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

Herein, we report a simple approach to generate stable<br>luminescent radicals in the presence of gentle UV irradiation. The newly generated radical<br>species are capable of emitting unusual red light with a maximum fluorescence quantum<br>efficiency of 4.6% at ambient conditions in the solid state. Additionally, the luminescent<br>radicals show extraordinary stability with more than one-year life-span at ambient conditions.<br>X-ray diffraction study combined with photophysical and computational analyses reveal that<br>the unique molecular symmetry breaking in the crystalline state lead to the unusual formation<br>and stabilization of radical ion pairs via the photo-induced electron transfer (PET) process. Such<br>results represent the first time to achieve stable emissive radicals in the solid state at ambient<br>conditions via in-situ PET process. <br>