title: A phonon scattering bottleneck for carrier cooling in lead chalcogenide nanocrystals.
abstract: The cooling dynamics of hot charge carriers in colloidal lead chalcogenide nanocrystals is studied by hyperspectral transient absorption spectroscopy. We demonstrate a transient accumulation of charge carriers at a high energy critical point in the Brillouin zone. Using a theoretical study of the cooling rate in lead chalcogenides, we attribute this slowing down of charge carrier cooling to a phonon scattering bottleneck around this critical point. The relevance of this observation for the possible harvesting of the excess energy of hot carriers by schemes such as multiexciton generation is discussed.
authors.affiliation: Photonics Research Group, Ghent University , 9000 Ghent, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Geiregat
authors.forename: Christophe
authors.initials: C
authors.lastname: Delerue
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Justo
authors.forename: Michiel
authors.initials: M
authors.lastname: Aerts
authors.forename: Frank
authors.initials: F
authors.lastname: Spoor
authors.forename: Dries
authors.initials: D
authors.lastname: Van Thourhout
authors.forename: Laurens D A
authors.initials: LD
authors.lastname: Siebbeles
authors.forename: Guy
authors.initials: G
authors.lastname: Allan
authors.forename: Arjan J
authors.initials: AJ
authors.lastname: Houtepen
authors.forename: Zeger
authors.initials: Z
authors.lastname: Hens
keywords: PbS; PbSe; electron−phonon interaction; multiple exciton generation; quantum dots; transient absorption spectroscopy