title: Size dependence of ultrafast charge dynamics in monodisperse Au nanoparticles supported on TiO₂ colloidal spheres.
abstract: Sub-nanosecond charge dynamics in monodisperse Au nanoparticles (NPs) supported on TiO2 colloidal spheres are studied as a function of NP diameter using ultrafast transient absorption spectroscopy. The decay of the transmittance changes observed in the region of the plasmon resonance of the Au NPs following photoexcitation of the TiO2 spheres are well-described by a bi-exponential function consisting of a fast component of 2 ps duration associated with electron-phonon scattering, followed by a slow and relatively weak component associated with phonon-phonon scattering. The decay constant characterising the latter component was found to be dependent on the size of the Au NPs, rising from 49 ± 3 to 128 ± 6 ps as the diameter of the Au NPs increased from 12.2 ± 2.2 nm to 24.5 ± 2.8 nm, respectively.
authors.affiliation: School of Physics and Astronomy & Photon Science Institute, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. marina.leontiadou@manchester.ac.uk.
authors.forename: Ali
authors.initials: A
authors.lastname: Al-Otaify
authors.forename: Marina A
authors.initials: MA
authors.lastname: Leontiadou
authors.forename: Flavia V E
authors.initials: FV
authors.lastname: dos Reis
authors.forename: Tatiana C
authors.initials: TC
authors.lastname: Damato
authors.forename: Pedro H C
authors.initials: PH
authors.lastname: Camargo
authors.forename: David J
authors.initials: DJ
authors.lastname: Binks