Correlation between the emission properties of Sn2+ center and the chemical composition of ZnO-P2O5 glasses

Abstract

Photoluminescence (PL) properties of Sn-doped zinc phosphate (Sn:xZP) glasses with different chemical compositions are investigated. Sn exists only in the form of Sn2+ in Sn:xZP glasses, which were prepared by a conventional melt-quenching method in Ar atmosphere. The glass-transition temperatures, Tg, of the Sn-doped glasses are lower than that of Sn-free glasses, and the change in the Tg values of Sn-doped glasses increases with increasing ZnO amount. Since the relative ratio of 4-fold coordinated Sn2+ becomes higher with increasing ZnO amount, the coordination state is found to depend significantly on the network structure and not on the optical basicity of the Sn:xZP glasses. The PL bandwidth, indicating the site distribution, becomes narrower as the ZnO amount increases. In addition, the PL decay lifetime in the Zn-rich glass is shorter compared to that of the P2O5-rich glasses, implying that the distribution of Sn2+ is also associated with the network structure. Thus, the network structure of the host matrix rather than the average optical basicity significantly influences the local structure of Sn2+ emission center.