Photoactivated fluorescence from individual silver nanoclusters

Fluorescence microscopy of nanoscale silver oxide (Ag2O) reveals strong pho toactivated emission for excitation wavelengths shorter than 520 nanometers . Although blinking and characteristic emission patterns demonstrate single -nanoparticle observation, Large-scale dynamic color changes were also obse rved. even from the same nanoparticle. Identical behavior was observed in o xidized thin silver films that enable Ag2O particles to grow at high densit y from silver islands. Data were readily written to these films with blue e xcitation; stored data could be nondestructively read with the strong red f luorescence resulting from green (wavelengths longer than 520 nanometers) e xcitation. The individual Luminescent species are thought to be silver nano clusters that are photochemically generated from the oxide.