Structure-conductivity correlation of organic molecular junctions

Abstract

Electric conductivity of molecular junctions with organic molecules was studied with a computational program IVSIESTA, which was developed in this project based on a density function theory package SIESTA and non-equilibrium Green¿s function formalism. Molecular junctions were simulated with extended molecule model. Using the program, molecular junctions based on various organic thiols were simulated with gold electrodes. The results were interpreted with molecular orbital analysis in zero-voltage equilibrium state. Structural factors (both chemical and geometric) were investigated and summarized. Several molecular diodes were constructed and simulated to test the rectification effect. It was shown the electronic coupling across the system is a crucial factor determining the conductivity of the junction. The program IVSIESTA may be employed to investigate the conductivity of various chemical structures. The knowledge of structure-conductivity correlation may be helpful in the design of new electronic functional molecules.