摘要
An optimized compound 9-(9,9-dimethylacridin-10(9 H)-yl)-6 H-benzo[c]ch-romen-6-one(MAB) was designed and synthesized based on our previously reported TADF emitter 6-(9,9-dimethylacridin-10(9 H)-yl)-3-methyl-1 H-isochromen-1-one(MAC) to further improve the performance of thermally activated delayed fluorescence(TADF)emitters. With the additional phenyl in coumarin-contained plane, MAB possesses an extended distribution of the lowest unoccupied molecular orbitals(LUMO), and thus realizes reduced electron exchange between the frontier molecular orbitals and a stretched molecular dipole moment compared with MAC. MAB based organic light-emitting diode(OLED)exhibits a remarkable maximum external quantum efficiency(EQE) of 21.7%, which is much better than the maximum EQE of MAC-based OLED with a value of 12.8%. Our work proves that extending the distribution of LUMO is a simple but effective method to improve the efficiency of TADF emitter.
为了进一步提高热激活延迟荧光(TADF)发射体的性能,我们基于之前报道的TADF材料MAC,设计并合成了优化的化合物MAB.通过在香豆素平面中加入苯基,扩展了MAB的最低未占据分子轨道(LUMO)的分布.与MAC相比, MAB减少了前沿分子轨道的电子交换并且延展了分子偶极矩,从而提升了材料性能.基于MAB的有机发光二极管(OLED)的最大外量子效率(EQE)为21.7%,远远高于采用MAC作为发光材料的OLED器件12.8%的最大EQE.我们的工作证明,扩展LUMO的分布是提高TADF材料性能的一种简单而有效的方法.
基金
supported by the National Natural Science Foundation of China (51773029, 51533005 and 51373190)
the National Key Research & Development Program of China (2016YFB0401002)
Collaborative Innovation Center of Suzhou Nano Science & Technology, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
the 111 Project and Qing Lan Project, China
