Synthesis of single-particle level white-light-emitting carbon dots via a one-step microwave method

A simple yet environmentally friendly and cost effective preparation method of white light emitting carbon dots (Cdots) is reported. The as-synthesized Cdots exhibit emission spectrum covering the entire visible region with color coordinates close to that of pure white light with high color rendering index (84-89) and variable correlated color temperature (5593-7490 K). In depth analytical characterization suggested that white light emission originated from single Cdot particles, which was corroborated by single particle imaging and a corresponding emission spectrum obtained using confocal laser scanning microscope. White light emitting capability of Cdots was found to be retained even when they were embedded in a polyvinyl alcohol (PVA) solid polymer matrix. The ease of synthesis combined with unique optical properties make these heavy-metal ion-free Cdots potential candidates for applications in light-emitting diodes and full-color display panels.