Self-assembly of gold nanorods

Self-assembly of gold nanorods (NRs) with aspect ratio of similar to 4.6 (1 2 nm in diameter and 50-60 nm in length) has been studied using transmissio n electron microscopy (TEM). Under appropriate conditions such as nanoparti cle concentration, solvent evaporation, narrow size distribution, ionic str ength, and surfactant concentration of the parent solution, gold nanorods a ssemble into one-, two-, and three-dimensional structures. Some of the thre e-dimensional assemblies extend to superlattices of NRs. The translation an d orientation symmetries of the self-assembled structures are determined. T he factors affecting the formation of the ordered self-assembly are discuss ed.