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) have received considerable attention due to their potential applications in anti-counterfeiting, bioimaging, and sensing. However, multifunctional polymer-based RTP materials endowed with color-tunability or stimulus-responsiveness are highly desirable but rarely reported. Herein, we have designed three pyridine-substituted triphenylamine derivatives and achieved ultralong RTP properties with both color-tunability and UV irradiation-responsiveness by embedding them into poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA) matrices, respectively. Notably, introducing the pyridine groups with the capabilities of promoting intersystem crossing (ISC) and forming hydrogen-bonding networks is essential for triggering efficient and ultralong RTP from doping PVA systems. Consequently, 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%. Moreover, by co-doping with the fluorescent dye rhodamine B, color-tunable persistent luminescence has been realized via phosphorescence energy transfer. More importantly, doping PMMA systems exhibit reversible UV irradiation-responsive ultralong RTP properties. Finally, various patterns are devised to demonstrate the potential applications of these doping PVA and PMMA systems in advanced anti-counterfeiting and information encryption. We believe this feasible and facile strategy to achieve multifunctional organic RTP materials with color-tunability and stimulus-responsiveness will provide new opportunities for high-tech applications.