Engineering Non-fullerene Acceptors as a Mechanism to ControlFilm Morphology and Energy Loss in Organic Solar Cells

Solution processable thin-film organic solar cells(TFOSCs) have attracted a lot of research attention in the past fewdecades, in the search for low-cost,flexible, and portable solarpanels. In light of this, tremendous progress has been made interms of improving materials design, device architecture, and easeof device fabrication processes. The choice of the donor andacceptor materials in the preparation of a polymer blend bulkheterojunction (BHJ) solar absorber medium is of greatimportance to the overall performance of organic solar cells(OSCs). The limitation in tuning the energy band structures offullerene molecules poses significant challenges to the progress inBHJ organic solar cells. In an attempt to cater to the challenges,small-molecule non-fullerene acceptors (NFAs) came into theOSC research space with the possibility of altering the optoelectronic properties of the polymer molecules that bring OSCs closer tothe realization of full-scale commercialization. This review discusses the role of NFAs in improvingfilm morphology and reducingenergy loss in TFOSCs. The recent development in engineering non-fullerene acceptors for solar energy conversion is presented anddiscussed in terms of reducing energy loss, improving solar cell performances.