In optimization of the device charge injection and electronic transport through the interface is very important. So, we can say that type of interface is very crucial for designing a device, especially at the molecular level. We have used DFT along with NEGF to study the interface between organic molecules and conductors. Koopman’s theorem along with electronic coupling for holes, which results from the mixing of the frontier orbitals of the two nearest donors (or acceptor) molecules with the orbitals of the bridging acceptor (donor) molecule, is studied to compute the coupling integral. While calculating density matrix NEGF approach is suitable for open systems, however diagonals from Kohn-Sham Hamiltonian are used for closed or periodic systems. The distinct electronic structure of molecule and electrode, shifts the molecular levels dramatically which in consequence changes the HOMO-LUMO gap. So, coupling between the molecule and electrode is very crucial for designing a device at the molecular level.

Molecular junction, Non-Equilibrium Green Function (NEGF), Band Theory, Density functional theory (DFT), Benzene