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Thickness-Dependent Dark-Bright Exciton Splitting and Phonon Bottleneck in CsPbBr(3)-Based Nanoplatelets Revealed via Magneto-Optical Spectroscopy

[Image: see text] The optimized exploitation of perovskite nanocrystals and nanoplatelets as highly efficient light sources requires a detailed understanding of the energy spacing within the exciton manifold. Dark exciton states are particularly relevant because they represent a channel that reduces...

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Detalles Bibliográficos
Autores principales: Wang, Shuli, Dyksik, Mateusz, Lampe, Carola, Gramlich, Moritz, Maude, Duncan K., Baranowski, Michał, Urban, Alexander S., Plochocka, Paulina, Surrente, Alessandro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9479212/
https://www.ncbi.nlm.nih.gov/pubmed/36036573
http://dx.doi.org/10.1021/acs.nanolett.2c01826
Descripción
Sumario:[Image: see text] The optimized exploitation of perovskite nanocrystals and nanoplatelets as highly efficient light sources requires a detailed understanding of the energy spacing within the exciton manifold. Dark exciton states are particularly relevant because they represent a channel that reduces radiative efficiency. Here, we apply large in-plane magnetic fields to brighten optically inactive states of CsPbBr(3)-based nanoplatelets for the first time. This approach allows us to access the dark states and directly determine the dark-bright splitting, which reaches 22 meV for the thinnest nanoplatelets. The splitting is significantly less for thicker nanoplatelets due to reduced exciton confinement. Additionally, the form of the magneto-PL spectrum suggests that dark and bright state populations are nonthermalized, which is indicative of a phonon bottleneck in the exciton relaxation process.