Nitrogen and phosphorus-doped green carbon dots with 'turn-off' fluorometric sensor for Fe3+ ions detection

Carbon dots (CDs) were paid more and more attention for detecting ferric ions (Fe3+) containing in the organism or environment. Thus, nitrogen and phosphorus co-doping green CDs were synthesized using p-Phenylenediamine as the carbon source and phosphoric acid as phosphorus source by the solvo-thermal method. As-prepared CDs were characterized by morphology, optical properties, and surface functional groups. The CDs can emit better green light peak at 511 nm excited by 380 nm UV light. Excitation independence property of N, P-CDs was determined by measuring the photoluminescence (PL) spectra with different excitation wavelengths. The ions detection ability was investigated by analyzing the emission intensity of CDs in eight different kinds of ions solutions and different concentrations of Fe3+ ions solutions. The N, P-CDs show high selectivity towards Fe3+ ions with a limit of detection (LOD) of 0.11 mu M in the concentration region of 300 to 450 mu M. The results illuminated that this kind of CDs can be a candidate material for Fe3+ ions detection.