Excitons and solar-harvesting potential of γ-graphyne

Abstract

First-principles and many-body calculations are employed to investigate the excitonic properties and solar-harvesting potential of γ-graphyne. The atomic structure was optimized using the Perdew–Burke–Ernzerhof (PBE) functional, the electronic structure was refined at the Heyd–Scuseria–Ernzerhof (HSE06) level, and the optical response was evaluated within both the independent-particle approximation (IPA) and the Bethe–Salpeter equation (BSE). The optical spectra are dominated by excitonic effects, with a binding energy of 132 meV and a lowest excitonic peak at 0.77 eV in the visible range. Photovoltaic analysis predicts maximum power conversion efficiencies of 28.08% at the IPA level and 23.84% at the BSE level, highlighting γ-graphyne as a promising candidate for excitonic and photovoltaic applications.