X-ray photoemission study of Pr3+ in zinc borate glasses

This work reports the X-ray photoelectron spectroscopy of a zinc borate glass activated by different concentrations (0, 1, 2, 4, and 8 mol%) of Pr3+. The modification induced on the glass structure by the Pr3+ ions was investigated, and a quantitative measure of the non-bridging-to-bridging-oxygen ratio around the Pr3+ ion was obtained. The analysis of the O 1s core line showed three components associated with oxygen atoms belonging to the glass host and bridging and non-bridging oxygen atoms surrounding the Pr3+ ions respectively. The experiments indicate that the coordination at the Pr3+ ions is formed by both bridging oxygen atoms and non-bridging oxygen atoms. The non-bridging-to-bridging-oxygen ratio remains constant with increase in the Pr3+-ion concentration. Analyses of the B 1s and Zn 2p core lines are also reported. The electronegativity equalization method has been used to describe the structure of the local environment around the Pr3+ ions.