The Formation of Supported Gold Nanostructures on Oxide Substrates Invited

Gold nanoparticles were produced using the solution-based synthetic protocols devised by Murphy and coworkers.These nanoparticles, which are 4 nm in diameter, were then dispersed onto an oxide substrate.The nanoparticles, which originally showed weak adhesion to the substrate, were then heated to temperatures approaching their melting point.This anneal resulted in nanoparticle adhesion strong enough to withstand aggressive sonication and swabbing.The strong adhesion is highly suggestive of the formation of a heteroepitaxial relationship capable of crystallographically aligning all nanoparticles in a single orientation.The nanoparticles also show a size reduction of 1 nm after the anneal which we attribute to a nanoparticle shape change, the loss of gold along the substrate due to surface diffusion and the destruction of the capping layer.These substrate-based nanoparticles should prove quite effective as seed materials for the nucleation of larger nanostructures with a higher degree of complexity.