用于深蓝色有机发光二极管且效率滚降小的纳秒时间尺度延迟荧光分子。

Nanosecond-time-scale delayed fluorescence molecule for deep-blue OLEDs with small efficiency rolloff.

作者信息

Kim Jong Uk, Park In Seob, Chan Chin-Yiu, Tanaka Masaki, Tsuchiya Youichi, Nakanotani Hajime, Adachi Chihaya

机构信息

Center for Organic Photonics and Electronics Research (OPERA) and Department of Applied Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.

JST, ERATO, Adachi Molecular Exciton Engineering Project, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.

出版信息

Nat Commun. 2020 Apr 14;11(1):1765. doi: 10.1038/s41467-020-15558-5.

Aromatic organic deep-blue emitters that exhibit thermally activated delayed fluorescence (TADF) can harvest all excitons in electrically generated singlets and triplets as light emission. However, blue TADF emitters generally have long exciton lifetimes, leading to severe efficiency decrease, i.e., rolloff, at high current density and luminance by exciton annihilations in organic light-emitting diodes (OLEDs). Here, we report a deep-blue TADF emitter employing simple molecular design, in which an activation energy as well as spin-orbit coupling between excited states with different spin multiplicities, were simultaneously controlled. An extremely fast exciton lifetime of 750 ns was realized in a donor-acceptor-type molecular structure without heavy metal elements. An OLED utilizing this TADF emitter displayed deep-blue electroluminescence (EL) with CIE chromaticity coordinates of (0.14, 0.18) and a high maximum EL quantum efficiency of 20.7%. Further, the high maximum efficiency were retained to be 20.2% and 17.4% even at high luminance.

表现出热激活延迟荧光（TADF）的芳香族有机深蓝色发光体能够将电致产生的单重态和三重态中的所有激子作为光发射来捕获。然而，蓝色TADF发光体通常具有较长的激子寿命，这会导致在有机发光二极管（OLED）中，在高电流密度和高亮度下，由于激子湮灭而出现严重的效率下降，即效率滚降。在此，我们报道了一种采用简单分子设计的深蓝色TADF发光体，其中同时控制了一个激活能以及具有不同自旋多重性的激发态之间的自旋 - 轨道耦合。在没有重金属元素的供体 - 受体型分子结构中实现了750纳秒的极快激子寿命。利用这种TADF发光体的OLED呈现出CIE色度坐标为（0.14, 0.18）的深蓝色电致发光（EL），以及20.7%的高最大EL量子效率。此外，即使在高亮度下，高最大效率仍保持在20.2%和17.4%。