Physical, Thermal, and Optical Properties of Mn and Nd Containing Barium Phosphate Glasses.

This work reports on various properties and analysis of optical interactions in phosphate glasses containing red-emitting Mn and near-infrared (NIR)-emitting Nd ions, which are of interest for energy applications and solar spectral converters. The glasses were made by melting with 50PO-(48 - )BaO-2MnO-NdO ( = 0, 0.5, 1.0, and 2.0 mol %) nominal compositions and characterized by X-ray diffraction, density and related physical properties, differential scanning calorimetry, dilatometry, UV-vis-NIR optical absorption, and photoluminescence spectroscopy with decay kinetics analysis. The glasses were X-ray amorphous, wherein the physical and thermal properties of the Mn/Nd-codoped glasses were largely impacted by NdO contents. The optical absorption spectra supported the occurrence of Mn ions and the lack of Mn in the codoped glasses, while the absorption due to Nd ions increased steadily with NdO contents. Analyzing the glass absorption edges via Tauc and Urbach plots was further pursued for a comparison. The photoluminescence evaluation showed a consistent suppression of the emission from Mn ions with increasing Nd concentration, while the decay kinetics revealed shorter lifetimes in connection with increased Mn → Nd transfer efficiencies. Excitation of Mn at 410 nm, however, led to the Nd NIR emission being most intense for 1.0 mol % NdO, despite the F emission decay analysis showing lifetime shortening throughout. Considering the compromise between red and NIR emissions, the Mn-containing glass doped with 0.5 mol % NdO is put in perspective with the concept of solar spectral conversion.