Kellar Ke, Jiaxiong Chen, Ming Zhang
Nov 2, 2018
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Influential Citations
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Journal
Science China Materials
Abstract
An optimized compound 9-(9,9-dimethylacridin-10(9H)-yl)-6H-benzo[c]ch-romen-6-one (MAB) was designed and synthesized based on our previously reported TADF emitter 6-(9,9-dimethylacridin-10(9H)-yl)-3-methyl-1H-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.摘要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.