Nanostructure synthesis at the solid-water interface: spontaneous assembly and chemical transformations of tellurium nanorods.

Bottom-up synthesis offers novel routes to obtain nanostructures for nanotechnology applications. Most self-assembly processes are carried out in three dimensions (i.e. solutions); however, the large majority of nanostructure-based devices function in two dimensions (i.e. on surfaces). Accordingly, an essential and often cumbersome step in bottom-up applications involves harvesting and transferring the synthesized nanostructures from the solution onto target surfaces. We demonstrate a simple strategy for the synthesis and chemical transformation of tellurium nanorods, which is carried out directly at the solid-solution interface. The technique involves binding the nanorod precursors onto amine-functionalized surfaces, followed by in situ crystallization/oxidation. We show that the surface-anchored tellurium nanorods can be further transformed in situ into Ag2Te, Cu2Te, and SERS-active Au-Te nanorods. This new approach offers a way to construct functional nanostructures directly on surfaces.

Transparent, conductive gold nanowire networks assembled from soluble Au thiocyanate.

Extremely long gold nanowires spontaneously assemble in a water-dimethylsulfoxide (DMSO) solution of Au(SCN)4(-). The Au nanowires were crystalline, exhibited a very high aspect ratio, and, importantly, were produced without co-addition of reducing agents. Transparent conductive films were formed by surface deposition of the nanowires and plasma treatment.