Thermally activated delayed fluorescence material-sensitized helicene enantiomer-based OLEDs: a new strategy for improving the efficiency of circularly polarized electroluminescence
Thermally activated delayed fluorescence material-sensitized helicene enantiomer-based OLEDs: a new strategy for improving the efficiency of circularly polarized electroluminescence
复制标题
热激活延迟荧光材料敏化螺旋烯对映体OLED：提高圆偏振电致发光效率的新策略
DOI：
10.1007/s40843-020-1496-7
复制
发表时间：
2020-11-04
影响因子：
8.1
通讯作者：
Chen, Chuan-Feng
中科院分区：
文献类型：
--
作者：
Li, Meng;Wang, Yin-Feng;Chen, Chuan-Feng
为了提高荧光圆偏振有机电致发光器件（CP-OLED）的效率，提出了一种热激活延迟荧光（TADF）材料敏化圆偏振发光（CPL）的新策略。因此，合成了一对螺烯对映体，（P）-HAI和（M）-HAI。具有刚性螺旋π-骨架的螺烯对映体具有较高的热稳定性和对映体稳定性，同时它们也表现出优异的物理化学性质，尤其是具有强的镜像CPL活性和较大的发光不对称因子（|闷闷不乐|）值约为6 × 10−3。值得注意的是，具有螺烯对映体作为发光体和TADF分子作为敏化剂的CP-OLED不仅显示出比没有TADF敏化剂的器件更好的性能，即2.6V的较低开启电压（VT）、5.3%的四倍最大外量子效率（EQEmax）和1000 cd m-2下1.9%的较低效率滚降，而且还表现出强烈的圆偏振电致发光（CPEL），电致发光不对称因子（gEL）值为−2.3 × 10−3和+3.0 × 10−3。同时，本研究也代表了第一个热激活敏化荧光CP-OLED显着提高效率和强烈的CPEL。
A new strategy of thermally activated delayed fluorescence (TADF) material-sensitized circularly polarized luminescence (CPL) has been proposed for improving the efficiencies of fluorescent circularly polarized organic light-emitting diodes (OLEDs) (CP-OLEDs). Consequently, a pair of helicene enantiomers, (P)-HAI and (M)-HAI, were synthesized. The helicene enantiomers with the rigid helical π-skeleton had highly thermal and enantiomeric stabilities, and they also showed excellent photophysical properties, especially, intense mirror-image CPL activities with large luminescence dissymmetry factor (|glum|) values of about 6 × 10−3. Notably, the CP-OLEDs with the helicene enantiomers as emitters and a TADF molecule as sensitizer not only displayed better performance of lower turn-on voltage (VT) of 2.6 V, four-fold maxmium-external quantum efficiency (EQEmax) of 5.3%, and lower efficiencies roll-off of 1.9% at 1000 cd m−2, than those of the devices without TADF sensitizer, but also exhibited intense circularly polarized electroluminescence (CPEL) with the electroluminescence dissymmetry factor (gEL) values of −2.3 × 10−3 and +3.0 × 10−3. Meanwhile, this study also represents the first thermally activated sensitized fluorescent CP-OLEDs with markedly enhanced efficiencies and intense CPEL.