Efficient Synthesis of Yellow‐Green Carbon Quantum Dots as a Sensitive Fluorescent Probe of Folic Acid

Bright yellow‐green carbon quantum dots (YGCDs) have been successfully synthesized by a simple and efficient hydrothermal method. Their luminescent absolute quantum yield reached 30.0% in 4 h. Compared with commonly reported solvothermal methods, the synthesis time was reduced by more than 70% by using tin oxide nanoparticles as a catalyst. Moreover, the fluorescence of YGCDs could be selectively quenched by folic acid (FA) molecules, and the relative fluorescence intensities of F/F0 was fitted perfectly in line decay curve versus the concentration of FA in the range of 2.0×10−8 mol/l to 1.0×10−5 mol/l (R2=0.9988). The detection limit of FA was below 2.0×10−8 mol/l, suggesting a promising fluorescent probe of folic acid. Bright yellow‐green carbon quantum dots (YGCDs) have been efficiently synthesized by a one‐step hydrothermal method, and the YGCDs could be used as a selective luminescent probe of folic acid in the range of 2.0×10−8 mol/l to 1.0×10−5 mol/l.