On the couplings in molecular charge transfer

Abstract

We address the importance of electronic couplings and system–environment couplings in molecular charge transfer processes. The first part introduces the fragment-orbital tunneling current and its relationship with electronic couplings. The fragment-orbital tunneling current shows the direction and magnitude of charge transfer and allows estimating the electronic coupling constant. The second part investigates optimal charge transport and the necessary alignment of molecules in view of electronic couplings. Simulating variously disordered molecular chains revealed that a significant strength of system–environment couplings allows chains with decreasing or increasing electronic couplings to show superior charge transport characteristics than the ideally aligned chain. The two parts portray the significance of electronic couplings and their varying effects caused by the environment.