The influence of copper and silver in various oxidation states on the photoluminescence of Ho3+/Yb3+ doped zinc-silicate glasses

Transition metals, such as silver or copper, can be used to enhance the photoluminescence of rare-earth ions. In this work, a novel zinc-silicate glass containing holmium and ytterbium was prepared and subsequently doped with silver or copper by means of ion exchange. The concentration of transition metals was evaluated by electron microprobe analysis (EMPA), and the oxidation state was analysed by absorption spectroscopy and transmission electron microscopy (TEM). The waveguiding properties of the prepared samples were evaluated by m-line spectroscopy. Most importantly, the effect of transition metals on the photoluminescence of Ho3+ ions was evaluated by photoluminescence spectroscopy. The results show that copper has no positive effect on the photoluminescence of Ho3+ ions. On the other hand, silver shows significant promise because the photoluminescence of the glass increased by as much as 20%. It has been determined that the main mechanism behind this increase is energy transfer from small clusters rather than the surface plasmon resonance of silver nanoparticles.