Ion beam sputtering deposition of silver nanoparticles and TiOx/ZnO nanocomposites for use in surface enhanced vibrational spectroscopy (SERS and SEIRAS)
1.Departamento de Química Analítica, Instituto Universitario de Investigación en Química Fina y Nanoquímica IUIQFN,Universidad de Córdoba,Córdoba,Spain;2.Institute of Analytical and Bioanalytical Chemistry,Ulm University,Ulm,Germany;3.Dipartimento di Chimica,Università degli Studi di Bari Aldo Moro,Bari,Italy;4.CNR-IFN and Dipartimento Interateneo di Fisica “Michelangelo Merlin”,Università degli Studi di Bari “Aldo Moro”,Bari,Italy;5.Dipartimento Interateneo di Fisica,Università degli Studi di Bari Aldo Moro,Bari,Italy
Abstract:
Hybrids consisting of silver nanoparticles (in varying fractions) and of TiOx/ZnO were prepared via top-down ion beam sputtering (IBS) deposition on silicon substrates. The deposited nanomaterials were characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. It is shown that such composites represent a viable substrate for use in both surface enhanced Raman spectroscopy (SERS) and surface enhanced infrared absorption spectroscopy (SEIRAS), as exemplarily shown for crystal violet as the model analyte. The C-H bending mode at about 1181 cm?1 and the C-N vibration at 1361 cm?1 observed in the SERS and SEIRAS spectra, respectively, have been used as analytical signal. The substrate consisting of TiOx NPs with 33% fraction of silver provides the strongest enhancement in SERS (up to 10,000-fold), while TiOx/AgNPs with thickness of 2 and 1 nm in ion beam sputtering, respectively, provides the best sensitivity in SEIRAS. The substrates also display photocatalytic activity as shown by the degradation of adsorbed crystal violet under ultraviolet irradiation.