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A Simple Approach to Achieve Organic Radicals with Unusual Solid-State Emission and Extraordinary Stability

submitted on 14.06.2020, 09:50 and posted on 16.06.2020, 11:27 by Xueqian ZHAO, zheng zhao, Junyi Gong, Chao Ma,, Parvej Alam, Yanpei wang, Jing Guo, Zebing Zeng, Zikai He, Herman H.-Y. Sung, ian duncan williams, Kam Sing Wong, Jacky W. Y. Lam, Ben Zhong Tang
Herein, we report a simple approach to generate stable
luminescent radicals in the presence of gentle UV irradiation. The newly generated radical
species are capable of emitting unusual red light with a maximum fluorescence quantum
efficiency of 4.6% at ambient conditions in the solid state. Additionally, the luminescent
radicals show extraordinary stability with more than one-year life-span at ambient conditions.
X-ray diffraction study combined with photophysical and computational analyses reveal that
the unique molecular symmetry breaking in the crystalline state lead to the unusual formation
and stabilization of radical ion pairs via the photo-induced electron transfer (PET) process. Such
results represent the first time to achieve stable emissive radicals in the solid state at ambient
conditions via in-situ PET process.


the National Natural Science Foundation of China (21788102), the Natural Science Foundation of Guangdong Province (2019B121205002 and 2019B030301003), the Research Grants Council of Hong Kong (16305618, 16305518, C6009-17G and AoE/P-02/12), the National Key Research and Development Program(2018YFE0190200), the Innovation and Technology Commission (ITC-CNERC14SC01), and the Science and Technology Plan of Shenzhen (JCYJ20180306174910791, and JCYJ20170818113530705 and JCYJ20170818113538482, and JCYJ20160229205601482 ).


Email Address of Submitting Author


The Hong Kong University of Science and Technology


China, Hong Kong

ORCID For Submitting Author


Declaration of Conflict of Interest

The authors declare no competing financial interest.