Theoretical design of Au–DPPh–Au molecular junction for use in organic field-effect transistors

Abstract

The electron transport properties of a newly designed model based on the molecular junction of 2,2′,6,6′-tetraphenyl-dipyranylidene (DPPh) between two Au electrodes were investigated. Density functional theory was applied in combination with the non-equilibrium Green's function method. In addition, scanning tunneling microscopy images and rectification ratio were analyzed to show the charge density intensity within the asymmetric and nonlinear behaviors of current (I) at applied voltages (V). The electronic properties, transmission coefficient, and I–V characteristics of the Au–DPPh–Au model along the z-axis are more favorable than that of the model along the y-axis. The different analyses showed that the Au–DPPh–Au model along the z-axis is a suitable molecular junction for use in organic field-effect transistor devices.