FRIDAY 11:00
MOLECULAR ELECTRONIC DEVICES BASED ON THE ARCHETYPICAL MOLECULAR WIRE: AN UNCAPPED OLIGOYNE
Santiago Martin
Universidad de Zaragoza, España
ABSTRACT
The advent of molecular-scale electronic devices demands the availability of suitable molecular components that can be integrated into a supramolecular assembly and subsequently connected to a macroscopic support. Among the various components needed for fabrication of effective devices are molecular wires. Polyynes are interesting compounds that have attracted considerable attention recently because they are the archetypical molecular wire and posses considerable potential for a number of applications such as molecular wires and switches in nanoelectronics or for optoelectronics. Here, nascent molecular electronic devices based on robust and reliable C-Au contacts are prepared upon efficient in situ cleavage of trimethylsilyl end groups of an oligoyne, Me3Si(CºC)SiMe3. In the first stage of the fabrication process, a high-ordered monomolecular layer of the oligoyne is formed onto the bottom electrode using the desilylation process. In the second stage, the modified gold substrate is incubated in a solution of gold nanoparticles (GNPs), which results in covalent attachment of the GNPs on top of the film via an alkynyl carbon–Au s-bond. The carbon–surface bonding as well as the covalent attachment of the metal particles to the monolayer via a heterolytic cleavage of the alkyne C–H bond is confirmed by surface-enhanced Raman scattering (SERS). The integrity of the organic monolayer and formation of the gold top-contact electrode is demonstrated through cyclic voltammetry experiments as well as with the click chemistry. Electrical properties of these metal-monolayer-metal devices are determined by recording I–V curves, which show a sigmoidal behaviour indicative of well-behaved junctions free of short circuits. In summary, the present desilylation strategy promises to prepare sandwich-like device structures of uncapped polyynes for their wider exploitation in molecular electronics.