Silver‐decorated carbon nanotube networks as SERS substrates

Abstract

We report on investigations upon a surface-enhanced Raman scattering (SERS) substrate produced from a two-dimensional single-walled carbon nanotube (SWNT) network decorated with Ag nanoparticles. Using the strong and unique Raman spectrum of SWNTs as a reference, the SWNT/Ag nanostructure can be considered to provide two regions: one with an ultrasensitive SERS response for single-molecule SERS (SMSERS) study; and another with uniform SERS enhancement over an area of several square millimeters for general SERS measurements. We report the appearance of an anomalous Raman feature at around 2180 cm -1 in the high-sensitivity region which exhibits the characteristics of SMSERS. The SERS performance of the uniform area was characterized using pyridine vapor adsorbed onto the substrate. The presence of the SWNT/Ag nanostructure enhanced the Raman intensity by over seven orders of magnitude, a factor comparable to or exceeding that obtained on SERS substrates reported by other groups. The results indicate great potential to produce highly sensitive, uniform SERS substrates via further fine-tuning of the nanostructure

Plasmon enhanced Raman scattering effect for an atom near a carbon nanotube

“…Under the assumption that the coupled CN-TLS system with the eigen states (3), (8) and (9) is initially in the ground state, the inelastic scattering of external EM radiation by this system only involves transitions between levels |0 , |1 and |2 , as shown in Fig. 3, top, due to the dipole moment selection rule restrictions.…”

“…High scattering intensities within narrow spectral bands reduce the probability for spectral overlapping to allow for better recognition of multiple markers, making SERS one of the most efficient optical sensing techniques. With the development of advanced nanomaterials, various SERS substrates are demonstrated [4][5][6][7][8][9][10]. However, there is still a need for inexpensive substrates of improved sensitivity and signal reproducibility, which require clear understanding of the underlying scattering mechanisms to be developed.…”

“…Most of the applications of carbon nanotubes (CNs) to increase the Raman scattering signal have been to decorate them with metallic nanoparticles [8,9], in order to obtain local EM field enhancement generated by the spatially confined plasmon modes of the nanoparticles with CNs only used as a network to support the particles. Only very recently, the chemical SERS effect with CNs alone, without any combination with metallic nanoparticles, was first reported by Andrada et al in [10], where molecules covalently bound to single wall CNs demonstrated the resonantly increased Raman signal that was even stronger than that of the nanotube itself.…”

Two facile routes for functionalization of WS2 nanotubes with silver nanoparticles

“…For example, carbon nanotubes (CNT) coated with Ag and Au nanoparticles have been found to be broad-band optical limiters [2]. Ag-CNT nanocomposites are widely used as mediators for highly-sensitive surface-enhanced Raman spectroscopy (SERS) [3][4][5]. AgNP-loaded CNT and TiO 2 nanotubes possess high efficiency in photocatalytic applications [6][7][8] including antibacterial photocatalysis in visible light [9].…”

Porosity‐Controlled Eggshell Membrane as 3D SERS‐Active Substrate

“…[11,12] A variety of three-dimensional (3D) nanostructures that exhibit high SERS enhancement have been reported, such as metallic nanohole arrays, [8] nanoporous metallic substrates, [13,14] metal modified microstructured optical fibre substrates, [2,8] nanowire-based substrates, [15] and nanotube networks decorated with metals. [16] Metallic NPs can also serve as effective hot spot, that is, sites that interconnect to the molecules adsorbed on the SERS-active substrate. [15,17] Jiang et al [5] demonstrated that porous structures contribute to the metallic NP aggregation onto nanowires; the corresponding nanogaps provided strong collective surface plasmon resonances with superior SERS activity.…”