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Title: Horizontal molecular orientation in solution-processed organic light-emitting diodes

Horizontal orientation of the emission transition dipole moments achieved in glassy vapor-deposited organic thin films leads to an enhancement of the light out-coupling efficiency in organic light-emitting diodes (OLEDs). Here, our combined study of variable angle spectroscopic ellipsometry and angle dependent photoluminescence demonstrates that such a horizontal orientation can be achieved in glassy spin-coated organic films based on a composite blend of a heptafluorene derivative as a dopant and a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl as a host. Solution-processed fluorescent OLEDs with horizontally oriented heptafluorene emitters were then fabricated and emitted deep blue electroluminescence with an external quantum efficiency as high as 5.3%.
Authors:
;  [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [1] ;  [2] ;
  1. Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
  2. (JST), ERATO, Adachi Molecular Exciton Engineering Project, c/o Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
  3. (Japan)
  4. (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
Publication Date:
OSTI Identifier:
22412624
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 6; 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; BIPHENYL; COUPLING; DIPOLE MOMENTS; ELECTROLUMINESCENCE; ELLIPSOMETRY; FLUORESCENCE; LIGHT EMITTING DIODES; MATHEMATICAL SOLUTIONS; ORIENTATION; PHOTOLUMINESCENCE; QUANTUM EFFICIENCY; SPIN; THIN FILMS; VAPOR DEPOSITED COATINGS; VISIBLE RADIATION