Tuning the Excitonic Properties of the 2D (PEA) 2 (MA) n −1 Pb n I 3 n +1 Perovskite Family via Quantum Confinement
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mass_in_PEA_MA_Pb_I-1.pdf
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Accepted version
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Author(s)
Dyksik, Mateusz
Wang, Shuli
Paritmongkol, Watcharaphol
Maude, Duncan K
Tisdale, William A
Baranowski, Michal
Plochocka, Paulina
Date Issued
2021
Journal
Journal of Physical Chemistry Letters
Publisher
American Chemical Society (ACS)
Version
Author's final manuscript
Abstract
© 2021 American Chemical Society. In atomically thin two-dimensional (2D) crystals, the excitonic properties and band structure scale strongly with the thickness, providing a new playground for the investigation of exciton physics in the ultimate confinement regime. Here, we demonstrate the evolution of the fundamental excitonic properties, such as reduced mass, wave function extension, and exciton binding energy, in the 2D perovskite (PEA)2(MA)n-1PbnI3n+1, for n = 1, 2, 3. These parameters are experimentally determined using optical spectroscopy in a high magnetic field up to 65 T. The observation of the interband Landau level transitions provides direct access to the reduced effective mass μ and band gap Eg. We show that μ increases with the number of inorganic sheets n, reaching the value of three-dimensional (3D) MAPbI3 already for n = 3. Our experimental observations contradict the general expectation that quantum confinement leads to an enhanced carrier mass, showing another aspect of the unprecedented flexibility in the design of the electronic properties of 2D perovskites.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Chemistry
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DOI of Published Version
https://doi.org/10.1021/acs.jpclett.0c03731
