Abstract
We have recently discovered a novel and easy method for preparing colored Ag films using an aqueous solution of sulfide as a coloring agent. In the presence of specific sulfide, the color of Ag films, initially silver, changes to yellow, red, and blue depending on the preparation conditions. It is of great scientific interest to elucidate the mechanism of the color change of the Ag films. In order to address the mechanism, these Ag films and Ag nanoparticles have been characterized in terms of their surface morphology, particle size and chemical compositions by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. As the results, we conclude that the color change of our Ag films comes from not surface plasmon resonance of due to the particle size change of the Ag nanoparticles but the thin film interference between Ag and Ag2S layers.
