eu²⁺sample produced broadband emission under near-ultraviolet light excitation,and the naked eye observed was cold white light.Using the principle of energy transfer between Eu-Mn ions,a single substrate of warm white light was achieved in Ca₉LiY_0.667?PO₄?₇:Eu²⁺,Mn²⁺phosphors.Single-phase Ca₉LiY_0.667?PO₄?₇:Eu²⁺,Mn²⁺phosphors and 395 nm InGaN chips were used to prepare white LEDs with higher color rendering index?Ra=90.2?and lower color temperature?CCT=3614 K?.Based on the above work,Ca₉LiY_0.667?PO₄?₇:Ce³⁺,Tb³⁺,Mn²⁺blue-green-red materials with adjustable luminous color was designed and prepared by changing the activated ions.The light emission of Ce³⁺in Ca₉LiY_0.667?PO₄?₇:Ce³⁺sample was explained by low temperature spectrum.Using the energy transfer of Ce³⁺-Tb³⁺,the emission color of Ca₉LiY_0.667?PO₄?₇:Ce³⁺,Tb³⁺phosphor was tuned from blue-purple to green.The tri-doped Ca₉LiY_0.667?PO₄?₇:Ce³⁺,Tb³⁺,Mn²⁺phosphors achieve warm white light emission from a single substrate and have good thermal stability.After 10 heating cycles of room temperature-150 ^oC,the sample still maintains good stability,which proves that the phosphor has potential applications in white LEDs.Based on the energy transfer between Bi-Eu,Ca₂MgWO₆:Bi³⁺,Eu³⁺luminescent materials were designed and prepared.Raman spectrum was used to explain the special yellow light emission of the Ca₂MgWO₆ host.By doping Bi³⁺,the yellow light emission of the phosphor is enhanced.Using the energy transfer between Bi³⁺and Eu³⁺,the phosphors luminous color is tuned from yellow to deep red.The temperature change spectra of Ca₂MgWO₆:Bi³⁺,Eu³⁺were tested.Bi³⁺and Eu³⁺ions showed superior temperature sensitivity.The mechanism was discussed.The results showed that the maximum absolute temperature sensitivity S_a and relative temperature sensitivity S_r were0.961 K^-1?523 K?and 8.52%K^-1?323 K?,respectively.This shows that the phosphor has potential applications in optical temperature sensing.