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

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. Furthermore, these states provide a direct pathway for dissociating excitons into longer-lived free carriers that substantially improve the performance of optoelectronic devices.
Authors:
ORCiD logo [1] ;  [2] ; ORCiD logo [1] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [5] ; ORCiD logo [5] ; ORCiD logo [3] ;  [6] ; ORCiD logo [6] ; ORCiD logo [1] ;  [7] ;  [3] ; ORCiD logo [4] ; ORCiD logo [1] ; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rice Univ., Houston, TX (United States)
  3. Northwestern Univ., Evanston, IL (United States)
  4. Institut National des Sciences Appliquees (INSA) de Rennes, Rennes (France)
  5. Univ. de Rennes 1, Rennes (France)
  6. Brookhaven National Lab. (BNL), Upton, NY (United States)
  7. Rice Univ., Houston, TX (United States)
Publication Date:
Report Number(s):
LA-UR-17-20088; BNL-204650-2018-JAAM
Journal ID: ISSN 0036-8075; TRN: US1800658
Grant/Contract Number:
AC52-06NA25396; 300034; 300035; SC0012541; 300033; SC0012704
Type:
Published Article
Journal Name:
Science
Additional Journal Information:
Journal Volume: 355; Journal Issue: 6331; Journal ID: ISSN 0036-8075
Publisher:
AAAS
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; Material Science
OSTI Identifier:
1434400
Alternate Identifier(s):
OSTI ID: 1414133; OSTI ID: 1437943