Highly sensitive multiplex-detection of surface-enhanced Raman scattering via self-assembly arrays of porous AuAg nanoparticles with built-in nanogaps

ABSTRACT Designing and fabricating highly dense porous nanoparticles (p-NPs) arrays with nanogaps are crucial for ultra-sensitive surface-enhanced Raman scattering (SERS) detection as they can provide both abundant built-in and inter nanogap-induced hotspots. Here, we demonstrate highly sensitive multiplex-detection of organic dyes using SERS substrates with the self-assembly arrays of porous AuAg alloy (p-AuAg) NPs. The p-AuAg NPs were fabricated by a thermal dewetting method of very thin Au/Ag bilayers and a subsequent dealloying approach, which result in multiple built-in and inter nanogaps between the nano-granules with a porous structure and the adjacent NPs as well as excellent porosity and a high surface-to-volume ratio. The SERS substrates with p-AuAg NPs for the detection of Rhodamine 6 G (R6G) molecules exhibited an excellent enhancement factor of approximately 7.8 × 106, good reproducibility with relative standard deviation