Structural Switching of Self-Assembled Monolayer by External Electric Field

Abstract

Self-assembled monolayers (SAMs) are used for adjusting the work function of metal electrodes in organic devices. Since the energy level difference between the HOMO or LUMO and the work function affects the electron injection through the metal-organic interfaces, fine tuning of the work function is of importance. To control the work function from external environment, external large electric field on low-density SAMs is reported to be effective. In order to obtain a direct evidence for the structural switching of the SAM, X-ray reflectivity measurements were performed. The result shows that the molecular tilting of 10• is induced by the external voltage application.