Pulsed laser deposition of Ag nanoparticles on titanium hydroxide/oxide nanobelt arrays for highly sensitive surface-enhanced Raman spectroscopy

Surface-enhanced Raman scattering (SERS) substrate of Ti(OH)4 nanobelt arrays (NBAs) was synthesized by a hydrothermal reaction, on which silver nanoparticles (NPs) were deposited by pulsed laser deposition (PLD). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed the effective high specific surface area with silver NPs decorated on three-dimensional NBAs. Using rhodamine 6G (R6G) as an analyte molecule, the highest enhancement factor of 106 and a maximum relative standard deviation (RSD) of 0.18 were obtained. It has been found that the specific morphology of these composite nanobelt arrays and the formation of Ag2O play important role for the high sensitivity Raman phenomenon. In addition, the surface plasmon resonance wavelength of Ag decorated Ti(OH)4 NBAs and the charge transfer from Ag NPs are also responsible for the enhancement ability. For comparison SERS was investigated with silver particles decorated on TiO2 NBAs, which is much less active.