Vapour sensing using hybrid organic–inorganic nanostructured materials

Small aromatic organothiol derivatives, with the structure HS–C6H4–X, have been used to stabilise gold nanoparticles. The nature of the functional group, X, is important for controlling the relative strength of the particle–particle and particle–solvent interactions and hence in determining the physical properties of these systems (e.g. solubility). Particles were stabilised with different ligands for which X=OH, –COOH, –NH2, and –CH3 and thin films of the particles were formed, by solution evaporation, on microelectrode patterned surfaces. The electronic behaviour indicates that conduction can be understood in terms of an activated electron tunnelling model. Finally, preliminary studies were carried out on the effect of exposure to different chemical vapours on the electronic transport properties.