title: Temporary Charge Carrier Separation Dominates the Photoluminescence Decay Dynamics of Colloidal CdSe Nanoplatelets.
abstract: Luminescent colloidal CdSe nanoplatelets with atomically defined thicknesses have recently been developed, and their potential for various applications has been shown. To understand their special properties, experiments have until now focused on the relatively short time scales of at most a few nanoseconds. Here, we measure the photoluminescence decay dynamics of colloidal nanoplatelets on time scales up to tens of microseconds. The excited state dynamics are found to be dominated by the slow (∼μs) dynamics of temporary exciton storage in a charge-separated state, previously overlooked. We study the processes of charge carrier separation and exciton recovery in pure CdSe nanoplatelets as well as in core-crown and core-shell CdSe/CdS nanoplatelets with high ensemble quantum yields of 50%, and discuss the implications. Our work highlights the importance of reversible charge carrier trapping and experiments over a wide range of time scales for the understanding of colloidal nanoemitters in general and nanoplatelets in particular.
authors: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands.
authors: Freddy T
authors: FT
authors: Rabouw
authors: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands.
authors: Johanna C
authors: JC
authors: van der Bok
authors: Laboratoire de Physique et d'Etude des Matériaux (LPEM), PSL Research University , ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France.
authors: Piernicola
authors: P
authors: Spinicelli
authors: Laboratoire de Physique et d'Etude des Matériaux (LPEM), PSL Research University , ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France.
authors: Benoît
authors: B
authors: Mahler
authors: Laboratoire de Physique et d'Etude des Matériaux (LPEM), PSL Research University , ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France.
authors: Michel
authors: M
authors: Nasilowski
authors: Laboratoire de Physique et d'Etude des Matériaux (LPEM), PSL Research University , ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France.
authors: Silvia
authors: S
authors: Pedetti
authors: Laboratoire de Physique et d'Etude des Matériaux (LPEM), PSL Research University , ESPCI-ParisTech, 10 rue Vauquelin, F-75231 Paris Cedex 5, France.
authors: Benoît
authors: B
authors: Dubertret
authors: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science , Princetonplein 1, 3584 CC Utrecht, The Netherlands.
authors: Daniël
authors: D
authors: Vanmaekelbergh
keywords: Colloidal nanoplatelets; charge carrier trapping; exciton recombination; photoluminescence decay