title: Hot plasmonic electrons for generation of enhanced photocurrent in gold-TiO2 nanocomposites.
abstract: In this manuscript, for the first time, we report a combination of electrophoretic and sintering approaches for introducing gold nanoparticles into nanoporous TiO2 films to generate 'hot' electrons resulting in a strong enhancement of photocurrent. The Au-TiO2 nanocomposite material was prepared by the electrophoretic deposition of gold nanoparticles into a porous nanoparticulate titanium dioxide film, creating a photoactive electrode. The composite film demonstrates a significant increase in the short circuit current (I sc) compared to unmodified TiO2 when excited at or close to the plasmon resonance of the gold nanoparticles. Then, we employed a thermal ripening process as a method of increasing the I sc of these electrodes and also as a method of tuning the plasmon peak position, with a high degree of selectivity. Photo-electrochemical investigations revealed that the increase in photocurrent is attributed to the generation and separation of plasmonically generated hot electrons at the gold/TiO2 interface and also the inter-band generation of holes in gold nanoparticles by photons with λ < 520 nm. Theoretical modelling outputs perfectly match our results obtained from photo-physical studies of the processes leading to enhanced photocurrent.
authors: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.
authors: Lorcan J
authors: LJ
authors: Brennan
authors: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.
authors: Finn
authors: F
authors: Purcell-Milton
authors: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.
authors: Aurélien S
authors: AS
authors: Salmeron
authors: Department of Physics and Astronomy, Ohio University, Athens, OH 45701 USA.
authors: Hui
authors: H
authors: Zhang
authors: Department of Physics and Astronomy, Ohio University, Athens, OH 45701 USA.
authors: Alexander O
authors: AO
authors: Govorov
authors: ITMO University, 197101 Saint Petersburg, Russia.
authors: Anatoly V
authors: AV
authors: Fedorov
authors: School of Chemistry and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland ; ITMO University, 197101 Saint Petersburg, Russia.
authors: Yurii K
authors: YK
authors: Gun'ko
keywords: Au-TiO2 nanocomposite; Hot electrons; Surface plasmon resonance; TiO2 films