Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy

Khadga J. Karki; Fei Ma; Kaibo Zheng; Karel Zidek; Abdelrazek Mousa; Mohamed A. Abdellah; Maria E. Messing; L. Reine Wallenberg; Arkadi Yartsev; Tõnu Pullerits

doi:10.1038/srep02287

Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy

Khadga J. Karki^*, Fei Ma, Kaibo Zheng, Karel Zidek, Abdelrazek Mousa, Mohamed A. Abdellah, Maria E. Messing, L. Reine Wallenberg, Arkadi Yartsev, Tõnu Pullerits

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

36 Scopus citations

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.

Original language	English
Article number	2287
Journal	Scientific Reports
Volume	3
DOIs	https://doi.org/10.1038/srep02287
State	Published - 2013
Externally published	Yes

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@article{8774b7371e464706b109692fb9835fe0,

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.",

author = "Karki, {Khadga J.} and Fei Ma and Kaibo Zheng and Karel Zidek and Abdelrazek Mousa and Abdellah, {Mohamed A.} and Messing, {Maria E.} and Wallenberg, {L. Reine} and Arkadi Yartsev and T{\~o}nu Pullerits",

note = "Funding Information: We gratefully acknowledge financial support from the Swedish Research Council, the Knut and Alice Wallenberg Foundation, the Wenner-Gren Foundations, Crafoord foundation and Swedish Energy Agency. We thank Torbj{\"o}rn Pascher for the help with the time-resolved experiments. Collaboration within nmC@LU is acknowledged.",

year = "2013",

doi = "10.1038/srep02287",

language = "英语",

volume = "3",

journal = "Scientific Reports",

issn = "2045-2322",

publisher = "Nature Publishing Group",

}

TY - JOUR

T1 - Multiple exciton generation in nano-crystals revisited

T2 - Consistent calculation of the yield based on pump-probe spectroscopy

AU - Karki, Khadga J.

AU - Ma, Fei

AU - Zheng, Kaibo

AU - Zidek, Karel

AU - Mousa, Abdelrazek

AU - Abdellah, Mohamed A.

AU - Messing, Maria E.

AU - Wallenberg, L. Reine

AU - Yartsev, Arkadi

AU - Pullerits, Tõnu

N1 - Funding Information: We gratefully acknowledge financial support from the Swedish Research Council, the Knut and Alice Wallenberg Foundation, the Wenner-Gren Foundations, Crafoord foundation and Swedish Energy Agency. We thank Torbjörn Pascher for the help with the time-resolved experiments. Collaboration within nmC@LU is acknowledged.

PY - 2013

Y1 - 2013

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84881356632&partnerID=8YFLogxK

U2 - 10.1038/srep02287

DO - 10.1038/srep02287

M3 - 文章

C2 - 23887181

AN - SCOPUS:84881356632

SN - 2045-2322

VL - 3

JO - Scientific Reports

JF - Scientific Reports

M1 - 2287

ER -

Multiple exciton generation in nano-crystals revisited: Consistent calculation of the yield based on pump-probe spectroscopy

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