Material and device design for organic solar cells: towards efficiency and stability

Organic solar cells (OSCs) have garnered significant attention as a novel photovoltaic technology and have been extensively investigated. In recent years, OSCs have made rapid strides in power conversion efficiency (PCE), demonstrating their significant potential in practical applications. In addition to high PCE, the practical application of OSCs demands a prolonged operating lifespan. The rational design of materials and devices to achieve efficient and stable OSCs is pivotal. This feature article presents a thorough analysis of our group’s studies on enhancing efficiency and stability through material and device design. We introduce a range of exceptional chlorine-mediated organic photovoltaic materials and systematically summarize chlorine atom (Cl) induced effects on energy levels, molecular stacking, active layer film morphology and photovoltaic performance. Furthermore, the use of single-crystal diffraction technology allows for a comprehensive understanding of inter-molecular packing and interaction at the molecular level. A series of highly efficient non-fullerene acceptors (NFAs) with three-dimensional (3D) network packing structures are developed and discussed. Subsequently, based on efficient 3D network brominated NFAs, the studies on polymer and oligomer acceptor materials are carried out and achieve efficient and stable OSCs. In addition to materials design, the development of the “quasiplanar heterojunction” (Q-PHJ) based OSC device also plays an important role in achieving superior efficiency and stability. These design experiences of materials and devices hope to provide valuable guidance for the development of efficient and stable OSCs.