A comprehensive review of PM6:BTP-eC9 based non-fullerene organic solar cells

Organic solar cells (OSCs), with their advantages such as lightweight, flexible and environmental sustainability, have attracted tremendous attention in the past decades. Among OSCs, the PM6:BTP-eC9 based OSCs has gained significant interest due to its wide spectral response, tunability of energy levels, processability and high power conversion efficiency (PCE), resulting in a substantial increase in published works. To date, the PCE of laboratory-grade PM6:BTP-eC9 based OSCs has exceeded 20 %. And this efficiency has laid a solid foundation for its industrial application. This paper mainly summarizes the comprehensive progress of PM6:BTP-eC9 based OSCs, providing detailed explanations on improvement methods such as interface layers modification, active layer morphology regulation, ternary strategy, and so on, seeking to comprehend the impact of various treatments on the performance of PM6:BTP-eC9 based OSCs and to broaden the utilization of PM6:BTP-eC9 materials. Additionally, we offer a perspective on the emerging prospects for PM6:BTP-eC9 based OSCs. Finally, this review may contribute to the thorough research of PM6:BTP-eC9 based OSCs and the realization of the material's full potential for future researchers in this field.