Article pubs.acs.org/JPCC
Watching Photoactivation in a Ru(II) Chromophore−Catalyst Assembly on TiO2 by Ultrafast Spectroscopy Li Wang,† Dennis L. Ashford,† David W. Thompson,‡ Thomas J. Meyer,† and John M. Papanikolas*,† †
Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States Department of Chemistry, Memorial University, St. John’s, NL A1B 1R1, Canada
‡
S Supporting Information *
ABSTRACT: This paper examines the ultrafast dynamics of the initial photoactivation step in a molecular assembly consisting of a chromophore (denoted [RuaII]2+) and a watersplitting catalyst (denoted [RubII]2+) anchored to TiO2. Photoexcitation of the chromophore is followed by rapid electron injection from the Ru(II) metal-to-ligand charge-transfer (MLCT) excited state. The injection process was followed via the decay of the bpy radical anion absorption at 375 nm. Injection is ∼95% efficient and exhibits multiple kinetic components with decay times ranging from
