title: Colloidal dual-band gap cell for photocatalytic hydrogen generation.
abstract: We report that the internal quantum efficiency for hydrogen generation in spherical, Pt-decorated CdS nanocrystals can be tuned by quantum confinement, resulting in higher efficiencies for smaller than for larger nanocrystals (17.3% for 2.8 nm and 11.4% for 4.6 nm diameter nanocrystals). We attribute this to a larger driving force for electron and hole transfer in the smaller nanocrystals. The larger internal quantum efficiency in smaller nanocrystals enables a novel colloidal dual-band gap cell utilising differently sized nanocrystals and showing larger external quantum efficiencies than cells with only one size of nanocrystals (9.4% for 2.8 nm particles only and 14.7% for 2.8 nm and 4.6 nm nanocrystals). This represents a proof-of-principle for future colloidal tandem cell.
authors.affiliation: Department of Physics and Stephenson Institute for Renewable Energy, The University of Liverpool, Chadwick Building, Peach Street, Liverpool, L69 7ZF, UK. w.li8@aston.ac.uk fjaeckel@liverpool.ac.uk.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Graeme
authors.initials: G
authors.lastname: O'Dowd
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Whittles
authors.forename: David
authors.initials: D
authors.lastname: Hesp
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Gründer
authors.forename: Vinod R
authors.initials: VR
authors.lastname: Dhanak
authors.forename: Frank
authors.initials: F
authors.lastname: Jäckel