Gao Yu, Zhang Shitong, Pan Yuyu, Yao Liang, Liu Haichao, Guo Yachen, Gu Qiang, Yang Bing, Ma Yuguang
State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, 130012, P. R. China.
Phys Chem Chem Phys. 2016 Sep 21;18(35):24176-84. doi: 10.1039/c6cp02778d. Epub 2016 Jun 3.
Excited state properties play a key role in the photoluminescence (PL) and electroluminescence (EL) performance of organic light-emitting diode (OLED) materials. The solvatochromic effects were observed in a series of triphenylamine (TPA)-phenanthroimidazole (PI) derivatives with the increase of solvent polarity, accompanied by the transformation of an excited state character from the locally-excited (LE) state to the charge-transfer (CT) state in the emission spectra. The excited state properties were systematically investigated in these donor-acceptor systems using time-dependent density functional theory (TD-DFT). The hybridization and de-hybridization processes between LE and CT states were resolved with an increasing number of phenyls along horizontal and vertical directions, respectively. We provide a novel insight into the fine modulation of the excited-state characters and compositions in the donor-acceptor system for the new-generation, low-cost and high-efficiency fluorescent OLED materials.
激发态性质在有机发光二极管（OLED）材料的光致发光（PL）和电致发光（EL）性能中起着关键作用。在一系列三苯胺（TPA）-菲并咪唑（PI）衍生物中，随着溶剂极性的增加观察到了溶剂化显色效应，同时发射光谱中激发态特征从局域激发（LE）态转变为电荷转移（CT）态。利用含时密度泛函理论（TD-DFT）在这些供体-受体体系中系统地研究了激发态性质。分别沿着水平和垂直方向，随着苯基数量的增加，LE态和CT态之间的杂化和去杂化过程得以解析。我们为新一代低成本高效荧光OLED材料的供体-受体体系中激发态特征和组成的精细调制提供了新的见解。
