Computational Study of Magic-Size CdSe Clusters with Complementary Passivation by Carboxylic and Amine Ligands

Abstract
The electronic and optical properties of tetrahedral CdSe magic clusters (average diameter.5 nm) protected by carboxyl and amine ligands, which correspond to previously reported experimental structures, are studied using density functional theory. We find extreme ligand packing densities, capping every single dangling bond of the inorganic core, strong dependence of the Z-type metal carboxylate binding on the amount of excess amine, and potential for improved photoluminescence upon replacing phenyl ligands with alkanes. The computed absorption spectra of the Cd35Se20 cluster agree well with experiments, resolving the 0.2 eV splitting of the first exciton peak due to spin-orbit coupling. We discuss the origin of the significant broadening of the optical spectra as due to phonons and structural variations in the ligand configurations and inorganic core apexes. © 2016 American Chemical Society.

Citation
Voznyy O, Mokkath JH, Jain A, Sargent EH, Schwingenschlögl U (2016) Computational Study of Magic-Size CdSe Clusters with Complementary Passivation by Carboxylic and Amine Ligands. The Journal of Physical Chemistry C 120: 10015–10019. Available: http://dx.doi.org/10.1021/acs.jpcc.5b10908.

Acknowledgements
We thank Jonathan Owen and Alex Beecher for fruitful discussions. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST), Award KUS-11-009-21, the Ontario Research Fund - Research Excellence Program, and the Natural Sciences and Engineering Research Council (NSERC) of Canada. Computational resources provided by KAUST IT and the SciNet HPC Consortium are gratefully acknowledged. SciNet is funded by the Canada Foundation for Innovation under the auspices of Compute Canada, the Government of Ontario, the Ontario Research Fund - Research Excellence Program, and the University of Toronto.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry C

DOI
10.1021/acs.jpcc.5b10908

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