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arXiv · 1709.09610

Addressing the exciton fine structure in colloidal nanocrystals: the case of CdSe nanoplatelets

Elena V. Shornikova·Louis Biadala·Dmitri R. Yakovlev·Victor F. Sapega·Yuri G. Kusrayev·Anatolie A. Mitioglu·Mariana V. Ballottin·Peter C. M. Christianen·Vasilii V. Belykh·Mikhail V. Kochiev·Nikolai N. Sibeldin·Aleksandr A. Golovatenko·Anna V. Rodina·Nikolay A. Gippius·Alexis Kuntzmann·Ye Jiang·Michel Nasilowski·Benoit Dubertret·Manfred Bayer
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Abstract

We study the band-edge exciton fine structure and in particular its bright-dark splitting in colloidal semiconductor nanocrystals by four different optical methods based on fluorescence line narrowing and time-resolved measurements at various temperatures down to 2 K. We demonstrate that all these methods provide consistent splitting values and discuss their advances and limitations. Colloidal CdSe nanoplatelets with thicknesses of 3, 4 and 5 monolayers are chosen for experimental demonstrations. The bright-dark splitting of excitons varies from 3.2 to 6.0 meV and is inversely proportional to the nanoplatelet thickness. Good agreement between experimental and theoretically calculated size dependence of the bright-dark exciton slitting is achieved. The recombination rates of the bright and dark excitons and the bright to dark relaxation rate are measured by time-resolved techniques.

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Elena V. Shornikova, Louis Biadala, Dmitri R. Yakovlev, Victor F. Sapega, Yuri G. Kusrayev, Anatolie A. Mitioglu, Mariana V. Ballottin, Peter C. M. Christianen, Vasilii V. Belykh, Mikhail V. Kochiev, Nikolai N. Sibeldin, Aleksandr A. Golovatenko, Anna V. Rodina, Nikolay A. Gippius, Alexis Kuntzmann, Ye Jiang, Michel Nasilowski, Benoit Dubertret, Manfred Bayer. 2017-09-27. Addressing the exciton fine structure in colloidal nanocrystals: the case of CdSe nanoplatelets. https://doi.org/10.1039/c7nr07206f

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