Substrate dependent surface plasmon resonance evolution of Ag nanoparticles treated in atmospheres

The evolution of surface plasmon resonance (SPR) with alternate air and H-2 treatment was investigated for silver nanoparticles on different SiO2-based substrates (soda-lime glass, quartz glass and mesoporous SiO2). It has been shown that evolution behaviours on the three substrates are very different. For silver nanoparticles on the mesoporous SiO2 substrate, alternate air and H2 heat treatment led to the alternate disappearance and appearance of the SPR, showing the reversibility of optical changes. For a soda-lime glass substrate, the SPR absorption also disappeared after the first run heat treatment in air and reappeared after subsequent H2 heat treatment, but the second run heat treatment in air could not induce the re-disappearance of the SPR. After alternate heating of the sample in air and H2 for four or more cycles, the SPR stayed almost unchanged. For a quartz glass substrate, however, the SPR absorption became negligible after alternate air and H2 heat treatment. Such effects of the substrate on the SPR are explained in terms of the subtle difference of the three SiO2-based substrates in micro-structure or chemical composition, and the redox of silver in the treatment atmospheres. This study could be important for the design and architectonics of new optical devices based on SiO2 materials and could also promote the understanding of the interaction of silver nanoparticles with the environment.