Cost-effective nanorough black nickel-based SERS substrates with statistically validated spatial uniformity
Year: 2026
Type: preprint
Abstract: Reliable surface-enhanced Raman scattering (SERS) substrates must combine high enhancement with spatially uniform and reproducible responses. Here, hierarchical rough black nickel (b-Ni) substrates were fabricated by electrodeposition and acid etching and coated with Ag or Au layers (5–50 nm). Their SERS performance was systematically evaluated using 4-mercaptobenzoic acid (4-MBA) and large-area Raman mapping (1.5 × 1.5 mm 2 ; 900 spectra per substrate), supported by statistical analysis of signal intensity, spatial variability, response distribution, and inter-band correlation. Metrics included median signed band areas, relative standard deviation (RSD), the median absolute deviation (MAD)-based coefficient of variation, the contribution of the 10% highest-response positions to the total positive response, and Spearman’s rank correlation coefficient. Ag-coated b-Ni substrates exhibited substantially stronger and more spatially uniform enhancement than Au-coated substrates, with performance increasing with Ag thickness. The 50 nm b-Ni/Ag architecture provided the optimal combination of signal strength and spatial reproducibility. Control experiments with bare b-Ni and flat Ag and Au films deposited on polished silicon confirmed that the enhancement arises from the synergistic effect of hierarchical b-Ni micro/nanoroughness and the plasmonic noble-metal coating. These results establish Ag-coated b-Ni as a simple, low-cost, and scalable platform for robust SERS measurements, reducing the need for extensive spatial screening.
Source: ChemRxiv
Institution: University of Eastern Finland
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Award: G6538831658
OpenAlex ID: W7223313083