Construction of a two-dimensional molecule-nanoparticle network using iron(II) bis(terpyridine) complex formation for molecular-device applications

We report a novel method to construct a two-dimensional network of gold nanoparticles and metal complex molecules. Terpyridine derivatives having a thiol group are adsorbed on a gold nanoparticle surface through formation of a gold-sulfur bond. A monolayer of nanoparticles is then formed on the water surface, then transferred onto a Si/SiO2, substrate. The introduction of Fe2+ from a Fe(BF4)(2) solution forms an iron(II) bis(terpyridine) complex, which simultaneously forms a network where the complex molecules interlink adjacent nanoparticles. The conductivity of the network, formed by the conjugated terpyridine derivative, is 4 or 5 orders of magnitude higher than that of non-conjugated derivatives. Conductivity is modulated by gate voltage when a conjugated derivative is used but not when a non-conjugated derivative is used. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.