Gold nanoparticle (AuNP) assemblies have uses in a wide range of technologies, such as catalysis, sensors, antennas, electronics, and medicine. Top-down approaches, e.g., nanolithography, provide complex non-periodic structures with high precision, but at high cost, low throughput and limited lateral coverage. On the other hand, bottom-up approaches, e.g., Langmuir-Blodgett deposition and micro-contact printing, allow for rapid construction of periodic nanostructures with fewer limitations on lateral coverage. These colloidal approaches, though, struggle with controlling structural characteristics and integrating into traditional device fabrication approaches. Recent simulations have indicated that additional structural control for these approaches could be afforded by combining repulsive particle-particles potentials with attractive particle-surface potentials. The effect of parameters such as ligand chemistry (citrate or mercaptopropanesulfonate), AuNP solution ionic strength (10-5 - 1 M) and AuNP concentration (10-12 - 10-7 M) on the order and density of AuNP assemblies is discussed. In addition, effects of post-assembly treatments, e.g., thermal annealing and exposure to salt solutions, are considered. Experiments indicate that the order and density of AuNP assemblies are predominately governed by the nature of the deposition solution (i.e., concentration, ionic strength and pH) along with the charge state of adsorbate head groups. Also, it is observed that post-assembly treatments minimally influence the order of electrostatically-bound AuNPs, thus indicating inherently strong particle-surface interactions. The processing-structure correlations elucidated by these studies have implications for technologies necessitating large area, deliberately designed nanoscale arrays, including next-generation MEMS, plasmonic and photovoltaic technologies.

Tuning the order and structure of nanoparticle monolayers with opposing particle-particle and particle-surface potentials

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.