Abstract Alternating electroluminescent copolymers, poly(9,9-dihexadecylfluorene-2,7-diyl-alt-2,2′-bithiophene-5,5′-diyl)s (PFC16BTs), were synthesized using two different routes of Suzuki coupling reaction in which either dibromo derivative of fluorene was reacted with diboronic acid ester of bithiophene or vice versa, with microwave-assisted (MA) or conventional (C) heating in high boiling point solvents, chlorobenzene (CB) and xylene (Xy). PFC16BT copolymers with various molecular weights (MW) were obtained depending on the synthetic conditions, and the influence on MW is discussed. The photophysical and electrochemical properties and the electroluminescence (EL) of the PFC16BT copolymers were studied and compared with those of poly(9,9-dioctylfluorene-2,7-diyl-alt-2,2′-bithiophene-5,5′-diyl)s (PFC8BTs) to reveal the impact of MW and the length of side chains on their properties. A slight dependence on the MW was only observed in the absorption spectra in solutions. Photoluminescence (PL) of PFC16BTs solutions emitted green light with a maximum of approximately 500 nm, whereas the PL emission spectra of thin films were redshifted with the maxima at 540 nm. The ionization potential (HOMO level) and electron affinity (LUMO level) values of 5.4 eV and 2.6 eV, respectively, were evaluated for PFC16BTs, which are similar to those for PFC8BTs. The electrochemical bandgap value of 2.8 eV was higher than the value of the optical bandgap of 2.4 eV. The PFC16BT copolymers with various MW were tested as an active layer in light-emitting devices (LEDs), and the results are compared with those of PFC8BT LEDs. The PFC16BT LEDs exhibited a luminance higher than 3500 cd m–2 and low onset voltages of approximately 2 V. The shape of the EL spectra of LEDs is similar to that of PL spectra of the thin films. PL emission of PFC16BT thin films and EL emission were blue shifted compared with those of PFC8BT, indicating a more pronounced aggregation in PFC8BT.

中文翻译：

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Poly(9,9-dihexadecylfluorene-2,7-diyl-alt -2,2'-bithiophene-5,5'-diyl) 的微波辅助和常规合成、光物理和电致发光

摘要 交替电致发光共聚物，poly(9,9-dihexadecylfluorene-2,7-diyl-alt-2,2'-bithiophene-5,5'-diyl)s (PFC16BTs)，使用两种不同的 Suzuki 偶联反应路线合成。其中芴的二溴衍生物与联噻吩的二硼酸酯反应，反之亦然，微波辅助 (MA) 或常规 (C) 在高沸点溶剂、氯苯 (CB) 和二甲苯 (Xy) 中加热。根据合成条件获得了不同分子量 (MW) 的 PFC16BT 共聚物，并讨论了对 MW 的影响。研究了 PFC16BT 共聚物的光物理和电化学性质以及电致发光 (EL) 并与聚 (9,9-二辛基芴-2,7-二基-alt-2,2'-bithiophene-5, 5'-diyl)s (PFC8BTs) 揭示 MW 和侧链长度对其性能的影响。仅在溶液的吸收光谱中观察到对 MW 的轻微依赖性。PFC16BTs 溶液的光致发光 (PL) 发出的绿光最大约为 500 nm，而薄膜的 PL 发射光谱红移，最大值为 540 nm。PFC16BTs 的电离电位（HOMO 能级）和电子亲和力（LUMO 能级）值分别为 5.4 eV 和 2.6 eV，与 PFC8BTs 的相似。2.8 eV 的电化学带隙值高于 2.4 eV 的光学带隙值。测试了具有不同 MW 的 PFC16BT 共聚物作为发光器件 (LED) 中的活性层，并将结果与​​ PFC8BT LED 的结果进行比较。PFC16BT LED 显示出高于 3500 cd m-2 的亮度和大约 2 V 的低起始电压。 LED 的 EL 光谱的形状类似于薄膜的 PL 光谱的形状。与 PFC8BT 相比，PFC16BT 薄膜的 PL 发射和 EL 发射发生蓝移，表明 PFC8BT 中的聚集更明显。