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Title: Strain effects on the work function of an organic semiconductor

Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ~0.05% tensile strain along the rubrene π-stacking direction. Lastly, the results provide the first concrete link between mechanical strain and WF of an organic semiconductor and have important implications for understanding the connection between structural and electronic disorder in soft organic electronic materials.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [7] ;  [8] ;  [2] ;  [1]
  1. Univ. of Minnesota, Minneapolis, MN (United States)
  2. Stanford Univ., CA (United States). Dept. of Materials Science and Engineering
  3. Cergy-Pontoise Univ., Cergy-Pontoise (France); King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia)
  4. Univ. of Minnesota, Minneapolis, MN (United States). Characterization Facility
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  6. Georgia Inst. of Technology, Atlanta, GA (United States)
  7. Univ. of Kentucky, Lexington, KY (United States)
  8. King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia)
Publication Date:
OSTI Identifier:
1259668
Grant/Contract Number:
DMR-0706011; DMR-1420013
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE