Coconcentration/Colocation Effects of Quasi Fabry–Pérot Cavity Structure with Anti‐Interference Feature on Light and Analytes: Accurate Raman Detection of Hg²⁺ under Diverse Real Environments

Abstract

A quasi Fabry–Pérot (F–P) cavity structure of zinc oxide/sliver nanowires coated with zeolitic imidazolate framework‐8 (ZnO/Ag NWs/ZIF‐8) is designed to precisely guide target analytes into the hotspot zones while hindering the entry of various potential interferents during Raman detection. Owing to the triple synergistic effect of the ZIF‐8 dielectric F–P cavity, ZIF‐8 microsponge, and backward light scattering caused by the ZnO/Ag NW tip, the structure of ZnO/Ag NWs/ZIF‐8 is verified to have unique coconcentration and colocation effects on light and analytes. The molecular sieving effect of the ZIF‐8 layer and the selectivity of the premodified reporter probe on ZnO/Ag NWs endow the ZnO/Ag NWs/ZIF‐8 with an important anti‐interference feature for diverse interferents in practical Raman detection of heavy‐metal ions. The analytical enhancement factor of ZnO/Ag NWs/ZIF‐8 is as high as 3.97 × 106, with a limit of detection for Hg2+ reaching 10−10 M; and the relative standard deviation is only 6.03%. The structure directly and successfully attains accurate Raman detection of diverse real samples containing Hg2+, without an additional pre‐extraction process. This research provides a novel way of improving Raman detection reliability under real scenarios and is a new attempt to precisely manipulate light and analytes by controlling the dielectric.

In Situ Detection of Organic Pollutants in Multiphase Solution Using Surface-Enhanced Raman Spectroscopy with PDMS/Grating/CuO NWs/Ag NP Multiscale Structure

“…17−19 EM is induced by the surface plasmon resonance, which can effectively enhance the local electric field, and is the main source of enhancement for most SERS substrates with enhancement factors (EF) of up to 10 6 −10 8. 20,21 CM can be attributed to the charge transfer between the SERS substrate and the probe molecules and is relatively weak with enhancement factors of 10 2 −10 4 . 22,23 With the assistance of the EM, noble metal nanoparticles (NPs) are widely used as SERS substrates.…”

“…Surface-enhanced Raman spectroscopy (SERS), a powerful spectral analysis technology by virtue of its ultrasensitivity and nondestruction, can specifically identify analyte molecules. − It has been widely applied in many fields such as biological sensing, , medical diagnostics, , chemical analysis, , environmental testing, , and food security. , It is generally accepted that the SERS enhancement mechanisms include electromagnetic mechanism (EM) and chemical mechanism (CM). − EM is induced by the surface plasmon resonance, which can effectively enhance the local electric field, and is the main source of enhancement for most SERS substrates with enhancement factors (EF) of up to 10 6 –10 8. , CM can be attributed to the charge transfer between the SERS substrate and the probe molecules and is relatively weak with enhancement factors of 10 2 –10 4 . , …”