title: Multiple exciton generation in nano-crystals revisited: consistent calculation of the yield based on pump-probe spectroscopy.
abstract: Multiple exciton generation (MEG) is a process in which more than one exciton is generated upon the absorption of a high energy photon, typically higher than two times the band gap, in semiconductor nanocrystals. It can be observed experimentally using time resolved spectroscopy such as the transient absorption measurements. Quantification of the MEG yield is usually done by assuming that the bi-exciton signal is twice the signal from a single exciton. Herein we show that this assumption is not always justified and may lead to significant errors in the estimated MEG yields. We develop a methodology to determine proper scaling factors to the signals from the transient absorption experiments. Using the methodology we find modest MEG yields in lead chalcogenide nanocrystals including the nanorods.
authors.affiliation: Department of Chemical Physics, Lund University, Box 124, 22100 Lund, Sweden. Khadga.Karki@chemphys.lu.se
authors.forename: Khadga J
authors.initials: KJ
authors.lastname: Karki
authors.forename: Fei
authors.initials: F
authors.lastname: Ma
authors.forename: Kaibo
authors.initials: K
authors.lastname: Zheng
authors.forename: Karel
authors.initials: K
authors.lastname: Zidek
authors.forename: Abdelrazek
authors.initials: A
authors.lastname: Mousa
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Abdellah
authors.forename: Maria E
authors.initials: ME
authors.lastname: Messing
authors.forename: L Reine
authors.initials: LR
authors.lastname: Wallenberg
authors.forename: Arkadi
authors.initials: A
authors.lastname: Yartsev
authors.forename: Tõnu
authors.initials: T
authors.lastname: Pullerits