Long Life-time Room-temperature Phosphorescence of Carbon Dots in Aluminum Sulfate

Herein we report the observation of room-temperature phosphorescence from carbon dots (CDs) embedded in aluminium sulfate. Phosphorescence emission in CDs was achieved by incorporating C=O/C=N functionalities on the carbon dots (CDs) in a single-step reaction. Benzene-1, 3, 5-tricarboxylic acid and formamide were used as precursors, and the resulting CDs in aqueous dispersion show excellent fluorescence in the blue region with quantum yield about 42.7%. On embedding CDs in aluminum sulfate, a green after-glow, with phosphorescence life-time of ∼876 ms was observed. The 1931 CIE color parameters corresponding to the phosphorescence emission (0.26, 0.36) indicated that the emission is in the white-gamut region of the chromaticity diagram.