Fast Dissociation and Reduced Auger Recombination of Multiple Excitons in Closely Packed PbS Nanocrystal Thin Films
- 27 March 2015
- journal article
- Published by American Chemical Society (ACS) in The Journal of Physical Chemistry Letters
- Vol. 6 (8), 1327-1332
- https://doi.org/10.1021/acs.jpclett.5b00293
Abstract
Exciton decay dynamics in chemically treated PbS quantum-dot (QD) films have been studied using femtosecond transient-absorption (TA) spectroscopy. In photoconductive QD films, a decay component with a lifetime of a few nanoseconds appeared in the TA signals because of exciton dissociation under weak excitation. Increasing excitation fluence resulted in additional fast-decay components corresponding to the lifetimes of multiple excitons, which decreased with increasing photoconductivity of the closely packed QD films. Auger recombination in photoexcited QDs was suppressed in highly photoconductive films. Our findings clearly show that the carrier transfer between the QDs dominates the lifetimes of single and multiple excitons.Keywords
Funding Information
- Japan Society for the Promotion of Science (25247052)
- Ministry of Education, Culture, Sports, Science, and Technology
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
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