Hot Zone Empowered Highly Sensitive Surface-Enhanced Raman Scattering Analysis Using Au@HOF Nanoparticles

Metal–organic frameworks (MOFs)-based core–shell hybrid substrates have drastically progressed in developing surface-enhanced Raman spectroscopy (SERS) detection. However, these substrates still face reliability issues, owing to the random adsorption of targets onto the active metal center of the outer MOFs structure. Herein, a strategy for analyzing SERS called the "hot zone" empowered analysis has been presented. This strategy involves the preparation of core–shell structures by using hydrogen-bonded organic frameworks (HOFs). By coating the designed HOF structure onto a Au nanoparticle, the probe molecules were concentrated and preferentially accumulated on the hot zone of the plasmonic Au core instead of competitively adsorbing on the metal-free HOF shell. Experimental and theoretical investigations revealed that the excellent SERS performance of the as-prepared Au@HOF is attributed to the effective delivery of the analyte to the hot zone and its subsequent enhancement. Moreover, when the proposed Au@HOF film was fabricated as an SERS chip, it demonstrated reliability in detecting pesticide residues in a real system. This study may stimulate further research on the functionalization of HOFs for broader applications. Notably, the developed "hot zone" empowered strategy provides a scientific framework for advancing the development of SERS sensing.