Etched-spiky Au@Ag plasmonic-superstructure monolayer films for triple amplification of surface-enhanced Raman scattering signals

Abstract

Generally, a high quality surface-enhanced Raman spectroscopy (SERS) substrate often requires a highly-tailorable electromagnetic (EM) field generated at nanoparticle (NP) surfaces by the regulation of the morphologies, components and roughness of NPs. However, most recent universal approaches are restricted to single components, and integrating these key factors into one system to achieve the theoretically maximum signal amplification is still challenging. Herein, we design a triple SERS signal amplification platform by the coordination of spiky Au NPs with rich-tip nanostructures, controllable silver nanoshell, as well as tailorable surface roughness into one nano-system. As a result, the theoretical electromagnetic field of the interfacial self-assembled 2D substrate can be improved by nearly 5 orders of magnitude, and the ideal tracing capability for the model SERS molecule can be achieved at levels of 5 × 10⁻¹¹ M. Finally, diverse analytes in pesticide residues, environmental pollutants as well as medically diagnose down to 10⁻¹¹ M and can be fingerprinted by the proposed SERS nano-platform. Our integrated triple amplification platform not only provides an effective SERS sensing strategy, but also makes it possible to simultaneously achieve high sensitivity, stability as well as universality into one plasmonic-based SERS sensing system.