Defect Spatial Configuration Modulating Site‐Dependent Luminescence in Eu 3+ ‐Activated Double Perovskite Phosphors
Weiwei Xiang, Yuxiang Li, Yongbin Hua, Jae Su YuABSTRACT
Understanding how defect configuration and site occupancy regulate luminescence remains a critical issue in multi‐site ceramic phosphors. Herein, theSr 2 CaTeO 6 double perovskite is employed as a material system to investigate the coupled effects of Eu 3+ site‐selective substitution and Na + charge compensation. Eu 3+ ions are introduced into A (Sr 2+ )‐ and B (Ca 2+ )‐sites, while Na + ions are incorporated via homo‐site and hetero‐site compensation to construct distinct defect configurations. The results reveal that the spatial distribution of compensating ions governs the local symmetry and lattice distortion around Eu 3+ emitters. Homo‐site compensation promotes Eu 3+ ‐Na + defect pairs, resulting in enhanced local distortion and asymmetric crystal fields, whereas hetero‐site compensation redistributes the electrostatic field and stabilizes the lattice. Consequently, tunable emission behavior is achieved, with A‐site substitution exhibiting red emission while B‐site substitution shows orange emission. Moreover, hetero‐site compensation significantly enhances thermal stability, as evidenced by higher activation energies and improved emission retention at elevated temperatures. Based on these findings, a comprehensive structure‐defect‐symmetry‐optical correlation is established. This work highlights the critical role of defect spatial configuration in ceramic phosphors and provides a fundamental strategy for designing high‐performance multi‐site luminescent materials.