Nano Archive

Multiple exciton generation in films of electronically coupled PbSe quantum dots

Luther, Joseph M. and Beard, Matthew C. and Song, Qing and Law, Matt and Ellingson, Randy J. and Nozik, Arthur J. (2007) Multiple exciton generation in films of electronically coupled PbSe quantum dots. NANO LETTERS, 7 (6). pp. 1779-1784.

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Official URL: http://pubs.acs.org/doi/full/10.1021/nl0708617

Abstract

We study multiple exciton generation (MEG) in electronically coupled films of PbSe quantum dots (QDs) employing ultrafast time-resolved transient absorption spectroscopy. We demonstrate that the MEG efficiency in PbSe does not decrease when the QDs are treated with hydrazine, which has been shown to greatly enhance carrier transport in PbSe QD films by decreasing the interdot distance. The quantum yield is measured and compared to previously reported values for electronically isolated QDs suspended in organic solvents at similar to 4 and 4.5 times the effective band gap. A slightly modified analysis is applied to extract the MEG efficiency and the absorption cross section of each sample at the pump wavelength. We compare the absorption cross sections of our samples to that of bulk PbSe. We find that both the biexciton lifetime and the absorption cross section increase in films relative to isolated QDs in solution.

Item Type:Article
Uncontrolled Keywords:CARRIER MULTIPLICATION; SOLAR-CELLS; SEMICONDUCTOR NANOCRYSTALS; OPTICAL-PROPERTIES; CHARGE SEPARATION; CDSE NANOCRYSTALS; COLLOIDAL PBSE; PHOTOLUMINESCENCE; PHOTOCONDUCTIVITY; SOLIDS
Subjects:Material Science > Functional and hybrid materials
Physical Science > Quantum phenomena
ID Code:6170
Deposited By:IoN
Deposited On:11 Sep 2009 12:29
Last Modified:11 Sep 2009 12:29

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