Luminescence efficiency growth in wide band gap semiconducting Bi2O3 doped Cd0.4Pb0.1B0.5 glasses and effect of γ-irradiation

Abstract

Cadmium lead borate glasses together with other glasses containing different Bi2O3-doping concentrations (2.5, 5, 7.5, 10mol%) were prepared by conventional melt annealing method. The density and molar volume values were calculated to obtain some insight on the packing density and arrangement in the network. Also their optical and structural properties have been characterized by means of X-ray diffraction, UV–visible spectroscopy, luminescence spectroscopy and FTIR spectroscopy. Optical measurements have been used to determine the optical band gap (Eg), Urbach energy (ΔE) and the refractive index (n). The results demonstrate the effective rule of Bi2O3 on the studied glasses. The undoped and Bi2O3 doped – glass show strong extended UV-near visible absorption bands which are attributed to the collective presence of both trace iron impurities from raw materials and also the sharing of bismuth Bi+3 ions. Furthermore, the luminescence intensity strongly increases with increasing Bi2O3 content which may be attributed to transfer of energy from transitions in its energy levels. It has been revealed that the decreasing values of optical band gap and band tail can be understood and related in terms of the structural changes that are taking place in the glass samples. The infrared absorption spectra of the prepared glasses show characteristic absorption bands related to the borate network (BO3, BO4 groups) together with vibrational modes due to Bi–O groups upon the introduction of Bi2O3. The prepared samples reveal a very limited response towards of gamma irradiation which reflects its shielding behavior towards the effect of such type of irradiation.