Exploration of photovoltaic behavior of fused triphenylamine moiety as core donor with modified acceptors: Star-shaped D-?-A conjugated systems

Fullerene-free organic chromophores have drawn considerable attention as successful photonic devices for organic solar cells. So, a series of novel non-fullerene-based donor molecules (HBTD2-HBTD9) were fabricated via structural modification of the terminal acceptor groups from HBTR1. In order to achieve the photovoltaic, photophysical, and electronic behavior of fore-said compounds, density functional theory/time-dependent density functional theory (DFT/TD-DFT) based analyses were accomplished at B3LYP functional along with 6-311G(d,p) basis set. The optical and electrical characteristics of the derivatives were compared with HBTR1 architecture. All designed molecules exhibited a lower EHOMO-ELUMO band gap (2.183-4.106 eV) with a red shift in absorbance compared to the reference compound (4.179 eV). All derivatives (HBTD2-HBTD9), except HBTD3, showed a greater exciton dissociation rate due to low binding energy (Eb =-0.337 to 1.400 eV) when compared with HBTR1 (Eb = 1.401 eV). Interestingly, HBTD9 manifested to be the prime candidate for non-fullerene organic solar cells (NF-OSCs) owing to the lowest energy band gap, large mobility of charges, and least value of binding energy while holding an excellent redshift value compared to all the designed chromo-phores. This study revealed that these chromophores would be potential competitors in manufacturing effective optoelectronic materials.