Tailoring the Work Function of Gold Surface by Controlling Coverage and Disorder of Polar Molecular Monolayers

We show here that the work function of Au can be controlled not only by the magnitude and direction of adsorbed polar molecules but also by the molecular coverage and (dis)order within the molecular patterns. Molecular monolayers composed of two types of molecules with opposite dipoles were deposited on Au films containing the changes of the work function due to variation of molecular coverage and disorder were monitored. The results indicate that the requirements on molecular layers covering Au surfaces are significantly relaxed and that partial, disordered monolayers can be used to tailor the work function of metal surfaces.