Silver Nanodisks: Synthesis, Characterization, and Self-Assembly

Abstract

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 °C 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.