Efficient deep-blue organic emitters are of particular significance in organic electroluminescence.In this work,by using an asymmetrically twisted and rigid molecular design strategy,a high-efficiency deep-blue bisphenanthroimidazole emitter,MBTPI,was successfully synthesized,characterized and applied in a high-performance deep-blue organic light-emitting device (OLED).It shows high decomposition temperature (496 ℃) and high glass transition temperature (190 ℃),which are favorable for device stability.Its molecular conjugation was efficiently controlled by an asymmetrically twisted and rigid molecular structure,which makes its emission band locates at deep blue region,and solid film emission quantum yield is as high as 74％.Theoretical calculation also proves the presence of asymmetrically twisted rigid molecular structure,and the methyl dose change the molecular geometry,but has little influence on frontier orbital distribution,which is beneficial for maintaining good bipolar transporting property.MBTPI-based non-doped OLED displays a stable and highly efficient deep-blue electroluminescence with CIE coordinates (0.15,0.07),which is very close to the NTSC deep-blue standard (0.14,0.08).External quantum efficiency is high up to 4.91％,which is comparable to the state-of-the-art deep-blue non-doped OLEDs with CIEy lower than 0.08.%本研究通过不对称、刚性扭曲的分子设计理念,合成了高效深蓝有机电致发光材料MB-TPI.该化合物具有很高的分解温度(496℃)与玻璃转化温度(190℃),有利于提高器件的稳定性;不对称刚性扭曲的分子构型有效控制了分子的整体共轭程度,使发光波长在深蓝光区,固体发光量子产率高达74％.理论计算验证了分子不对称扭曲的构型,并且发现甲基的引入对前线轨道分布影响不大,分子保留了较好的双极性质.基于MBTPI的非掺杂器件发射出非常高效的深蓝光.色纯度为(0.15,0.07),非常接近NTSC的蓝光标准(0.14,0.08).最大外量子效率为4.91％,并且效率滚降很小,为性能最好的非掺杂深蓝光器件之一.
展开▼
