Copolyfluorenes containing pendant bipolar groups: Synthesis, optoelectronic properties and applications
作者:Chia-Shing Wu、Yun Chen
DOI:10.1039/c0jm00707b
日期:——
This article reports the synthesis of copolyfluorenes (P1–P3) containing pendant bipolar groups (2.1–8.2 mol%), directly linked to hole-transporting triphenylamine and electron-transporting aromatic 1,2,4-triazole, by the Suzuki coupling reaction and their application in improving PLED performance of conventional MEH-PPV. The bipolar groups not only suppress undesirable green emission of polyfluorene under thermal annealing, but also promote electron- and hole-affinity of the resulting copolyfluorenes. Blending bipolar model compound M0 with MEH-PPV results in enhancement of device performance [ITO/PEDOT:PSS/M0 + MEH-PPV/Ca(50 nm)/Al(100 nm)]. Maximum luminance and luminance efficiency were increased from 3160 cd/m2 and 0.24 cd/A of MEH-PPV-only device to 6830 cd/m2 and 0.50 cd/A. Moreover, blending the bipolar copolyfluorenes with MEH-PPV further improves the device efficiency, with the maximum luminance and luminance efficiency being significantly enhanced up to 11090 cd/m2 and 0.56 cd/A (ca. 0.4 wt% of bipolar residue), respectively. Our results demonstrate the efficacy of the bipolar copolyfluorenes and model compound M0 in enhancing emission efficiency of MEH-PPV.
本文报道了通过铃木偶联反应合成含有双极性悬垂基团(2.1-8.2 mol%)的共聚芴(P1-P3),这些双极性悬垂基团与空穴传输的三苯胺和电子传输的芳香族 1,2,4- 三唑直接相连,并将其应用于改善传统 MEH-PPV 的聚光发光性能。双极性基团不仅抑制了热退火条件下聚烯烃的不良绿色发射,而且还提高了所得共聚芴的电子和空穴亲和性。将双极性模型化合物 M0 与 MEH-PPV 混合可提高器件性能 [ITO/PEDOT:PSS/M0+MEH-PPV/Ca(50nm)/Al(100nm)]。最大亮度和亮度效率从纯 MEH-PPV 器件的 3160 cd/m2 和 0.24 cd/A 提高到 6830 cd/m2 和 0.50 cd/A。此外,将双极共聚芴与 MEH-PPV 混合可进一步提高器件效率,最大亮度和亮度效率分别显著提高到 11090 cd/m2 和 0.56 cd/A(约 0.4 wt%的双极残留物)。我们的研究结果证明了双极性共聚芴和模型化合物 M0 在提高 MEH-PPV 发射效率方面的功效。