Study On Upconversion Properties Of Li Doped C12A7/Yb/Tm And C12A7/Yb/Mn Polycrystals

With the increasing demand of optical materials,the luminescent materials prepared by using up-conversion principle show many advantages in many fields.However,the applications in solar cells and optical display suffer from the low conversion efficiency and low light color purity.Therefore,Li⁺and Mn²⁺were used in this paper to adjust the light color and fluorescence intensity of C12A7/Yb/Tm materials to overcome the deficiency caused by rare earth ions.The optimal synthesis parameters of Li⁺/Yb³⁺/Tm³⁺/C12A7 and Mn^2+/Yb³⁺C12A7were explored.Through TG curve,XRD phase analysis and up-conversion luminescence test,the pre-sintering temperature,sintering temperature and sintering time were determined at 739?,1100?and 5 h,respectively.Materials with good up-conversion luminescence properties were obtained.The effects of different rare earth doped ions and Li⁺on luminescence properties were studied,and their ion concentrations were determined as Yb³⁺?8 mol%?,Tm³⁺?1 mol%?and Li⁺?5 mol%?,respectively.Then,the doping of Li⁺was further analyzed to discuss the improvement of luminescence performance,and the influence of the content of quenching ions(OH^-and CO₃^2-)on luminescence was studied.The energy transfer efficiency of Yb³⁺was significantly improved through the calculation of fluorescence lifetime,and the optical color output with relatively pure and high intensity was obtained.The influence of laser power and temperature on its mechanism and temperature sensitive property is discussed,and the luminescence process of the material is determined?blue light:¹G₄?³H₆,red light:¹G₄?³F₄?.In combination with fluorescence intensity ratio technology,the relationship between temperature and luminescence was explored,and the temperature coefficient of materials doped with Li⁺was calculated as0.233%k^-1,which was greatly improved compared with the temperature coefficient doped with Tm³⁺in different matrix materials.The luminescence characteristics of Mn²⁺are used to make up for the deficiency of rare earth ion luminescence,which successfully realizes the adjustment of light color and high-intensity white fluorescence.The mechanism of Mn²⁺and Yb³⁺in the whole luminescence process is studied.The mechanism of orange fluorescence is derived from decay of ⁴T₁?⁴G?.And blue fluorescence is produced by the virtual level decay of Yb³⁺.It calculated that the lifetime of Mn²⁺at 1.0 mol%was 2514.8?s.It indicates that this material has great application potential in light color adjustment.