Solution‐Processed Sandwich‐Structured Organic Photovoltaics

Current organic photovoltaic (OPV) devices still rely on complex multilayer architectures, which inevitably increase OPV production costs. Here, we propose a simple sandwich‐structured OPV device composed solely of a bottom electrode/active layer/top electrode configuration, without additional charge transport layers. By introducing perfluorosulfonic acid polymers (PFSAs) into the PH1000 bottom electrode, the electrode work function is effectively enhanced, thereby improving the hole extraction and transport. Based on the PFSA‐modified PH1000 and the dual‐functional top electrode, the all‐solution‐processed laboratory‐fabricated devices achieve a power conversion efficiency (PCE) of 10.1% and a fill factor of 70.1%, while maintaining an average visible transmittance of ≈30%. The PFSA‐modified electrode is compatible with laser scribing, enabling series‐connected modules with an effective area of 10 cm 2 and a PCE of 7.44%. Importantly, enhanced interfacial hydrophobicity enables the devices to retain about 70% of their initial PCE after 20 days in air. This work demonstrates a sandwich‐structured device design strategy that simplifies the device architecture while maintaining high PCE, providing a promising route toward scalable fabrication of OPV devices.