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Single sea urchin-MoO3 nanostructure for surface enhanced Raman spectroscopy of dyes.
Prabhu B R
,
Bramhaiah K
,
Singh KK
,
John NS
.
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Enhancing the surface-enhanced Raman scattering (SERS) activity of semiconductor metal oxide nanostructures by controlling the morphology and oxygen vacancies towards trace detection of organics is of significant interest. In this study, MoO3 with a novel sea urchin morphology is synthesized employing chemical bath deposition and consists of hundreds of ∼15 μm long spikes originating from the core forming 20-40 micron globular structures. The spikes taper to form 20 nm sharp tips. SERS of rhodamine 6G (R6G) over MoO3 sea urchins has been investigated and compared to that of 1D h-MoO3 nanorod arrays. The SERS activity is morphology dependent and the sea urchin-like morphology exhibits higher SERS activity with an enhancement factor (EF) of the order 105 and a detection limit of 100 nM, while for h-MoO3 nanorods, the corresponding values are 103 and 1 μM, respectively. X-ray photoelectron spectroscopy reveals a high concentration of Mo+5 states in sea urchins indicating lattice oxygen vacancies. The observed EF is quite high for a metal oxide substrate and is attributed to the enhanced charge transfer between analyte molecules and the substrate promoted by the oxygen vacancies along with surface defects and hydroxyl groups on MoO3 sea urchins providing more active sites for the adsorption of probe molecules. The role of oxygen vacancies is confirmed by the lower EF value exhibited by the stoichiometric 1D h-MoO3. Raman mapping of a single sea urchin is achieved with good R6G intensity and indicates that the tips of spiky features are involved in SERS enhancement. The reusability of substrates is shown for repeated cycles of R6G adsorption by UV irradiation exploiting the photocatalytic activity of MoO3 nanostructures.
Fig. 1. (a) FESEM images of MoO3 sea urchins on a Si substrate synthesized by chemical bath deposition, (b) magnified image of a single MoO3 sea urchin; inset shows the EDS spectra and (c) EDS composite map of Mo L (red) and O K (green) levels from a single sea urchin. Yellow colour is seen due to the overlap of green and red in the same region (see Fig. S3†).
Fig. 2. XRD pattern of MoO3 sea urchin structures.
Fig. 3. (a) FTIR spectra and (b) Raman spectra of the as-synthesized MoO3 sea urchin micro-nanostructures (♦ α-MoO3 and ● MoO3·0.33H2O).
Fig. 4. TEM images of MoO3 sea urchins: (a) low magnification image; inset shows the complete view of one sea urchin. (b) High magnification image of (a), (c) HRTEM image of a spine and (d) SAED pattern from the spines of sea urchins.
Fig. 5. XPS of MoO3 sea urchin structures: (a) Mo 3d and (b) O 1s spectra.
Fig. 6. (a) SERS spectra of 1 mM R6G coated on various substrates on bare glass, h-MoO3 nanorods/Si and MoO3 sea urchins/glass and (b) Raman band intensity bar diagram (* denotes α-MoO3 Raman peaks).
Fig. 7. (a) SERS spectra of various concentrations of R6G coated on MoO3 sea urchin structures (* denotes α-MoO3 signatures) and (b) plot of R6G concentration versus Raman peak intensity (612 cm−1 and 1358 cm−1).
Fig. 8. SERS intensity mapping of 100 μM R6G adsorbed on a single sea urchin MoO3 (a) 612 cm−1 peak (green); inset shows the optical image of a single MoO3 sea urchin with R6G (b) 1358 cm−1 peak (blue) and (c) SERS spectra of R6G in the tip and middle regions of the MoO3 sea urchin nanostructures.
Fig. 9. Raman intensity bar diagram of 612 cm−1 and 1358 cm−1 peaks of R6G in the spike region of various MoO3 sea urchins across the substrate at 10 random positions.
Fig. 10. MoO3 sea urchins as renewable SERS substrates: (a) SERS of 100 μM R6G before and after UV treatment and (b) reusability of MoO3 sea urchin substrates for 100 μM R6G tested for five runs before and after UV treatment (* denotes α-MoO3 peaks).
Bate,
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Bate,
Micelle-Directing Synthesis of Ag-Doped WO3 and MoO3 Composites for Photocatalytic Water Oxidation and Organic-Dye Adsorption.
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Bramhaiah,
Films of Reduced Graphene Oxide with Metal Oxide Nanoparticles Formed at a Liquid/Liquid Interface as Reusable Surface Enhanced Raman Scattering Substrates for Dyes.
2017,
Pubmed
Cong,
Noble metal-comparable SERS enhancement from semiconducting metal oxides by making oxygen vacancies.
2015,
Pubmed
,
Echinobase
Diaz-Droguett,
One-step synthesis of MoO3 and MoO3-x nanostructures by condensation in gas: effect of the carrier gas.
2010,
Pubmed
Dong,
Local and remote charge-transfer-enhanced Raman scattering on one-dimensional transition-metal oxides.
2010,
Pubmed
Jensen,
Resonance Raman scattering of rhodamine 6G as calculated using time-dependent density functional theory.
2006,
Pubmed
Kavitha,
Improved surface-enhanced Raman and catalytic activities of reduced graphene oxide-osmium hybrid nano thin films.
2017,
Pubmed
Klimov,
Mechanisms for photogeneration and recombination of multiexcitons in semiconductor nanocrystals: implications for lasing and solar energy conversion.
2006,
Pubmed
Liang,
Interfacial synthesis of a three-dimensional hierarchical MoS2-NS@Ag-NP nanocomposite as a SERS nanosensor for ultrasensitive thiram detection.
2017,
Pubmed
Lin,
Surface-enhanced Raman spectroscopy: substrate-related issues.
2009,
Pubmed
Lin,
Ultrasensitive SERS Detection by Defect Engineering on Single Cu2 O Superstructure Particle.
2017,
Pubmed
Liu,
Reaction pathway and free-energy barrier for reactivation of dimethylphosphoryl-inhibited human acetylcholinesterase.
2009,
Pubmed
Liu,
Novel Fabrication and Enhanced Photocatalytic MB Degradation of Hierarchical Porous Monoliths of MoO3 Nanoplates.
2017,
Pubmed
Musumeci,
SERS of semiconducting nanoparticles (TiO(2) hybrid composites).
2009,
Pubmed
Park,
Novel fabrication of Ag thin film on glass for efficient surface-enhanced Raman scattering.
2006,
Pubmed
Schlücker,
Surface-enhanced Raman spectroscopy: concepts and chemical applications.
2014,
Pubmed
Sreedhara,
Synthesis, characterization, and properties of few-layer MoO3.
2013,
Pubmed
Tan,
Noble-Metal-Free Materials for Surface-Enhanced Raman Spectroscopy Detection.
2016,
Pubmed
Tan,
Plasmonic MoO3-x@MoO3 nanosheets for highly sensitive SERS detection through nanoshell-isolated electromagnetic enhancement.
2016,
Pubmed
Tan,
Three dimensional design of large-scale TiO(2) nanorods scaffold decorated by silver nanoparticles as SERS sensor for ultrasensitive malachite green detection.
2012,
Pubmed
Wang,
Remarkable SERS Activity Observed from Amorphous ZnO Nanocages.
2017,
Pubmed
Wang,
Enhanced Raman scattering as a probe for 4-mercaptopyridine surface-modified copper oxide nanocrystals.
2007,
Pubmed
Wu,
Metal oxide semiconductor SERS-active substrates by defect engineering.
2017,
Pubmed
Zong,
Surface-Enhanced Raman Spectroscopy for Bioanalysis: Reliability and Challenges.
2018,
Pubmed