Recent developments in non-fullerene-acceptor-based indoor organic solar cells

For over a decade, donor-acceptor blends composed of organic donors and fullerene acceptors dominated indoor organic solar cells (IOSCs). Numerous researchers have invested time to conduct extensive studies on developing new donor acceptor materials, interlayers, minimizing energy losses, and enhancing the open-circuit voltage ( V _OC ) through device and material engineering, and optimizing device architectures to achieve highly efficient, environmentally stable, and commercially acceptable IOSCs. Through such efforts, the maximum power conversion efficiencies (PCEs) of IOSCs have surpassed 35%. In this regard, the transition from a fullerene to non-fullerene acceptor (NFA) is a useful strategy for enhancing the PCEs of IOSCs by allowing adjustment of the energy levels for compatibility with the indoor light spectrum and by improving photon absorption in the visible range, thereby boosting photocurrent generation and enhancing V _OC . NFA-based indoor organic photovoltaic systems have recently drawn interest from the scholarly community. To compete with the standard batteries used in the Internet of Things devices, additional research is needed to enhance several characteristics, including manufacturing costs and device longevity, which must maintain at least 80% of their initial PCEs for more than 10 years. Further development in this field can greatly benefit from a thorough and comprehensive review on this field. Hence, this review explores recent advances in IOSCs systems based on NFAs. First, we explain several methods used to create extremely effective IOSCs, IOSCs based on fullerene acceptors are next reviewed and discussed. The disadvantages of using fullerene acceptors in IOSCs are noted. Then, we introduce NFAs and explore existing research on the subject. Finally, we discuss the commercial potential of NFA-based IOSCs and their future outlook.