Yin Wenping, Li Hanchen, Chesman Anthony S R, Tadgell Ben, Scully Andrew D, Wang Mingchao, Huang Wenchao, McNeill Christopher R, Wong Wallace W H, Medhekar Nikhil V, Mulvaney Paul, Jasieniak Jacek J
ARC Centre of Excellence in Exciton Science, Monash University, Clayton 3800, Victoria, Australia.
Department of Materials Science and Engineering, Monash University, Clayton3800, Victoria, Australia.
ACS Nano. 2021 Jan 26;15(1):1454-1464. doi: 10.1021/acsnano.0c08794. Epub 2021 Jan 13.
The extensive use of halomethanes (CHX, X = F, Cl, Br, I) as refrigerants, propellants, and pesticides has drawn serious concern due to their adverse biological and atmospheric impact. However, there are currently no portable rapid and accurate monitoring systems for their detection. This work introduces an approach for the selective and sensitive detection of halomethanes using photoluminescence spectral shifts in cesium lead halide perovskite nanocrystals. Focusing on iodomethane (CHI) as a model system, it is shown that cesium lead bromide (CsPbBr) nanocrystals can undergo rapid (<5 s) halide exchange, but only after exposure to oleylamine to induce nucleophilic substitution of the CHI and release the iodide species. The extent of the halide exchange is directly dependent on the CHI concentration, with the photoluminescence emission of the CsPbBr nanocrystals exhibiting a redshift of more than 150 nm upon the addition of 10 ppmv of CHI. This represents the widest detection range and the highest sensitivity to the detection of halomethanes using a low-cost and portable approach reported to date. Furthermore, inherent selectivity for halomethanes compared to other organohalide analogues is achieved through the dramatic differences in their alkylation reactivity.
卤代甲烷（CHX，X = F、Cl、Br、I）作为制冷剂、推进剂和杀虫剂被广泛使用，因其对生物和大气的不利影响而备受关注。然而，目前尚无用于检测它们的便携式快速准确监测系统。这项工作介绍了一种利用卤化铯铅钙钛矿纳米晶体中的光致发光光谱位移来选择性和灵敏地检测卤代甲烷的方法。以碘甲烷（CHI）作为模型系统，研究表明溴化铯铅（CsPbBr）纳米晶体能够快速（<5秒）进行卤化物交换，但前提是要先暴露于油胺中，以引发CHI的亲核取代并释放出碘化物。卤化物交换的程度直接取决于CHI的浓度，在添加10 ppmv的CHI后，CsPbBr纳米晶体的光致发光发射出现超过150 nm的红移。这代表了迄今为止报道的使用低成本便携式方法检测卤代甲烷时最宽的检测范围和最高的灵敏度。此外，通过卤代甲烷与其他有机卤化物类似物在烷基化反应活性上的显著差异，实现了对卤代甲烷的固有选择性。
