Femtosecond laser-assisted synthesis of highly photoluminescent carbon nanodots for Fe³⁺ detection with high sensitivity and selectivity

Carbon nanodots (C-dots) were synthesized by femtosecond laser ablation of graphite powders in polyethylene glycol (PEG_200N) solutions with different graphite concentrations. The photoluminescent quantum yield (PLQY) of the C-dots was effectively enhanced by decreasing the graphite concentration, and its value could reach 21%. Detailed work showed that the C-dots prepared with a low raw material concentration possessed high PLQY because they contained fewer trap defects in the carbogenic core and a larger quantity of surface functional groups on the surface. Taking advantage of their high photoluminescence properties, the C-dots were used as effective fluorescent nanosensor probes for sensitive and selective detection of Fe³⁺ ions.