Asymmetric thermally activated delayed fluorescence (TADF) emitters with 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (OBA) as the acceptor and highly efficient blue-emitting OLEDs
Asymmetric thermally activated delayed fluorescence (TADF) emitters with 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (OBA) as the acceptor and highly efficient blue-emitting OLEDs
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以 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (OBA) 作为受体的不对称热激活延迟荧光 (TADF) 发射器和高效蓝光 OLED
DOI：
10.1039/c9tc04115j
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发表时间：
2019
影响因子：
6.4
通讯作者：
Wu Zhaoxin
中科院分区：
文献类型：
--
作者：
Song Dongdong;Yu Yue;Yue Ling;Zhong Daokun;Zhang Yindi;Yang Xiaolong;Sun Yuanhui;Zhou Guijiang;Wu Zhaoxin
通过在5，9-二氧杂-13 b-boranaphtho [3，2，1-de]蒽（OBA）受体（A）的中心苯环硼原子间位引入不同的给体（Ds），制备了一系列新型有机发光材料。此外，它们的热，物理，电化学和电致发光（EL）性能进行了详细的表征。电子物理结果表明，这些基于OBA的分子采用D-A构型，并表现出有效的热激活延迟荧光（TADF）特性，其反向系统间交叉常数（kRISC）约为105 s-1。研究表明，在OBA受体中引入-Br基团可以使kRISC增加2至3倍。重要的是，深蓝色TADF发射体OBA-O显示出0.84的高光致发光量子产率（PLQY），而其具有-Br基团的蓝色类似物OBA-BrO在掺杂膜状态下表现出甚至更高的PLQY，为0.92。由于其具有较高的PLQY值，基于OBA基TADF发光体的掺杂有机电致发光器件（OLED）表现出了优异的电致发光（EL）性能。CIE（0.17，0.17）的蓝光OLED显示出最大的外量子效率（ηext）为17.8%，电流效率（ηL）为33.2 cd A−1，功率效率（ηP）为34.2 lm W−1，而蓝绿色器件的最大外量子效率（η ext）为22.5%，电流效率（η L）为49.2 cd A−1，功率效率（η P）为56.9 lm W−1。因此，这些基于TADF发射体的OBA受体的巨大潜力通过它们的EL数据清楚地证明。此外，这些基于OBA的不对称分子将丰富这种类型的TADF发射器的结构多样性。
A series of new organic emitters was prepared by introducing various donors (Ds) to the meta-position of the boron atom in the central phenyl ring in the acceptor (A) of 5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene (OBA). Moreover, their thermal, photophysical, electrochemical and electroluminescent (EL) properties were characterized in detail. The photophysical results revealed that these OBA-based molecules adopted a D–A configuration and exhibited efficient thermally activated delayed fluorescence (TADF) properties with a reverse inter-system crossing constant (kRISC) in the order of 105 s−1. It has been shown that introducing the –Br group to the OBA acceptor could increase kRISC by 2 to 3 times. Importantly, the deep-blue TADF emitter OBA-O showed a high photoluminescent quantum yield (PLQY) of 0.84, while its blue analog OBA-BrO with the –Br group exhibited an even higher PLQY of 0.92 in the doped film state. Benefitting from their high PLQYs as blue-emitting TADF emitters, the doped organic light-emitting diodes (OLEDs) based on these OBA-based TADF emitters exhibited attractive electroluminescent (EL) performances. The blue-emitting OLEDs with CIE (0.17, 0.17) showed the maximum external quantum efficiency (ηext) of 17.8%, current efficiency (ηL) of 33.2 cd A−1 and power efficiency (ηP) of 34.2 lm W−1, while that for the bluish-green device were 22.5%, 49.2 cd A−1 and 56.9 lm W−1, respectively. Thus, the great potential of these TADF emitter-based OBA acceptors was clearly demonstrated by their EL data. In addition, these asymmetric OBA-based molecules will enrich the structural diversity of this type of TADF emitter.