The Strain‐Modulated Single‐Mode Laser of Perovskite Microsheets with Grooves on Ultrathin Flexible Mica

Abstract Inorganic perovskites have become a widely investigated candidate for fabrication of high‐performance micro‐devices due to their excellent optoelectronic properties and stability to the environment. Especially, their excellent lasing characteristics as a micro/nanolaser source, combined with flexible substrates, have great potential in the field of wearable or foldable photonic device applications. Here, the high‐quality CsPbBr 3 perovskite microsheets with stress‐induced grooves are directly prepared on the ultrathin fluorine mica by the chemical vapor deposition method, and the single‐mode lasers are realized in these large‐size (>15 × 15 µm) microsheets. Thanks to the flexibility of mica, bending induced tensile strain on CsPbBr 3 microsheet causes the laser mode blueshift continuously and reversibly with 15.3 meV % −1 , this can be well explained by the Lorentz oscillator model under lasing conditions. Furthermore, by using the first‐principles calculation, it is clarified that the bandedge blueshift originates from the distortion of {PbBr 6 } 4− octahedra and the consequential increase of the bond length of Pb‐Br 3 and the Pb‐Br 3 ‐Pb bond angle. This work opens up a new way to realize on‐chip single‐mode lasers with microstructures, and is helpful for the application of flexible photonic device in the fields of integrated on‐chip sensors.