Optical properties and structural rigidity of [(GeSe2)75(Sb2Se3)25]100−xTex chalcogenide glasses for potential applications in infrared filters and lenses

Chalcogenide glasses are promising candidates for advanced optical applications due to their tunable optical properties and structural stability. This paper presents the theoretical and optical investigations of the [(GeSe₂)₇₅(Sb₂Se₃)₂₅]_100−xTe_x (x = 0, 2.5, 5, 7.5, 10) chalcogenide glass system. Bulk samples have been fabricated using the classic melt quenching technique, followed by thermal evaporation to deposit thin films on glass substrates. Optical parameters, including the absorption coefficient, optical bandgap, and Urbach energy, have been estimated using absorbance spectra. A blue shift in the absorption edge has been observed, resulting in decreased optical bandgap values. A blue shift in the absorption edge has been observed, resulting in decreased optical bandgap values, while the refractive index increased with Te addition, attributed to increased material density. The mean coordination number values exceeded 2.4, indicating a rigid glassy structure. Additionally, the system demonstrated enhanced infrared transmission with a red shift in the absorbance spectra. The increased optical density and packing density with Te doping suggest potential optical applications, i.e., in infrared filters and lenses.