Two novel bipolar isomers, namely 3,5-bis(3-(9H-carbazol-9-yl)phenyl)isonicotinonitrile (m-DCzPyCN), and 3,5-bis(9-phenyl-9H-carbazol-3-yl)isonicotinonitrile (3-DCzPyCN), are designed and synthesized by selecting cyanopyridine as n-type unit and N-phenylcarbazole as p-type unit. Two peripheral carbazoles are conjugated through their C-3 atom with the central cyanopyridine in 3-DCzPyCN but are indirectly linked through the N-9 atom via meta-phenylene bridges in m-DCzPyCN. The linking strategy had significant effect on the physical properties of the isomers. The single-carrier device study reveals that 3-DCzPyCN has much better positive and negative charge balancing ability than m-DCzPyCN. The 3-DCzPyCN hosted green phosphorescent organic light-emitting diode exhibits superior performance over m-DCzPyCN, with the maximum current efficiency of 84.1 cd A⁻¹ and external quantum efficiencies of 24.2% and low efficiency roll-off. At an extremely high brightness of 10000 cd m⁻², the efficiency still remained at 78.4 cd A⁻¹, which corresponds to a roll-off of 6.7% from the maximum value. Even at an ultra-high brightness of 100000 cd m⁻², the efficiency is reduced by 47.0%. The superior performance of 3-DCzPyCN is ascribed to its remarkable charge balancing capability, which is the combined result of the cyanopyridine as n-type unit and the conjugated linking strategy between p- and n-type moieties.

两种新型的双极性异构体，即3,5-双（3-（9 H-咔唑-9-基）苯基）异烟碱腈（m -DCzPyCN）和3,5-双（9-苯基-9 H-咔唑-3以氰基吡啶为n型单元，以N-苯基咔唑为p型单元，设计合成了β-基）异烟碱腈（3-DCzPyCN）。两个外围咔唑通过与在3-DCzPyCN中央氰基吡啶其C-3原子结合而是通过N-9原子经由间接链接的元亚苯基桥在米-DCzPyCN。连接策略对异构体的物理性质有重大影响。单载流子器件研究表明，3-DCzPyCN具有比正负电荷平衡更好的电荷平衡能力m -DCzPyCN。3-DCzPyCN承载的绿色磷光有机发光二极管表现出优于m -DCzPyCN的性能，最大电流效率为84.1 cd A ^-1，外部量子效率为24.2％，并且低效率滚降。在10000 cd m ^-2的极高亮度下，效率仍然保持在78.4 cd A ^-1，这对应于最大值的6.7％的下降。即使在100000 cd m ^-2的超高亮度下，效率降低了47.0％。3-DCzPyCN的卓越性能归因于其出色的电荷平衡能力，这是氰基吡啶作为n型单元以及p型和n型部分之间共轭连接策略的综合结果。