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

A quasi Fabry-Perot (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 x 10(6), 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.