Short-Axis Substitution Approach Selectively Optimizes Electrical Properties of Dibenzothiophene-Based Phosphine Oxide Hosts
Short-Axis Substitution Approach Selectively Optimizes Electrical Properties of Dibenzothiophene-Based Phosphine Oxide Hosts
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短轴取代方法选择性优化二苯并噻吩基氧化膦主体的电性能
DOI：
10.1021/ja308273y
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发表时间：
2012-11-21
影响因子：
15
通讯作者：
Liu, Shiyong
中科院分区：
文献类型：
--
作者：
Han, Chunmiao;Zhang, Zhenson;Liu, Shiyong
采用短轴取代法合成了两种以二苯并硫苯(DBT)为基础的氧膦主体化合物，分别命名为4-二苯基磷酰二苯并噻吩基(DBTSPO)和4，6-二(二苯基磷酰基)二苯并噻吩基(DBTDPO)，目的是选择性地调节电学性质。短轴取代和给电子的S原子参与共轭的共同作用有效地抑制了二苯基氧化膦吸电子基团对前线分子轨道和光学性质的影响。因此，DBTSPO和DBTDPO具有几乎相同的空穴注入能力和激发能级，而更多的电子传输DPPO和对称的构型使DBTDPO具有更强的电子注入/传输能力。结果，基于这种短轴替代效应，成功地实现了对电学性质的选择性调节。DBTDPO的前三重态能级(T-1)高达290 eV，最高占据轨道和最低空轨道能级分别为-6.05和-2.50 eV，载流子输运能力得到改善，支持其蓝白光有机电致发光二极管作为迄今报道的最好的低压驱动器件，最低的起始驱动电压为2.4V，最低的驱动电压为30lmW-1，并且具有良好的效率稳定性。
Two dibenzothiophene (DBT)-based phosphine oxide hosts, named 4-diphenylphosphoryl dibenzothiophene (DBTSPO) and 4,6-bis(diphenylphosphoryl) dibenzothiophene (DBTDPO), were prepared by short-axis substitution with the aim to selectively adjust electrical properties. The combined effects of short-axis substitution and the involvement of electron-donating S atom in conjugation effectively suppress the influence of electron-withdrawing diphenylphosphine oxide (DPPO) moieties on the frontier molecular orbitals and the optical properties. Therefore, DBTSPO and DBTDPO have the nearly same hole injection ability and the excited energy levels, while more electron transporting DPPOs and the symmetrical configuration endow DBTDPO with enhanced electron-injecting/transporting ability. As the result, on the basis of this short-axis substitution effect, the selective adjustment of electrical properties was successfully realized. With the high first triplet energy level (T-1) of 290 eV, the suitable energy levels of the highest occupied molecular orbital and the lowest unoccupied molecular orbital of -6.05 and -2.50 eV and the improved carrier -transporting ability, DBTDPO supported its blue- and white emitting phosphorescent organic light emitting diodes as the best low-voltage-driving devices reported so far with the lowest driving voltages of 2.4 V for onset and 30 lm W-1 and excellent efficiency stability.