Production of nitrogen-doped carbon quantum dots with controllable emission wavelength, excellent sensing of Fe3+ in aqueous solution, and potential application for stealth quick response coding in the visible regime

Nitrogen-doped carbon quantum dots (N-CQDs) exhibit a high quantum yield with controllable emission wavelength and intensity in the blue-green regime. N-CQDs were tested and determined to be thermally and optically stable during 150 °C heat treatment and prolonged UV irradiation. Potential applications of N-CQDs were demonstrated, including excellent Fe3+ sensing in aqueous solution, fluorescent polymer fibres, and stealth quick response coding at visible wavelengths.