Abstract
The realization of high-yield, low-threshold carrier multiplication (CM) in semiconductor quantum dots (QDs) is a promising step toward third-generation photovoltaics (PV). Recent studies of QD solar cells have shown that CM can indeed produce greater-than-unity quantum efficiencies in photon-to-charge- carrier conversion, establishing the relevance of this process to practical PV technologies. While being appreciable, the reported CM yields are still not high enough for a significant increase in the power conversion efficiency over traditional bulk materials. At present, the design of nanomaterials with improved CM is hindered by a poor understanding of the mechanism underlying this process. Here, we present a possible solution to this problem by introducing a model that treats CM as a competition between impact-ionization-like scattering and non-CM energy losses. Importantly, it allows for evaluation of expected CM yields from fairly straightforward measurements of Auger recombination (inverse of CM) and near-band-edge carrier cooling. The validation of this model via a comparative CM study of PbTe, PbSe, and PbS QDs suggests that it indeed represents a predictive capability, which might help in the development of nanomaterials with improved CM performance.
| Original language | English |
|---|---|
| Pages (from-to) | 2061-2068 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 4 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Jun 20 2013 |
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ASJC Scopus subject areas
- Materials Science(all)
Cite this
Carrier multiplication in quantum dots within the framework of two competing energy relaxation mechanisms. / Stewart, John T.; Padilha, Lazaro A.; Bae, Wan Ki; Koh, Weon Kyu; Pietryga, Jeffrey M.; Klimov, Victor I.
In: Journal of Physical Chemistry Letters, Vol. 4, No. 12, 20.06.2013, p. 2061-2068.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Carrier multiplication in quantum dots within the framework of two competing energy relaxation mechanisms
AU - Stewart, John T.
AU - Padilha, Lazaro A.
AU - Bae, Wan Ki
AU - Koh, Weon Kyu
AU - Pietryga, Jeffrey M.
AU - Klimov, Victor I
PY - 2013/6/20
Y1 - 2013/6/20
N2 - The realization of high-yield, low-threshold carrier multiplication (CM) in semiconductor quantum dots (QDs) is a promising step toward third-generation photovoltaics (PV). Recent studies of QD solar cells have shown that CM can indeed produce greater-than-unity quantum efficiencies in photon-to-charge- carrier conversion, establishing the relevance of this process to practical PV technologies. While being appreciable, the reported CM yields are still not high enough for a significant increase in the power conversion efficiency over traditional bulk materials. At present, the design of nanomaterials with improved CM is hindered by a poor understanding of the mechanism underlying this process. Here, we present a possible solution to this problem by introducing a model that treats CM as a competition between impact-ionization-like scattering and non-CM energy losses. Importantly, it allows for evaluation of expected CM yields from fairly straightforward measurements of Auger recombination (inverse of CM) and near-band-edge carrier cooling. The validation of this model via a comparative CM study of PbTe, PbSe, and PbS QDs suggests that it indeed represents a predictive capability, which might help in the development of nanomaterials with improved CM performance.
AB - The realization of high-yield, low-threshold carrier multiplication (CM) in semiconductor quantum dots (QDs) is a promising step toward third-generation photovoltaics (PV). Recent studies of QD solar cells have shown that CM can indeed produce greater-than-unity quantum efficiencies in photon-to-charge- carrier conversion, establishing the relevance of this process to practical PV technologies. While being appreciable, the reported CM yields are still not high enough for a significant increase in the power conversion efficiency over traditional bulk materials. At present, the design of nanomaterials with improved CM is hindered by a poor understanding of the mechanism underlying this process. Here, we present a possible solution to this problem by introducing a model that treats CM as a competition between impact-ionization-like scattering and non-CM energy losses. Importantly, it allows for evaluation of expected CM yields from fairly straightforward measurements of Auger recombination (inverse of CM) and near-band-edge carrier cooling. The validation of this model via a comparative CM study of PbTe, PbSe, and PbS QDs suggests that it indeed represents a predictive capability, which might help in the development of nanomaterials with improved CM performance.
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U2 - 10.1021/jz4004334
DO - 10.1021/jz4004334
M3 - Article
VL - 4
SP - 2061
EP - 2068
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 12
ER -