Surface Potential Mapping of SAM-Functionalized Organic Semiconductors by Kelvin Probe Force Microscopy

Kelvin probe force microscopy measurements on rubrene single crystals partially coated with fluorinated and non-fluorinated SAM derivatives are employed to determine the SAM-induced surface potentials caused by an interfacial charge-transfer doping process resulting in an interface dipole. The surface potential and topographic information in turn allow calculation of the effective intramolecular electric fields and carrier densities due to doping in the SAM-modified rubrene crystals.