Yang Bing, Kim Soo-Kang, Xu Hai, Park Young-Il, Zhang Houyu, Gu Cheng, Shen Fangzhong, Wang Chunlei, Liu Dandan, Liu Xiaodong, Hanif Muddasir, Tang Shi, Li Weijun, Li Feng, Shen Jiacong, Park Jong-Wook, Ma Yuguang
State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.
Chemphyschem. 2008 Dec 1;9(17):2601-9. doi: 10.1002/cphc.200800513.
Herein, we describe the molecular electronic structure, optical, and charge-transport properties of anthracene derivatives computationally using density functional theory to understand the factors responsible for the improved efficiency and stability of organic light-emitting diodes (OLEDs) with triphenylamine (TPA)-substituted anthracene derivatives. The high performance of OLEDs with TPA-substituted anthracene is revealed to derive from three original features in comparison with aryl-substituted anthracene derivatives: 1) the HOMO and LUMO are localized separately on TPA and anthracene moieties, respectively, which leads to better stability of the OLEDs due to the more stable cation of TPA under a hole majority-carrier environment; 2) the more balanceable hole and electron transport together with the easier hole injection leads to a larger rate of hole-electron recombination, which corresponds to the higher electroluminescence efficiency; and 3) the increasing reorganization energy for both hole and electron transport and the higher HOMO energy level provide a stable potential well for hole trapping, and then trapped holes induce a built-in electric field to prompt the balance of charge-carrier injection.
在此，我们使用密度泛函理论通过计算描述蒽衍生物的分子电子结构、光学和电荷传输性质，以了解使用三苯胺（TPA）取代的蒽衍生物的有机发光二极管（OLED）效率提高和稳定性增强的原因。与芳基取代的蒽衍生物相比，TPA取代的蒽的OLED的高性能源于三个主要特征：1）最高占据分子轨道（HOMO）和最低未占分子轨道（LUMO）分别局域在TPA和蒽部分，这由于在空穴多数载流子环境下TPA阳离子更稳定而导致OLED具有更好的稳定性；2）更平衡的空穴和电子传输以及更容易的空穴注入导致更大的空穴 - 电子复合率，这对应于更高的电致发光效率；3）空穴和电子传输的重组能增加以及更高的HOMO能级为空穴俘获提供了一个稳定的势阱，然后被俘获的空穴会诱导一个内建电场以促进电荷载流子注入的平衡。
