Hyperbranched framework of interrupted π‐conjugated polymers end‐capped with high carrier‐mobility moieties for stable light‐emitting materials with low driving voltage |
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Authors: | Feng Liu Ju‐Qing Liu Ran‐Ran Liu Xiao‐Ya Hou Ling‐Hai Xie Hong‐Bin Wu Chao Tang Wei Wei Yong Cao Wei Huang |
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Institution: | 1. Jiangsu Key Laboratory for Organic Electronics & Information Displays and Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing 2100046, China;2. Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China |
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Abstract: | A novel series of soluble hyperbranched interrupted π‐conjugated polymers (HICPs) based on complicated 9,9‐diarylfluorenes (CDAFs) branching core and end‐capped with high carrier‐mobility pyrene moieties were synthesized via the “A2 + A′2 + B3” type Suzuki coupling condensation. The new polymer architecture improves the spectrum stability than the corresponding linear and hyperbranched polymers in PLEDs. Besides, it overcomes the drawback of high driving voltage of common interrupted π‐conjugated polymers. CDAF1 exhibits excellent thermal and morphological stability with a decomposition temperature (Td) higher than 445 °C and a glass transition temperature (Tg) up to 128 °C. No obvious low‐energy green emission band at 520 nm was observed under extreme thermal annealing conditions in air at 200 °C for 12 h. The CDAF1 device shows stable blue emission with the peak at 422 and 447 nm. The Commission International d'Eclairage (CIE) 1931 coordinates is (0.18, 0.16) and the brightness reaches 1051 cd/m2 at 15.7 V. White PLED based on CDAF1/MEH‐PPV blends exhibits a low turn‐on voltage of 4.8 V with voltage‐independent CIE of (0.32, 0.32). Molecular simulations were used to investigate the conformation and interchain interaction. HICPs based on CDAFs tethered with high‐mobility moieties are promising stable blue and host materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6451–6462, 2009 |
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Keywords: | diarylfluorenes hyperbranched hyperbranched polymers light‐emitting diodes (LED) light‐emitting polymers nonconjugated polymers pyrenes pyrolysis |
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