Structural, optical, and radiation shielding properties of Bismuth-boro-tellurite glass doped with thulium oxide

Nowadays, the biggest production in glass manufacturing is silica. The primary ingredients of silica glass production are limestone, soda ash, and silica and sand. Unfortunately, this glass production may raise global temperature because of its melting temperature. Lead is one of the important elements in the production of optical properties and radiation-shielding glass due to its high density, high atomic number, and high degree of stability. However, the toxicity of lead can harm the environment and is carcinogenic to the human body. Lead can bioaccumulate in organisms and the production processes of lead will effect on environmental quality. From the problem, there is a need to replace lead with other elements that safer. The bismuth boro-tellurite based glass doped with thulium oxide was successfully synthesised by the conventional melt quenching method. These series glass compositions are {[(B2O3)0.25(TeO2)0.75]0.75 [(Bi2O3)0.25]}1-x [Tm2O3]x; where x = 0, 0.005, 0.010, 0.015, 0.020, 0.025, 0.030 mol %. The effect of Tm2O3 in bismuth boro-tellurite glasses on structural, optical properties, and gamma radiation shielding has been studied. The density measurement (Archimedes principle), amorphous phase (X-ray diffraction), structural changes (Fourier Transform Infrared (FTIR)) and theoretical calculation of parameter radiation shielding (WinXCom and Phy-X program) are provided for supportive evidence to gamma shielding and optical properties. The results show the glass densities increase with the increase of Tm2O3 content which is due to the high molar weight and also on an atomic radius of the glass modifier compared to the glass network TeO2–B2O3. The increase in the densities of glasses is also due to the increase in the number of non-bridging oxygen (NBO) atoms and the replacement of a low– density oxide B2O3 (2.46 g/cm3) and TeO2 (5.67 g/cm3) by a high–density oxide Bi2O3 (8.99 g/cm3), and Tm2O3 (8.6 g/cm3). XRD results show the glasses are amorphous in nature, with slightly tendencies toward crystallinity. From the FTIR spectra, it can be seen that the glasses consist of TeO3, TeO4, BO3, and BO4 structural units. The optical band gap energy which was calculated from Tauc’s plots decreases with an increased amount of Tm2O3 and increased the non-bridging oxygen (NBO) atmos. The increasing value of Urbach energy is attributed to the increasing defect in the glass structure. The shift of the absorption edge and decrease of Eg value are attributed to the progressive increase in the concentration of non-bridging oxygen (NBO) atoms. Present results also showed the shielding properties improved with increasing amounts of Tm2O3. The theoretical data of shielding parameters showed that Compton scattering is a major interaction in gamma energy. The {[(B2O3)0.25(TeO2)0.75]0.75 [(Bi2O3)0.25]}0.970 [Tm2O3]0.030 glass sample were found to give the lowest mean free path and half value layer compared to other glass samples. The result of this glass sample even outperformed some standard concrete and commercial radiation shielding glasses.