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

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 CsPbBr₃ 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 CsPbBr₃ 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 {PbBr₆}⁴⁻ octahedra and the consequential increase of the bond length of Pb-Br₃ and the Pb-Br₃-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.