New Insights in the Excitonic Emission of ZnS Colloidal Quantum Dots

We have studied the electronic and optical properties of wurtzite ZnS colloidal quantum dots by means of atomistic empirical pseudopotential method complemented by configuration interaction calculations. For this purpose, we have developed a new set of reliable pseudopotentials (for Zn and S) which...

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Bibliographic Details
Published in:Journal of physical chemistry. C 2014-05, Vol.118 (19), p.10502-10508
Main Authors: Zeng, Zaiping, Garoufalis, Christos S, Baskoutas, Sotirios
Format: Article
Language:English
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Summary:We have studied the electronic and optical properties of wurtzite ZnS colloidal quantum dots by means of atomistic empirical pseudopotential method complemented by configuration interaction calculations. For this purpose, we have developed a new set of reliable pseudopotentials (for Zn and S) which give an accurate and balanced description of ZnS bulk properties. Our results for the size-dependent optical gap are found to be in excellent agreement with the experimental measurements, offering valuable information with regard to the nature of the near-band-edge excitons. In particular, it is found that not only the first optically allowed exciton is an A-exciton for the full range of dot sizes but also all the pronounced emission peaks exhibit an in-plane polarization (i.e., A or B excitons). Under normal conditions, the C-exciton emissions which are common in the ZnO analogues are found to be inactive in the lower part of the excitonic spectrum of ZnS colloidal quantum dots.
ISSN:1932-7447
1932-7455
DOI:10.1021/jp5024108