Lead–germanate glasses: an easy growth process for silver nanoparticles and their promising applications in photonics and catalysis

Abstract

In this study, we report non-conventional silver nanoparticle growth on the surface of lead–germanate oxide glasses. Thermal annealing at around the glass transition temperature (T_g) under a nitrogen atmosphere enables the growth of silver thin films on the glass surface. The nanoparticle growth was monitored by scanning electron microscopy (SEM) and UV-visible spectroscopy as a function of the annealing time. The characteristic temperatures were obtained by differential thermal analysis (DTA) and the influence of the Ag⁺ ion content on the glass stability (GS) parameters was evaluated. Additionally, the apparent activation energy of crystallization (E) was calculated. The silver thin films obtained after different annealing times were applied as a substrate for luminescence enhancement of the Eu(btfa)₃·bipy rare earth europium complex. The catalytic activity of the Ag-doped glasses was tested for the reduction of p-nitrophenol in the presence of NaBH₄. The catalytic performance of the unannealed glass demonstrated an unexpected good efficiency compared with the annealed glass samples.