A stimuli responsive lanthanide-based hydrogel possessing tunable luminescence by efficient energy transfer pathways

Energy transfer as an important component in light-harvesting antenna systems can mimic effectively natural photosynthesis processes,showing great potential in optoelectronic devices.Herein,we report a responsive polymeric hydrogel based on the combination of excited state intramolecular proton transfer(ESIPT)molecule(Salicylic acid,Sal)and terbium(Ⅲ)(Tb3+),as enabled by external stimuli to construct artificial light-harvesting antenna systems.Benefiting from unique photophysical properties of Sal,the synthesized hydrogel displays a temperature-dependent reversible opaque ? transparent states tran-sition,accompanied with an interesting photoluminescence behavior.Moreover,by further incorporating europium(Ⅲ)(Eu3+)into the hydrogel,we demonstrate well-defined cascades of energy transfer that provides a tunable optical output from the collection of lanthanides by the excitation of a common sensitizer(Sal)upon base vapor stimulation.Efficient energy transfer efficiency from Tb3+to Eu3+,as high as 97.8％,was also obtained as established by the time-resolved fluorescence spectroscopy analysis.