An effective surface-enhanced Raman scattering template based on a Ag nanocluster-ZnO nanowire array
ABSTRACT An effective surface-enhanced Raman scattering (SERS) template based on a 3D hybrid Ag nanocluster (NC)-decorated ZnO nanowire array was fabricated through a simple process of depositing Ag NCs on ZnO nanowire arrays. The effects of particle size and excitation energy on the Raman scattering in these hybrid systems have been investigated using rhodamine 6G as a standard analyte. The results indicate that the hybrid nanosystem with 150 nm Ag NCs produces a larger SERS enhancement factor of 3.2 x 10(8), which is much higher than that of 10 nm Ag NCs (6.0 x 10(6)) under 532 nm excitation energy. The hybrid nanowire arrays were further applied to obtain SERS spectra of the two-photon absorption (TPA) chromophore T7. Finite-difference time-domain simulations reveal the presence of an enhanced field associated with inter-wire plasmon coupling of the 150 nm Ag NCs on adjacent ZnO nanowires; such a field was absent in the case of the 10 nm Ag NC-coated ZnO nanowire. Such hybrid nanosystems could be used as SERS substrates more effectively than assembled Ag NC film due to the enhanced light-scattering local field and the inter-wire plasmon-enhanced electromagnetic field.
SourceAvailable from: Kundan SivashanmuganSensors and Actuators B Chemical 10/2014; 207:430-436. · 3.84 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: We report exciton and phonon properties of pure and Ag-modified ZnO nanostructures are prepared using solution-based refluxing route. X-ray diffraction studies show lower angle shift in the characteristic diffraction peaks of ZnO. Additional diffraction peaks related to nano-sized Ag were observed from XRD. Broad absorption band (which covers the 400–1000 nm range) results from surface plasmon resonance (SPR) absorption of metallic silver is observed from optical absorption studies. Enhancement in luminescence and Raman scattering is observed in Ag-modified sample when compared with pure ZnO sample. This is attributed to the presence of metallic Ag in the samples, and we attempted to understand the observed enhancement from the perspective of the local field associated with the metal nanoparticles.Plasmonics 03/2015; DOI:10.1007/s11468-015-9877-6 · 2.74 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: SnO2–ZnO nanocomposite thin films, prepared by a simple carbothermal reduction based vapor deposition method, were irradiated with 8 MeV Si3+ ions for engineering the morphological and optical properties. The surface morphology of the nanocomposites was studied by atomic force microscopy (AFM), while the optical properties were investigated by photoluminescence spectroscopy (PL) and Raman spectroscopy. AFM studies on the irradiated samples revealed growth of nanoparticles at lower fluence and a significant change in surface morphology leading to the formation of nanosheets and their aggregates at higher fluences. A tentative mechanism underlying the observed ion induced evolution of surface morphology of SnO2–ZnO nanocomposite is proposed. PL studies revealed strong enhancement in the UV emissions from the nanocomposite thin film at lower fluence, while a drastic decrease in the UV emissions along with a significant enhancement in the defect emissions has been observed at higher fluences.Ceramics International 03/2015; 637:119-126. DOI:10.1016/j.ceramint.2015.03.071 · 2.09 Impact Factor