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False multiple exciton recombination and multiple exciton generation signals in semiconductor quantum dots arise from surface charge trapping.

Authors :
Tyagi, Pooja
Kambhampati, Patanjali
Source :
Journal of Chemical Physics. 3/7/2011, Vol. 134 Issue 9, p094706. 10p. 1 Diagram, 9 Graphs.
Publication Year :
2011

Abstract

Multiple exciton recombination (MER) and multiple exciton generation (MEG) are two of the main processes for assessing the usefulness of quantum dots (QDs) in photovoltaic devices. Recent experiments, however, have shown that a firm understanding of both processes is far from well established. By performing surface-dependent measurements on colloidal CdSe QDs, we find that surface-induced charge trapping processes lead to false MER and MEG signals resulting in an inaccurate measurement of these processes. Our results show that surface-induced processes create a significant contribution to the observed discrepancies in both MER and MEG experiments. Spectral signatures in the transient absorption signals reveal the physical origin of these false signals. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
134
Issue :
9
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
59154928
Full Text :
https://doi.org/10.1063/1.3561063