Volatile Additive‐Assisted Processing of Organic Photovoltaics in Ambient Air

Organic photovoltaics (OPVs) have achieved power conversion efficiencies (PCEs) exceeding 20% in laboratory‐scale cells, yet their scalable manufacturing remains challenging because of the difficulty in controlling molecular assembly during film formation under ambient conditions. Here, we report a volatile‐additive‐mediated kinetic regulation strategy for efficient OPV fabrication in ambient air without post‐deposition thermal treatment. By incorporating the highly volatile additive 2,4‐dichlorotoluene (DCT) into the photoactive‐layer ink, we modulate the film‐solidification process and regulate molecular assembly in non‐fullerene acceptor‐based blends. The rapid evaporation of DCT promotes compact molecular packing and reduces water accessibility within the active layer. As a result, OPV cells fabricated entirely in ambient air achieve PCEs exceeding 20%, approaching the performance of devices processed under an inert atmosphere. This strategy is further extended to large‐area OPV modules, demonstrating high efficiency and reproducibility. These findings establish volatile‐additive‐mediated kinetic control as a practical approach to efficient and scalable OPV manufacturing under ambient conditions.