Fluorinated Benzothiadiazole-Based Polymers for Organic Solar Cells: Progress and Prospects.

The integration of fluorinated benzothiadiazole (FBT) into donor-acceptor (D-A) copolymers represents a major advancement in the field of organic solar cells (OSCs). The fluorination process effectively fine-tunes the energy levels, reduces the highest occupied molecular orbital levels, and enhances the open-circuit voltages of the polymers. Furthermore, fluorination improves molecular packing and crystallinity, which significantly boosts the charge transport and overall device performance. This review provides a detailed analysis of the progress made with FBT-based polymers in OSCs, classifying these materials according to their copolymerization units. It discusses the design strategies and structure-property relationships that have emerged as well as the current challenges and future directions for optimizing these polymers. By offering a comprehensive overview of the existing research, this review aims to facilitate the development of high-performance FBT-based organic photovoltaic materials, ultimately contributing to the advancement of sustainable energy solutions.