Exploring the Proton Conductivity across the C-Dots Doped Cellulose Nanocrystal Biopolymer

Abstract Biopolymers have gained significant attention across the energy, fuel, bioelectronics, and biomedical applications owing to their intrinsic protonic conductivity. Among them, polysaccharides represent a class of low-cost and abundant biomacromolecules suitable for constructing functional biopolymers. In this work, we present a novel strategy to enhance proton conduction in biopolymer systems by integrating varying concentrations of carbon dot (C-Dot)-derived surface functional groups into a cellulose nanocrystal (CNC) biopolymer. Blue-, green-, and red-emitting C-Dots, with varying degrees of oxygen-rich surface functional groups and heterocyclic nitrogen-enriched core states, were incorporated as dopants into the CNC biopolymer. Notably, the inclusion of B-, G-, and R-C-Dots led to ∼2-, 4-, and 10-fold enhancements in protonic conductivity, respectively, compared to pristine CNC biopolymer. This approach provides an effective pathway for designing advanced self-assembled biopolymer proton-conducting materials for next-generation bioprotonic applications.