posted on 2024-02-15, 09:29authored byYuting Ye, Jiqiang Wang, Zhuo Fang, Yongda Yan, Yanquan Geng
Surface-enhanced Raman spectroscopy
has emerged as a powerful spectroscopy
technique for detection with its capacity for label-free, nondestructive
analysis, and ultrasensitive characterization. High-performance surface-enhanced
Raman scattering (SERS) substrates with homogeneity and low cost are
the key factors in chemical and biomedical analysis. In this study,
we propose the technique of atomic force microscopy (AFM) scratching
and nanoskiving to prepare periodic folded gold (Au) nanostructures
as SERS substrates. Initially, folded Au nanostructures with tunable
nanogaps and periodic structures are created through the scratching
of Au films by AFM, the deposition of Ag/Au films, and the cutting
of epoxy resin, reducing fabrication cost and operational complexity.
Periodic folded Au nanostructures show the three-dimensional nanofocusing
effect, hotspot effect, and standing wave effect to generate an extremely
high electromagnetic field. As a typical molecule to be tested, p-aminothiophenol has the lowest detection limit of up to
10–9 M, owing to the balance between the electromagnetic
field energy concentration and the transmission loss in periodic folded
Au nanostructures. Finally, by precisely controlling the periods and
nanogap widths of the folded Au nanostructures, the synergistic effect
of surface plasmon resonance is optimized and shows good SERS properties,
providing a new strategy for the preparation of plasmonic nanostructures.