Ultrathin Diamond-like Carbon Film Coated Silver Nanoparticles-Based Substrates for Surface-Enhanced Raman Spectroscopy

Abstract

We have demonstrated that by coating with a thin dielectric layer of tetrahedral amorphous carbon (ta-C), a biocompatible and optical transparent material in the visible range, the Ag nanoparticle-based substrate becomes extremely suitable for surface-enhanced Raman spectroscopy (SERS). Our measurements show that a 10 Å or thicker ta-C layer becomes efficient to protect the oxygen-free Ag in air and prevent Ag ionizing in aqueous solutions. Furthermore, the Ag nanoparticles substrate coated with a 10 Å ta-C film shows a higher enhancement of Raman signals than the uncoated substrate. These observations are further supported by our numerical simulations. We suggest that biomolecule detections in analytic assays could be easily realized using ta-C-coated Ag-based substrate for SERS especially in the visible range. The coated substrate also has higher mechanical stability, chemical inertness, and technological compliance, and may be useful, for example, to enhance TiO2 photocatalysis and solar-cell efficiency by the surface plasmons.

Functionalized Graphene Nanocomposites

“…SERS technique has been implemented widely by a broad scientific research community for chemical and biological sensing and measurements. This technique combines the capability of molecular fingerprinting with ultrahigh sensitivity (Liu, Cao et al 2010). Increases in the intensity of the Raman signal have been observed by factors up to 10 6 , reaching in particular cases the single-molecule detection level.…”

Dissolvable Trimolybdate Nanowires as Ag Carriers for High-Efficiency Antimicrobial Applications

“…In some biological applications, it should be rather interesting if Ag composites or nanoparticles could be delivered to target tissues and/or cells with a controllable carrier of nanomaterial. Similar concepts have already been well presented in studies on drug delivery of molecular medicines, characterization, imaging, and targeting with carbon nanotubes, nanowires, and other nanomaterials [16][17][18][19][20][21][22][23][24][25][26][27][28]. However, in these approaches, side effects caused by the residual nanomaterials inside tissues or cells become a great concern.…”

Linear and Planar Periodic Arrays of Metallic Nanospheres: Fabrication, Optical Properties and Applications

“…[226][227][228][229][230][231][232] As an example, we recall the work by Beermann et al 226 in which detailed Raman images are obtained by mapping the Raman shift (wavenumber) intensity of peaks integrated over 1468 -1614 cm -1 (indeed, the Raman shift range) from Rhodamine 6G (R6G, generally used as a dye with fluorescence properties) adsorbed on the periodic array of gold nanoparticles. The array has a square lattice with periods a = b = 740 nm and is made of gold squares with a height of 50 nm, with lateral dimensions fixed along x equal to dx = 250 nm and variable along y, equal to dy = 250, 340, 440, 540, and 630 nm, and is fabricated with EBL on top of a 200 nm thick gold film, onto a silicon substrate.…”