A universal strategy for achieving dual cross-linked networks to obtain ultralong polymeric room temperature phosphorescence

Efficient polymeric room-temperature phosphorescence (PRTP) with excellent processability and flexibility is highly desirable but still faces formidable challenge. Herein, a general strategy is developed for efficient PRTP through photo-polymerization of phosphor monomers and N -isopropylacrylamide (NIPAM) spontaneously without a crosslinker. Remarkably ultralong lifetime of 3.54 s with afterglow duration time of 25 s and decent phosphorescent quantum efficiency of 13% are achieved. This efficient PRTP has been demonstrated to be derived from the synergistic effect of the covalent and hydrogen bonds networks formed through photo-polymerization of NIPAM. The electron paramagnetic resonance (EPR) spectra confirmed that methyl radicals are generated under the irradiation of ultraviolet light and promote the formation of covalent cross-linking networks. This strategy has also been proved to be generalizable to several other phosphor monomers. Interestingly, the polymer films display ultrahigh temperature resistance with long afterglows even at 140 °C and unexampled ultralong lifetime of 2.45 s in aqueous solutions. This work provides a simple and feasible avenue to obtain efficient PRTP.