Research progress in small-molecule donor-polymer acceptor organic photovoltaic cells

Organic solar cells (OSCs), characterized by their lightweight, flexibility, solution-processability for large-area fabrication, and low cost, exhibit significant complementary advantages to silicon-based photovoltaics, positioning them as a cutting-edge research frontier in clean energy. Among emerging architectures, small-molecule donor/polymer acceptor (SDPA)-based OSCs have attracted considerable attention due to their unique active layer stability, particularly their ability to maintain optimized phase-separated morphology under high-temperature conditions (>85 °C), offering potential to overcome the stability bottleneck in organic photovoltaic industrialization. However, the current record power conversion efficiency (PCE) of SDPA-OSCs remains at 12.1 %, significantly lagging behind mainstream bulk heterojunction systems (PCE >20 %). To advance the efficiency of SDPA-OSCs, extensive efforts have been devoted to optimizing materials, device engineering, and processing techniques. This review systematically summarizes recent progress in SDPA-OSCs from the perspectives of device architecture and active layer processing. Key focus areas include the impact of device structure engineering (conventional vs. inverted configurations) and active layer fabrication strategies (bulk heterojunction solution-coating and layer-by-layer deposition techniques) on charge carrier transport and device performance. By establishing robust "material structure–morphology–device performance" correlations, this work provides critical insights and technical references for developing high-efficiency SDPA-OSCs. Furthermore, future research directions and challenges in material innovation, morphology control, and scalable manufacturing are discussed to guide the advancement of SDPA-based organic photovoltaics.