Research Progress and Prospects of Halogen and Cyano Substitution Strategies in Donor Materials

Organic solar cells (OSCs) have emergedas one of the fastest‐growing research directions in the photovoltaic field due to their unique low‐cost solution processing characteristics, compatibility with large‐area fabrication, and excellent flexible device performance. In recent years, advances in new photovoltaic materials and optimized device fabrication processes have pushed the power conversion efficiency of single‐junction OSCs beyond the critical milestone of 20%. Although the efficiency threshold for commercial‐scale OSC applications is nearing achievement, its industrialization process still faces the critical challenge of further reducing manufacturing costs. In this article, we summarize the application of halogen‐substitution strategy in donor material design. Furthermore, we propose exploring cyano‐substitution strategy and simplifying polymer monomer structures, which may open new avenues for developing next‐generation low‐cost, high‐performance donor materials.