Bright Multicolor Bandgap Fluorescent Carbon Quantum Dots for Electroluminescent Light-Emitting Diodes

Themonochrome light-emitting diodes (LEDs) from blue to red that directly use multicolor bandgap fluorescent carbon quantum dots (MCBF-CQDs) as the active emission layer will be reported. The MCBF-CQDs were synthesized by a facile solvothermal method and exhibited emission color from blue to red with a quantum yield (QY) up to 75%. Even without using hole transport layer, the maximum luminance (L max ) of blue LEDs reached about 136 cd/m 2 , a record for CQDs-based monochrome electroluminescent LEDs. We further demonstrated the distinctive advantage of such LEDs, the remarkably stable and voltage-independent emission color, which enabled the BF-CQDs great opportunities to achieve high-performance LEDs. Also presented are white LEDs (WLEDs) fabricated by using BF-CQDs blended poly(N-vinyl carbazole) as the emissive layer, which showed a high-performance even comparable to semiconductor QDs-based LEDs.