Synthesis of poly(N‐9‐ethylcarbazole‐exo‐norbornene‐5,6‐dicarboximide) for hole‐transporting layer in hybrid organic light‐emitting devices |
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| Authors: | Myeon‐Cheon Choi Jae‐Chul Hwang Chiwan Kim Youngkyoo Kim Chang‐Sik Ha |
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| Institution: | 1. Department of Polymer Science and Engineering, Pusan National University, Busan 609‐735, Republic of Korea;2. Organic Nanoelectronics Laboratory, Department of Chemical Engineering, Kyungpook National University, Daegu 702‐701, Republic of Korea |
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| Abstract: | We synthesized new polynorbornene dicarboximide (PCaNI) functionalized with hole‐transporting carbazole moieties and its copolymer (PCaNA) by ring‐opening metathesis polymerization (ROMP), where the PCaNA was further reacted with 3‐amino‐triethoxysilane to prepare PCaNI/silica hybrid. We also investigated the feasibility of PCaNI and PCaNI/silica hybrid (PCaSi) as a hole‐transporting material for hybrid organic light emitting devices (HOLEDs). To improve the performance of the PCaNI‐based HOLEDs, N,N′‐diphenyl‐N,N′‐(3‐methylphenyl)‐1,1′‐biphenyl]‐4‐4′‐diamine (TPD) was also introduced into the PCaNI matrix. Results showed that PCaNI exhibited high glass transition temperature (～260 °C) and high optical transparency in the visible region. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PCaNI were measured as 5.6 and 2.2 eV, while the TPD‐doped PCaNI showed 5.7 eV (HOMO) and 2.6 eV (LUMO). The PCaNI/silica hybrid nanolayers showed excellent solvent resistance due to the formation of covalent bonds between ITO and PCaNI. The HOLEDs with PCaNI/TPD or PCaSi/TPD hybrid nanolayers exhibited relatively higher luminance (～10,000 cd/m2), lower operating voltage (～6.5 V at 300 cd/m2), and higher current efficiency (～2.7 cd/A). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 |
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| Keywords: | carbazole hole‐transporting materials hybrid OLED organic light‐emitting device polynorbornene |
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