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Title: White top-emitting organic light-emitting diodes with solution-processed nano-particle scattering layers

A random scattering approach to enhance light extraction in white top-emitting organic light-emitting diodes (OLEDs) is reported. Through solution processing from fluorinated solvents, a nano-particle scattering layer (NPSL) can be deposited directly on top of small molecule OLEDs without affecting their electrical performance. The scattering length for light inside the NPSL is determined from transmission measurements and found to be in agreement with Mie scattering theory. Furthermore, the dependence of the light outcoupling enhancement on electron transport layer thickness is studied. Depending on the electron transport layer thickness, the NPSL enhances the external quantum efficiency of the investigated white OLEDs by between 1.5 and 2.3-fold. For a device structure that has been optimized prior to application of the NPSL, the maximum external quantum efficiency is improved from 4.7% to 7.4% (1.6-fold improvement). In addition, the scattering layer strongly reduces the undesired shift in emission color with viewing angle.
Authors:
 [1] ;  [2] ; ;  [1] ;  [1] ;  [3]
  1. Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden (Germany)
  2. (Germany)
  3. (United Kingdom)
Publication Date:
OSTI Identifier:
22486207
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COLOR; LAYERS; LIGHT EMITTING DIODES; PERFORMANCE; PROCESSING; QUANTUM EFFICIENCY; RANDOMNESS; SCATTERING; SCATTERING LENGTHS; SOLVENTS; THICKNESS