AIE featured copper nanoclusters encapsulated in ZIF-8 for sensing Hg2+ and visualizing latent fingerprint

AIE featured CuNCs@ZIF-8 was constructed with blue fluorescence in aqueous solution. • The CuNCs@ZIF-8 probe detecting Hg 2+ via a turn-on response with LOD of 30 nM. • The probe enabled reliable detection of Hg 2+ in real samples. • CuNCs@ZIF-8 powder achieved the visualization of fingerprint with third level. Mercury ions (Hg 2+ ) as the most toxic heavy metal, poses serious threat to human health, environment and ecosystem. Therefore, the development of precise, convenient and portable fluorescent probe for the real-time monitoring Hg 2+ has become imperative. Here, the aggregation-induced emission (AIE) featured copper nanoclusters (CuNCs) encapsulated in a zeolitic imidazolate framework (ZIF-8) (CuNCs@ZIF-8) were fabricated and exhibited bright blue emission, AIE property, excellent water solubility, and stability. The emission of CuNCs enhanced more than 6 folds after encapsulating into ZIF-8 validating the AIE feature, with quantum yield of 11.49% and lifetime of 9.67 μs. The enhancement of fluorescence can be deduced originating from the restricted intramolecular motion of CuNCs confined within the rigid ZIF-8. Notably, the CuNCs@ZIF-8 exhibited highly selective response toward Hg 2+ , and the limit of detection was determined at 30 nM. Spectroscopic investigations revealed that the fluorescence enhancement was not caused by generation of new emissive species or typical charge-transfer processes. This behavior can be attributed to the combined influence of Hg 2+ -CuNCs interactions and the confinement effect of the ZIF-8 framework, suppressed non-radiative decay and promoted AIE emissions. With the excellent selectivity and stability, the CuNCs@ZIF-8 was successfully applied for monitoring Hg 2+ in real water samples with satisfactory recoveries. The robust emission of the CuNCs@ZIF-8 enabled its utilization in visualizing latent fingerprint, providing high-resolution recognition of level 3 features. In general, this work offered a feasible strategy underscoring its great potential for multiple applications with practicality and reliability in environmental monitoring and forensic analysis. Download: Download high-res image (338KB) Download: Download full-size image