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Highly Efficient Simple‐Structure Blue and All‐Phosphor Warm‐White Phosphorescent Organic Light‐Emitting Diodes Enabled by Wide‐Bandgap Tetraarylsilane‐Based Functional Materials
Author(s) -
Gong Shaolong,
Sun Ning,
Luo Jiajia,
Zhong Cheng,
Ma Dongge,
Qin Jingui,
Yang Chuluo
Publication year - 2014
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201400149
Subject(s) - diphenylphosphine oxide , phosphorescence , materials science , quantum efficiency , phosphor , phosphorescent organic light emitting diode , iridium , oled , diphenylphosphine , band gap , ambipolar diffusion , photochemistry , diphenylamine , homo/lumo , optoelectronics , molecule , fluorescence , nanotechnology , layer (electronics) , chemistry , organic chemistry , electron , polymer chemistry , optics , physics , quantum mechanics , phosphine , metallurgy , catalysis
Two host materials of {4‐[diphenyl(4‐pyridin‐3‐ylphenyl)silyl]phenyl}diphenylamine ( p ‐PySiTPA) and {4‐[[4‐(diphenylphosphoryl)phenyl](diphenyl)silyl]phenyl}diphenylamine ( p ‐POSiTPA), and an electron‐transporting material of [(diphenylsilanediyl)bis(4,1‐phenylene)]bis(diphenylphosphine) dioxide (SiDPO) are developed by incorporating appropriate charge transporting units into the tetraarylsilane skeleton. The host materials feature both high triplet energies (ca. 2.93 eV) and ambipolar charge transporting nature; the electron‐transporting material comprising diphenylphosphine oxide units and tetraphenylsilane skeleton exhibits a high triplet energy (3.21 eV) and a deep highest occupied molecular orbital (HOMO) level (‐6.47 eV). Using these tetraarylsilane‐based functional materials results in a high‐efficiency blue phosphorescent device with a three‐organic‐layer structure of 1,1‐bis[4‐[ N,N ‐di( p ‐tolyl)‐amino]phenyl]cyclohexane (TAPC)/ p ‐POSiTPA: iridium(III) bis(4′,6′‐difluorophenylpyridinato)tetrakis(1‐pyrazolyl)borate (FIr6)/SiDPO that exhibits a forward‐viewing maximum external quantum efficiency (EQE) up to 22.2%. This is the first report of three‐organic‐layer FIr6‐based blue PhOLEDs with the forward‐viewing EQE over 20%, and the device performance is among the highest for FIr6‐based blue PhOLEDs even compared with the four or more than four organic‐layer devices. Furthermore, with the introduction of bis(2‐(9,9‐diethyl‐9 H ‐fluoren‐2‐yl)‐1‐phenyl‐1 H ‐benzoimidazol‐ N,C 3 )iridium acetylacetonate [(fbi) 2 Ir(acac)] as an orange emitter, an all‐phosphor warm‐white PhOLED achieves a peak power efficiency of 47.2 lm W −1 , which is close to the highest values ever reported for two‐color white PhOLEDs.