A Two‐Dimensional Ruddlesden–Popper Perovskite Nanowire Laser Array based on Ultrafast Light‐Harvesting Quantum Wells

Abstract Miniaturized nanowire nanolasers of 3D perovskites feature a high gain coefficient; however, room‐temperature optical gain and nanowire lasers from 2D layered perovskites have not been reported to date. A biomimetic approach is presented to construct an artificial ligh‐harvesting system in mixed multiple quantum wells (QWs) of 2D‐RPPs of (BA) 2 (FA) n−1 Pb n Br 3n+1 , achieving room‐temperature ASE and nanowire (NW) lasing. Owing to the improvement of flexible and deformable characteristics provided by organic BA cation layers, high‐density large‐area NW laser arrays were fabricated with high photostability. Well‐controlled dimensions and uniform geometries enabled 2D‐RPPs NWs functioning as high‐quality Fabry–Perot (FP) lasers with almost identical optical modes, high quality (Q) factor (ca. 1800), and similarly low lasing thresholds.