基于喹喔啉和吡啶并吡嗪及咔唑和二苯胺衍生物电子给体-受体结构荧光材料的合成和光电性能

通过α-二酮与邻苯二胺、吡啶二胺缩合反应，构建了喹喔啉和吡啶并吡嗪衍生物作为电子受体，分别以二苯胺、咔唑衍生物为电子给体，合成了4个具有电子给体-电子受体结构的氮杂环荧光材料F1~F4。通过低温荧光/磷光光谱、荧光寿命测试，结合密度泛函理论计算可知，F1~F4均为荧光小分子。室温荧光光谱结果表明，利用电子给体和受体的电子效应不同可以调控材料的发光颜色，其中三苯胺相对于苯基咔唑的供电子能力更强，表现为F1比F2、F3比F4红移现象更加明显；而吡啶并吡嗪具有多氮的缺电子结构，与喹喔啉相比共轭程度增加，导致F3比F1、F4比F2发生的斯托克斯位移数值增大。总之，F1~F4的甲苯溶液最大荧光光谱发射峰位于529、464、568和507 nm，荧光寿命分别为12.21、2.61、9.76和6.03 ns，荧光量子效率最高可达98.2%，具有良好的发光性能。将F1~F4发光材料掺杂在主体材料中制备了有机电致发光二极管DF1~DF4。所得器件DF1和DF3性能更好，最大电流效率分别为13.38和11.98 cd·A^-1，且最大外量子效率分别达到4.8%和4.5%。

Synthesis and photoelectric properties of fluorescence materials with electron donor-acceptor structures based on quinoxaline and pyridinopyrazine, carbazole, and diphenylamine derivatives

Four nitrogen heterocyclic fluorescent materials F1 - F4 with electron donor - acceptor structures were synthesized based on quinoxaline and pyridinopyrazine derivatives, which were constructed by the condensation reaction of α-diketone with o-phenylenediamine and pyridine diamine. Their photophysical properties were studied in detail. By testing of the fluorescence lifetimes and low-temperature fluorescence/phosphorescence spectra of F1-F4, combined with density functional theory calculations, it can be concluded that all four molecules are fluorescent small materials. Compounds F1-F4 showed photoluminescence spectra with peaks at 529, 464, 568, and 507 nm, respectively, with photoluminescence quantum efficiencies (PLQYs) of up to 98.2% in toluene. Additionally, positive solvatochromism was recorded from the emission spectra of four compounds in solvents with different polarities,further confirming their intramolecular charge transfer nature. Furthermore, the lifetimes of four compounds were 12.21, 2.61, 9.76, and 6.03 ns, respectively. To further explore the functionalized applications of these fluorescent molecules, they were doped as luminescent materials in organic light- emitting diodes (DF1 - DF4). Among them, devices DF1 and DF3 achieved maximum current efficiencies of 13.38 and 11.98 cd·A^-1 and maximum external quantum efficiencies of 4.8% and 4.5% with low-efficiency roll-off, which are related to the high PLQYs of molecules F1 and F3.