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Title: Lithium fluoride injection layers can form quasi-Ohmic contacts for both holes and electrons

Thin LiF interlayers are typically used in organic light-emitting diodes to enhance the electron injection. Here, we show that the effective work function of a contact with a LiF interlayer can be either raised or lowered depending on the history of the applied bias. Formation of quasi-Ohmic contacts for both electrons and holes is demonstrated by electroluminescence from symmetric LiF/polymer/LiF diodes in both bias polarities. The origin of the dynamic switching is charging of electrically induced Frenkel defects. The current density–electroluminescence–voltage characteristics can qualitatively be explained. The interpretation is corroborated by unipolar memristive switching and by bias dependent reflection measurements.
Authors:
; ;  [1] ; ;  [2] ;  [3]
  1. Molecular Materials and Nanosystems and Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)
  2. Instituto de Telecomunicações, Av. Rovisco, Pais, 1, 1049 – 001, Lisboa, Portugal and Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)
  3. Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany and King Abdulaziz University, Jeddah (Saudi Arabia)
Publication Date:
OSTI Identifier:
22351009
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 12; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CURRENT DENSITY; ELECTRIC POTENTIAL; ELECTROLUMINESCENCE; ELECTRON BEAM INJECTION; ELECTRONS; FRENKEL DEFECTS; HOLES; INJECTION; LAYERS; LIGHT EMITTING DIODES; LITHIUM FLUORIDES; ORGANIC SEMICONDUCTORS; POLYMERS; REFLECTION; SYMMETRY; WORK FUNCTIONS