Pulsed laser deposited Ag nanoparticles on nickel hydroxide nanosheet arrays for highly sensitive surface-enhanced Raman scattering spectroscopy

In the present work, silver nanoparticles (NPs) were deposited on nickel hydroxide nanosheet (NS) arrays by pulsed laser deposition (PLD) for surface-enhanced Raman scattering (SERS) spectroscopy. The effective high specific surface area with silver NPs decorated on the NS arrays was revealed by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The microstructure and optical property of this three-dimensional (3D) substrate were investigated by X-ray diffraction (XRD) and UV-vis spectra, respectively. Using rhodamine 6G (R6G) as probe molecules with the concentration down to 10−5 M, the Ag/Ni(OH)2 composite film exhibits very high Raman scattering enhancement ability, possessing an enhancement factor as high as 5 × 106. It has been found that the enhancement ability of the substrate was strongly dependent on the size and interparticle gap of Ag NPs rather than the testing position on the film surface. In addition, the 3D structure of Ni(OH)2 NS arrays and the charge transfer of Ag NPs may be responsible for this high sensitivity Raman phenomenon.