Photoluminescence Tuning via Cation Substitution in Oxonitridosilicate Phosphors: DFT Calculations, Different Site Occupations, and Luminescence Mechanisms

• DOI: 10.1021/cm500844v
• Publication Date: 2014-04-07T17:46:22Z
• Authors: Guogang Li; Chun Che Lin; Wei-Ting Chen; Maxim S. Molokeev; Victor V. Atuchin; Chang-Yang Chiang; Wuzong Zhou; Chin-Wei Wang; Wen-Hsien Li; Hwo-Shuenn Sheu; Ting-Shan Chan; Chonggeng Ma; Ru-Shi Liu
• Keywords: фотолюминесценция; светодиоды белого свечения; XRD, рентгеновская дифрактометрия; 02 engineering and technology; оксонитриды; 0210 nano-technology

Tuning and optimizing luminescent properties of oxonitridosilicates phosphors are important for white light-emitting diode (WLED) applications. To improve the color rendering index, correlated color temperature and thermal stability of layer-structured MSi2O2N2:Eu (M = Sr, Ba) phosphors, cation substitutions have been used to adjust their luminescent properties. However, the underlying mechanisms are still unclear. In this research, a series of (Sr1–xBax)Si2O2N2:Eu (0 ≤ x ≤ 1) compounds were prepared by solid-state reaction, after which systematic emission variations were investigated. The crystal structures of (Sr1–xBax)Si2O2N2:Eu (0 ≤ x ≤ 1) are nominally divided into three sections, namely, Phase 1 (0 ≤ x ≤ 0.65), Phase 2 (0.65 < x < 0.80), and Phase 3 (0.80 ≤ x ≤ 1) based on the X-ray diffraction measurements. These experimental results are further confirmed by optimizing the crystal structure data with first-principle calculations. Continuous luminescence adjustments from green to yellow are observed...