Structural ordering and charge variation induced by cation substitution in (Sr,Ca)AlSiN3:Eu Phosphor Red-emitting phosphor materials have been extensively developed to increase the color rendering index and stability in white light-emitting diodes (LEDs). Nitridosilicate phosphors, such as MAlSiN3:Eu2+ (M = Ca, Sr), exhibit high chemical and thermal stabilities because of their rigid structures. In the present study, disordering of Si/Al in the clusters of (Si/Al)N4 clusters is introduced in the framework through via cation substitution to induce charge variation from Eu3+ to Eu2+, and simultaneously improves the thermal stability and luminescent properties of the phosphor. The structure of the phosphor has been modified through cation substitution to induce charge variation and a rearrangement of neighboring nitride clusters, and, consequently, enhance its luminescent behavior. Substitution of Ca2+ by Sr2+ cations expanded the lattice volume and the b-c plane, but shortened the distance between the layers along the a axis. Lattice distortion of the framework introduced high-coordination sites in the Sr/Eu centers and adequate space, thereby facilitating charge variation of activators under reduced atmosphere, as detected through X-ray absorption near-edge structure spectroscopy. As such, the photo luminescent intensity of the phosphors increased by more than 10%, and a blue shiftblueshift occurred. Cation substitution induced a special change in the anion environment, as indicated in the solid-state Raman spectra. Moreover, a typical ordering variations in the SiN¬4 and AlN4 clusters are generated in the lattice. Meanwhile, neighbor sequences of (Si/Al)N4 around the divalent centers were observed through solid-state nuclear magnetic resonance spectroscopy. The modified ordering distribution resulted in a rigid structure and improved the thermal quenching behavior. This study promotes the research of into neighbor sequences for selective tetrahedral sites, such as Li, Mg, Al, and Si coordinated by N atoms in contact with cation sites. In conclusion, these results do not only confirm the local structure through a subtle analysis technology but also improve the phosphor properties for LEDs applications. Reference “Structural Ordering and Charge Variation Induced by Cation Substitution in (Sr,Ca)AlSiN3:Eu Phosphor” Yi-Ting Tsai, Chang-Yang Chiang, Wuzong Zhou, Jyh-Fu Lee, Hwo-Shuenn Sheu, Ru-Shi Liu, J. Am. Chem. Soc., 2015, 137, 8936. Professor Ru-Shi Liu Department of Chemistry rsliu@ntu.edu.tw Reference Yi-Ting Tsai, Chang-Yang Chiang, Wuzong Zhou, Jyh-Fu Lee, Hwo- Shuen Sheu, Ru-Shi Liu. (2015). Structural Ordering and Charge Variation Induced by Cation Substitution in (Sr,Ca)AlSiN3:Eu Phosphor, Journal of the American Chemical Society, 137(28), 8936. DOI: 10.1021/jacs.5b06080 Professor Ru-Shi Liu Department of Chemistry rsliu@ntu.edu.tw