Uranyl‐ion Directed Hydrogelation of Cholate for Enhanced Emission Resolution and Energy Transfer‐driven Sensing

In this work, we report the first example of an actinide (UO 2 2+ ) induced hydrogel formation. We discovered that the gel phase led to a remarkable improvement in the resolution of the emission from the uranyl cation. This phenomenon was previously seen only in sophisticated uranyl complexes in organic solvents or in the solid‐state. The organized and confined gel microenvironment facilitated efficient energy transfer from UO 2 2+ → Eu 3+ in the hydrogel matrix. Additionally, this “ turn‐on ” energy transfer strategy provided a simple method for uranyl sensing using commercially available ingredients.