Detection of Halomethanes Using Cesium Lead Halide Perovskite Nanocrystals

The extensive use of halomethanes (CH3X, X = F, Cl, Br, I) as refrigerants, propellants, and pesticides has drawn serious concern due to their adverse biological atmospheric impact. However, there are currently no portable rapid accurate monitoring systems for detection. This work introduces an approach the selective sensitive detection using photoluminescence spectral shifts in cesium lead halide perovskite nanocrystals. Focusing on iodomethane (CH3I) a model system, it is shown that bromide (CsPbBr3) nanocrystals can undergo (<5 s) exchange, but only after exposure oleylamine induce nucleophilic substitution CH3I release iodide species. extent exchange directly dependent concentration, with emission CsPbBr3 exhibiting redshift more than 150 nm upon addition 10 ppmv CH3I. represents widest range highest sensitivity low-cost reported date. Furthermore, inherent selectivity compared other organohalide analogues achieved through dramatic differences alkylation reactivity.