南京大学化学和化工学院You-Xuan Zheng团队近日取得一项新成果。经过不懈努力，他们开发出手性螺旋轴诱导蓝色热激活延迟荧光材料，用作高效圆偏振、低效率滚降的OLED。 相关论文于2021年1月20日发表在《德国应用化学》杂志上。

这项工作提出了一种手性螺轴策略，它不仅将圆偏振发光（CPL）特性引入到热活化延迟荧光（TADF）分子中，而且还增强了分子内通过空间电荷转移（TSCT）的过程。

螺旋分布吩恶嗪和2-三氟甲基-9H-9-噻吨酮-10,10-二氧化物分别作为供体和受体单元。得到的TADF对映体，(R / S)-OSFSO有在470nm的发射峰，在共掺杂膜中0.022 eV的小的单线态-三线态能量差（ΔEST）及81.2%的高光致发光量子产率（PLQY）。

基于（R）-OSFSO和（S）-OSFSO的圆偏振OLEDs（CP-OLEDs）表现出明显圆偏振电致发光（CPEL）信号，其非对称系数高达3.0×10^‐3，最大外部量子产率为20.0%。更多的是，基于（R/S）-OSFSO的器件展示出引人注目的低效率滚降：EQE在1000 cd/m²下为19.4%（~3.5%滚降），这在所有CP-OLEDs的结果中名列前茅。

附：英文原文

Title: Chiral Spiro‐Axis Induced Blue Thermally Activated Delayed Fluorescence Material for Efficient Circularly Polarized OLEDs with Low Efficiency Roll‐off

Author: Yi-Pin Zhang, Xiao Liang, Xu-Feng Luo, Shi-Quan Song, Si Li, Yi Wang, Zhi-Ping Mao, Wen-Ye Xu, You-Xuan Zheng, Jing-Lin Zuo, Yi Pan

Issue&Volume: 20 January 2021

Abstract: This work presents a chiral spiro‐axis strategy which not only introduced the circularly polarized luminescence (CPL) property into thermally activated delayed fluorescence (TADF) molecules but also enhanced the intramolecular through space charge transfer (TSCT) process. Spiral distributed phenoxazine and 2‐(trifluoromethyl)‐  9H  ‐thioxanthen‐9‐one‐10,10‐dioxide act as donor and acceptor units, respectively. The resulting TADF enantiomers, (R/S)‐OSFSO, display emission maxima at 470 nm, small singlet‐triplet energy gap (ΔEST) of 0.022 eV and high photoluminescence quantum yield (PLQY) of 81.2% in co‐doped film. The circularly polarized OLEDs (CP‐OLEDs) based on (R)‐OSFSO and (S)‐OSFSO display obvious circularly polarized electroluminescence (CPEL) signals with dissymmetry factor up to 3.0×10^‐3  and maximum external quantum efficiency (EQE_max) of 20.0%. Moreover, the devices based on (R/S)‐OSFSO show remarkably low efficiency roll‐off with an EQE of 19.3% at 1000 cd/m²  (roll‐off ≈3.5%), which are among the top results of CP‐OLEDs.

DOI: 10.1002/anie.202015411

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202015411