Stable and Low-threshold Whispering-Gallery-Mode Lasing from Modified CsPbBr3 Perovskite Quantum Dots@SiO2 Sphere

Abstract Miniaturized solid-state lasers have obtained great development for their outstanding properties. Among the optical gain materials discovered so far, CsPbBr3 perovskite quantum dots (QDs) have been recognized as one of the most promising candidates due to the direct bandgap, narrow emission linewidth and high quantum yield. Herein, we report the fabrication of whispering-gallery-mode (WGM) lasers from the unmodified CsPbBr3 QDs and the 2-hexyldecanoic acid (DA) modified CsPbBr3 QDs. Thanks to the strong binding energy between DA ligand and QDs, the modified CsPbBr3 QDs show much better optical properties than that of the common CsPbBr3 QDs. In comparison with the unmodified CsPbBr3 QDs, the lasing threshold of WGM lasers obtained from the modified CsPbBr3 QDs is decreased from 126.81 and 261.97μJ/cm2 to 5.47 and 88.49 μJ/cm2 under one-photon and two-photon pump excitation, respectively. Besides, WGM lasers based on the modified CsPbBr3 QDs demonstrate higher stability than that of common CsPbBr3 QDs WGM lasers under the same continuously pumping over ten hours. This work may not only enrich the application of the ligand modified CsPbBr3 QDs but also provide a strategy for the facile design of low-threshold WGM lasers.