  The final performance of a molecular electronic device is determined by the
chemical structure of the molecular wires used in its assembly. Molecular
place-exchange was used to incorporate di-thioacetate terminated molecules into
ordered arrays of dodecanethiol capped gold nanoparticles. X-ray photoelectron
spectroscopy confirmed successful molecular replacement. Room-temperature
molecular conductance of a statistically large number of devices reveals that
conductance is enhanced by up to two orders of magnitude for the di-thioacetate
terminated molecules. Density functional theory transport calculations were
performed on five different configurations of the di-thioacetate molecules
between gold electrodes, and the calculated average conductance values are in
good agreement with the conductance experimentally-observed trend. Our findings
highlight important cooperative effects of bridging neighboring gold
nanoparticles and choice of appropriate molecular wires when designing devices
for efficient transport.

Materials Science