Decoration of Gold Nanoparticles on Surface-Grown Single-Walled Carbon Nanotubes for Detection of Every Nanotube by Surface-Enhanced Raman Spectroscopy

Abstract

An electroless deposition method comprised of seed formation and subsequent seeded growth is developed for the decoration of surface-grown single-walled carbon nanotubes (SWCNTs) with gold nanoparticles of controlled size and interparticle distance. The density of the gold nanoparticles is determined by the density of seeds. Gold seeds are used for the SWCNT arrays grown on SiO(x)/Si substrates. For the dense SWCNT arrays on quartz, palladium seeds are used because it is much easier to obtain higher quantities of seeds. Attributed to both the seed formation specified on SWCNTs and the succedent efficient seeded growth process, the gold nanoparticles deposit on SWCNTs with very high selectivity. This electroless method shows no selectivity on types, defects, and conductivity of the SWCNTs, and thus ensures the uniform decoration of all SWCNTs on the wafer. Most importantly, this method provides the possibility to realize the optimal configurations of gold nanoparticles on SWCNTs for obtaining maximal surface-enhanced effects and consequently surface-enhanced Raman spectrum (SERS) of each SWCNT. Thus, both the in situ Raman detection of every SWCNT including those nonresonant with laser energy and the observation of the radial breathing modes of SWCNTs originally undetectable with resonance Raman spectroscopy are achieved. Further investigations over the effect of the laser wavelength and the interparticle distance on the SERS enhancement factors of SWCNTs prove that the coupled surface plasmon resonance absorption of the high-density gold nanoparticles decorated on SWCNTs contributes most to the strong surface enhancement.

Chirality-specific growth of single-walled carbon nanotubes on solid alloy catalysts

“…they are resonant with the excitation laser or not 27 , further confirm the domination of the RBM peaks at ,197 cm 21 (Extended Data Fig. 2).…”

Optical visualization and polarized light absorption of the single-wall carbon nanotube to verify intrinsic thermal applications

“…Similar efforts have been reported to make CNT visible under an ordinary optical microscope to easily manipulate CNTs, such as electroplating Au nanoparticles 26 and depositing TiO 2 particles 27 . Compared with the previous methods, in our strategy, the visualization process is reversible because the nanotube will recover to its naked form without any change in structure when it returns to room temperature (proven by comparing the TEM feature and ED pattern before and after the melting process).…”

The synthesis of nitrogen-doped carbon nanotubes/gold composites and their application to the detection of thioridazine

“…After the decoration of gold NPs, the D-band is shifted to 1,360 cm −1 because of the interaction of N-CNTs and gold. Whereas the intensity of Gband at 1,593 cm −1 increases dramatically due to the strong surface enhancement effects of gold NPs [26].…”