Unraveling the role of Au clusters vs. plasmonic particles on the defects-induced Mn2+luminescence promoted by Si in phosphate glass

This paper reports on the elucidation of the synergistic effect of gold particles on the defects-induced photoluminescence (PL) of Mn 2+ ions in phosphate glass promoted by silicon as reductant. The glasses studied were prepared by melt-quenching with fixed MnO 2  and Si contents, while the concentration of Au 2 O 3  was varied to assess the role of non-plasmonic  vs.  plasmonic Au clusters on Mn 2+  PL. Glass structural features were examined by Fourier transform-infrared spectroscopy and O 1 s X-ray photoelectron spectroscopy, with thermal behavior assessed by differential scanning calorimetry. Optical extinction, transmission electron microscopy, and PL spectroscopy with time-resolved measurements were then employed. The data supports non-plasmonic Au clusters as main species at the origin of the enhanced Mn 2+ emission. Potential causes for the variation in the PL properties are discussed, wherein an energy transfer pathway originating at Au clusters is proposed to account for the non-resonant UV-excited PL from Mn 2+  ions.