Chiroptical luminescent nanostructured cellulose films†
In this work we report a straightforward and scalable method to fabricate luminescent and iridescent chiral nanomaterials with potential metal ion sensing capacity for environmental and biological applications. Nitrogen-doped carbon dots (N-CDs) were synthesized by a hydrothermal reaction of D-glucose and melamine. New free-standing chiral nematic composite materials with randomly distributed nanoparticles were prepared after N-CD co-assembled with CNCs via evaporation-induced self-assembly (EISA). The left-handed twisted, layered structure of chiral CNC composites remains intact for all the studied compositions, providing both iridescent and photoluminescent properties to our films. Structural, thermal, morphological and photophysical properties of the films were further explored. Overall, our experimental findings reveal that hydrothermal synthesis of melamine and D-glucose is an effective approach to obtain luminescent materials that can be combined with CNCs to obtain photonic films that retain long-range chiral nematic organization. These new functional materials have potential application as luminescent sensors for metal ions or bioimaging purposes.