Poly(catecholamine) Coated CsPbBr <sub>3</sub> Perovskite Microlasers: Lasing in Water and Biofunctionalization
Sangyeon Cho, Seok Hyun Yun
Abstract
Abstract Lead halide perovskite (LHP) is a promising material for various optoelectronic applications. Surface coating on particles is a common strategy to improve their functionality and environmental stability, but LHP is not amenable to most coating chemistries because of its intrinsic weakness against polar solvents. Here, a novel method of synthesizing LHP microlasers in a super‐saturated polar solvent using sonochemistry and applying various functional coatings on individual microlasers in situ is described. Cesium lead bromine perovskite (CsPbBr 3 ) microcrystals, capped with organic poly‐norepinephrine (pNE) layers, are synthesized. The catechol group of pNE coordinates to bromine‐deficient lead atoms, forming a defect‐passivating and diffusion‐blocking shell. The pNE layer enhances the material lifetime of CsPbBr 3 in water by 2000‐fold, enabling bright luminescence and lasing from single microcrystals in water. Furthermore, the pNE shell permits biofunctionalization with proteins, small molecules, and lipid bilayers. Luminescence from CsPbBr 3 microcrystals is sustained in water over 1 h and observed in live cells. The functionalization method may enable new applications of LHP laser particles in water‐rich environments.