Uniaxial plasmon coupling through longitudinal self-assembly of gold nanorods

We report a new paradigm for tuning the optical properties of gold nanorods by organizing them longitudinally, using thioalkylcarboxylic acid based bifunctional molecules. The rationale behind the selection of the bifunctional molecule is based on the fact that the thiol group binds to the ends of the nanorods, which further assembles in a longitudinal fashion through cooperative hydrogen bonding between the carboxylic groups. A generalized procedure for uniaxial plasmon coupling through longitudinal self-assembly of An nanorods, initially to dimers and further to linear assemblies, is presented. Uniaxial modulation of interplasmon coupling through stepwise self-assembly of An nanorods will have application in nanoelectronics and plasmonics.