Web Release Date: October 25,
General Method for Extended Metal Nanowire Synthesis: Ethanol Induced Self-Assembly
and
Singapore-MIT Alliance, 4 Engineering Drive 3, National University of Singapore, Singapore 117576, Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, and Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260
Received: August 24, 2007
In Final Form: September 21, 2007
Abstract:
A new template-free method to form extended nanowires from the spontaneous self-assembly and fusion of discrete metal nanoparticles has been developed. The key strategy was the use of a weak polar solvent (ethanol) to suitably destabilize the metal nanoparticles in a hydrosol. The number of nanoparticles that were assembled and fused into an extended crystalline structure was found to depend on the dielectric constant of the solvent system. Three distinctive fusion modes consistent with HRTEM analysis of the products were hypothesized, which could satisfactorily explain the formation and the structures of the nanowires. This method of nanowire synthesis is simple, scalable, and capable of producing nanowires with virtually "clean" surfaces. The synthesis method can also be extended to other metals, such as palladium and platinum.
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