SERS Spectroscopy Used To Study an Adsorbate on a Nanoscale Thin Film of CuO Coated with Ag

Abstract

In this work, 5, 15, and 30 nm Ag island films over CuO thin films (AgFOCuF) were prepared as SERS substrates. The spectra of 4-mercaptopyridine (4-Mpy) adsorbed on these AgFOCuF and bare Ag island films are compared. The Raman spectrum of a bare 5 nm Ag island film is weak. However, the Raman signal of 4-Mpy from 5 nm AgFOCuF substrate is enhanced and can be readily ascribed to surface plasma resonance of silver and charge transfer between the silver and CuO nanoparticles. Moreover, the difference between the spectra of 4-MPY adsorbed on CuO film partially covered with Ag island film and CuO film entirely covered with Ag film confirms that the observed Raman scattering arises from the interaction between CuO film and Ag island film.

Analysis on superhydrophobic silver decorated copper Oxide nanostructured thin films for SERS studies

“…6(a)) shows a high symmetry corresponding to the position of Cu 2p1/2 and Cu 2p3/2 peaks centered at the binding energy values of 954.3 and 934.2 eV, respectively. The calculated difference in binding energy (23 eV) corresponds to the characteristic value for CuO and the absence of binding energy peaks of metallic Cu confirms the existence of Cu in oxidized states only [24]. The XPS curves of Ag 3d region in Fig.…”

“…When silver nanoparticles come into contact with a p-type semiconductor (CuO), electrons flow from Ag to CuO for the equilibration state of the fermi level between the two. This phenomenon occurs because the work functions of Ag (4.1 eV) [25] is lower than that of CuO (5.3 eV) [24]. It also deforms the bands (valence and conduction) of CuO to move relatively down to the fermi level.…”

“…11(a)) due to the silver deposition where the Inter silver nanoparticles give larger enhancement [30]. Also, a depletion layer may be formed at the interface between CuO and Ag due to the different work functions [24], which reduces the rate of recombination. Thus, charge transfer occurs from Ag to CuO with 514 nm excitation.…”

Efficient surface enhanced Raman scattering from Cu2O porous nanowires transformed from CuO nanowires by plasma treatments

“…On the other hand, semiconductors generally show much weaker SERS effects than metals, which are attributed to fewer free electrons being available for resonance, and this is the reason for the decrease in enhancement factors of SERS. From previously reported SERS measurements of CuO and Cu 2 O substrates [24,29], no enhancement of Raman signals was detected, and the enhancement of Raman intensity was less than one for both substrates. However, the Cu 2 O porous nanowires prepared in this work show strong Raman scatterings and the maximum enhancement factor is around 73.8.…”

Monoclinic Copper(I) Selenide Nanocrystals and Copper(I) Selenide/Palladium Heterostructures: Synthesis, Characterization, and Surface‐Enhanced Raman Scattering Performance

“…Thus, the combination of metal nanoparticles with semiconductors to form heterostructures is an effective approach to enhance SERS activity as a result of the synergetic effects between the components. [18,31,32] Several new types of hybrid SERS substrates, such as ZnO/Ag, [18,33] Ag 2 S/Ag, [26] and Cu 2 S/Ag, [32] have been prepared in recent years. Copper selenides exhibit particular optical, superionic, thermoelectric, and photoelectric properties and considerable progress has been made on their applications in electronic and optoelectronic devices.…”