Thermal and structural studies of Bismuth Borate glasses modified with Gadolinium Oxide for solid state lighting applications

Abstract

Bismuth based borate glasses with combination B2O3 –Bi2O3 – Gd2O3 - K2O-Li2O (BBiGdKLi) were prepared by melt-quenching method at 1250 °C for thermal and structural properties investigation.. Glass transition temperature (Tg) was observed at 681 K in heat capacity (Cp) vs temperature plot. As the temperature increases the specific heat or heat capacity also increases but a sudden fall in Cp was noticed at 962 K which is known to be crystalline temperature (Tc) of BBiGdKLi glass. Borate units comprising non-bridging oxygen (NBO) such as υ(B-O-Gd/Bi/K/Li) occured due to asymmetric stretching vibration at 976 cm-1 revealed in Raman spectrum excited by 532 nm laser. B1s, Bi 4f and Gd 4d binding energies from the XPS spectra of BBiGdKLi glass are corresponding to 188.9, 156.35 & 161.75 and 156.35 & 161.7 eV, respectively. The thermal behavior of BBiGdKLi glass suggest that these glasses could be significant materials for solid state lighting applications.