Engineering the Synthesis of Luminescent Carbon Dots With Ultra High-Quantum Yield Using Experimental Design Approach in Order to Develop Sensing Applications

Carbon dots have been employed in a series of exciting fields such as bioimaging, drug delivery, fluorescent probing and analysis, photo-catalysis. Improving fluorescence performance of carbon dots could result in broadening their applications, especially, in sensing and bioimaging systems. The purpose of this study is to fabricate carbon dots by means of the hydrothermal method and designing an experiment in order to reach the highest quantum yield so as to develop their sensing and bioimaging applications. An experimental program was designed by taking into account factors effects on the quantum yield of carbon dots. The influencing variables to synthesize carbon dots in this project are citric acid concentration (F
₁
), reaction temperature (F
₂
), ethylenediamine concentration (F
₃
) and reaction time (F
₄
). By applying the experiment the quantum yield of carbon dots presents the maximum result of 85.69% at the optimal conditions of citric acid: 0.2 g, reaction temperature: 175°C, Ethylenediamine:
$480~\mu \text{L}$
and reaction time: 4:43 h, which was the highest quantum yield from such carbon dots. These carbon dots have been applied as a fluorescence probe for Fe
³⁺
ions determination with a perfect detection limit of 0.32 ppm. They were put to use for bioimaging of human ovarian carcinoma SKOV3 cells, which proved to be of outstanding biocompatibility.