Ultraefficient Non-Doped Deep Blue Fluorescent OLED: Achieving a High EQE of 10.17% at 1000 cd m-2 with CIEy<0.08

作者：Du, Chunya; Liu, Hui; Cheng, Zhuang; Zhang, Shaoqin; Qu, Zexing; Yang, Dezhi; Qiao, Xianfeng; Zhao, Zujin; Lu, Ping^*

来源：Advanced Functional Materials, 2023, 33(45).

DOI：10.1002/adfm.202304854

• deep-blue emitters
• hot exciton mechanism
• low efficiency roll-off
• non-doped devices
• organic light-emitting diodes

The pursuit for efficient deep blue material is an ever-increasing issue in organic optoelectronics field. It is a long-standing challenge to achieve high external quantum efficiency (EQE) exceed 10% at brightness of 1000 cd m(-2) with a Commission International de L'Eclairage (CIEy) <0.08 in non-doped organic light-emitting diodes (OLEDs). Herein, this study reports a deep blue luminogen, PPITPh, by bonding phenanthro[9,10-d]imidazole moiety with m-terphenyl group via benzene bridge. The non-doped OLED based on PPITPh exhibits an exceptionally high EQE of 11.83% with a CIE coordinate of (0.15, 0.07). The EQE still maintains 10.17% at the brightness of 1000 cd m(-2), and even at a brightness as high as 10000 cd m(-2), an EQE of 7.5% is still remained, representing the record-high result among non-doped deep-blue OLEDs at 1000 cd m(-2). The unprecedented device performance is attributed to the reversed intersystem crossing process through hot exciton mechanism. Besides, the maximum EQE of orange phosphorescent OLED with PPITPh as host is 32.02%, and remains 31.17% at the brightness of 1000 cd m(-2). Such minimal efficiency roll-off demonstrates that PPITPh is also an excellent phosphorescent host material. The result offers a new design strategy for the enrichment of high-efficiency deep blue luminogen.

• 单位
  吉林大学