Dynamic room-temperature phosphorescence by reversible transformation of photo-induced free radicals

Room-temperature phosphorescence (RTP) with a dynamic feature endows organic luminescent materials with promising application in optoelectronic fields. However, it remains a formidable challenge to obtain dynamic RTP materials. Herein, we reported a strategy for dynamic RTP via reversible transformation of radicals under external stimuli. RTP gradually disappeared with continuous UV-light irradiation owing to the conversion of NDIA to NDIA·− in NDIA/PVA film, which can be recovered by oxidation with oxygen. Regarding the excellent reversibility and repeatability, the potential applications for round-the-clock anti-counterfeiting and tag were first demonstrated. This finding not only outlines a principle to synthesize new RTP materials with dynamic behavior, but also expands the scope of applications of dynamic RTP materials.