Résumé
Carbon dots (CDs) are an emerging smart material that is applied in a wide range of applications including sensors, photocatalysis, bioimaging, and optoelectronic devices. In recent decades, CDs have been an alternative to semiconductor-based quantum dots due to their unique optical properties. CDs are highly fluorescent, zero in dimensional (<10 nm), sp2 and sp3 hybridized carbon core with highly surface-functionalized nanomaterials. While thousands of studies have already been published, carbon dot research is still emerging due to its unique structural and photoluminescent properties. Herein, we report a synthesis of highly fluorescent, amphiphilic, solid-state yellow luminescent, dual emissive carbon dots and their fabrication as strip probes for metal ion sensing. Remarkably, a simple tuning of the stoichiometric ratio of precursors leads to solid-state yellow luminescent and dual emissive CDs. In addition, we investigated, how nitrogen speciation, graphitization and surface functionality of carbon dots (CDs) can impact the structure-optical property relationship of CDs in solution and solid-state. We fabricated CDs-based fluorescent strips and utilized them as an ON-OFF fluorescence sensor to detect Hg2+ metal ions in an aqueous medium with great sensitivity and selectivity. These results would give an approach for tuning the fluorescence and structural characteristics of CDs to develop a simple strip-based probe without a self-quenching issue for sensor applications.