Manipulation of Molecular Aggregation States to Realize Polymorphism, AIE, MCL, and TADF in a Single Molecule

• Published in: Angewandte Chemie International Edition 2018-09, Vol.57 (38), p.12473-12477
• Main Authors: Huang, Bin, Chen, Wen‐Cheng, Li, Zijing, Zhang, Jinfeng, Zhao, Weijun, Feng, Yan, Tang, Ben Zhong, Lee, Chun‐Sing
• Format: Article
• Language: English
• Subjects: Agglomeration; aggregation-induced emission; Anthraquinone; Emission; Fluorescence; mechanochromic luminescence; Mechanoluminescence; multicolor emission; Organic materials; Phenothiazine; Photoluminescence; Photons; Polymorphism; thermally activated delayed fluorescence
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201806800

Multifunctional emitting materials are scarce and need to be further explored. Now, a newly anthraquinone derivative, 2‐(phenothiazine‐10‐yl)‐anthraquinone (PTZ‐AQ) was designed and synthesized and found to demonstrate polymorphism, multi‐color emission, aggregation‐induced emission (AIE), mechanochromic luminescence (MCL), and thermally activated delayed fluorescence (TADF) in its different solid forms. It is shown for the first time that TADF properties of a compound can be systematically tuned via its aggregation state. The optimized PTZ‐AQ crystal shows a small singlet–triplet energy splitting of 0.01 eV and exhibits red TADF with a photoluminescence quantum yield as high as 0.848. This study shows that the unique multiple functions can be integrated into one single compound through controlling the aggregation states, which provides a new strategy for the investigation and application of multifunctional organic materials. An anthraquinone derivative demonstrates polymorphism, aggregation‐induced emission (AIE), mechanochromic luminescence (MCL), and thermally activated delayed fluorescence (TADF) in its different solid forms. The optimized PTZ‐AQ crystal exhibits red TADF with a small singlet–triplet energy offset of 0.01 eV and with a high photoluminescence quantum yield of 0.848.