Microscopic Mechanism of the Heat‐Induced Blueshift in Phosphors and a Logarithmic Energy Dependence on the Nearest Dopant–Vacancy Distance
Jing Xu, Xueli Huang, Xiyue Cheng, Myung‐Hwan Whangbo, Shuiquan Deng
Abstract
Abstract Heat‐induced blueshift (HIB) observed in many luminescent materials is a puzzling phenomenon that has remained unexplained for decades. By using the high‐throughput first‐principles calculations and energy‐screening techniques, we generated a number of model structures for five phosphors, RbLi[Li 3 SiO 4 ] 2 :Eu 2+ , Na[Li 3 SiO 4 ]:Eu 2+ , K[Li 3 SiO 4 ]:Eu 2+ , Sr[LiAl 3 N 4 ]:Eu 2+ , and Ca[LiAl 3 N 4 ]:Eu 2+ . Our analyses suggest, to a first approximation, a logarithmic energy dependence on the nearest distance between the dopant and the metal‐cation vacancy. By identifying the transition energies from the electronic structures calculated for the screened model structures, we show that the vibration of the Eu 2+ ion lying in an asymmetric and anharmonic potential well couples with the electronic states, leading to their HIB phenomena.