Cu-Pd Bimetal and CuPt Alloy Nanotubes Derived From Cu Nanowires: Novel Amplification Media for Surface-Enhanced Raman Spectroscopy

Abstract

Surface-plasmons of metals have been utilized to enhance the Raman spectra of various adsorbed moieties for over decades. While amplification of the spectral intensity takes place on most of the metals, due to their superb properties, Au, Ag and Cu surfaces represent the benchmark in surface-enhanced Raman spectroscopy. In this paper, we show that Cu-Pd bimetal and CuPt alloy nanotubes derived from Cu nanowires by simple galvanic exchange reactions are suitable for the efficient enhancement of Raman spectra when dispersed on Si surfaces. Amplification factors of 120× on Cu nanowires, 150× on Cu-Pd bimetal nanotubes and 250× on CuPt alloy nanotubes in reference to the substrate are measured for rhodamine 6G and methyl violet model compounds. We also show that the nanotubes dispersed on Au surfaces can contribute to a further intensity enhancement of the substrate and detect analytes adsorbed from 10-6 M analyte concentrations. Our results obtained using bimetallic and alloy nanomaterials shed light on a new strategy to synthetize and apply new types of metal nanostructures and compositions for surfaceenhanced Raman spectroscopy in the future.

Active site-dominated electromagnetic enhancement of surface-enhanced Raman spectroscopy (SERS) on a Cu triangle plate

“…18 As the large smooth surface is not conducive to the enhancement of Raman scattering, chemical bottom-up colloid systems are investigated to improve the SERS application. 19 The morphology, roughness, and cluster aggregation of different copper materials may lead to distinguishing from enhancement factors (EFs). 20,21 Spherical-and rod-copper nanoparticles surface modied by poly(allylamine) were used as SERS-active substrates with EFs in the order of 10 4 .…”