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Tuning Energy Levels of Electron‐Transport Materials by Nitrogen Orientation for Electrophosphorescent Devices with an ‘Ideal’ Operating Voltage
Author(s) -
Su ShiJian,
Sasabe Hisahiro,
Pu YongJin,
Nakayama Kenichi,
Kido Junji
Publication year - 2010
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.200904249
Subject(s) - materials science , phosphorescence , electroluminescence , iridium , optoelectronics , electron , oled , voltage , nitrogen , electron transport chain , pyridine , layer (electronics) , low voltage , fluorescence , nanotechnology , optics , electrical engineering , organic chemistry , chemistry , physics , biochemistry , engineering , quantum mechanics , catalysis
A series of 1,3,5‐triazine‐core‐containing electron‐transport materials (ETMs) are reported as an undoped electron‐transport layer (ETL), whose energy levels can be tuned by introducing pyridine rings on the periphery of the molecule and also orientation of nitrogen. An unprecedented low operating voltage of 2.42 V, corresponding to the emitting photon energy ( hv ), was achieved for the fac‐tris(2‐phenylpyridine) iridium (Ir(PPy)3) based green phosphorescent OLEDs at 100 cd m −2 without consumption of their efficiency. Moreover, the threshold voltage for electroluminescence can be even 0.1 ∼ 0.2 V lower than the minimum value of hv /e.