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 (R ² = 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.