Novel NaI improved Ge–Ga–Te far-infrared chalcogenide glasses

•Ge–Ga–Te glass matrix can dissolve content of NaI as much as 35at.%.•The lowest absorption cut-off wavelength is 1645nm.•The highest value of ΔT corresponding to (Ge15Ga10Te75)85(NaI)15 glass is 120°C.•Studied glass system has a wide IR transmission window between 1.6 and 20μm. In this study, a novel Te-based glass system was investigated. Some properties of Ge–Ga–Te–NaI chalcogenide glasses such as physical, thermal and optical transmitting were discussed. XRD patterns show this glass system with best amorphous state can dissolve content of NaI as much as 35at.%. The lowest cut-off wavelength of glass samples is 1645nm which is the smallest wavelength among the reported Te-based glasses doping with halide. DSC curves indicate that all glass samples have good thermal stabilities (ΔT>100°C) and the highest ΔT value corresponding to (Ge15Ga10Te75)85(NaI)15 glass is 120°C which is 8°C greater than that of Ge–Ga–Te host glass. The infrared spectra manifest Ge–Ga–Te–NaI chalcogenide glass system has a wide infrared transmission window between 1.6μm and 20μm. Consequently, Ge–Ga–Te–NaI glasses can be a candidate material for far infrared optic imaging and bio-sensing applications.