Broadband visible luminescence in tin fluorophosphate glasses with ultra-low glass transition temperature

The structure of tin fluorophosphate glasses and their low melting point properties have attracted a great deal of attention recently, but their own luminescent features have not been well studied. Photoluminescence properties of ultra-low glass transition temperature (<200 °C) tin fluorophosphate glasses with varying SnO/SnF₂ molar ratios at room temperature have been investigated in the present study. Broad photoluminescence in the range from 400 nm to 700 nm, originating from the S₁-S₀ and T₁-S₀ transitions of Sn²⁺ with the ultra-high concentration (70 mol%), was obtained. And the SnF₂-SnO-P₂O₅ glasses exhibited a fast decay lifetime of 2 ns. Both wavelengths of the excitation peak and emission peak depend on the local structure of Sn²⁺, which is influenced by different SnO/SnF₂ molar ratios. White light can be generated by appropriately altering the SnO/SnF₂ molar ratios in the SnF₂-SnO-P₂O₅ glasses. The ultra-low glass transition temperature SnF₂-SnO-P₂O₅ glasses without rare earth elements are a possible candidate for future high white light emission.