Synthesis of Carbon Quantum Dots from Jujubes for Detection of Iron(III) Ions.

In this work, carbon quantum dots (CQDs) were synthesized from jujubes via a hydrothermal process. The as-prepared CQDs have average sizes of about 3.12 nm and emit blue photoluminescence (PL) in the range 380-530 nm, depending on the excitation wavelength. The functional group compositions and structures of the CQDs were investigated via Fourier transform infrared spectroscopy and X-ray powder diffraction. Based on these analyses, a linear relationship was obtained between the relative fluorescence intensity and concentration of Fe3+ within the range of 0 to 200 μM (R2 = 0.9927). Fe3+ quenched the PL intensity of the CQDs more than other heavy metals, which indicates that CQDs can be used effectively as an Fe3+ sensing media.