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. (C) 2015 Elsevier B.V. All rights reserved.