Black Au-Decorated TiO₂ Produced via Laser Ablation in Liquid

Abstract

The rational combination of plasmonic and all-dielectric concepts within hybrid nanomaterials provides a promising route toward devices with ultimate performance and extended modalities. Spectral matching of plasmonic and Mie-type resonances for such nanostructures can only be achieved for their dissimilar characteristic sizes, thus making the resulting hybrid nanostructure geometry complex for practical realization and large-scale replication. Here, we produced amorphous TiO2 nanospheres decorated and doped with Au nanoclusters via single-step nanosecond-laser irradiation of commercially available TiO2 nanopowders dispersed in aqueous HAuCl4. Fabricated hybrids demonstrate remarkable light-absorbing properties (averaged value ≈96%) in the visible and near-IR spectral range mediated by bandgap reduction of the laser-processed amorphous TiO2 as well as plasmon resonances of the decorating Au nanoclusters. The findings are supported by optical spectroscopy, electron energy loss spectroscopy, transmission electron microscopy, and electromagnetic modeling. Light-absorbing and plasmonic properties of the produced hybrids were implemented to demonstrate catalytically passive SERS biosensor for identification of analytes at trace concentrations and solar steam generator that permitted to increase water evaporation rate by 2.5 times compared with that of pure water under identical 1 sun irradiation conditions.

Smart design of high‐performance surface‐enhanced Raman scattering substrates

“…Secondly, due to the smaller bandgap and higher DOS of 2D a ‐TiO 2 , the vibronic coupling in the substrate‐molecule system is stronger, which can promote the PICT resonance and enhance the remarkable SERS activity effectively. Since then, more TiO 2 based amorphous substrates have been reported, such as amorphous TiO 2 nanotubes decorated with Ag/Au NPs, which indicates high SERS enhancement due to the effect of EM enhancement and CT enhancement simultaneously 114,115 . Moreover, hydrogenation is an effective method to improve SERS activity of black TiO 2 nanowires, during which the amorphous shell is generated 116 …”

Emergence of Surface-Enhanced Raman Scattering Probes in Near-Infrared Windows for Biosensing and Bioimaging

“…Lately, through the combination of a plasmonic metal and semiconductor, a series of photocatalytic self-cleaning SERS substrates were developed, which made the SERS substrates recyclable. − In fact, the semiconductor itself has been proven to be the substrate material for SERS activity. Semiconductors have a frequency slightly lower than that of metal substrates.…”

All-dielectric thermonanophotonics

“…Further progress in this field can be done with hybrid metaldielectric NPs, where Mie-like and plasmonic resonances coupling results in high light energy conversion efficiencies (e.g. with TiO 2 /Au NPs [198]).…”