Metal‐Less Top Electrode Semitransparent Organic Solar Modules with an Average Visible Transmission of 51% and a Light Utilization Efficiency of 4%

Abstract Semitransparent organic modules (STOMs) are of particular interest due to potential applications in building‐integrated photovoltaics though upscaling without significant performance losses while ensuring an aesthetic appearance for window applications remains a major research obstacle. This study presents two types of STOMs with an area of 11.4 cm², exhibiting homogeneous appearance while retaining up to 92% of their respective small‐area cell power conversion efficiency (PCE). Precise laser structuring minimized the area loss originating from the sub‐cell series interconnection, allowing narrow cell stripes down to 1.25 mm. This enables a metal‐less top electrode composed solely of PEDOT:PSS without compromising fill factor. For a module, an additional challenge is to ensure a low resistance series interconnection between sub‐cells. This is realized with a novel approach based on a direct contact between PEDOT:PSS and a thin Ag layer within the back electrode. For the first design, the latter incorporates Al‐doped ZnO and Ag attaining a PCE of 6.1% with an average visible transmission (AVT) of 47.5%. A more elaborate design features an extended back electrode using TiO₂ and SiO₂ for improved optical performance (PCE = 7.9%), reaching an unprecedented AVT of 50.8% and a light utilization efficiency (LUE = AVT x PCE) of 4.0%.