Interfacial dipole and geminate pair energetics at pentacene/C60 heterojunctions

We present a first-principles density functional theory (DFT) which is successful in classes of problemstraditionally considered "too tough for DFT". The basic elements of this method are briefly reviewed(first principles tuning of the Baer-Neuhauser-Livshits range-separated hybrid), but the focus is onrecent applications. Unlike most DFT approximations, our approach yields orbital energies that closelyapproximate the ionization potentials and electron affinity of atoms, molecules, clusters and solids. Wedemonstrate the success of the method in treating the breaking of 3 electron bonds and reactionbarriers. The time-dependent version of the method falls within the Runge-Gross TDDFT framework,using generalized time-dependent Kohn-Sham equations. The method is capable of describing Rydbergand electron-transfer excitations. We give examples with comparison to experiment on coumarin dyes,aromatic molecular complexes and bipeptides. Finally, we discuss an application to molecularelectronics, where a gate potential tunes the conductance level of a molecular junction. Concepts suchas Coulomb blockade and exciton binding energy are clearly illustrated using the orbital energies of ourfirst principles DFT method.