Ordered Nanocap Array Composed of SiO₂-Isolated Ag Islands as SERS Platform

Abstract

SERS-active substrate is fabricated by cosputtering Ag and SiO2 onto two-dimensional polystyrene (PS) colloidal particle templates in a magnetron sputtering system. When Ag and SiO2 are cosputtered onto ordered PS templates, the SiO2-isolated Ag island (SiO2-Ag) nanocap arrays with nanogaps and nanoscaled surface roughness form on PS particles, in which "hot spots" are facilely engineered on three-dimensional nanostructures. The surface-enhanced Raman scattering (SERS) activities of the SiO2-Ag nanocap arrays vary nonmonotonically and depend on the film thickness and surface roughness strongly. Under the optimized conditions, the SERS signal intensity of 4-aminothiophenol (PATP) is employed to evaluate the SERS ability (4.41 × 10(5)). The addition of SiO2 not only avoids photobleaching and background fluorescence but also decreases the oxidation rate of Ag and increases the stability of Ag particles. The results demonstrate the potential applications of this technique in reproducible SERS substrate.

Ordered array of Ag semishells on different diameter monolayer polystyrene colloidal crystals: An ultrasensitive and reproducible SERS substrate

“…Lots of SERS substrates with “hot spots” have been prepared by different ways including chemical functional method9, electron lithography technique10 and self-assembled aggregation1112. Relatively speaking, as a simple, economic and effective way, nanosphere lithography (NSL) can be used to fabricate uniformly ordered nanoparticle arrays because of its good monodispersity, wide size range and realizable1314151617181920212223242526. For instance, by using NSL, Van Duyne’s group fabricated Au and Ag nanoparticle array on self-assembly monolayer polystyrene or silica nanospheres13141516.…”

“…Zhang et al . fabricated SiO 2 -Ag nanocap arrays via thermal evaporation deposition on two-dimensional polystyrene spheres (PS) colloidal particle templates23. Zhao et al .…”

Increasing local field by interfacial coupling in nanobowl arrays

“…To overcome these problems, the various assembled nanostructures including nanorods, nutshells and nanocap periodic arrays, have been investigated for strong surface plasma coupling properties. [13][14][15] The periodic nanostructures are usually fabricated by self-assembled techniques such as electron-beam lithography, 16 electrochemical metal growth, 17 nanoimprint lithography, 18 nanosphere lithography (NSL) technology [19][20][21][22][23][24][25] and so on. In these methods, combining NSL with a layer-by-layer (LBL) lm deposition is a kind of high efficient method for the fabrication of nanostructure arrays, most materials including noble metal, semiconductor and dielectric all can be used.…”

Tailoring Size and Coverage Density of Silver Nanoparticles on Monodispersed Polymer Spheres as Highly Sensitive SERS Substrates

“…Different kinds of silver-based SERS actives ubstrates have been widely described, such as silver colloids, [7,8] silver nanostructure arrays, [9][10][11] and template supporteds ilver nanoparticles (AgNPs). [12][13][14][15][16] Traditional silver colloidsp repared via wet chemicala pproaches remain the most common type of SERS active materials.…”

“…Two-dimensional (2D) or three-dimensional( 3D) ordereds ilver nanostructure arrays were exploiteda sh ighly SERS active platform, which can provide good signalr eproducibility,b ut the complicated process to prepare the orderedS ERS arrays is usually time consuming and high cost. [11,17,18] One of the solutions to overcome the aggregation or clustero fA gNPst he in bulk colloids and meanwhile avoid the high cost and complicated process as fabricatings ilver SERS active substrates is depositing the AgNPs onto non plasmonic templates. Unlike the metallic nanoparticles in bulk colloids,t he AgNPsa re tightly bonded onto the solid supports via metal-affinitive functional groups, which can effectively preventt he random movement and aggregation of the AgNPs, and thus provide SERS signals with higher activity, stability and reproducibility.M any approaches have been reported to fabricate silver-based SERS active substrate by means of at emplate.…”