Controlling the thermally activated delayed fluorescence of axially chiral organic emitters and their racemate for information encryption
Bingjia Xu, Zicun Song, Minmin Zhang, Qingqing Zhang, Long Jiang, Chao Xu, Lijun Zhong, Changlin Su, Qiqi Ban, Cong Liu, Fengqiang Sun, Yi Zhang, Zhenguo Chi, Zujin Zhao, Guang Shi
Abstract
A pair of axially chiral organic enantiomers were facilely prepared through a one-pot sequential synthesis. They exhibit circularly polarized luminescence activities and have thermally activated delayed fluorescence (TADF) and aggregation-induced emission enhancement properties. Meanwhile, these two enantiomers present remarkable and reversible thermochromism in the crystalline state, enabling dual-colour TADF switching between orange and red. However, when they form cocrystals, the resulting racemate shows opposite thermochromic behaviors. These intriguing results probably emanate from their different optical activities, leading to distinct molecular packing modes and molecular conformation variations. Moreover, information encryption based on thermochromism of organic enantiomers and their racemate has been presented for the first time. This work may expand the application scope of chiral organic luminogens and pave a new way to construct intelligent luminescent systems.