Abstract
This work reports on various physicochemical properties and energy conversion processes in phosphate glasses containing Sn(2+) and Nd(3+) ions of interest for luminescence-based applications. The glasses were prepared by melting with 50P(2)O(5)-(49 - x)-BaO-1Nd(2)O(3)-xSnO (x = 0, 1.0, 3.0, 5.0, 7.0, and 9.0 mol %) nominal compositions and characterized by X-ray diffraction, (119)Sn Mössbauer spectroscopy, density and related physical properties, Raman spectroscopy, differential scanning calorimetry, dilatometry, optical absorption, and photoluminescence (PL) spectroscopy. X-ray diffraction confirmed the noncrystalline nature of the glasses. The (119)Sn Mössbauer evaluation allowed for estimating the relative amounts of Sn(2+) and Sn(4+) in the glasses, which showed that Sn(2+) occurrence was favored. The densities showed variations without definite trends; additional physical parameters were then determined such as Sn(2+)-Nd(3+) distances based on (119)Sn Mössbauer results. The characterization by Raman spectroscopy showed no significant structural variation was induced as SnO replaced BaO. The thermal properties of the codoped glasses assessed were however found to be impacted mostly by Sn(2+) at high nominal SnO contents. Absorption spectra supported consistent occurrence of Nd(3+) ions among the codoped glasses. The PL evaluation showed that exciting Sn(2+) centers in the UV (e.g., near 290 nm) results in near-infrared emission from Nd(3+), which was maximized for SnO added at 5 mol %. The visible PL data were consistent with the presence of Sn(2+) in the glasses and showed dips in the emission spectra, indicating the energy transfer to Nd(3+) ions. The Nd(3+) decay times were however similar among the different samples.