Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites

J. C. Blancon, H. Tsai, W. Nie, C. C. Stoumpos, L. Pedesseau, C. Katan, M. Kepenekian, C. M.M. Soe, K. Appavoo, M. Y. Sfeir, S. Tretiak, P. M. Ajayan, M. G. Kanatzidis, J. Even, J. J. Crochet, A. D. Mohite

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Abstract

Understanding and controlling charge and energy flow in state-of-the-art semiconductor quantum wells has enabled high-efficiency optoelectronic devices. Two-dimensional (2D) Ruddlesden-Popper perovskites are solution-processed quantum wells wherein the band gap can be tuned by varying the perovskite-layer thickness, which modulates the effective electron-hole confinement. We report that, counterintuitive to classical quantum-confined systems where photogenerated electrons and holes are strongly bound by Coulomb interactions or excitons, the photophysics of thin films made of Ruddlesden-Popper perovskites with a thickness exceeding two perovskite-crystal units (>1.3 nanometers) is dominated by lower-energy states associated with the local intrinsic electronic structure of the edges of the perovskite layers. These states provide a direct pathway for dissociating excitons into longer-lived free carriers that substantially improve the performance of optoelectronic devices.

Original languageEnglish
Pages (from-to)1288-1292
Number of pages5
JournalScience
Volume355
Issue number6331
DOIs
Publication statusPublished - Mar 24 2017

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Blancon, J. C., Tsai, H., Nie, W., Stoumpos, C. C., Pedesseau, L., Katan, C., Kepenekian, M., Soe, C. M. M., Appavoo, K., Sfeir, M. Y., Tretiak, S., Ajayan, P. M., Kanatzidis, M. G., Even, J., Crochet, J. J., & Mohite, A. D. (2017). Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites. Science, 355(6331), 1288-1292. https://doi.org/10.1126/science.aal4211