Chemical Engineering Department, National Tsing-Hua University, Hsinchu 30041, Taiwan, ROC.
J Am Chem Soc. 2011 Jun 29;133(25):9634-7. doi: 10.1021/ja111521p. Epub 2011 Jun 6.
Polymer light-emitting diodes (PLEDs) suffer from inadequate lifetimes because of the use of environmentally sensitive metals as the cathodes. We present the use of water/methanol-soluble polyfluorene grafted with 18-crown-6 chelating to K(+) as the electron-injection layer (EIL) for deep-blue-emission PLEDs, allowing the use of environmentally stable Al as the cathode since electron donation from the 18-crown-6 can reduce K(+) to a stable "pseudometallic state", enabling it to act as an intermediate step for electron injection. Furthermore, when poly(ethylene oxide) was blended into the EIL to provide hole blocking (HB), the device exhibited the highest performance reported to date for a deep-blue-emission PLED based on a conjugated polymer as the emitting layer, with a brightness of 54,800 cd/m(2) and an external quantum efficiency of 5.42%. The use of such an EI-HB layer opens a broad avenue leading toward industrialization of PLEDs.
聚合物发光二极管（PLED）由于使用对环境敏感的金属作为阴极，因此存在寿命不足的问题。我们提出了使用水/甲醇可溶性聚芴接枝 18-冠-6 螯合 K（+）作为电子注入层（EIL）的方法，用于深蓝光发射 PLED，因为 18-冠-6 的电子捐赠可以将 K（+）还原为稳定的“类金属状态”，从而使其能够作为电子注入的中间步骤。此外，当将聚（氧化乙烯）混入 EIL 中以提供空穴阻挡（HB）时，该器件表现出迄今为止报道的基于共轭聚合物作为发射层的深蓝光发射 PLED 的最高性能，亮度为 54,800 cd/m²，外量子效率为 5.42%。这种 EI-HB 层的使用为 PLED 的工业化开辟了广阔的途径。
