Giant exciton oscillator strength and radiatively limited dephasing in two-dimensional platelets

Naeem, Ali, Masia, Francesco ORCID: https://orcid.org/0000-0003-4958-410X, Christodoulou, Sotirios, Moreels, Iwan, Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314 and Langbein, Wolfgang ORCID: https://orcid.org/0000-0001-9786-1023 2015. Giant exciton oscillator strength and radiatively limited dephasing in two-dimensional platelets. Physical Review B 91 (12) , 121302(R). 10.1103/PhysRevB.91.121302

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Abstract

We measured the intrinsic ground-state exciton dephasing and population dynamics in colloidal quasi-two-dimensional (2D) CdSe nanoplatelets at low temperature (5–50 K) using transient resonant four-wave mixing in heterodyne detection. Our results indicate that below 20 K the exciton dephasing is lifetime limited, with the exciton population lifetime being as fast as 1 ps. This is consistent with an exciton lifetime given by a fast radiative decay due to the large in-plane coherence area of the exciton center-of-mass motion in these quasi-2D systems compared to spherical nanocrystals. The radiative rate in such 2D platelet systems can be controlled by the platelet area over orders of magnitude.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy Biosciences
Subjects:	Q Science > Q Science (General) Q Science > QC Physics
Additional Information:	PDF uploaded in accordance with publisher's policies at http://www.sherpa.ac.uk/romeo/issn/1098-0121/ (accessed 12.11.15)
Publisher:	American Physical Society
ISSN:	1098-0121
Date of First Compliant Deposit:	30 March 2016
Date of Acceptance:	23 February 2015
Last Modified:	24 Nov 2024 01:45
URI:	https://orca.cardiff.ac.uk/id/eprint/72441

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