Plasmonic Spherical Nanoparticles Coupled with Titania Nanotube Arrays Prepared by Anodization as Substrates for Surface-Enhanced Raman Spectroscopy Applications: A Review

Abstract

As surface-enhanced Raman spectroscopy (SERS) continues developing to be a powerful analytical tool for several probes, four important aspects to make it more accessible have to be addressed: low-cost, reproducibility, high sensibility, and recyclability. Titanium dioxide nanotubes (TiO2 NTs) prepared by anodization have attracted interest in this field because they can be used as safe solid supports to deposit metal nanoparticles to build SERS substrate nanoplatforms that meet these four desired aspects. TiO2 NTs can be easily prepared and, by varying different synthesis parameters, their dimensions and specific features of their morphology can be tuned allowing them to support metal nanoparticles of different sizes that can achieve a regular dispersion on their surface promoting high enhancement factors (EF) and reproducibility. Besides, the TiO2 photocatalytic properties enable the substrate’s self-cleaning property for recyclability. In this review, we discuss the different methodological strategies that have been tested to achieve a high performance of the SERS substrates based on TiO2 NTs as solid support for the three main noble metal nanoparticles mainly studied for this purpose: Ag, Au, and Pt.

Hybrid Nanostructures Based on TiO2 Nanotubes with Ag, Au, or Bimetallic Au–Ag Deposits for Surface-Enhanced Raman Scattering (SERS) Applications

“…The separation of nanotubes and their open porosity also ensure that the nanoparticles deposited by physical methods penetrate deep into them, decorating not only the surface but also their internal and external walls. All these factors lead to the formation of specific morphologies of plasmonic metals on TiO 2 nanotubes with a 3D character. , …”

“…All these factors lead to the formation of specific morphologies of plasmonic metals on TiO 2 nanotubes with a 3D character. 15,16 An important research aspect is a search for SERS substrates with good controllability regarding surface morphology and topography, chemical stability, simplicity of formation, and relatively low production costs. Therefore, an effective solution to improve the chemical stability of SERS substrates, particularly those based on Ag, while maintaining a high enhancement factor (EF) is the possibility of producing nanostructures or hetero-nanostructures with a more stable metal such as Au.…”

Application of Anodic Titanium Oxide Modified with Silver Nanoparticles as a Substrate for Surface-Enhanced Raman Spectroscopy

“…Deposition of close-packed Ag nanoparticles with narrow edges on the ATO matrix could be highly preferable. Furthermore, presented electrodeposition techniques allow control over the distribution of silver nanoparticles on the ATO surface [ 38 , 39 ]. Considering the gap in knowledge regarding the insufficient amount of information about the effect of deposition parameters on the ATO/Ag interface, in the presented study, we evaluate the effect of Ti anodization parameters and Ag deposition parameters on the morphology and uniformity of ATO/Ag composites.…”

WO3 Nanopores Array Modified by Au Trisoctahedral NPs: Formation, Characterization and SERS Application

“…It is possible to form some nanostructures from pure plasmonic metals by lithography [ 2 ] and electrochemistry [ 3 ], but the simplest way is to form a nanostructured material from another material and then cover its surface with a plasmonic layer. Such a solution was applied for TiO 2 [ 4 ] and ZrO 2 NTs (Nanotubes) [ 5 ], ZnO nanorods [ 6 ], and InP nanowires [ 7 ]. However, the main limitation of this method results from the fact that the deposited plasmonic layer flattens the nanostructure’s surface.…”