Molecular design for low-cost organic photovoltaic materials

The development of low-cost and high-performance organic photovoltaic (OPV) materials is currently a major focus of research in the OPV field because the material costs of state-of-the-art OPV cells are prohibitive for industrialization. When analysing state-of-the-art OPV materials, including polymer electron donors and small-molecule electron acceptors, the main prerequisites for high photovoltaic performance, including optoelectronic and morphological properties, are quite clear. However, low-cost materials, consisting of simpler building blocks with fewer chemical substitution positions, present challenges in simultaneously obtaining desirable optoelectronic and morphological properties. In this Review, we first summarize key factors in the molecular design of high-performance OPV materials. Subsequently, we discuss research progress and challenges faced in the molecular design of low-cost materials. Finally, we outline key thoughts and insights related to the molecular design of future low-cost OPV materials with a focus on efficiency and stability.