Red-emitting, self-oxidizing carbon dots for the preparation of white LEDs with super-high color rendering index

Carbon dots (CDs), as a kind of carbon nanomaterials, have attracted widespread attention due to their unique structure and excellent optical properties, and they are low-cost, environmentally friendly and biocompatible. However, the development of near-infrared (NIR) emission CDs remains a challenge. In this study, we successfully prepared CDs with a maximum emission of 714 nm using citric acid as the carbon source, thiourea and ammonium fluoride as the dopant source, and N,N-dimethylformamide as the solvent. The quantum yield (QY) is as high as 22.64%. Interestingly, the prepared CDs self-oxidize in the presence of oxygen, resulting in a blue shift of their emission. Therefore, they can be used to prepare white light-emitting diodes (WLEDs) without adding other fluorescent substances. Notably, the work presented herein constitutes the first report of WLEDs preparation from single CDs.

Automated summary

The study successfully prepared CDs with a maximum emission of 714 nm and a quantum yield as high as 22.64%, which can self-oxidize and emit white light, making them suitable for preparing WLEDs.