Template assisted deposition of Ag nanoparticle arrays for surface-enhanced Raman scattering applications

Dealloying Ag–Al Alloy to Prepare Nanoporous Silver as a Substrate for Surface‐Enhanced Raman Scattering: Effects of Structural Evolution and Surface Modification

“…As reported elsewhere, a smaller pore size or interparticle distance favors the SERS enhancement by enhancing the localized electromagnetic fields from nanoscale metallic particles and the electromagnetic coupling between the neighboring particles. [4,19,23] The ligament widths of the present NPS samples are proportional to the Ag content of the precursor alloys and can be explained as follows: After complete dealloying of the Ag-Al alloys by free corrosion, no noticeable volume reduction is observed. Therefore, less Al in the precursor alloys meant that less voids were formed, and finally, resulted in smaller pore (channel) sizes and larger ligament sizes.…”

“…To evaluate the SERS performance of the as-prepared substrate, the enhancement factor (EF) of Ag NP modified NPS was calculated (a detailed description of the calculation is given in the Supporting Information). [4,6,35,36] At an Ag colloid concentration of 6 10 À4 g mL…”

“…Many techniques, including lithography, self-assembly, and template-based synthesis, have been reported to prepare ordered arrays of nanoparticles. [4,5,7] Chemical dealloying (selective etching of one or more lessnoble elements from an alloy) is a technique different from those mentioned above for the preparation of nanostructured metal materials. It is simple and economical.…”

Controlled Fabrication of Noble Metal Nanomaterials via Nanosphere Lithography and Their Optical Properties

“…As a welldeveloped template, PAA offers amazing simplicity and convenience for nanofabrication due to the capabilities of forming high-density, well-aligned, and hexagonally packed sub-100-nm pores, the ability to control the 3D pore structures by simply varying the anodization conditions, and the ease of selectively removing the template after fabrication (Chong, Zheng et al 2006). As shown in Figure 12, one typical PAA-LIGA process includes (Lombardi, Cavallotti et al 2007): (a) formation of a 300 nm thick PAA film on Al by a two step anodization process in 0.3M oxalic acid; (b) dissolution of unoxidized Al; (c) barrier layer etching in 5wt% phosphoric acid; (d) transfer of the PAA mask onto Au-coated Si followed by a thermal treatment to improve the adhesion of the films to the substrate; (e) Ag electrodeposition through the PAA pores; (f) PAA mask removal. By carefully controling the sizes and interpore spacing of the nanoholes, very uniform Ag nanorods with controlled interspacing can be fabricated by electroplating.…”

“…Progresses in PAA-LIGA have shown its abilities not only in the synthesis of the traditional high aspect ratio nanomaterials, such as nanorods (Pan, Zeng et al 2000;Lombardi, Cavallotti et al 2007;Xu, Meng et al 2009)and nanowires (Hong, Bae et al 2001;Xu, Zhang et al 2005), but also some unique nanostructures, such as porous metallic nanorods by galvanic exchange reaction (Mohl, Kumar et al 2010), Y-junction nanowires and multiply branched nanomaterials due to its flexibility in the pore structure control according to the principle 1 s V n  , where V s is the anodizing voltage for stem pores and n is the number of branched pores from that stem (Meng, Jung et al 2005;Xu, Meng et al 2009). The combination of NSL and PAA-LIGA has been further developed to create hierarchically ordered nanowire arrays, as schematically shown in Figure 13A (Chong, Zheng et al 2006).…”