Surface Potential Measurement of Oligothiophene Ultrathin Films by Kelvin Probe Force Microscopy

Abstract
Surface structures and local surface potential of oligothiophene single molecular films deposited on metal substrates were investigated by Kelvin probe force microscopy using the frequency modulation detection method. Two-dimensional growth of the dimethylquinquethiophene (DM5T) films with the molecular axes perpendicular to the metal substrates was observed. Furthermore, the obtained surface potential of the DM5T film was 170 mV higher than that of Pt substrate and 200 mV lower than that of Ta substrate.