Achieving nearly zero-thermal quenching luminescence of tellurate phosphor via substitution of alkaline earth metal

Abstract

The luminescent thermostability of phosphor is a crucial factor for white light-emitting diode (w-LED) application. To improve the luminescent thermostability, the diverse modulation strategies were proposed. In this study, it was shown that cationic substitution can greatly enhance the luminescence thermostability in the Dy3+-activated BaLaLiTeO6 double perovskite phosphor. With the substitution of alkaline earth metal cations (Sr2+, Ca2+ and Mg2+) for Ba2+, the variations of the Dy3+ local symmetry and structural rigidity contribute to the improved emission intensity and thermostability, respectively. In particular, the MgLaLiTeO6:Dy3+ (MLLT:Dy3+) phosphor exhibits exceptional thermostability. When the temperature was increased up to 473 K, the luminescence intensity only loses 4.1 % of the initial level, and it is known as nearly zero-thermal quenching. Moreover, a w-LED device was assembled with the MLLT:Dy3+ phosphor as yellow component. The satisfactory electroluminescence performance was obtained. The results revealed that the phosphor is of great potential for the w-LED applications.