Controllable Fluorescence Quantum Yield of Carbon Quantum Dots Synthesised by Plasma Electrochemical Method

ABSTRACT Carbon quantum dots were synthesised in an environmentally friendly and efficient way using the plasma electrochemical method with folic acid as a precursor. By taking online measurements of the 90‐min synthesis process, we observed that the fluorescence quantum yield (QY) varied with the reaction time. The optimisation of reaction time and other experimental parameters can effectively improve the QY of carbon quantum dots. The results demonstrate that an increase in nitrogen doping leads to an increase in QY. In this paper, the QY of carbon quantum dots was increased from 0.64% to 13.72% by optimising the experimental parameters, which provides an effective way to increase the QY of carbon quantum dots synthesised by the plasma electrochemical method or other methods.