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Title: Stability improvement of organic light emitting diodes by the insertion of hole injection materials on the indium tin oxide substrate

The degradation of organic light-emitting diodes (OLEDs) is a very complex issue, which might include interfacial charge accumulation, material diffusion, and electrical-induced chemical reaction during the operation. In this study, the origins of improvement in device stability from inserting a hole injection layer (HIL) at the indium tin oxide (ITO) anode are investigated. The results from aging single-layer devices show that leakage current increases in the case of ITO/hole transport layer contact, but this phenomenon can be prevented by inserting molybdenum oxide (MoO{sub 3}) or 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN{sub 6}) as an HIL. Moreover, X-ray photoemission spectroscopy suggests that the diffusion of indium atoms and active oxygen species can be impeded by introducing MoO{sub 3} or HAT-CN{sub 6} as an HIL. These results reveal that the degradation of OLEDs is related to indium and oxygen out-diffusion from the ITO substrates, and that the stability of OLEDs can be improved by impeding this diffusion with HILs.
Authors:
; ; ; ;  [1] ;  [1] ;  [2]
  1. Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 106, Taiwan (China)
  2. (China)
Publication Date:
OSTI Identifier:
22271118
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 12; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DIFFUSION; EMISSION SPECTROSCOPY; HOLES; INDIUM COMPOUNDS; LAYERS; LEAKAGE CURRENT; LIGHT EMITTING DIODES; MOLYBDENUM OXIDES; OXYGEN; PHASE STABILITY; PHOTOEMISSION; SUBSTRATES; TIN OXIDES; X-RAY SPECTROSCOPY