Localized surface plasmon resonance of Au/TiO 2 (110): substrate and size influence from in situ optical and structural investigation

• Published in: Nanoscale advances Vol. 2; no. 6; pp. 2448 - 2461
• Main Authors: Soldo-Olivier, Y., Abisset, A., Bailly, A., De Santis, M., Garaudée, S., Lacipière, J., Coati, A., Garreau, Y., Saint-Lager, M.-C.
• Format: Journal Article
• Language: English
• Published: 17-06-2020
• ISSN: 2516-0230; 2516-0230
• DOI: 10.1039/D0NA00165A

Localized Surface Plasmon Resonance (LSPR) of noble metal nanoparticles has attracted a lot of attention in recent years as enhancer of the photocatalytic activity in the visible light domain. Rare are the experimental
in situ
studies, coupling structural and optical responses, but they are mandatory for a deep understanding of the mechanisms underlying LSPR. Herein we present an
in situ
investigation during the growth of gold nanoparticles (NPs) on TiO
2
(110) in the 2–6 nm size range. We probed the structural and morphological properties of the supported nanoparticles by performing GIXRD and GISAXS simultaneously with their optical response in p and s polarizations recorded by SDRS. The rutile surface state turns out to have a major effect on the Au NPs growth and on their plasmonic response, both in frequency and vibration modes. The roughening of the TiO
2
(110) surface weakens the interaction strength between the NPs and the substrate, favoring the growth of textured in-plane randomly orientated NPs. Compared to the epitaxial clusters growing on the flat TiO
2
surface, these textured NPs are characterized by a LSPR blue shift and by the presence of LSPR vibration modes perpendicular to the surface for sizes smaller than about 4 nm.