Graphene Nanoribbons as Low Band Gap Donor Materials for Organic Photovoltaics: Quantum Chemical Aided Design

Graphene nanoribbons (GNRs) are strips of graphene cut along a specific direction that feature peculiar electronic and optical properties owing to lateral confinement effects. We show here by means of (time-dependent) density functional theory calculations that GNRs with properly designed edge structures fulfill the requirements in terms of electronic level alignment with common acceptors (namely, C-60), solar light harvesting, and singlet-triplet exchange energy to be used as low band gap semiconductors for organic photovoltaics.