Jin Ruifa, Xin Jingfan
College of Chemistry and Life Sciences, Chifeng University, Chifeng, China.
Inner Mongolia Key Laboratory of Photoelectric Functional Materials, Chifeng University, Chifeng, China.
Front Chem. 2020 Sep 30;8:577834. doi: 10.3389/fchem.2020.577834. eCollection 2020.
A series of donor-acceptor (D-A) tricoordinated organoboron derivatives (-) have been systematically investigated for thermally activated delayed fluorescent (TADF)-based organic light-emitting diode (OLED) materials. The calculated results show that the designed molecules exhibit small singlet-triplet energy gap (Δ ) values. Density functional theory (DFT) analysis indicated that the designed molecules display an efficient separation between donor and acceptor fragments because of a small overlap between donor and acceptor fragments on HOMOs and LUMOs. Furthermore, the delayed fluorescence emission color can be tuned effectively by introduction of different polycyclic aromatic fragments in parent molecule . The calculated results show that molecules , , and possess more significant Stokes shifts and red emission with small Δ values. Nevertheless, other molecules exhibit green (, , and ), light green ( and ), and blue ( and ) emissions. Meanwhile, they are potential ambipolar charge transport materials except that and can serve as electron and hole transport materials only, respectively. Therefore, we proposed a rational way for the design of efficient TADF materials as well as charge transport materials for OLEDs simultaneously.
一系列供体-受体（D-A）三配位有机硼衍生物（-）已被系统地研究作为基于热激活延迟荧光（TADF）的有机发光二极管（OLED）材料。计算结果表明，所设计的分子呈现出较小的单重态-三重态能隙（Δ）值。密度泛函理论（DFT）分析表明，由于供体和受体片段在最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）上的重叠较小，所设计的分子在供体和受体片段之间表现出有效的分离。此外，通过在母体分子中引入不同的多环芳族片段，可以有效地调节延迟荧光发射颜色。计算结果表明，分子、和具有更显著的斯托克斯位移和较小Δ值的红色发射。然而，其他分子表现出绿色（、和）、浅绿色（和）以及蓝色（和）发射。同时，除了和分别只能作为电子传输材料和空穴传输材料外，它们都是潜在的双极性电荷传输材料。因此，我们提出了一种合理的方法，可同时设计用于OLED的高效TADF材料以及电荷传输材料。
