Layer-by-layer growth of metal-metal bonded supramolecular thin films and its use in the fabrication of lateral nanoscale devices.

Layer-by-layer self-assembly of metal-metal bonded supramolecules is demonstrated and utilized to fabricate lateral nanoelectronic devices. Mercaptoethylpyridine is used to bind to Au substrates and to template the sequential assembly of alternating layers of redox active dirhodium complexes [Rh2(DAniF)2]2(O2CCH2CO2)2 (DAniF = N,N'-di-p-anisylformamidinate) and conjugated organic ligands trans-1,2-bis(4-pyridyl)ethylene. Optical spectroscopy and atomic force microscopy show that the structure and composition of these thin films are similar to those found in tightly packed single crystals. Electrochemical studies of these films grown on Au substrates reveal a reversible oxidation wave at approximately 406 mV, corresponding to the one electron oxidation of the Rh24+ center. This directed assembly technique has been used to fabricate lateral nano-electronic devices in which the supramolecules span the channels. Tailoring the chemistry of the templating ligand enables assembly on desired surfaces and engineering the chemistry of the supramolecules' dimetal units and coordinating ligands may tune the device characteristics.