Π–π stacking: a strategy to improve the electron mobilities of bipolar hosts for TADF and phosphorescent devices with low efficiency roll-off. Issue 13 (21st March 2017)

• Record Type: Journal Article
• Authors: Cai, Minghan; Song, Xiaozeng; Zhang, Dongdong; Qiao, Juan; Duan, Lian
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 13(2017)
• Page Start: 3372
• Page End: 3381
• Publication Date: 2017-03-21
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Optical materials -- Research -- Periodicals; Electronics -- Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7tc00733g
• Languages: English
• ISSNs: 2050-7526

Abstract

Abstract : π–π stacking can improve the electron mobilities of bipolar hosts for TADF and phosphorescent devices with low efficiency roll-off. Abstract : A series of D–π–A type bipolar hosts based on triphenylene/carbazole were designed and synthesized. π–π stacking of the triphenylene units between two adjacent molecules renders these hosts high electron mobilities above 1 × 10 −4 cm 2 V −1 s −1, and their electron and hole mobilities can be regulated through varying the connection position and π moieties. Due to more balanced charge mobilities, aD1 -based green thermally activated delayed fluorescence (TADF) device achieved the highest external quantum efficiency (EQE) of 16.3%, and its EQE could still maintain 15.3% and 13.8% at the high luminance of 5000 cd m −2 and 10 000 cd m −2, respectively.D1 -based green phosphorescent devices also exhibited the highest EQE of 18.6% with a reduced roll-off to 17.6% at 5000 cd m −2 and 16.2% at 10 000 cd m −2 .