Oxygen Incorporation-Induced SERS Enhancement in Silver Nanoparticle-Decorated ZnO Nanowires

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a sensitive and nondestructive technique used for the detection of molecules, traditionally applied on noble-metal or semiconductor substrates. Point defect introduction has been applied to increase the enhancement of semiconductor templates due to more efficient charge transfer; however, they are still limited by low detection sensitivity and inferior SERS enhancement. Here we propose a universal approach of oxygen incorporation into metal oxide nanowire/metal nanoparticle templates that allows for greater SERS enhancement due to localized surface plasmon resonance excitation, point defect-induced optical gap shrinking, and wettability change of the substrate. We report up to 5-fold Raman relative peak intensity enhancement after annealing-induced oxygen introduction. This approach is applied to defect formation in metal oxide semiconductor nanowires such as ZnO, WO 3 , TiO 2 , and NiO and is applicable for a wide variety of probe molecules, making the method suitable for medical, security, and environmental applications.

Latest Novelties on Plasmonic and Non-Plasmonic Nanomaterials for SERS Sensing

“…Figure 5 c displays the effect of the annealing temperature of Ag/ZnO nanowires on the SERS spectra of (meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (TMPyP) molecules. A LOD of 100 nM is found for TMPyP molecules with Ag/ZnO nanowires annealed at 200 °C (see Figure 5 d) [ 86 ].…”

“…( d ) SERS spectra of TMPyP recorded on Ag/ZnO nanowires annealed at 200 °C for various concentrations of TMPyP. Inset in ( d ) displays the whole spectrum with fluorescence signal that appears when the concentration is superior or equal to 10 −5 M. All the figures are reprinted (adapted) with permission from [ 86 ], Copyright 2020 American Chemical Society.…”

Oxygen Vacancy Dynamics in Highly Crystalline Zinc Oxide Film Investigated by PIERS Effect

“…In addition, the SERS effect is also very useful for studying the surface catalytic reactions in order to know their mechanism and their intermediate species involved in these reactions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In this SERS field, an alternative section has emerged named photo-induced enhanced Raman spectroscopy (PIERS), which gives the possibility of having supplementary chemical enhancement of the Raman signal compared to conventional SERS, by employing a photo-activated semiconductor substrate [ 17 , 18 , 19 , 20 ]. This supplementary chemical enhancement is due to the presence of surface oxygen vacancies (V ) created during the pre-irradiation of the semiconductor substrate by UV light [ 17 , 18 , 19 , 20 ].…”

“…In this SERS field, an alternative section has emerged named photo-induced enhanced Raman spectroscopy (PIERS), which gives the possibility of having supplementary chemical enhancement of the Raman signal compared to conventional SERS, by employing a photo-activated semiconductor substrate [ 17 , 18 , 19 , 20 ]. This supplementary chemical enhancement is due to the presence of surface oxygen vacancies (V ) created during the pre-irradiation of the semiconductor substrate by UV light [ 17 , 18 , 19 , 20 ]. In the literature, it is well-reported that UV light can allow the creation of defects/vacancies in different materials (nanostructured or not), such as metal oxides [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], silicon dioxide [ 25 , 26 ], and single-wall carbon nanotubes [ 27 ], for instance.…”

Enhanced efficient and sensitive SERS sensing via controlled Ag‐nanoparticle‐decorated 3D flower‐like ZnO hierarchical microstructure

“…In order to solve these problems, noble metal/semiconductor hybrid materials show stronger SERS signal benefiting from higher aspect ratio and surface area [9,10]. Up to now, ZnO with different nano-morphologies has been widely studied [11][12][13][14][15], such as nanorods, nanosheets, nanowires, nanospheres, nanotubes and nanoflowers [16][17][18][19]. Especially, Ag nanoparticles supported on ZnO carrier are attractive.…”