Dynamic Phosphorescent Gel with Dual Supramolecular Interactions for Visualization of Moisture Monitoring

Abstract

Pure organic room-temperature phosphorescence (RTP) has attracted widespread attention due to its large Stokes shift and long luminescent lifetime. Gels, as synthetically created soft materials, are noted for their adsorption capacity, ease of preparation, and degradability. However, stimuli-responsive gels with controllable RTP emission were rarely reported. In this study, a RTP supramolecular gel with visualization of humidity-response was developed through construction of dual non-covalent interactions. Firstly, the assembly process of fluorescent compound (Upy3-BrBP) and cucurbit[8]uril (CB[8]) successfully induced RTP emission. Moreover, the complex could act as crosslinkers to connect disordered hydrogen-rich polymers into regularly ordered polymer networks, generating a supramolecular gel and significantly enhancing RTP leading to nearly pure RTP emission. The phosphorescent quantum yield increased sharply by 19.2 times, and the phosphorescence lifetime extended by 8.6 times. More importantly, the formed supramolecular gel could visualize the ambient humidity and its change through RTP variation from shining green to dark blue. This RTP supramolecular gel offers a new strategy for the development of visualized intelligent sensing materials.