Solution-processed bipolar small molecular host materials for single-layer blue phosphorescent organic light-emitting diodes
Solution-processed bipolar small molecular host materials for single-layer blue phosphorescent organic light-emitting diodes
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DOI：
10.1039/c3tc31641f
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发表时间：
2014-01-01
影响因子：
6.4
通讯作者：
Chen, Chao-Tsen
中科院分区：
文献类型：
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作者：
Lee, Yi-Ting;Chang, Yung-Ting;Chen, Chao-Tsen
三种基于双-[3,5-二(9H-咔唑-9-基)苯基]结构部分的新型可溶液加工小分子主体材料已开发用于蓝色磷光（FIrpic掺杂剂）有机发光二极管。所有三种主体材料均具有 155-175 摄氏度的高玻璃化转变温度 (T(g)s)，这表明通过溶液法制备的非晶薄膜具有良好的形态稳定性。而 N,N-双-[3,5-二(9H-咔唑-9-基)苯基]甲胺 (CzPAMe) 具有最高的固态三线态能隙 (ET)，为 2.73 eV，四-[3,3',5,5'-(9H-咔唑-9-基)]三苯基氧化膦 (CzPPO) 和 N， N-双-[3,5-二(9H-咔唑-9-基)苯基]嘧啶-2-胺(CzPAPm)是两种主体材料，由于苯基氧化膦和嘧啶的缺电子单元，它们对于电荷传输具有潜在的双极性。由于 CzPAPm 的 ET (2.56 eV) 不足，CzPPO 或 CzPAMe 器件明显优于有或没有 1,3-双[(4-叔丁基苯基)-1,3,4-恶二唑基]亚苯基 (OXD-7) 共主体的 CzPAPm 器件。特别是，由于没有OXD-7共主体，也没有真空热沉积额外的电子传输层，CzPPO单层器件超越了CzPAMe器件，电流效率高达9.32 cd A(-1)（或功率效率4.97 lm W-1），是相同制造工艺和相同器件配置的小分子器件中效率最高的之一。
Three new solution processable small molecular host materials based on the bis-[3,5-di(9H-carbazol-9-yl) phenyl] structural moiety have been developed for blue phosphorescent (FIrpic dopant) organic light-emitting diodes. All three host materials have been characterized as having high glass transition temperatures (T(g)s), 155-175 degrees C, indicative of good morphological stability of their amorphous thin films prepared from the solution process. Whereas N,N-bis-[3,5-di(9H-carbazol-9-yl) phenyl] methylamine (CzPAMe) has the highest solid state triplet energy gap (ET) of 2.73 eV, tetrakis-[3,3',5,5'-(9H-carbazol-9-yl)] triphenylphosphine oxide (CzPPO) and N, N-bis-[3,5-di(9H-carbazol-9-yl) phenyl] pyrimidin-2-amine (CzPAPm) are two host materials which are potentially bipolar for charge transport due to the electron deficient units of phenylphosphine oxide and pyrimidine, respectively. Due to the insufficient ET (2.56 eV) of CzPAPm, CzPPO or CzPAMe devices are significantly better than CzPAPm devices with or without a 1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD-7) co-host. Particularly, having no OXD-7 co-host and no vacuum thermal-deposited extra electron transporting layer, single-layer devices of CzPPO surpass CzPAMe devices and reach current efficiencies as high as 9.32 cd A(-1) (or power efficiency of 4.97 lm W-1), one of the highest efficiencies among small molecular devices with the same fabrication process and same device configuration.