Multicolor Carbon Dots for Warm White Light-Emitting Diodes with a High Color Rendering Index of 93.2

Multicolor carbon dots (CDs) with compatible physical and chemical properties have tremendous potential applications in full-color display and photoelectric devices. In this work, red, green, and blue-emissive CDs (R-, G-, and B-CDs) were synthesized from o-, m-, and p-phenylenediamine under identical reactions for the first time. Mechanism exploration has shown that the photoluminescence of G- and B-CDs was dominantly core-state emissions while that of R-CDs was also heavily influenced by surface-state emissions. Superior WLEDs were fabricated exploiting the three CDs as compositing white phosphors, emitting warm white light with a correlated color temperature of 3248 K, CIE coordinates of (0.41, 0.38), and a high color rendering index value of 93.2, surpassing most phenylenediamine-derived CDs WLEDs. Most importantly, the WLEDs also demonstrated high stabilities under different working conditions and environments, highlighting their practicality.