Impact of π-linker modifications on the photovoltaic performance of rainbow-shaped acceptor molecules for high performance organic solar cell applications

Abstract

Non-fullerene acceptor (NFA) materials attracted a huge attention because of their tendency to improve the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, we intended to demonstrate the efficient designing of a series of Rain-bow shaped materials (LB1 to LB5). These acceptor materials are designed by various end-capped modifications in a synthetically reported π-linker CH1007 molecule (reference R). The photovoltaic, optoelectronic, structural-property relationship, and physiochemical properties are specifically realized by using density functional theory (DFT) and time-dependent (TD-DFT) at B3LYP/6-31G (d,p). Our designed materials (LB1 to LB5) significantly occupied a narrower energy bandgap (Eg) (Eg = 1.87–2.01 eV) in-contrast to R and found highly red-shifted in absorption spectrum with lower excitation energies. The reorganization energy studies showed that the newly designed materials (LB1 to LB5) exhibited a better electronic mobility (λh = 0.0153 to 0.0190) as compared with R (λh = 0.0194). The higher open circuit voltage (Voc), and lower binding energy (Eb) values suggested that these designed materials (LB1 to LB5) are best fitted to prepare highly efficient OSCs devices. To study the charge transfer behavior, a donor:acceptor (D:A) blend study has also been performed to estimate an efficient charge transport phenomenon at the D:A interface. The outcomes of all analysis suggested that this designed series (LB1 to LB5) could be effective for the future development of highly efficient OSCs devices.