Waste chicken eggshell as low-cost precursor for efficient synthesis of nitrogen-doped fluorescent carbon nanodots and their multi-functional applications

A novel one-step top-down method is developed for the efficient synthesis of nitrogen-doped carbon nanodots (NCNDs) by using calcination treatment of waste chicken eggshell as resources. Based on the usage of urea as a dopant, the as-synthesized NCNDs are referred to as NCND 1 (no dopant) and NCND 2. The structural and composition analysis indicate that NCND 2 possesses a mean particle diameter of 2.6 nm and an amorphous carbon structure with a lattice spacing of 0.38 nm. Despite having a low N-content (similar to 4%), the as-prepared NCND 1 was also found to exhibit excellent photoluminescent properties, low cytotoxicity and could be effectively used for bioimaging, in conjunction with NCND 2. The multi-functional capability of NCND 2 is further demonstrated for stamping, printing, and forensic applications. This work may pave the way for employing carbonaceous waste materials as potential precursors in the synthesis of carbon nanomaterials for wide technological applications.