Energy transfer mechanism and luminescence properties of green phosphors Sr2YF7: Dy3+, Tb3+
Miao Yan, Lina Liu, Yabin Wang, Yifan Liu, Xiaoqing Pei, Lin Fan, Hai Lin, Shasha Li, Weiling Yang, Zhong‐Min Su, Chun Li, Fanming Zeng
Abstract
In this study, color-adjustable Sr 2 YF 7 : xDy 3+ , and yTb 3+ light-emitting phosphors were synthesized through the hydrothermal method . Systematic experiments were performed to determine the optimal doping concentration for Sr 2 YF 7 : xDy 3+ phosphor with x = 0.03, resulting in a distinctive light blue emission band attributed to the 4 F 9/2 → 6 H 15/2 transition. The energy transfer within the double-doped system of Sr 2 YF 7 : Dy 3+ , yTb 3+ (y = 0, 0.06–0.1) was examined by analyzing spectral overlap and reductions in emission lifetimes. Moreover, the mechanism governing this energy transfer phenomenon was investigated. The concentration proportion of Dy 3+ /Tb 3+ in Sr 2 YF 7 phosphors was modulated to achieve color modulation, transitioning from light blue to vibrant green emissions in Sr 2 YF 7 : Dy 3+ , Tb 3+ samples. The intensity of green emission increased with increasing Tb 3+ ion concentrations because of the dynamics of energy migration from Dy 3+ to Tb 3+ levels ( 4 F 9/2 + 7 F 6 → 6 H 15/2 + 5 D 4 ). Based on calculations using steady-state rate equations, Tb 3+ ion doping effectively reduced ionic spacing and consequently amplified the green emission. Furthermore, the results indicated that the luminous intensity ratio of Sr 2 YF 7 : 0.03Dy 3+ , 0.07 Tb 3+ phosphors at 423/303K was notably high at 93.59 %, indicating high thermal stability. Thus, Sr 2 YF 7 phosphors co-doped with Dy 3+ and Tb 3+ emerge as potential candidates for application in advanced illumination technologies.