Multicolor Tunable\nAIE Fluorescent Hydrogels Containing\nEuropium Ionic Complexes via the “One-Pot Method”

The coordination of multiple luminescent\ncenters in a\nsimple and\nefficient way is a difficult challenge for realizing the tunable multicolor\nfunction of fluorescent hydrogels. In this work, we synthesized a\nfluorescent hydrogel with multicolor conversion via a “one-pot\nmethod,” which greatly simplifies the tedious steps of preparing\nfluorescent hydrogels. The luminescence intensity and color of the\nsynthesized DPA-Eu/TPE@PVA hydrogel can be modulated by various stimuli,\nsuch as the excitation wavelength, pH, and presence of Fe<sup>3+</sup> ions. The entire work centers on the rational introduction of the\nlight-emitting molecule tetrakis(4-hydroxyphenyl)ethylene (TPE-4OH)\nand the lanthanide ionic complex 2,6-pyridinedicarboxylic acid-Eu\n(DPA-Eu) into the poly(vinyl alcohol) (PVA) polymer network. Since\nthe luminescence mechanisms of these two molecules differ, with the\nformer emitting light with the aid of the aggregation-induced emission\n(AIE) effect and the latter emitting light through energy transfer\nvia metal dynamic coordination bonds, individual luminescent molecules\ncan be controlled independently under specific stimuli. The realization\nof this tunable multicolor fluorescence function has contributed to\nits application in fields such as sensors, probes, and information\nencryption.