Correlation between preparation conditions and the photoluminescence properties of Sn2+ centers in ZnO–P2O5 glasses
Photoluminescence (PL) and coordination states of Sn2+ centers in 1SnO–68ZnO–31P2O5 (SZP31) glass prepared under different conditions are examined. When prepared in air, the local coordination state of Sn2+ centers depends on the starting material. In contrast, the PL properties of Sn2+ centers of the glass prepared under inert atmosphere conditions are independent of the starting material because of elimination of the oxidation reaction. 119mSn Mössbauer and X-ray absorption fine structure analyses indicate that most of the Sn2+ centers in the SZP31 glass prepared in an inert atmosphere exist at a SnO-like coordination state, possessing a coordination number greater than 2. It is assumed that the more highly coordinated Sn2+ is the origin of high PL intensity with high quantum efficiency.