Influence of\nCarbon-Nitride Dot-Emitting Species and\nEvolution on Fluorescence-Based Sensing and Differentiation

Carbon dots have attracted widespread interest for sensing\napplications\nbased on their low cost, ease of synthesis, and robust optical properties.\nWe investigate structure–function evolution on multiemitter\nfluorescence patterns for model carbon-nitride dots (CNDs) and their\nimplications on trace-level sensing. Hydrothermally synthesized CNDs\nwith different reaction times were used to determine how specific\nfunctionalities and their corresponding fluorescence signatures respond\nupon the addition of trace-level analytes. Archetype explosives molecules\nwere chosen as a testbed due to similarities in substituent groups\nor inductive properties (i.e., electron withdrawing), and solution-based\nassays were performed using ratiometric fluorescence excitation–emission\nmapping (EEM). Analyte-specific quenching and enhancement responses\nwere observed in EEM landscapes that varied with the CND reaction\ntime. We then used self-organizing map models to examine EEM feature\nclustering with specific analytes. The results reveal that interactions\nbetween carbon-nitride frameworks and molecular-like species dictate\nresponse characteristics that may be harnessed to tailor sensor development\nfor specific applications.