Fluorescent carbon dots production: A direct flame synthesis approach

A direct one-step synthesis based on flame synthesis for the large production of fluorescent carbon dots (FCD) is proposed. A moiety of tunable parameters can be explored. Specifically, FCD features - typically the visible emission and the quantum yield - could be varied by changing the fuel composition or equivalence ratio. By simply changing the relative percentages of ethylene/benzene in the fuel or moving across the classical soot threshold limit for equivalence ratio it is shown how FCD properties can be tuned. Fluorescent nanocarbons presenting typical carbon nanodot characteristics could be obtained by extraction and simple filtration (<20 nm) of the carbon nanoparticles produced in flame. By changing the fuel composition, nanocarbons fluorescing from yellow to blue and showing a quantum yield moving from 3 to 10% could be easily produced. Similar behaviour has been found by changing the equivalence ratio in a pure ethylene flame. The properties FCD are directly defined by the flame reactor conditions without any further modifications that is a key advantage for large-scale production.