We demonstrate two efficient blue-green thermally activated delayed fluorescence (TADF) compounds comprising a dimeric phenylcarbazole and four cyano substituents on the phenyl rings. A comparison of the 2,6-dicyano-substituted derivative (26IPNDCz) with the 3,5-dicyano-substituted derivative (35IPNDCz) shows that 26IPNDCz provides a larger dihedral angle and a lower decrease in the energy difference between the first singlet and triplet excited states (ΔEST) and the TADF lifetime. An organic light-emitting diode based on 26IPNDCz afforded an external quantum efficiency of 10% with reduced efficiency roll-off.
我们展示了两种高效的蓝绿色热激活延迟荧光(TADF)化合物,它们由二聚体苯基
咔唑和苯基环上的四个
氰基取代基组成。对 2,6-二
氰基取代衍
生物(26I
PNDCz)和 3,5-二
氰基取代衍
生物(35I
PNDCz)进行比较后发现,26I
PNDCz 的二面角更大,第一个单重态和三重态激发态之间的能差(ΔEST)和 TADF 寿命的下降幅度更小。基于 26I
PNDCz 的有机发光二极管的外部量子效率为 10%,效率滚降降低。