Cooperative enhancement mechanisms in a coral-inspired SERS substrate for real-time contaminant detection

Surface-enhanced Raman scattering (SERS) is valuable in environmental monitoring, biochemistry, and food safety. However, conventional SERS substrates are limited by non-uniform hot spot distribution, low molecular capture efficiency, and inadequate stability. This study introduces a nitrogen (N)-doped coral-like graphene/silicon (Si) substrate created using a dual biomimetic approach inspired by coral structures. By in-situ growing vertically aligned three-dimensional branched N-doped graphene arrays on a Si substrate, the structure exhibits an ultra-large specific surface area (85% porosity) and abundant active sites, enhancing molecular capture. Simulations and analyses demonstrate that the resulting biomimetic structure supports broadband plasmon resonance, creating an electromagnetic hot spot for localized field amplification. The hierarchical porosity facilitates the capture of molecules, while N doping enhances charge transfer. The biomimetic substrate achieves detection limits as low as 10^-11 M for rhodamine 6G (R6G) and erythrosine B (EB), and 10^-10 M for the environmental pollutant crystal violet (CV), with a Raman enhancement factor (EF) of 5.8 × 10⁶. It shows excellent signal uniformity, relative standard deviation (RSD) < 5%, and retains over 95% activity after 5 detection cycles and 40 days of storage. This biomimetic substrate has successfully detected trace CV in river water samples without pretreatment, demonstrating robust anti-interference capabilities. This research introduces a biomimetic design for SERS substrates, enhancing functionality for better use in environmental monitoring and rapid analysis.