It is a persistent challenge to develop efficient, low roll-off, pure blue light emitting materials. Here, employing rigid carbazole (Cz) and phenyl-phenanthroimidazole (PPI) moieties to reduce the energy loss caused by non-radiative transitions, two deep-blue fluorescent emitting materials, 2-(4-(9H-carbazol-9-yl)phenyl)-1-(3,5-difluorophenyl)-1H-phenanthro[9,10-d]imidazole (2FPPICz) and 2-(4′-(9H-carbazol-9-yl)-[1,1′-biphenyl]-4-yl)-1-(3,5-difluorophenyl)-1H-phenanthro[9,10-d]imidazole (2FPPIPCz), are synthesized and fully characterized. The non-doped organic light-emitting diodes (OLEDs) with 2FPPICz and 2FPPIPCz as emitters represent deep-blue emission with Commission International de L’Éclairage (CIE) coordinates of (0.160, 0.045) and (0.150, 0.075) and an excellent maximum external quantum efficiency (EQE) of 4.3% and 5.6%, respectively. Furthermore, the OLED with 2FPPIPCz exhibits low efficiency roll-off at high luminance.

中文翻译：

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基于咔唑/菲并咪唑衍生物的高效非掺杂深蓝色荧光有机发光二极管

开发高效，低滚降的纯蓝色发光材料是一项持续的挑战。在这里，采用硬质咔唑（Cz）和苯基菲并咪唑（PPI）部分来减少由非辐射跃迁引起的能量损失，两种深蓝色荧光发射材料，2-（4-（9 H-咔唑-9-基）苯基）-1-（3,5-二氟苯基）-1 H-菲基[9,10- d ]咪唑（2FPPICz）和2-（4'-（9 H-咔唑-9-基）-[1，合成并充分表征了1'-联苯基] -4-基）-1-（3,5-二氟苯基）-1 H-菲基[9,10- d ]咪唑（2FPPIPCz）。具有2FPPICz的非掺杂有机发光二极管（OLED）作为发射源的2FPPIPCz和2FPPIPCz代表深蓝色发射，国际照明委员会（CIE）坐标为（0.160，0.045）和（0.150，0.075），出色的最大外部量子效率（EQE）分别为4.3％和5.6％ 。此外，具有2FPPIPCz的OLED在高亮度下显示出低效率滚降。