Synthesis and characterization of polyfluorenes containing bisphenazine units |
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| Authors: | Ming Wang Hui Tong Yanxiang Cheng Zhiyuan Xie Lixiang Wang Xiabin Jing Fosong Wang |
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| Affiliation: | 1. State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China;2. Graduate School of Chinese Academy of Sciences, Beijing 100039, People's Republic of China |
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| Abstract: | Novel conjugated copolymers based on 9,9‐dioctylfluorene and bisphenazine (BP) were synthesized by Suzuki polymerization. Energy transfer from the conjugated main chain to the BP moieties was observed. Full energy transfer was achieved when the molar content of the bisphenazine was 20% (20BPPF) in toluene solution. The similar phenomena were observed even for 1% bisphenazine content copolymer (1BPPF) in film. The lowest occupied molecular orbital (LUMO) energy levels (?3.06 eV) of the copolymers were lower than that of the polyfluorene homopolymer (PFO; ?2.65 eV), indicating that the introduction of the BP unit was benefit to electron injection. Single‐layer electroluminescent devices (ITO/PEDOT:PSS/polymer/LiF/Al) were fabricated to investigate their electroluminescence (EL) performances. The maximum brightness and current efficiency of all BPPF copolymers surpassed the PFO homopolymer. The best single‐layer device was based on 5BPPF, with a maximum brightness of 1532 cd/m2 and current efficiency of 1.09 cd/A. Much higher efficiency could be achieved for multilayer EL devices of 5BPPF (ITO/PEDOT:PSS/PVK/polymer/TPBI/LiF/Al), which showed a maximum current efficiency of 10.01 cd/A. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1990–1999, 2010 |
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| Keywords: | bisphenazine energy transfer electrochemistry heteroatom‐containing polymers light‐emitting diodes (LED) polyfluorene |
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