Enlarging Environmental Asymmetry by the Site Tailoring to Enhance Luminescence Properties of Sm<sup>3+</sup> in the (Gd,Na)<sub>3</sub>(Ga,In)<sub>2</sub>(Ga,Ge)<sub>3</sub>O<sub>12</sub> Garnet
Jiajun Feng, Y. B. Yu, Hongji Song, Zibo Chen, Yingxiang Zhu, Jiahui Liu, Jingtian Xie, Lianfen Chen, Junhao Li
Abstract
A structural design strategy was employed to develop NaGd 2 Ga 2 InGe 2 O 12:Sm 3+ (NGGIG:Sm 3+ ) garnet phosphors, optimizing the local coordination environment to enhance luminescence performance. By tailoring site occupation, Sm 3+ ions were incorporated into an asymmetric crystal field, where a statistical probability model confirmed that ∼97% of Sm 3+ ions reside in distorted coordination environments, promoting electric dipole(ED) transitions. The phosphors exhibit a high red-to-orange ( R / O ) intensity ratio of 2.97, contributing to enhanced red emission. CIE chromaticity coordinates of (0.61, 0.39) indicate a significant shift toward the red region, and the phosphors retain over 70% of their luminescence intensity at 400 K, demonstrating good thermal stability. These characteristics make NGGIG:Sm 3+ a promising candidate for high-performance red phosphors in solid-state lighting applications, highlighting the effectiveness of site engineering in garnet structures for optimizing luminescence efficiency and stability.