Enhanced mid-IR luminescence of Tm3+ ions in Ga2S3 nanocrystals embedded chalcohalide glass ceramics

Chalcohalide glass with a composition of 65GeS2-25Ga2S3-10CsI (in mol%) doped with 0.6 wt% Tm3+ ions was prepared by conventional melt-quench method. By heat treating the precursor glass at 20 °C above its glass transition temperature Tg for different durations, IR transparent glass ceramics were obtained. X-ray diffraction (XRD) and scanning electron microscope (SEM) showed that Ga2S3 crystallites were precipitated after heat treatment and their grain sizes were in nano-scale and increased with the elongation of heat treated time. Mid-IR luminescence properties of the glass and transparent glass ceramic samples were investigated. The emissions at 2.3 and 3.8 μm corresponding to optical transitions of 3H4 → 3H5 and 3H5 → 3F4 of Tm3+ ions were significantly enhanced by the presence of Ga2S3 nanocrystals and reached a maximum after 8 hours treatment.