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

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.