Cost-effective large-area Ag nanotube arrays for SERS detections: effects of nanotube geometry

Abstract

This study demonstrated highly-ordered metallic nanotube arrays (MeNTAs) with a precisely controlled geometric shape to promote surface-enhanced Raman scattering (SERS). Using both simulation and experimental methods, we designed and fabricated MeNTAs with nanotube geometries that possess a large surface area to absorb probe molecules as well as geometric features capable of inducing hot spots for SERS enhancement. The proposed top-down wafer-scale lithographic and sputter-deposition process is a simple and cost-effective approach to the fabrication of 1 mm×1 mm MeNTA at room temperature. Simulation results of nanotubes with various materials (Au, Ag, and Cu), diameters (100-1500 nm), geometric shapes (circle, equilateral triangle and square) and triangle corner curvatures (ranging from 0 to 300 nm) identified Ag triangles with sharp tips as the geometry best suited to SERS enhancement. The SERS spectra of crystal violet molecules generated from the Ag MeNTAs verified the patterns observed in computational simulations, wherein the effects of MeNTA on SERS decreased with an increase in the size of the nanotubes. Enhancement factor of 1.06×10 9 was obtained from our triangular Ag MeNTA, confirming its efficacy as an ultrahigh sensitivity SERS-active substrate.

Triangular Silver Nanoplates/Graphene Oxide Nanohybrids on Flexible Substrates for Detection of Bacteria via Surface-Enhanced Raman Spectroscopy

“…16 Furthermore, according to the finite-difference time-domain (FDTD) simulation results reported in previous research studies, the electromagnetic field around the tip of the triangular plate is significantly enhanced. 46 Figure 1f shows a comparison of the results obtained for the SERS signals used to detect the same concentration of adenine using TAgNPs prepared with different edge lengths at a laser wavelength of 633 nm. The SERS signal strengths in the wavelength region of 730−736 cm −1 were calculated and compared.…”

Parameter-free quantum hydrodynamic theory for plasmonics: Electron density-dependent damping rate and diffusion coefficient

“…Plasmonic nanostructure can be used to reduce the size of optical devices and enhance the light-matter interaction for their ability to localize electromagnetic field well below the diffraction limit [1][2][3][4][5][6][7][8][9][10][11][12][13]. Many novel phenomena have been reported, such as quantum emitterplasmon bound state [14,15], reversible decay dynamics [16,17], polarization dependence of fluorescence [18,19], position dependent dipole-dipole interaction [20], enhanced solar energy conversion [21,22], biomedicine [23][24][25], surface-enhanced Raman scattering [26,27], plasmon rulers with ultrahigh sensitivity [28], plasmonic photocatalysis [29], plasmonic nanoantennas [30], sensors [31], plasmon laser [32], nano-optical tweezers [33], etc.…”