Facile and Rapid Synthesis of Yellow-Emission Carbon Dots for White Light-Emitting Diodes

A one-pot microwave-assisted hydrothermal approach was developed to quickly synthesize yellow fluorescent carbon dots (CDs) using o -phenylenediamine and urea as raw materials. The optimized reaction temperature of 140°C and reaction time of 10 min were adopted to synthesize the CDs with photoluminescence quantum yield of 4.23%. The as-prepared CDs exhibit yellow fluorescence ( λ em  ∼ 563 nm) and an excitation-independent PL emission in the region of 440–700 nm. The CDs were combined with a blue chip ( λ ex  = 420 nm) to fabricate white light-emitting diodes (WLEDs) and realize white light emission. The WLED has the color coordinates of (0.30, 0.30) and the correlated color temperature of 7915 K, which is suitable for office and outdoor illumination. The results demonstrate that as-obtained CDs can be a promising candidate as yellow-emitting phosphors for WLEDs.