WO 3 Nanopores Array Modified by Au Trisoctahedral NPs: Formation, Characterization and SERS Application.

The WO ₃ nanopores array was obtained by an anodization method in aqueous solution with addition of F ^- ions. Several factors affecting the final morphology of the samples were tested such as potential, time, and F ^- concentrations. The morphology of the formed nanopores arrays was examined by SEM microscopy. It was found that the optimal time of anodization process is in the range of 0.5-1 h. The nanopores size increased with the increasing potential. The XPS measurements do not show any contamination by F ^- on the surface, which is common for WO _x samples formed by an anodization method. Such a layer was successfully modified by anisotropic gold trisoctahedral NPs of various sizes. The Au NPs were obtained by seed-mediated growth method. The shape and size of Au NPs was analysed by TEM microscopy and optical properties by UV-VIS spectroscopy. It was found that the WO ₃ -Au platform has excellent SERS activity. The R6G molecules could be detected even in the range of 10 ^-9 M.