Optical Hot Spot Generation by the Plasmonic Coupling of Au Nanoparticles in the Nanospaces of Mesoporous Titanium(IV) Oxide.
Langmuir
; 37(5): 1838-1842, 2021 Feb 09.
Article
en En
| MEDLINE
| ID: mdl-33513306
ABSTRACT
An in situ reduction technique consisting of chemisorption of 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and subsequent reaction with HAuCl4 has been developed for depositing Au nanoparticles (NPs) uniformly in the depth direction of a mesoporous TiO2 nanocrystalline film (Au/TMCTS/mp-TiO2). The TMCTS monolayer is further converted into silicon oxide by heating in the air (Au/SiOx/mp-TiO2). In the absorption spectra of Au/SiOx/mp-TiO2 prepared at varying HAuCl4 concentrations (C), the localized surface plasmon resonance (LSPR) band of Au NPs significantly broadens C ≈ 1.22 mM at 546 nm to be split into two peaks around 500 and 700 nm at C ≥ 2.43 mM, whereas such a phenomenon is not observed for the usual Au NP-loaded TiO2 particles. Three-dimensional-finite difference time domain simulations showed that the unique optical property of Au/SiOx/mp-TiO2 stems from the effective LSPR coupling of very close Au NPs and partial fusions in the nanospaces of mp-TiO2. Further, the optical hot spots in Au/TMCTS/mp-TiO2 as well as Au/SiOx/mp-TiO2 generate an intense local electric field giving increase to a great enhancement of the absorption in the infrared spectrum of the TMCTS monolayer on mp-TiO2.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Langmuir
Asunto de la revista:
QUIMICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Japón