Improved Interfacial Adhesion of Bulk Heterojunction and PEDOT‐Based Transport Layers in Organic Photovoltaics through Rubbing Process

With the continuous advancement of organic photovoltaic (OPV) technology, it has unlocked boundless opportunities for industrial development. In terms of OPV industrialization, the use of inverted device architecture combined with all‐solution coating remains the most effective approach to simultaneously meet the dual demands of low‐cost and high‐throughput production. However, this approach also highlights a long‐standing challenge in the OPV industry, the poor adhesion between hydrophilic hole transport layers (HTLs), such as poly(3,4‐ethylenedioxythiophene) (PEDOT)‐based colloids, and the hydrophobic bulk heterojunction (BHJ) layers. This adhesion issue often leads to delamination, posing reliability risks, particularly for flexible devices. To address this challenge, our study proposes a method that utilizes alignment cloth to rub the surface of the BHJ layer, thereby increasing the contact area and enhancing adhesion with the PEDOT‐based colloid HTL. This technique significantly improves the adhesion between the hydrophilic HTL and hydrophobic BHJ layer, enhancing the flexibility and reliability of the devices while maintaining high efficiency. This process offers significant insights for the OPV industry and production methods, potentially serving as a revolutionary approach for future module manufacturing is believed.