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A Bipolar Transporter as an Efficient Green Fluorescent Emitter and Host for Red Phosphors in Multi‐ and Single‐Layer Organic Light‐Emitting Diodes
Author(s) -
Ye Jun,
Chen Zhan,
Wang Kai,
An Feifei,
Yuan Yi,
Chen Wencheng,
Yang Qingdan,
Zhang Xiaohong,
Lee ChunSing
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402925
Subject(s) - phosphor , phosphorescence , triphenylamine , common emitter , fluorescence , materials science , quantum yield , homo/lumo , oled , optoelectronics , photochemistry , diode , analytical chemistry (journal) , chemistry , layer (electronics) , optics , nanotechnology , organic chemistry , molecule , physics
Multifunctional donor–acceptor compound 4,4′‐bis(dibenzothiophene‐ S,S ‐dioxide‐2‐yl)triphenylamine ( DSTPA ) was obtained by linking a strongly electron‐withdrawing core and a strongly electron‐donating core with a biphenyl bridge in linear spatial alignment. DSTPA not only has suitable HOMO and LUMO levels for easily accepting both holes and electrons, it was also demonstrated to have a high fluorescence quantum yield of 0.98 and a high triplet energy level of 2.39 eV. Versatile applications of DSTPA for bipolar transport, green fluorescent emission, and sensitizing a red phosphor were systematically investigated in a series of multi‐ and single‐layer organic light‐emitting devices. In traditional multilayer devices, it shows excellent performance both in an undoped fluorescent device (used as a green emitter and achieving maximum current and power efficiencies (CE and PE) of 12.6 cd A −1 and 9.4 Lm W −1 , respectively) and in a red phosphorescent device (used as a host and achieving maximum CE and PE of 26.4 cd A −1 and 26.3 Lm W −1 , respectively). Furthermore, DSTPA was also simultaneously used as an emitter, a hole transporter, and an electron transporter in a single‐layer device showing CE and PE of 5.1 cd A −1 and 4.7 Lm W −1 , respectively. A single‐layer red phosphorescent device with efficiencies of 11.7 cd A −1 and 12.6 Lm W −1 was obtained by doping DSTPA with a red phosphor. The performances of all of the devices in this work are comparable to the best of their corresponding classes in the literature.