Solid Additive Engineering for High-Efficiency Organic Solar Cells: Categories, Mechanisms, and Perspectives

Abstract

Organic solar cells (OSCs) have been widely studied as a promising technology for solar energy conversion, owing to their advantages including light weight, flexibility, low-cost manufacturing, and tunable semitransparency. Since the performance of OSCs is tightly coupled to nanoscale morphology of the active layer, various morphology modulation strategies have been developed in the field. In recent years, solid additive (SA) engineering has emerged as a pivotal strategy for precise morphology control in OSCs, demonstrating potential for enhancing power conversion efficiency (PCE), long-term stability, and compatibility with low-cost and eco-friendly scalable fabrication. This review covers the latest advances in SA engineering, the classification of SAs, and the working mechanisms by which SAs regulate active layer morphology and enhance device performance. Notably, SAs are classified into three categories based on their interacting objects: (i) SAs functioning through interactions with acceptors, (ii) SAs functioning through interactions with donors, and (iii) SAs functioning through synergistic interactions with both donors and acceptors. Furthermore, effective theoretical calculation methods are summarized to help design tailored SAs for specific donor:acceptor systems by predicting their intermolecular interactions. Finally, the remaining challenges and perspectives on future research in SA engineering for accelerating the commercialization of OSCs are discussed.