Applicability Evaluation of Bright Green-Emitting Carbon Dots in the Solid State for White Light-Emitting Diodes

Self-quenching-resistant and bright green-emitting carbon dots (CDs) in the solid state were synthesized via a facile hydrothermal method. Their structure, optical properties together with their thermal and photostabilities, as well as their applicability in white LEDs were investigated. The obtained CDs have nearly spherical shape with a size around 4-5nm. The resulting powder CDs show excitation-independent emission behavior, and can be excited over a broad range from 300-450nm. Under optimal excitation at 400nm, the resultant powder CDs yield bright and broad green emission around 505nm with full width at half maximum (FWHM) of about 110nm and under 360nm excitation with lifetime of 15.8ns. A potential application of the green-emitting CDs was evaluated by constructing a white light-emitting diode lamp. The fabricated white LED lamp emitted bright, warm white light with excellent color rendering properties (a color rendering index of 86.9 and a correlated color temperature of 3863K).