The quantum-confined Stark effect (QCSE) is an established optical modulation mechanism, yet top-performing modulators harnessing it rely on costly fabrication processes. Here, we present large modulation amplitudes for solution-processed layered hybrid perovskites and a modulation mechanism related to the orientational polarizability of dipolar cations confined within these self-assembled quantum wells. We report an anomalous (blue-shifting) QCSE for layers that contain methylammonium cations, in contrast with cesium-containing layers that show normal (red-shifting) behavior. We attribute the blue-shifts to an extraordinary diminution in the exciton binding energy that arises from an augmented separation of the electron and hole wavefunctions caused by the orientational response of the dipolar cations. The absorption coefficient changes, realized by either the red- or blue-shifts, are the strongest among solution-processed materials at room temperature and are comparable to those exhibited in the highest-performing epitaxial compound semiconductor heterostructures.
|Original language||English (US)|
|State||Published - Oct 11 2018|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-11-009-21
Acknowledgements: The work presented in this publication was supported by funding from the Natural Sciences and Engineering Research Council (NSERC) of Canada and from an award (KUS-11-009-21) from the King Abdullah University of Science and Technology. Computations were performed on the General Purpose Cluster supercomputer at the SciNet HPC Consortium. SciNet is funded by: the Canada Foundation for Innovation under the auspices of Compute Canada; the Government of Ontario; Ontario Research Fund—Research Excellence; and the University of Toronto. CHESS is supported by the NSF & NIH/NIGMS via NSF award DMR-1332208. Work was also partially funded by Huawei Canada. We thank E. Palmiano, R. Wolowiec, and D. Kopilovic for assistance in the course of study. We also thank R. Sabatini, L. Quan, O. Ouellette, A. Proppe, J. Fan, M. Saidaminov, A. Jain, M. Liu, and Z. Yang for assistance in the lab and for fruitful discussions.