Toward Kilogram‐Scale Preparation of Full‐Color Carbon Dots by Simply Stirring at Room Temperature in Air

Abstract Large‐scale production of full‐color carbon dots (CDs) at room temperature under atmospheric pressure will promote their industrial application. Herein, o‐phenylenediamine is used as a single‐precursor carbon source and hydrogen peroxide as an oxidant. Kilogram‐scale CDs are obtained by stirring these reactants at room temperature in air for 30 min. After purification and acid treatment, blue‐, green‐, and red‐fluorescence CDs with photoluminescence peaks at 481, 539, and 625 nm are obtained with quantum yields of 21.76%, 27.12%, and 13.06%, respectively. Based on chemical structural characterizations, a reasonable formation mechanism is deduced, with blue, green, and red fluorescence arising from carbon nuclei stacked in conjugate planes containing fragments of quinoxaline, 2,3‐diaminophenazine (2,3‐DAPN), and protonated 2,3‐DAPN, respectively. High‐quality multi‐color and white light‐emitting diodes are successfully fabricated to demonstrate potential commercial applications in display and illumination.