Raman-Inactive Metal–Organic Framework Nanoribbons as Plasmonic-Nanocavity Spacers and Molecular Trappers for SERS Detection

The integration of plasmonic nanostructures with metal–organic frameworks (MOFs) has emerged as a powerful strategy to enhance the sensitivity and selectivity of surface-enhanced Raman spectroscopy (SERS). While the resultant hybrid systems exploit localized surface plasmon resonance for electric-field enhancement and MOF porosity for molecular enrichment, their practical applications are hindered by challenges, including intrinsic Raman interference from MOFs, precise control over MOF dimensions, and restricted plasmon coupling configurations. Herein we present a promising design featuring Raman-inactive MOF nanoribbons embedded within plasmonic nanogaps between a gold film and gold nanospheres (NSs). The sub-10 nm MOF interlayer eliminates Raman background while maximizing electromagnetic enhancement. The resultant Au-film/MOF/NSs architecture enables remarkable SERS performances with enhancement factors of 1010 across diverse molecular sizes. This work not only enriches the toolbox of MOF-based plasmonic sensing platforms, but also opens the way for further exploration into other Raman-inactive MOFs and mechanisms.