Vinyl-type polynorbornene with 9,9′-(1,1′-biphenyl)-4,4′-diylbis-9H-carbazole side groups as a host material for highly efficient green phosphorescent organic light-emitting diodes
Vinyl-type polynorbornene with 9,9′-(1,1′-biphenyl)-4,4′-diylbis-9H-carbazole side groups as a host material for highly efficient green phosphorescent organic light-emitting diodes
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DOI：
10.1039/c0jm03755a
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发表时间：
2011-03
影响因子：
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通讯作者：
J. Park;Changhun Yun;T. K. Koh;Y. Do;S. Yoo;Mh Lee
中科院分区：
文献类型：
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作者：
J. Park;Changhun Yun;T. K. Koh;Y. Do;S. Yoo;Mh Lee
研究了带有9，9 ′-（1，1 ′-联苯基）-4，4 ′-二基双-9H-咔唑（CBP）侧基的可溶性聚异戊二烯（P1）作为有机电致发光器件中绿色发光体的主体材料。使用钯（II）催化剂进行降冰片烯单体的乙烯基加成聚合，与1-辛烯链转移剂结合有效地产生P1。P1表现出高的热稳定性，具有高的分解温度（Td 5> 451 °C）和玻璃化转变温度（Tg > 361 °C）。HOMO（英语：HOMO）-5.5 eV）和LUMO（ca. -2.1 eV）能级，三重态能量为ca。2.60 eV表明P1适合作为绿色发光体的主体材料。基于P1基质掺杂不同浓度（1-6 wt%）的fac-Ir（ppy）3的发光层的溶液处理器件显示稳定的绿色发射和高的器件性能。当fac-Ir（ppy）3的最佳掺杂浓度为2wt%时，器件的外量子效率和功率效率分别达到7.2%和11 lm/W。发现器件性能略低于具有分子CBP主体的PhOLED，但高于基于PVK的器件。结果表明，与聚异戊二烯主链的良好加工性相结合，P1（ca. 10 - 3和10 - 5 cm 2/Vs）以及CBP侧基继承的大三重态能量是具有溶液处理的P1主体：发射体层的磷光OLED的高性能的主要原因。
The soluble polynorbornene (P1) bearing 9,9′-(1,1′-biphenyl)-4,4′-diylbis-9H-carbazole (CBP) side groups was investigated as a host material for green emitters in phosphorescent OLED devices. The vinyl addition polymerization of norbornene monomers using Pd(II) catalyst efficiently produces P1 in combination with 1-octene chain transfer agent. P1 exhibits high thermal stability with high decomposition (Td5 > 451 °C) and glass transition temperatures (Tg > 361 °C). The HOMO (ca. −5.5 eV) and LUMO (ca. −2.1 eV) levels with the triplet energy of ca. 2.60 eV suggest that P1 is suitable for a host material for green emitters. The solution-processed devices based on the emissive layers containing P1host doped with various concentration of fac-Ir(ppy)3 (1–6 wt%) display stable green emission of fac-Ir(ppy)3 with high device performances. The external quantum efficiency and power efficiency reach 7.2% and 11 lm/W, respectively, at the optimum doping concentration of fac-Ir(ppy)3 (2 wt%). The device performances are found to be slightly lower than those of PhOLED with molecular CBP host but higher than those of a PVK-based device. It is shown that in conjunction with the good processability of polynorbornene backbones, the high levels of the effective hole and electron mobilities of P1 (ca. 10−3 and 10−5 cm2/Vs, respectively) as well as large triplet energy inherited from CBP side groups are mainly responsible for the high performance of the phosphorescent OLEDs with solution-processed P1host:emitter layers.