Facile Shape-Controlled Fabrication of Copper Nanostructures on Borophosphate Glasses: Synthesis, Characterization, and Their Highly Sensitive Surface-Enhanced Raman Scattering (SERS) Properties

We demonstrate air-stable
copper-doped nanostructured borophosphate
samples, which were prepared by a facile, low cost, and green synthesis
method. The thermal annealing, in a reducing hydrogen atmosphere,
enables the formation of metallic copper nanostructures, which was
confirmed by X-ray powder diffraction (XRD), scanning electron microscopy
(SEM), and optical absorption. The optical spectra show a main intense
surface plasmon resonance (SPR) band centered at 579 nm. The shapes
of the nanostructures, morphology, and thickness of the copper nanostructures
coating are chosen to be suitable for SERS applications. These samples
exhibited very high SERS enhancement factors (EF), depending on thermal
annealing time, with excellent reproducibility. The estimated EFs
have been found in the range between 107 and 108.