On the origin of near-IR luminescence in Bi-doped materials (II). Subvalent monocation Bi⁺ and cluster Bi5³âº luminescence in AlCl3/ZnCl2/BiCl3 chloride glass.

Broadband NIR photoluminescence (from 1000 to 2500 nm) was observed from partially reduced AlCl3/ZnCl2/BiCl3 glass, containing subvalent bismuth species. The luminescence consists of three bands, assigned to Bi⁺ , Bi24⁺, and Bi5³âº ions. The physical and optical characteristics of these centers and possible contribution to NIR luminescence from bismuth-doped oxide glasses are discussed.