Effects of particle size and annealing on plasmon-induced charge separation at self-assembled gold nanoparticle arrays

Abstract

Two-dimensional periodic Au nanoparticle arrays were constructed on TiO₂ thin films by a micelle lithography method and seed-mediated photoelectrochemical growth. Their adjustable interparticle distance allows investigation of a particle size effect on plasmon-induced charge separation (PICS) efficiencies without interference from particle aggregation or plasmon coupling. External or internal PICS efficiencies were found to increase and decrease, respectively, with an increase in particle diameter from 25 to 38 nm. Improvement of the contact between Au nanoparticles and TiO₂ by annealing enhanced the intensity of a plasmonic interface mode and both external and internal PICS efficiencies.