Electric field effects on organic photovoltaic heterojunction interfaces: The model case of pentacene/C₆₀

The applied electric field on organic heterojunction interface can significantly affect organic photovoltaic (OPV) performance. Here, to explore electric field effects on OPV heterojunction interface, the pentacene/C₆₀ complexes with face-on and edge-on configurations were constructed as model system, based upon quantum chemistry calculations that take into account of solid polarization effects and apply density functional with optimally tuned range separation parameters, we systematically studied the electric fields effects on the complexes’ geometries, electronic structures, excitation and spectral properties, as well as the rate constants of charge transfer (CT), exciton dissociation (ED) and charge recombination (CR) processes. The electric field can effectively modify interface electronic structures and energy level alignments, and the increasing of electric field that is perpendicular to interface can increase CT energetic loss, reduce the lowest CT excitation energy and the open-circuit voltage. The introducing electric field can modulate the kinetics of electron processes at heterojunction interface.