Carboxymethylcellulose and rare earth metal cation self-assembly: Tunable encapsulation of carbon dots in a multifunctional transparent film

Due to their unique properties, carbon dots have attracted significant interest across diverse fields. However, obstacles such as uneven size distribution in the course of synthesis and excessive aggregation lead to fluorescence quenching during solidification process. Moreover, conventional doping procedures frequently yield carbon dot films with constrained functionality, inferior durability, and harsh environments, thereby restricting their practical applications. To address these issues, this study fabricates N-doped carbon dots via a straightforward hydrothermal approach and incorporates them into CMC films by metathesis with CeCl3 & sdot;7H2O, resulting in a unique carbon dot-encapsulated film. This film overcomes the problem of fluorescence quenching caused by excessive aggregation of carbon dots and allows for size control by adjusting the concentration of Ce(III). The resulting film achieves extreme transparency and superior performance compared to existing UV-blocking films. In addition, the film exhibits exceptional resistance to acids and bases, bleaching, excellent mechanical properties, and good thermal and water stability. Based on these properties, the film achieves size-controlled in-situ photoluminescence, full UV shielding, Cu2+ ion detection, anti-counterfeiting, and information encryption. The water-processable and water-adhesive characteristics of CMC enable its use in real-life situations, opening the door to wider use of solid-state carbon dots for multifunctional and intelligent applications.