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

Abstract 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 displayed a temperature-dependent reversible opaque ↔ transparent states transition, accompanying with an interesting photoluminescence behavior. Moreover, by further incorporating europium (III) (Eu3+) into the hydrogel, we demonstrated 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%, also was obtained as established the time-resolved fluorescence spectroscopy analysis.