First Principle Theoretical Designing of U-Shaped Fullerene-Free Acceptor Molecules for Efficient Indoor and Outdoor Organic Solar Cell Applications

An efficient molecular modelling approaches drawing a great attention from the scientific community to further boost the photovoltaic performances of the solar cell’s materials. For this purpose, various end-capped and bridged-core modifications have been carried-out to construct a suitable molecule best fitted for solar cell applications. Herein, we have designed a small-molecule based fullerene-free acceptor materials (IOD1-IOD7) for organic solar cells (OSCs) by doing end-capped modifications, and characterized them theoretically by employing various quantum chemical density functional theory (DFT) and time-dependent (DFT) approaches. The specific key features of the designed materials (IOD1-IOD7) essential for the solar cell applications have been estimated by investigating their absorption maxima, reorganization energy and open-circuit voltages (Voc) values.  The other key parameters such as, electronic structures, frontier molecular orbitals, exciton binding energy, and charge transfer phenomenon has also been studied theoretically. The outcomes of these theoretical characterizations revealed that all the newly designed non-fullerene acceptor materials exhibit a wide-ranging absorption efficiency and exciton dissociation constant values, with quite lower LUMO energy level, ensuring a boost in various photo-physical and in opto-electronic properties of the designed materials, which will eventually improve the power conversion efficiency (PCE) of the OSCs devices.