A Study on the Anti-thermal Dy<sup>3+</sup>/Eu<sup>3+</sup> Co-doped BaLa<sub>4</sub>Si<sub>3</sub>O<sub>13</sub> Red Phosphors for White-Light-Emitting Diodes and Optical Thermometry Applications
Fan Liao, Bingqing Shen, Weiwei Wu, Yuanpeng Zhang, Jianxu Hu
Abstract
A series of Dy3+/Eu3+ co-doped BaLa4Si3O13 phosphors were synthesized by a solid-state reaction method. The Dy3+/Eu3+ co-doped BaLa4Si3O13 phosphors exhibit superior thermal behavior to the corresponding Dy3+ singly doped and Eu3+ singly doped BaLa4Si3O13 phosphors. A remarkable enhancement of thermal stability is observed as the Eu3+ concentration increases. The emission intensity is enhanced by a factor of ∼1.1 at 423 K compared to that at 298 K for the 11 mol % Eu3+ doped sample. The improved thermal stability is ascribed to the enhanced energy transfer from Dy3+ to Eu3+ at high temperature, which enhances the Eu3+ emission and effectively compensates the thermal quenching-induced emission reduction. The synthesized phosphors can further be employed as optical thermometry materials, with the highest relative sensitivity (Sr) of 1.462% K–1 at 497 K. The results demonstrate that employing energy transfer is an effective strategy to design anti-thermal phosphors and the synthesized Dy3+/Eu3+ co-doped BaLa4Si3O13 phosphors show great potential as red phosphors for white-light-emitting diodes and optical temperature sensing applications.