Au-WO3 Nanocomposite Coatings for Localized Surface Plasmon Resonance Sensing

Abstract

Localized surface plasmon resonance (LSPR) gas sensors are gaining increasing importance due to their unique tuneable functional properties. Au-WO3−x nanocomposite coatings, in particular, can be outstandingly sensitive to many different gases. However, a proper understanding of their optical properties and the way in which those properties are correlated to their structure/microstructure, is still needed. In this work, Au-WO3 nanocomposite coatings, with Au contents between 0–11 atomic percent, were grown using reactive magnetron co-sputtering technique and were characterized concerning their optical response. The precipitation of Au nanoparticles in the oxide matrix was promoted through thermal annealing treatments until 500 °C. Along with the Au nanoparticles’ morphological changes, the annealing treatments stimulated the crystallization of WO3, together with the appearance of oxygen-deficient WO3−x phases. Through theoretical simulations, we have related the LSPR effect with the different structural and morphological variations (namely, size and distribution of the nanoparticles and their local environment), which were a function of the Au content and annealing temperature. Our results suggest that local voids were present in the vicinity of the Au nanoparticles, for all temperature range, and that they should be present in a wide variety of Au-WO3 nanocomposites. A theoretical study concerning the refractive index sensitivity was carried out in order to predict the optimal coating design parameters for gas sensing experiments.

Antimicrobial Polymeric Surfaces Using Embedded Silver Nanoparticles

“…On the other hand, the pronounced red-shift of the LSPR peak is a confirmation of the NP thermal embedding process. As the NPs penetrate the surface of the polymer, their average surrounding refractive index increases, which causes the buildup of polarization charges that weakens the total restoring force on the dielectric side of the interface, resulting in a lower energy (red-shifted) LSPR scattering peak [35]. Therefore, these optical results are well consistent with the idea of thermally embedded NPs in the PC/Ag/180 • C case.…”

“…Further annealing above Tg causes a pronounced narrowing and red-shift of the LSPR scattering band to 548 nm. The narrowing of the LSPR peak can be understood as a narrowing of the NP size and shape distribution curves [34,35] caused by NP diffusion and recrystallization. On the other hand, the pronounced red-shift of the LSPR peak is a confirmation of the NP thermal embedding process.…”

NIR shielding performance and spectral selectivity of PVB interlayer films loaded with composite fillers derived from CsWO3 coupled with Au nanorods

“…This factor contributed to the increased NIR absorbance and the higher spectral selectivity of the PVB/(Au NR @CsWO 3 ) film. 39,40 This was not the case for the Au NR and CsWO 3 fillers, which were physically mixed and lacked evidence indicating the incorporation of Au atoms in the CsWO 3 crystals.…”

Novel Approach to Synthesize Nanostructured Gallium Oxide for Devices Operating in Harsh Environmental Conditions

“…In order to quickly and efficiently detect various gases in aggressive environments (i.e., high temperature, pressure and radiation, corrosive, explosive or toxic environment, etc. [13]), gas sensors made of materials with the required structural and electronic properties are essential for the sustainable detection of gas emissions in these particular harsh conditions [14].…”