Dyes and Pigments ( IF 4.5 ) Pub Date : 2018-01-11 , DOI: 10.1016/j.dyepig.2018.01.014 Ran Zhang , Hao Sun , Yun Zhao , Xinxue Tang , Zhonghai Ni
A series of dipolar 1,3,6,8-tetrasubstituted pyrene-based compounds (py1, py2, mpy1 and mpy2) were designed and synthesized with two 4-tert-butylphenyl segments at 1,8-positions and two electron-transporting benzimidazole moieties at 3,6-sites of the pyrene core. These compounds were structurally characterized and their photoelectric properties were investigated by spectroscopy, electrochemical and theoretical studies. Moreover, the structure of compound py1 was determined by single-crystal X-ray diffraction analysis, indicating that the compound has a non-coplanar structure and there is no π-π stacking between the molecules. The benzimidazole moieties attached on the pyrene ring via para- and meta-linking modes and by changing the molecular linkage from para-to meta-mode can effectively tune the emission to pure blue region. The four compounds exhibit high absolute fluorescence quantum yields in dichloromethane (99.89–100%) and in film states (54.56–86.78%). In addition, the meta-linked compounds mpy1 and mpy2 exhibit higher absolute fluorescence quantum efficiencies in solution and film states than the para-linked compounds py1 and py2, which demonstrates that the meta-linked architecture can more effectively twist the molecule and suppress the intermolecular interactions. All these compounds exhibit high thermal stability and can form morphologically stable amorphous thin films with glass transition temperature in the range of 182–215 °C. Two types of non-doped blue OLED devices were fabricated using compounds py2 and mpy2 as representatives to investigate their light-emitting and electron-transporting properties and the devices exhibit promising device performance. The devices using meta-linked compound mpy2 as emitting and electron-transporting layers shows pure blue color purity (0.16, 0.10) with high current and power efficiencies (2.70 cd A−1, 1.97 l m W−1).
中文翻译:
含电传输苯并咪唑基团的偶极1,3,6,8-四取代pyr基蓝色发射体:合成,结构,光学性质,电化学和电致发光
设计并合成了一系列偶极的1,3,6,8-四取代pyr基化合物(py1,py2,m py1和m py2),在1,8位有两个4-叔丁基苯基链段,两个电子在the核心的3,6-位上转运苯并咪唑部分。对这些化合物进行了结构表征,并通过光谱学,电化学和理论研究研究了它们的光电性能。此外,通过单晶X射线衍射分析确定了化合物py1的结构,表明该化合物具有非共面结构并且分子之间没有π-π堆积。zi环上连接的苯并咪唑部分通过对位-和间位-linking模式和通过从改变分子连锁对-to元-mode能有效地调谐发射纯蓝色区域。四种化合物在二氯甲烷(99.89–100%)和薄膜状态(54.56–86.78%)中均显示出很高的绝对荧光量子产率。此外,元-连接的化合物中号PY1和米PY2表现出更高的绝对荧光量子效率在溶液和膜状态比对位-连接的化合物PY1和PY2,这表明该元连接结构可以更有效地扭曲分子并抑制分子间的相互作用。所有这些化合物都具有很高的热稳定性,并可以形成形态稳定的非晶态薄膜,玻璃化转变温度在182–215°C的范围内。以化合物py2和m py2为代表,制造了两种类型的非掺杂蓝色OLED器件,以研究其发光和电子传输特性,并且该器件表现出令人鼓舞的器件性能。使用间连接的化合物m py2作为发射层和电子传输层的器件显示出纯蓝色纯度(0.16,0.10),具有高电流和功率效率(2.70 cd A -1,1.97 l m W -1)。