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Title: Improvement of light extraction efficiency and reduction of driving voltage in organic light emitting diodes using a plasmonic crystal

Two-dimensional periodic corrugation was introduced into the surface of metallic cathodes of organic light-emitting diodes (OLEDs) to extract surface plasmon energy, which is trapped in that surface, as free-space photons. The dependence of the improvement factor of the emission efficiency on the modulation depth of the corrugation was systematically investigated. The corrugation was fabricated by using a colloidal lithography technique, which can be easily applied to a wide area. The obtained maximum improvement factor in current efficiency was 1.67 for an OLED with a 40 nm modulation depth, whereas the improvement in power efficiency was 2.35 for an OLED with a 60 nm modulation depth. We attributed the former improvement factor purely to optical effects and the latter to both optical and electrical effects, namely, a reduction of the electrical resistance of the organic layers due to the introduced corrugation.
Authors:
 [1] ;  [2] ;  [3]
  1. Advanced Device Laboratory, RIKEN, Hirosawa, Wako, Saitama 351-0198 (Japan)
  2. (Japan)
  3. Advanced Technology Laboratory, Oji Holding Corporation, Shinonome, Koto-ku, Tokyo 135-8558 (Japan)
Publication Date:
OSTI Identifier:
22283094
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 9; 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; CATHODES; CRYSTALS; EFFICIENCY; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; LAYERS; LIGHT EMITTING DIODES; MODULATION; ORGANIC COMPOUNDS; PERIODICITY; PHOTON EMISSION; PHOTONS; SURFACES