Using Polycarbonate Membranes as Templates for the Preparation of Au Nanostructures for Surface-Enhanced Raman Scattering

Abstract

Polycarbonate membranes (PCM) of various pores sizes (400, 200, 100 and 50 nm) were used as templates for gold deposition. The electrodeposition from gold ions resulted in the formation of gold nanotubes when large pores size PCMs (400 and 200 nm) were used. On the other hand, gold nanowires were predominant for the PCMs with smaller pores size (100 and 50 nm). Surface-enhanced Raman scattering (SERS) from the probe molecule 4-mercaptopyridine (4-MPy) was obtained from all these nanostructures. The SERS efficiency of the substrates produced using the PCM templates were compared to two commonly used SERS platforms: a roughened gold electrode and gold nanostructures electrodeposited through organized polystyrene spheres (PSS). The SERS signal of the probe molecule increased as the pore diameter of the PCM template decreased. Moreover, the SERS efficiency from the nanostructures produced using 50 nm PCM templates was four and two times better than the signal from the roughened gold electrode and the PSS template, respectively. The SERS substrates prepared using PCM templates were more homogenous over a larger area (ca. 1 cm2), presented better spatial and sample to sample reproducibility than the other substrates. These results show that SERS substrates prepared using PCM templates are promising for the fabrication of planar SERS platforms for analytical/bioanalytical applications.

Biosynthesis of gold nanowires using sugar beet pulp

“…Nanowires of noble metals have been fabricated using various methods such as wet chemical synthesis based on a seed mediated growth mechanism [5], solutions phase methods based on capping agents [6], reverse micellar or polyol process [7] and template-based methods using nanoporous silica [8], polycarbonate membranes [9] or carbon nanotubes [10]. Self assembly of nanowires to integrate these structures directly into various devices has been developed [11].…”

Propagation lengths of surface plasmon polaritons on metal films with arrays of subwavelength holes by infrared imaging spectroscopy

“…13,14 Recent reviews exist on mesh plasmonics and its applications, 11,15 including one of our own work, 12 which pushes extraordinary transmission into the mid-IR region to overlap with the vibrational spectra of molecules on mesh. Interest in both local and propagating SPs 7,16,17 exists because they exhibit high electric fields at the surface of the metal 18 for supersensitive surface enhanced Raman spectroscopy, 19 reduced wavelengths relative to the incident radiation for subwavelength optics 5,7,20 and near field scanning optical microscopy, 21 increased transmission to facilitate superlensing 14 and more sensitive absorption spectroscopy, 22 confinement to two dimensions 9 to advance the probing of subwavelength nanospaces, potential for bridging photonics and electronics ͑plasmonics 23 ͒, sensitivity as sensors 17 for bioanalytical assays with SP attenuated total reflection, and more efficient collection of fluorescence 24 using SP coupled emission. All of the above are due in large part to SPmediated optical properties.…”

Sputtered gold-coated ITO nanowires by alternating depositions from Indium and ITO targets for application in surface-enhanced Raman scattering

“…In this case, the metal nanostructures are grown on a substrate (glass, silicon, polymer, etc.) by a number of physical and chemical methods [28][29][30]. An emergent alternative is to fabricate nanostructured metal oxides, which may grow with different morphologies, and to cover these nanostructures with one of the SERS-active metals.…”