2018年度修士修了の伊藤聖君（Takashi Ito）と笹部久宏准教授の高効率・長寿命深赤色有機ELに資するジベンゾフラン含有n型ホスト材料群に関する「A Series of Dibenzofuran-based N-Type Exciplex Host Partners Realizing High Efficiency and Stable Deep Red Phosphorescent OLEDs」と題する論文が Wiley の Chemistry An European Journal (IF: 5.1) に Hot Paper として受理され、Front Cover に選出されました！
Title: A Series of Dibenzofuran-based N-Type Exciplex Host Partners Realizing High Efficiency and Stable Deep Red Phosphorescent OLEDs
By Takashi Ito, Hisahiro Sasabe*, Yuichiro Watanabe, and Junji Kido*, Chem. Eur. J. 2019, accepted as Hot paper, and selected as Front Cover.
Abstract: Deep red to near-infrared (NIR) OLEDs, which yield emission peak wavelengths beyond 660 nm, are applicable as a unique light source in plant growth or health- monitoring systems. Compared with other visible spectrum region OLEDs, however, research in the field of deep red OLEDs is not as advanced. In this work, three new types of dibenzofuran-based host materials are developed as n-type exciplex host partners. Combining these with a deep red iridium complex, bis(2,3- diphenylquinoxaline)iridium(dipivaloylmethane) [(DPQ)2Ir(dpm)] and NPD as a p-type exciplex host partner, a highly efficient deep red OLED can be realized with a maximum external quantum efficiency (EQE) of over 16% with Comission Internationale de l'Éclairge (CIE) coordinates of (0.71, 0.28). In addition, the effect of doping concentration and the p/n ratio of the exciplex host on the OLED’s efficiency and lifetime is investigated. Consequently, the optimized device exhibits a EQE of over 15% and 6× longer lifetime operating at high brightness of 100 cd m–2 compared with other state-of-the-art deep red OLEDs.