Insights into enhanced broadband near-infrared emission of Bi-doped aluminosilicate glass by the addition of SnO

A series of Bi/Sn co-doped aluminosilicate glasses were prepared and the optical and structural properties of the samples were investigated. The near-infrared (NIR) luminescence properties of the glass were significantly improved by the co-doping of Bi and Sn. The NIR emission peaks of samples exhibit near 1220 nm. The addition of SnO changes the glass structure and induces a decrease in the number of negative charges in the local field of Bi, which causes the Bi valence state to change from a high valence state to a low valence state. The appropriate amount of Bi ₂O ₃ increases the number of Bi luminescent centers and realizes the transformation of the luminescent centers from Bi ⁺ to Bi ⁰. These results suggest that regulating the doping concentration of SnO and Bi ₂O ₃ is a convenient method to control the valence state of active ions and enhance the NIR luminescence properties of aluminosilicate glasses.