RT Journal Article
SR Electronic
T1 Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites
JF Science
JO Science
FD American Association for the Advancement of Science
DO 10.1126/science.aal4211
A1 Blancon, J.-C.
A1 Tsai, H.
A1 Nie, W.
A1 Stoumpos, C. C.
A1 Pedesseau, L.
A1 Katan, C.
A1 Kepenekian, M.
A1 Soe, C. M. M.
A1 Appavoo, K.
A1 Sfeir, M. Y.
A1 Tretiak, S.
A1 Ajayan, P. M.
A1 Kanatzidis, M. G.
A1 Even, J.
A1 Crochet, J. J.
A1 Mohite, A. D.
YR 2017
UL http://science.sciencemag.org/content/early/2017/03/08/science.aal4211.abstract
AB Understanding and controlling charge and energy flow in state-of-the-art semiconductor quantum-wells has enabled high-efficiency optoelectronic devices. Two-dimensional 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 photo-generated electrons and holes are strongly bound by Coulomb interactions or excitons, the photo-physics 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 significantly improve the performance of optoelectronic devices.