Preparation, phase formation and photoluminescence properties of ZnO-SiO_2-B_2O_3 glasses with different ZnO/B_2O_3 ratios

摘要

Classes in ZnO-SiO_2-B_2O_3 ternary system with different ZnO/B_2O_3 ratios were studied as scintillating materials. Differential thermal analysis and X-ray diffraction patterns showed that nucleation of willem-ite and zinc oxide was considerably facilitated with increasing the ZnO/B_2O_3 ratio. Photoluminescence spectra showed a reduction in intensity over the UV region upon this increment prior to the formation of crystalline phases. Optical basicity as a measure of nonbridging oxygens (NBOs) is elaborated in this study as a major cause of this effect. However, near band edge emission (NBE) after crystallization implied an increase in intensity upon the increment of the ZnO/B_2O_3 ratio which proved the key role of willemite and zinc oxide as UV emission centers.