Record‐Breaking Efficient and Mechanically‐Robust Ambient‐Air‐Processed Carbon‐Based Flexible Perovskite Photovoltaics Through Effective and Benign‐to‐Plastics Green‐Antisolvent Quenching

Abstract Lightweight and bendy plastic‐based perovskite solar cells (PSCs) are considered strong emerging rivals to the rigid heavy‐block photovoltaics made of conventional crystalline‐silicon. To further increase the competitiveness of these devices, the research community is nowadays searching for compatible, effective and scalable strategies to achieve efficiencies of >20%, while their development using lower‐cost and greener materials is also increasingly investigated. From the precursor solutions and prenucleation state of perovskites to the fully crystallized materials, this disclosure provides key findings that benefit fundamental understanding for streamlining antisolvent quenching methods toward the development of high‐performance and stable flexible‐plastic PSCs under ambient atmospheric conditions. Evidencing the importance of the concurrent consideration of a series of antisolvent physical properties for a group of primary and secondary monohydric alcohols, a breakthrough achievement is attained. Mirror‐like, pinhole‐free, monolayered vertically‐aligned (high‐aspect‐ratio) grained and mechanically‐robust ambient‐air‐processed perovskite structures are developed using 2‐butanol as a non‐toxic and benign‐to‐plastics (evidenced by nano‐mechanics) antisolvent alternative to the reference chlorobenzene. To this end, a new literature record of 20.09% for scalable carbon‐based flexible PSCs is achieved (power‐to‐weight performance 1.05 Wg −1 , at 190 gm −2 ), also demonstrating highly‐robust unencapsulated devices under the ISOS‐D‐1 protocol conditions (T 85 >1000 h) and bending fatigue (T 80(5‐mm‐radius) >5000 bending cycles).