Study On Synthesis And Upconversion Properties Of Sr/Yb/Tm/C12A7 Polycrystalline

Rare Earth ions doped with 12CaO·7Al₂O₃?C12A7?is a promising up--conversion luminescent material,which is widely studied because of its unique photoelectric properties.In this paper,a high temperature solid-phase method was used to synthesize the Yb³⁺/Tm³⁺doping with C12A7.By introducing Sr²⁺into the C12A7 polycrystalline materials doped with Yb³⁺and Tm³⁺,the upconversion luminescence intensity has been successfully enhanced.The up-conversion luminescence performance after doping Sr²⁺is studied,and the mechanism of up-conversion luminescence is discussed.After grinding and mixing the powder raw material,the pressing piece has been put into the high-temperature furnace under 1200?sintering 6h,the C12A7 polycrystalline materials doped Yb³⁺,Tm³⁺and bivalent alkaline earth ions(Mg²⁺,Sr²⁺,Ba²⁺)can be obtained.It is shown that the C12A7 polycrystalline material can be used as the up-conversion substrate in this process by XRD phase analysis and Raman spectroscopy test.Through the test of the up-conversion luminescence spectrum,it is confirmed that the influence of doping Sr²⁺is more significant,the up-conversion performance can be improved,so this paper probes into the influence of Sr²⁺ions doping with Yb³⁺/Tm³⁺/C12A7 polycrystalline.Adding Sr₂CO₃ to the C12A7 raw materials doped with Yb³⁺and Tm³⁺,the Sr²⁺was successfully mixed,the up-conversion luminous intensity was greatly improved,the doping Yb³⁺concentration was 5%,the doping Tm³⁺concentration was 2%.The higher conversion blue light and higher conversion red light were obtained when the doping concentration of Sr²⁺was 10%,and the output of the up-converted fluorescence has been better realized.Through the up-conversion power curve,the up-conversion of blue light has been determined to be three-photon process,the up-conversion of red light was three photons and accompanied with two-photon process,and combining the energy level transition spectra of Yb³⁺ions and Tm³⁺ions,the up-conversion fluorescence mechanism of the prepared samples has been explored.The fluorescence lifetime attenuation curves of Tm³⁺ions on 475 nm band and 650 nm band were fitted respectively by using the energy level life fitting analysis,indicating that the introduction of Sr²⁺ions will change the lifetime of these fluorescent energy levels,affect the energy transfer process of the up-conversion fluorescence,and improve the energy transfer efficiency.The up-conversion luminous intensity was enhanced.From the analysis of the up-conversion spectra,it is found that the light color of the converted luminescence on the system is not changed after doping Sr²⁺.The intensity of the up-conversion fluorescence at different temperature and power were measured.Using Tm³⁺ion temperature coupling energy level,the Yb³⁺/Tm³⁺/C12A7 temperature sensitive coefficients was 1683/T²,and the application foreground of the material in temperature sensor has been explored.