Detection of nano-interfacial space charge field at metal–organic film interface by SHG and surface potential

At the metal–organic film nano-interface, surface polarization phenomena are observed, due to the displacement of excess charges from metal to the films as well as alignment of polar dipoles. Surface potential method has been employed to examine these surface polarization phenomena, and the distribution of space charges and distribution of electronic density of states have been determined. However, for further understanding of the nanometric interface phenomena, it is very helpful to develop an experimental method that can detect electrical and optical phenomena induced by the space charge formation. In this paper, it is shown that optical second harmonic generation measurement is effective through our experiment on phthalocyanine films deposited on Al and Au electrodes.