DFT study of benzothiadiazole based small molecules for high efficiency organic photovoltaics

This study employs density functional theory (DFT) and time-dependent DFT (TD-DFT) to design and evaluate eight novel non-fullerene acceptors (NFAs) (G1–G8) for organic solar cells (OSCs). The molecules were engineered through strategic terminal group modification of a reference indacenodithiophene (IDT)-benzothidiazole (BT) based structure. All designed systems exhibit substantially reduced bandgaps (1.73–2.00 eV) and redshifted absorption profiles (λmax = 688–803 nm) compared to the reference molecule (REF), leading to enhanced light-harvesting capabilities (LHE = 0.988–0.998). Marcus charge transfer theory calculations revealed high hole hopping rates (Kh ≈ 10¹⁵ s⁻¹) and low reorganization energies (λh =…

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  Qassim University