Department of Chemistry, Hubei Key Lab on Organic and Polymeric Optoelectronic Materials, Wuhan University, Wuhan 430072, People's Republic of China.
Chem Asian J. 2010 Feb 1;5(2):278-84. doi: 10.1002/asia.200900433.
A series of 9,9'-spirobifluorene/oxadiazole hybrids with various linkages between two components, namely SBF-p-OXD (1), SBF-m-OXD (2), and SBF-o-OXD (3) are designed and synthesized through Suzuki cross-coupling reactions. The incorporation of a rigid and bulky spirobifluorene moiety greatly improves their thermal and morphological stability, with T(d) (decomposition temperature) and T(g) (glass transition temperature) in the ranges of 401-480 degrees C and 136-210 degrees C, respectively. 2 and 3 with meta- and ortho-linkage display higher triplet energy and blue-shifted absorption and emission than their para-linked analogue 1 owing to the decreasing pi-conjugation between the two components. Their HOMO and LUMO energy levels depend on the linkage modes within the range of 5.57-5.64 eV and 2.33-2.49 eV, respectively. Multilayer deep red electrophosphorescent devices with 1-3 as hosts were fabricated and their EL efficiencies follow the order of 3 (o)>2 (m)>1 (p), which correlates with their triplet energy and the separation of HOMO and LUMO distributions at molecular orbitals. The maximum external quantum efficiencies of 11.7% for green and 9.8% for deep red phosphorescent organic light-emitting diodes (OLEDs) are achieved by using 2 and 3 as host materials, respectively.
通过 Suzuki 交叉偶联反应，设计并合成了一系列具有不同连接方式的 9,9'-螺二芴/噁二唑杂化物，即 SBF-p-OXD（1）、SBF-m-OXD（2）和 SBF-o-OXD（3）。刚性和庞大的螺二芴部分的引入极大地提高了它们的热稳定性和形态稳定性，其 T(d)（分解温度）和 T(g)（玻璃化转变温度）分别在 401-480°C 和 136-210°C 的范围内。由于两个部分之间的π共轭减少，具有间位和邻位连接的 2 和 3 显示出比其对位连接类似物 1 更高的三重态能量和蓝移吸收和发射。它们的 HOMO 和 LUMO 能级在 5.57-5.64 eV 和 2.33-2.49 eV 的范围内取决于连接模式。以 1-3 为主体的多层深红光电致磷光器件被制备，它们的 EL 效率遵循 3（o）>2（m）>1（p）的顺序，这与它们的三重态能量和分子轨道上 HOMO 和 LUMO 分布的分离有关。使用 2 和 3 作为主体材料，分别实现了绿光和深红光磷光有机发光二极管（OLED）的最大外量子效率为 11.7%和 9.8%。
