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 usu- ally 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.
Keywords
Cite
@article{arxiv.1302.6711,
title = {Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy},
author = {Khadga J. Karki and Fei Ma and Kaibo Zheng and Karel Zidek and Abdelrazek Mousa and Mohamed A. Abdellah and Maria Messing and L. Reine Wallenberg and Arkadi Yartsev and Tonu Pullerits},
journal= {arXiv preprint arXiv:1302.6711},
year = {2013}
}