Achieving Tunable Organic Afterglow and UV-Irradiation-Responsive Ultralong Room-Temperature Phosphorescence from Pyridine-Substituted Triphenylamine Derivatives

Amorphous polymers with ultralong room-temperature phosphorescence (RTP) are highly promising for various applications. Particularly, polymer-based RTP materials with multiple functions such as color-tunability or stimulus-response are highly desirable for multilevel anti-counterfeiting but are rarely reported. Herein, a facile strategy is presented to achieve a series of polymer-based RTP materials with ultralong lifetime, multicolor afterglow, and reversible response to UV irradiation by simply embedding pyridine-substituted triphenylamine derivatives into the polymer matrix poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA), respectively. Notably, the pyridine group with the capabilities of promoting intersystem crossing and forming hydrogen-bonding interactions is essential for triggering ultralong RTP from the doping PVA system, among which the doping film TPA-2Py@PVA exhibits excellent RTP property with an ultralong lifetime of 798.4 ms and a high quantum yield of 15.2%. By further co-doping with the commercially available fluorescent dye, multicolor afterglow is obtained via phosphorescence energy transfer. Meanwhile, the doped PMMA system exhibits reversible photoactivated ultralong RTP properties under continuous UV irradiation. Finally, potential applications of these doped PVA and PMMA systems with ultralong lifetime, multicolor afterglow, and photoactivated ultralong RTP in multidimensional anti-counterfeiting are demonstrated.