標題: A Bipolar Host Material Containing Triphenylamine and Diphenylphosphoryl-Substituted Fluorene Units for Highly Efficient Blue Electrophosphorescence
作者: Hsu, Fang-Ming
Chien, Chen-Han
Shu, Ching-Fong
Lai, Chin-Hung
Hsieh, Cheng-Chih
Wang, Kang-Wei
Chou, Pi-Tai
應用化學系
Department of Applied Chemistry
公開日期: 9-Sep-2009
摘要: Highly efficient blue electrophosphorescent organic light-emitting diodes incorporating a bipolar host, 2,7-bis(diphenylphosphoryl)-9-[4-(N,N-diphenylamino)phenyl]-9-phenylfluorene (POAPF), doped with a conventional blue triplet emitter, iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C(2)]picolinate (FIrpic) are fabricated. The molecular architecture of POAPF features an electron-donating (p-type) triphenylamine group and an electron-accepting (n-type) 2,7-bis(diphenylphosphoryl)fluorene segment linked through the sp(3)-hybridized C9 position of the fluorene unit. The lack of conjugation between these p- and n-type groups endows POAPF with a triplet energy gap (ET) of 2.75 eV, which is sufficiently high to confine the triplet excitons on the blue-emitting guest. In addition, the built-in bipolar functionality facilitates both electron and hole injection. As a result, a POAPF-based device doped with 7 wt% FIrpic exhibits a very low turn-on voltage (2.5 V) and high electroluminescence efficiencies (20.6% and 36.7 lm W(-1)). Even at the practical brightnesses of 100 and 1000cd m(-2), the efficiencies remain high (20.2%/33.8 lm W(-1) and 18.8%/24.3 lm W(-1), respectively), making POAPF a promising material for use in low-power-consumption devices for next-generation flat-panel displays and light sources.
URI: http://dx.doi.org/10.1002/adfm.200900703
http://hdl.handle.net/11536/6683
ISSN: 1616-301X
DOI: 10.1002/adfm.200900703
期刊: ADVANCED FUNCTIONAL MATERIALS
Volume: 19
Issue: 17
起始頁: 2834
結束頁: 2843
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