Banana-Shaped Nonfullerene Acceptor Molecules for Highly Stable and Efficient Organic Solar Cells

We efficiently designed and theoretically characterized five (LE1-LE5) new nonfullerene acceptor (NFA) molecules for organic solar cell (OSC) applications. These designed molecules have great potential to further improve the power conversion efficiency (PCE) of OSC devices. The designing of these molecules has been done by incorporating various end-capped units on the reference molecule (CH1007) to further improve the photovoltaic performances of the materials. The theoretical characterization of these designed (LE1-LE5) materials has been carried out along with the reference (R) molecule to explore their structure-property relationship and photovoltaic and optoelectronic characteristics by various density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches. Furthermore, narrower band gaps and highly red-shifted absorption behavior in contrast to R have been realized among all newly designed (LE1-LE5) materials. Therefore, these NFA materials can be efficiently applied to fabricate OSC devices after blending with any suitable band gap polymer (PTB7-Th) material. Our investigations have confirmed that the designed nonfullerene acceptors (NFAs) (LE1-LE5) could be suitable candidates to achieve excellent device performances and offer significant directions to design effective NFAs for efficient OSCs.