Luminescent properties of fluorophosphate glasses with lead chalcogenides molecular clusters

Fluorophosphate glasses containing lead, selenium, and sulfur exhibit an intense luminescence in the 400-620 nm spectral region when excited by the 240-420 nm radiation. This luminescence is due to the presence of (PbSe)n and/or (PbS)n molecular clusters in the glasses, which appear in the as-prepared glasses before quantum dots formation. The thermal treatment at temperatures less than the glass transition temperature results in the red-shift of the luminescence bands and in an increase in the luminescence intensity. Heating the thermally treated glass samples leads to the reversible thermal quenching of the luminescence.