Void-free buried interface for scalable processing of p-i-n-based FAPbI3 perovskite solar modules

Formamidinium lead iodide (FAPbI3) has emerged as one of the most promising perovskite semiconductors for perovskite solar cells (PSCs), demonstrating high power conversion efficiency (PCE) and good stability. However, only a few reports address the scalable processing and fabrication of FAPbI3 perovskite solar modules. Here, we report a void-free perovskite-buried interface in p-i-n-based PSCs, which enables us to upscale lab-scale solar cells (<1 cm2) to mini-module dimensions (>10 cm2). An innovative combination of a moderate N2 flow during vacuum-assisted growth (VAG) control of the perovskite thin films as well as the employment of MACl as an additive eliminates interfacial voids in blade-coated large-area FAPbI3 layers, enabling respective PCEs of 20.0% and 18.3% in blade-coated PSCs (0.105 cm2) and fully scalable modules (aperture area of 12.25 cm2 and geometric fill factor of 96.3%). This is a remarkable advance in upscaling FAPbI3-based perovskite photovoltaics.