Stable Core–Shell Structure Nanocrystals of Cs4PbBr6-Zn(moi)2 Achieved by an In Situ Surface Reconstruction Strategy for Optical Anticounterfeiting
Zero-dimensional Cs4PbBr6 nanocrystals (NCs) possess attractive photoluminescence (PL) properties and feature facile chemical synthesis, making them promising for application in luminescent materials. However, Cs4PbBr6 remains sensitive to polar solvents and thermal stimuli because of soft ionic nature of Cs4PbBr6 and dynamic behavior of surface ligands. Herein, a strategy controlled by an in situ surface coordination reaction is developed to fabricate stable NCs with a Cs4PbBr6-Zn(moi)2 core–shell structure. It was found that the Cs4PbBr6 surface regulated by the use of 2-mercaptoimidazole (called moi) and the coordination between the −NH group of moi and Zn2+ is critical for the formation of Cs4PbBr6-Zn(moi)2 core–shell NCs. Meanwhile, the thickness of the Zn(moi)2 shell can be facilely controlled by the growth time because of the solubility of moi and Zn(OAc)2·2H2O in ethyl acetate. Compared to bare Cs4PbBr6, Cs4PbBr6-Zn(moi)2 NCs exhibited highly improved polar solvent resistance and thermal stability. By combining the sensitivity of Cs4PbBr6 and the stability of Cs4PbBr6-Zn(moi)2, we used two NCs as PL security inks to fabricate optical anticounterfeiting labels. Thus, the disposable or reusable optical anticounterfeiting label is achieved by changing the external dual-stimuli. This work provides a novel strategy to enhance the stability of Cs4PbBr6 and develop its potential interest for application in anticounterfeiting technologies.
危险品化学品经营许可证（带存储）