Study on the color tunability and energy transfer mechanism in Tm3+/Dy3+ co-doped LiLaSiO4 phosphors

Abstract

Many color-tunable LiLaSiO4: αTm3+, βDy3+ phosphors were prepared using the traditional high-temperature solid-phase method. The phase composition, surface morphology, fluorescence spectrum, fluorescence lifetime, energy transfer mechanism, and color coordinates of the samples were analyzed using XRD, SEM, TEM and fluorescence spectrometer. The results show that LiLaSiO4: αTm3+ phosphor emits high intensity blue light at 460 nm and the concentration quenching point of Tm3+, α = 0.015 mol. In LiLaSiO4: αTm3+, βDy3+ phosphors, as the doped Dy3+ doping increases, the luminescence intensity of Tm3+ gradually decreases, the luminescence intensity of Dy3+ first increases and then decreases. The concentration quenching point of Dy3+, β = 0.015 mol. Adjustable light-emitting color can be obtained by changing the doping molar mass of Dy3+ or the wavelength of the excitation light. There is an effective energy transfer between Tm3+→Dy3+. The energy transfer mechanism is the electric dipole-electric dipole interaction, and the energy transfer efficiency reaches 90.11% when β = 0.06 mol. The quantum yield of LiLaSiO4:0.015 Tm3+,0.015Dy3+ was 39.0%. The single-matrix white light LiLaSiO4: αTm3+, βDy3+ phosphors with excellent performance is a prospective material for of white LEDs.