Ultra long-lived radiative trap states in CdSe quantum dots

Mohamed Abdellah, Khadga J. Karki*, Nils Lenngren, Kaibo Zheng, Torbjörn Pascher, Arkady Yartsev, Tõnu Pullerits

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

Surface states and traps play an important role in the photophysics of colloidal quantum dots. These states typically lead to large red-shifted photoluminescence. We have used steady-state and time-resolved spectroscopic techniques to investigate the nature of the traps and their lifetimes in colloidal CdSe quantum dots. We conclude that at least two different types of traps contribute to the photoluminescence. The trapping is more pronounced at higher excitation energies compared to the band edge excitation. Hole trapping is dominant in CdSe quantum dots. The time-resolved photoluminescence and pump-probe measurements show that the trapped holes live for longer than tens of microseconds at room temperature.

Original languageEnglish
Pages (from-to)21682-21686
Number of pages5
JournalJournal of Physical Chemistry C
Volume118
Issue number37
DOIs
StatePublished - 18 Sep 2014
Externally publishedYes

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