Rapid synthesis and optical properties of CsPbBr₂Cl perovskite nanolasers

Nanostructures able to generate laser emission in a broad spectral range of 420-820 nm have become highly demanded objects for nanophotonic and optoelectronic applications such as photonic integrated circuits and ultrasensitive Fabry-Pérot nanosensors. The latter require high quality factors (Q) of stimulated emission which can be achieved in cesium lead halide perovskite nanowires (NWs). In this regard, it is difficult to underestimate the relevance of their rapid and scalable synthesis at ambient conditions. In this work we study optical properties of high-quality CsPbBr₂Cl NWs emitting in the 510-520 nm range manufactured by spraying at ambient conditions. The mechanism of NWs formation is based on their ligand-assisted reprecipitation (LARP). Ligands that form bonds with surface Pb atoms and, hence, prevent agglomeration of perovskite crystallites are supposed to be chosen according to the size of the certain perovskite unit cell. This approach allows obtaining numerous separate nanowires with lateral sizes of less than 1 μm and lengths of 2-50 μm. When the NWs are pumped with UV pulsed excitation above the lasing threshold (P ≈ 55 μJ cm^-2) they exhibit high-quality stimulated emission with Q-factors at lasing modes up to 5600.