Dipole-improved gating of azulene-based single-molecule transistors

Abstract

Single-molecule field-effect transistors (FETs) are promising to break the development bottleneck of device miniaturization, which is of great significance for realizing the development of more than Moore. However, the field-effect properties under gating need to be further improved. Here, we design an azulene-based single-molecule FET with two opposite dipole moments in a single molecule and ionic liquid gating. This kind of FET shows ambipolar characteristics and better gate controllability with a high on–off current ratio, which is about five times higher than that of single-molecule FET based on the naphthalene molecule. According to both experimental and theoretical research, the high efficiency of gate control is related to the inherent dipole moment of azulene, which results in a lower conductance in the off-state, higher polarizability of azulene, and an effective energy level shift of the molecule. These studies offer a proven method to build single-molecule FETs with high gating regulation efficiency, thus promoting the development of practical single-molecule electronic devices.