Moderate Trap Engineering for Enhanced Thermal Stability and High Efficiency in a Bi<sup>3+</sup>-Doped Phosphor
Shuai Wei, Zeyu Lyu, Zheng Lu, Pengcheng Luo, Luhui Zhou, Dashuai Sun, Taixing Tan, Sida Shen, Hongpeng You
Abstract
Trap engineering is widely applied to contend with thermal quenching of phosphors. However, the incidental detriment of the luminescent efficiency has long been neglected. Herein, we propose a paradigm for achieving a high-performing Bi 3+ -doped phosphor with moderate trap engineering. Through introducing appropriate traps in a neutral atmosphere and proper doping concentration, we have successfully created a novel Ba 2 GdAlO 5:Bi 3+ yellow phosphor that exhibits exceptional thermal stability (104.1%@423 K) and a high internal quantum yield (82.78%), which is the top performance among Bi 3+ -doped phosphors. The oxygen vacancy and Bi 2+ were identified as the responsible traps through X-ray photoelectron spectroscopy, while their depth was measured to be 0.9 eV by using thermoluminescence. Notably, the phosphor exhibited photochromism upon near-ultraviolet (n-UV) excitation and could be bleached through heat treatment. These observations highlight its potential for various applications. Finally, two white lighting devices with a color rendering index exceeding 90 were prepared with n-UV LED chips by applying Ba 2 GdAlO 5:Bi 3+ as one of the phosphors. This study not only provides a high-performance Bi 3+ -doped phosphor suitable for high-quality white LED (WLED) lighting but also proposes a methodology for designing phosphors with high efficiency and thermal stability..