title: Optimal metal domain size for photocatalysis with hybrid semiconductor-metal nanorods.
abstract: Semiconductor-metal hybrid nanostructures offer a highly controllable platform for light-induced charge separation, with direct relevance for their implementation in photocatalysis. Advances in the synthesis allow for control over the size, shape and morphology, providing tunability of the optical and electronic properties. A critical determining factor of the photocatalytic cycle is the metal domain characteristics and in particular its size, a subject that lacks deep understanding. Here, using a well-defined model system of cadmium sulfide-gold nanorods, we address the effect of the gold tip size on the photocatalytic function, including the charge transfer dynamics and hydrogen production efficiency. A combination of transient absorption, hydrogen evolution kinetics and theoretical modelling reveal a non-monotonic behaviour with size of the gold tip, leading to an optimal metal domain size for the most efficient photocatalysis. We show that this results from the size-dependent interplay of the metal domain charging, the relative band-alignments, and the resulting kinetics.
authors.affiliation: The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond Safra Campus Givat-Ram, Jerusalem 91904, Israel.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Ben-Shahar
authors.affiliation: Dipartimento di Fisica, IFN-CNR, Politecnico di Milano, 20133 Milan, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Scotognella
authors.affiliation: Dipartimento di Fisica, IFN-CNR, Politecnico di Milano, 20133 Milan, Italy.
authors.forename: Ilka
authors.initials: I
authors.lastname: Kriegel
authors.affiliation: Dipartimento di Fisica, IFN-CNR, Politecnico di Milano, 20133 Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Moretti
authors.affiliation: Dipartimento di Fisica, IFN-CNR, Politecnico di Milano, 20133 Milan, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Cerullo
authors.affiliation: Department of Chemistry, University of California and Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, USA.|The Sackler Institute for Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel.
authors.forename: Eran
authors.initials: E
authors.lastname: Rabani
authors.affiliation: The Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Edmond Safra Campus Givat-Ram, Jerusalem 91904, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Banin