novel carbon quantum dots: green and facile synthesis, characterization and its application in on-off-on fluorescent probes for ascorbic acid

Nanostructures have proved to be a very attractive option for sensor application due to their physical and chemical properties. in recent years, carbon quantum dots as a new member of carbon nanostructures has been widely used in the field of sensors. in this work, carbon quantum dots was synthesized via green precursors using hydrothermal method. the prepared products were characterized via with x-ray diffraction (xrd) analysis, transmission electron microscopy (tem), ft-ir, uv-vis, and photoluminescence (pl) spectroscopy. the results revealed that the prepared carbon quantum dots provide excitation-dependent fluorescence emission. the obtained findings from photoluminescence spectroscopy revealed that as-prepared carbon quantum dots could be applied as a fluorescent probe for detection of ascorbic acid. the pl of carbon quantum dots can be significantly quenched by cr(vi), which follows a dynamic quenching mechanism. as ascorbic acid enters the solution, cr(vi) reduced to cr(iii) which cause the turn back the carbon quantum dots fluorescence and a good linearity in range of 0.06–0.18 mm.