Silver nanodisks: Synthesis, characterization, and self-assembly

A new form of silver nanostructured materials, silver nanodisks, are generated by a solution-phase approach. In this method, truncated triangular silver nanoplates are at first fabricated through seed-mediated growth of silver particles in the presence of concentrated cetyltrimethylammonium bromide (CTAB). Subsequent aging of the obtained triangular silver nanoplate solution at 40 degreesC leads to the formation of silver nanodisks. Transmission electron microscopy and atomic force microscopy studies show that the nanodisks have a thickness of the order of 20-30 nm and a diameter around 60 nm. X-ray and electron diffraction analyses reveal that the nanodisks are single crystals and with their basal plane as the (111) lattice plane. These nanodisks display a strong surface plasmon absorption band at 475 nm. The formation of a self-assembled monolayer of CTAB on the basal plane is suggested to account for both the anisotropic growth from triangular' nanoplates to nanodisks and the formation of large-scale necklace-like nanostructures.