Gold nanorods grown directly on surfaces from microscale patterns of gold seeds

We report a strategy for patterning surfaces with high aspect ratio gold nanorods (Au NRs) by using a poly(dimethylsiloxane) (PDMS) stamp to microcontact print 3-5 nm diameter gold nanoparticle (Au NP) seeds onto mercaptan-functionalized Si/SiOx surfaces and subsequently grow the seeds into An NRs via seed-mediated reduction of HAuCl4 with ascorbic acid in the presence of cetyltrimethylammonium bromide (CTAB). The patterns also contain a large number of spherical particles, which are largely removed and separated from NRs using adhesive tape. The same PDMS stamp was used more than 30 times to produce well-defined patterns without reinking with Au NP seeds. Controlled patterning of Au NRs on surfaces is important for electronics, sensing, optical, and plasmonic applications.