pH-Sensitive Silver-Containing Carbon Dots Based on Folic Acid

Herein, Ag-containing carbon dots (Ag-CDs) was synthesized based on folic acid. In a neutral solution, its fluorescence emission owns a structure fixing fluorescent species with the emission maximum at 400 nm and an excitation-wavelength dependent fluorescent species, respectively. By comparing fluorescent emission and excitation spectra, the electronic absorption origins of these fluorescent species were assigned. With the assistance of UV-Vis absorption and XPS, the pH-regulating fluorescence mechanism of Ag-CDs was studied and proposed. A particularly strong fluorescence emitter was observed at pH ~12 with a mixing coordination structure as Ag(CDs-NH2)OH. The as-prepared Ag-CDs might be developed into a fluorescent sensor, especially at extremely basic conditions.

Automated summary

Ag-containing carbon dots (Ag-CDs) were synthesized based on folic acid. The electronic absorption origins of different fluorescent species were assigned by comparing their emission and excitation spectra. The pH-regulating fluorescence mechanism of Ag-CDs was studied, and a particularly strong fluorescence emitter was observed at pH ~12, which could be developed into a fluorescent sensor for extremely basic conditions.