Study on the color tunability and energy transfer mechanism in Tb3+, Sm3+ co-doped LiLaSiO4 phosphors

Abstract

A several of LiLaSiO4: xTb3+, ySm3+ (LLSO) phosphors were synthesized by high-temperature solid-phase reaction. Through SEM, XRD and fluorescence spectrometer, the phase, morphology, luminescence properties and energy transfer of the samples were systematically analyzed and discussed. Under an excitation of 378 nm wavelength, LLSO: xTb3+ phosphors emit green light, and the concentration quenching point of Tb3+ ions was x = 0.08. In LLSO: xTb3+, ySm3+ phosphors, When Sm3+ ions doping molar mass fraction increases, the fluorescence intensity of Tb3+ ion decreases while the fluorescence intensity of Sm3+ ions first strengthen and then weaken. The concentration quenching point of Sm3+ ions was y = 0.04. By changing the proportion of Sm3+ and Tb3+ ions, the luminous color can be adjusted from green to red. There is effective energy transfer between Tb3+→Sm3+. The molar mass fraction of doping Sm3+ ions is y = 0.10, the energy transfer efficiency reaches 96.67%. The energy transfer mechanism is the quadrupole-quadrupole interaction. The quantum yield is 22.34%. Therefore, LLSO: xTb3+, ySm3+ phosphors have certain potential application value in the field of ultraviolet-near ultraviolet white LEDs.