Near-infrared photoluminescence enhancement and radiative energy transfer in RE-doped zinc-silicate glass (RE = Ho, Er, Tm) after silver ion exchange

Abstract

Co-doping of rare-earth-doped glasses with silver is a promising option to enhance the photoluminescence of rare-earth (RE) ions. The enhancement of the emission of erbium has been demonstrated with great effect, but the research on the effect of silver on the near-infrared luminescence of holmium- and thulium-doped glass has been scarce. We have prepared a set of zinc-silicate glass samples doped by Ho3+/Yb3+, Er3+/Yb3+ and Tm3+/Yb3+ ions and co-doped them with silver to clarify the mechanisms behind luminescence enhancement and explore the possibility of enhancing the luminescence of holmium- and thulium-doped glass. Our results show that silver dimers increase the luminescence of RE-doped glass upon excitation in the visible range via the energy-transfer mechanism. Moreover, the photoluminescence enhancement has been observed upon excitation at 975 nm due to a combination of effects such as the structural changes of a silicate matrix and the SPR effect of silver nanoparticles.