Mechanochemical All‐in‐Powder Strategy with Intrinsic Additive Incorporation for High‐Efficiency and Durable Perovskite Solar Cells

Abstract Perovskite solar cells (PSCs) have emerged as highly cost‐effective photovoltaic devices, offering impressive performance metrics. However, their fabrication faces challenges such as unstable reproducibility and industrial scalability, primarily due to their heavy reliance on specific additives, including methylammonium chloride (MACl) in the perovskite layer and lithium bis(trifluoromethanesulfonyl)imide (Li‐TFSI) in the hole transport material (HTM). These challenges can potentially be mitigated through the premixing of all components, including additives, on a larger scale. To address this, a mechanochemical method, specifically ball‐milling, to synthesize perovskite powder with incorporated MACl and HTM powder containing Li‐TFSI is employed. The perovskite fabricated from powder synthesized under optimized milling conditions exhibits a more homogeneous composition compared to conventionally produced perovskite. Notably, the powder retains its composition even after three months of storage and demonstrates exceptional stability under harsh conditions, including 85% relative humidity and 100 °C thermal stress. In powder‐based perovskite solar cells, using isopropyl alcohol (IPA) as an anti‐solvent leads to superior‐quality perovskite formation compared to chlorobenzene. Furthermore, under optimized milling conditions, Li‐doped HTM powder is synthesized and employed in PSC fabrication. Consequently, powder‐based PSCs fabricated with IPA achieve a maximum power conversion efficiency of 24.33%.