Pump-probe transient absorption spectroscopy has been used to study the excited-state dynamics of CdTe nanocrystals (NCs) on the picosecond time scale.  Selective excitation of the two lowest energy transitions, 1S3/2(h)-1S(e) and 2S3/2(h)-1S(e), was used to separate and measure each carrier's contribution to the intraband relaxation dynamics. The results reveal unexpected behavior, including a significant contribution to the transient bleaching from the valence band hole and a new bleach feature shifted to lower energy from the 1S3/2(h)-1S(e) [band edge] peak. These results demonstrate important photophysical differences between CdTe and CdSe NCs on this time scale. Understanding these differences is a key first step in understanding the behavior of nanoheterostructures based on CdTe, and may shed light on the photophysics of other types of semiconductor NCs as well.

Unexpected behavior in the ultrafast excited state absorption of CdTe nanocrystals-comparison with the CdSe system

244th National Meeting (2012)

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