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.