Films of metal nanocrystals formed at aqueous-organic interfaces

Nanocrystalline films of Au, Ag, and Cu have been prepared at the toluene-water interface by the interaction of metal-triphenylphosphine complexes in the organic layer with partially hydrolyzed tetrakishydroxymethylphosphonium chloride in the aqueous layer. The nanocrystals have been characterized by a host of microscopic and spectroscopic techniques. The free-standing films could be transferred from the interface onto solid supports. Furthermore, films could be dissolved to yield either a hydrosol or an organosol with the help of appropriate surfactants.