Graphitized carbon dots emitting strong green photoluminescence

Water-soluble graphitized carbon dots (GCDs) with strong green photoluminescence (PL) and distinct visible-absorption have been prepared by one-step carbonization of ethylene glycol in the presence of concentrated sulfuric acid at 80 °C. The PL of GCDs is centered at about 519 nm with the full width at half maximum (FWHM) as small as 38 nm. The fluorescent quantum yield of the prepared GCDs was as high as 62.9%, without any pre- or post-treatment or any passivation agent. IR and XPS results demonstrated that GCDs were functionalized with carboxylic and hydroxyl groups, maintaining their remarkable PL even in strong acidic or high salt media. Due to the broad and strong absorption in the visible region, GCDs combined with titania achieved a better visible-activity in the photocatalytic degradation of dyes.