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Considering the increased demand and potential of photovoltaic devices in clean, renewable electrical and hi-tech applications, non-fullerene acceptor (NFA) chromophores have gained significant attention. Herein, six novel NFA molecules IBRD1–IBRD6 have been designed by structural modification of the terminal moieties from experimentally synthesized A2-A1-D-A1-A2 architecture IBR for better integration in organic solar cells (OSCs). To exploit the electronic, photophysical and photovoltaic behavior, density functional theory/time dependent-density functional theory (DFT/TD-DFT) computations were performed at M06/6-311G(d,p) functional. The geometry, electrical and optical properties of the designed acceptor molecules were compared with reported IBR architecture. Interestingly, a reduction in bandgap (2.528–2.126 eV), with a broader absorption spectrum, was studied in IBR derivatives (2.734 eV). Additionally, frontier molecular orbital findings revealed an excellent transfer of charge from donor to terminal acceptors and the central indenoindene-core was considered responsible for the charge transfer. Among all the chromophores, IBRD3 manifested the lowest energy gap (2.126 eV) with higher λmax at 734 and 745 nm in gaseous phase and solvent (chloroform), respectively due to the strong electron-withdrawing effect of five end-capped cyano groups present on the terminal acceptor. The transition density matrix map revealed an excellent charge transfer from donor to terminal acceptors. Further, to investigate the charge transfer and open-circuit voltage (Voc), PBDBT donor polymer was blended with acceptor chromophores, and a significant Voc (0.696–1.854 V) was observed. Intriguingly, all compounds exhibited lower reorganization and binding energy with a higher exciton dissociation in an excited state. This investigation indicates that these designed chromophores can serve as excellent electron acceptor molecules in organic solar cells (OSCs) that make them attractive candidates for the development of scalable and inexpensive optoelectronic devices. [ABSTRACT FROM AUTHOR]

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 E HOMO - E LUMO 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 (E b = −0.337 to 1.400 eV) when compared with HBTR1 (E b = 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 chromophores. This study revealed that these chromophores would be potential competitors in manufacturing effective optoelectronic materials. • Designing of acridine based donor materials (HBTD2 - HBTD9) from HBTR1 via efficient acceptors. • Study of photovoltaic properties of aforesaid compounds through DFT. • Investigation of opto-electronic properties at B3LYP/6-311G(d,p) functional of DFT. • Efficacy of designed compounds was explored by investigating open circuit voltage. [ABSTRACT FROM AUTHOR]