Rigid clusteroluminogens of p(C3O2)n polyesters for detection of deuterated water

Abstract

The rapid expansion of nuclear energy confronts ecological challenges, especially the analysis of heavy water (D₂O) in radioactive wastewater. The unique red carbon (C₃O₂) molecule spontaneously polymerizes into highly conjugated fluorescent structures, p(C₃O₂)_n, enabling us to deeply investigate their recognition mechanism for D₂O, as aggregation-induced emission luminogens. Density functional theory calculations and experiments reveal the π–π stacking crystal structure of p(C₃O₂)_n nanosheets in an aggregated state, enhancing their fluorescence properties in solution. This allows for highly sensitive, fast (< 0.2 s), and stable detection of D₂O, with a minimum detection limit of 2.91×10⁻⁵%, unaffected by external factors. The fluorescence quenching is attributed to hydrogen bond formation between -C=O groups and D₂O's D atoms (static quenching) and intramolecular electron transfer (dynamic quenching). Thus, p(C₃O₂)_n polyesters serve as an effective luminescent probe for D₂O sensing, offering a novel approach for designing conjugated fluorescent polyesters.