Novel Ag/Au Nanocubes Modified the Negative/Positive Charge on the Surface and Their Application in Surface-Enhanced Raman Scattering

Abstract

Bimetallic nanostructures have received considerable attention in recent years due to their widespread use in applications such as photonics, catalysis and surface-enhanced Raman scattering (SERS) detection. In this work, a simple and effective strategy has been developed to synthesize Ag/Au@negative(COOˉ)-Ag/Au@positive(NH₃⁺ ) charge on the nanocubes’ (with hollow or porous structures) surfaces, based on a galvanic replacement reaction and co-reduction method of the corresponding ions. The prepared bimetallic Ag/Au@NH₃⁺-Ag/Au@COOˉ nanocubes have been characterized by UV–vis, TEM, and XRD. Our results show that the SERS technique is able to detect R6G within wide concentration range, i.e. 10⁻¹⁶ – 10⁻⁸ M, with lower limit of detection (LOD) being 10⁻¹⁶ M. It demonstrates that the Ag/Au@NH₃⁺-Ag/Au@COOˉ nanocubes have potential applications in SERS for the detection of biomolecules or dye molecules.