3,5‐Dibromoanisole as Multifunctional Solid Additive to Enhance the Performance of Organic Solar Cells

Comprehensive Summary Strategic design of solid additives for regulating molecular aggregation and crystallinity in organic photovoltaic systems is crucial for enhancing device efficiency and stability. Herein, we introduce 3,5‐dibromoanisole (DBA) , a volatile solid additive synergistically integrating halogen and alkoxy functionalities, to optimize the PM6:Y6 active layer. DBA simultaneously interacts with both PM6 and Y6, promoting face‐on molecular orientation and fibrillar network formation. Consequently, DBA‐treated devices achieve a power conversion efficiency (PCE) of 18.34% , with a short‐circuit current density ( J SC ) of 28.24 mA·cm –2 and a fill factor (FF) of 78.6%, surpassing the control device (PCE = 17.13%). Notably, the DBA additive exhibits exceptional stability and demonstrates broad applicability across multiple material systems. This study establishes a universal framework for designing multifunctional solid additives, paving the way for scalable, high‐efficiency organic solar cells (OSCs).