Electrostatic investigation into the bonding of poly(phenylene) thiols to gold

The advancement of nanotechnology relies on the understanding of electrical connection to individual molecules. Electrostatic surface potential measurements of self-assembled monolayers can provide insight into the structural and electronic properties of molecules attached to surfaces. In this paper we report on the electrostatic potential of poly(phenylene) thiol molecules bound to gold surfaces. Kelvin force microscopy is used to probe self-assembled monolayers of a series of phenyl, biphenyl, and triphenyl thiol molecules. The dipole moments of the isolated molecules have been determined and show similar electronic trends. A difference in polarity between the isolated molecules and the electrostatic surface potential of a monolayer attached to gold reflects the electron transfer on to the bound molecule.