Fully evaporated interfacial layers for high-performance and batch-to-batch reproducible organic solar modules

Abstract

Significant advancements in research have been made in recent years, with single-junction organic solar cells achieving efficiencies exceeding 20%. However, scaling up laboratory prototypes to large-area commercial modules remains challenging due to the absence of high-quality thin-film deposition techniques, particularly for ultra-thin interfacial layers. In here, we demonstrate a fully vacuum-processed approach utilizing InCl3 as hole-contact and C60/BCP as electron-contact interlayers, respectively, which guarantees dense and uniform charge transporting layers, while also ensuring consistent batch-to-batch reproducibility of module performance. In addition, such ultra-thin InCl3 layer significantly reduces the surface free energy of ITO substrates, thereby inhibiting the coffee ring effect during the active layer deposition, and obtaining a more homogeneous film in a large-scale size. As a result, we measured a power conversion efficiency of 16.5% (certified efficiency: 15.8%) under 1-sun illumination for the best-performing organic solar modules (aperture area = 15.6 cm2) with a geometric fill factor of 95.5%, making them highly completive amongst recently reported modules at similar size. Most importantly, our vacuum-processed interlayers exhibit excellent reproducibility and scale-up ability, paving a way to accelerate the industrialization of organic photovoltaic technology.