One-Pot Synthesis\nof Multicolor Carbon Dots from PET\nPlastic Waste for White Light-Emitting Diodes

Conversion of PET waste into carbon dots (CDs) is an\nattractive\napproach to plastic pollution control. However, the preparation of\nred–yellow CDs is still challenging, and the preparation methods\nare complex. In this study, a one-pot solvothermal method was developed\nfor the preparation of CDs from PET waste. Through nitrogen source\nand solvent screening, multicolor (blue–red) CDs with high\nquantum yield (QY) were prepared. The reaction temperature and catalyst\ndosage significantly influence the production yield and QY of the\nCDs. The optimized CD showed a relative yield of 42.7%, a high QY\nof 47.8%, and a red photoluminescence color. The morphology, crystal\nstructure, surface chemistry, and optical performance of CDs were\ncharacterized. The red and yellow fluorescence was mainly due to the\nmolecular state mechanism. White light-emitting diodes with cool and\nwarm white light and a high color rendering index were constructed\nusing yellow and red CDs.