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Title: Thermally activated delayed fluorescence from {sup 3}nπ* to {sup 1}nπ* up-conversion and its application to organic light-emitting diodes

Intense nπ* fluorescence from a nitrogen-rich heterocyclic compound, 2,5,8-tris(4-fluoro-3-methylphenyl)-1,3,4,6,7,9,9b-heptaazaphenalene (HAP-3MF), is demonstrated. The overlap-forbidden nature of the nπ* transition and the higher energy of the {sup 3}ππ* state than the {sup 3}nπ* one lead to a small energy difference between the lowest singlet (S{sub 1}) and triplet (T{sub 1}) excited states of HAP-3MF. Green-emitting HAP-3MF has a moderate photoluminescence quantum yield of 0.26 in both toluene and doped film. However, an organic light-emitting diode containing HAP-3MF achieved a high external quantum efficiency of 6.0%, indicating that HAP-3MF harvests singlet excitons through a thermally activated T{sub 1} → S{sub 1} pathway in the electroluminescent process.
Authors:
; ;  [1] ;  [1] ;  [2] ;  [1] ;  [3]
  1. Department of Chemistry and Biochemistry, and Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
  2. (Japan)
  3. (WPI-I2CNER), Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
Publication Date:
OSTI Identifier:
22303955
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 1; 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; CONVERSION; DOPED MATERIALS; ELECTROLUMINESCENCE; EXCITED STATES; EXCITONS; FILMS; FLUORESCENCE; HETEROCYCLIC COMPOUNDS; LIGHT EMITTING DIODES; NITROGEN ADDITIONS; ORGANIC SEMICONDUCTORS; PHOTOLUMINESCENCE; QUANTUM EFFICIENCY; TOLUENE