Laser-induced fluorescent micro-structures in silver nanoparticle based films

An optical method for the formation of micron sized line features within silver nanoparticle based films using focused laser irradiation is developed. The observed light-induced effect is a strong function of light flux producing line features with widths of less than 5 μm, which can be controlled by careful selection of the focused incident beam waist. A potentially useful local feature is generated just outside the region of laser exposure; the film displays significant fluorescence emission across the visible spectrum. The source of the fluorescence is attributed to the presence of hydrated citrate salts that have been decomposed due to local heating and recrystallized as confirmed by electron microscopy and confocal fluorescence spectroscopy.