Template-Assisted Electrodeposition of Urchin-Like Ag-Nanoplate-Assembled Nanorod Arrays and Their Structurally Enhanced SERS Performance

Abstract

An effective template-assisted electrodeposition approach is demonstrated for growing large-area, hexagonally arranged arrays of urchin-like Ag-nanoplate-assembled nanorods grafted on the polystyrene spheres (PSs) as homogeneous and sensitive surface-enhanced Raman scattering (SERS) substrates. The urchin-like Ag-nanoplate-assembled nanorod arrays are fabricated by first transferring the ordered hexagonally arranged PS colloidal monolayer onto the silicon wafer as the template, and then electrodepositing ZnO nanorods onto the surface of each PS, and finally assembling Ag-nanoplates onto each ZnO nanorod on the PSs via electrodeposition in silver nitrate and citric acid electrolyte. Because of the ordered arrangement of the PS arrays and the high-density sub-10 nm gaps between the neighboring building blocks, the hierarchical urchin-like Ag-nanoplate-assembled one-dimensional nanostructure arrays can offer uniform and abundant “hot spots” for sensitive and reproducible SERS effect. Using the urchin-like hierarchical Ag-nanoplate-assembled nanorod arrays as SERS substrates, 1 pM rhodamine 6 g (R6G), 10pM para-aminothiophenol (p-ATP), and 1 μM PCB-77 (one congener of polychlorinated biphenyl, a notorious member of persistent organic pollutant) are identified respectively, showing promising potentials in rapid detection of organic environmental pollutants.