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.