White-Light-Emitting Carbon Dots Prepared by the Electrochemical Exfoliation of Graphite

The single-step synthesis of white-light-emitting carbon dots (CDs) through a green, facile and cheap electrochemical route by using graphite rods as the carbon source is reported. Under UV excitation, the aqueous dispersion of as-synthesised CDs exhibit broad-band emission, which covers a significant fraction of the visible spectrum, owing to the heterogeneity in particle size and surface functional groups. The CDs were further explored for their potential as UV-to-visible colour convertors under remote-phosphor technology by capping a lambda=365 nm UV light-emitting diode (LED) chip with CD-loaded poly(methyl methacrylate) to obtain the following colour parameters: Commission Internationale de l'Eclairage chromaticity coordinates (0.35, 0.37), colour rendering index (88) and correlated colour temperature (4802 K).