Regulating red-shifted phosphorescence of carbon dots via introducing magnesium chloride

(525 nm) owing to increased conjugation and a narrowed bandgap, with the narrowed gap derived from coordination between magnesium and C[double bond, length as m-dash]O. These CDs showed excitation-dependent phosphorescence, which was tunable from cyan to red by varying excitation wavelengths. Additionally, we synthesized a series of phosphorescent CDs by employing different carbon sources, among which the magnesium-doped CDs consistently displayed red-shifted phosphorescence, thus proving the universality of this strategy and providing an innovative approach for regulating the phosphorescence of CDs.