White Emissive Carbon Dots Actuated by the H-/J-Aggregates and Förster Resonance Energy Transfer

Carbon dots (CDs) have been demonstrated to be fluorescent materials for the new phosphor-free white light-emitting diodes (WLEDs). Herein, we synthesized a novel white CDs (WCDs). The spectrum highly matches the solar light spectrum (AM 1.5), which is a potentially high-color-quality lighting source material. The CDs contain blue, green, and red emissive centers produced from catechol, o-phenylenediamine, and their complexes, respectively. In addition, the photoluminescence mechanism had been revealed; three emission centers could be excited by a single UV source actuated by the formation of H- and J-aggregates and FRET between the CDs. Then the phosphor-free WLEDs were fabricated with a UV chip encapsulated with silicon resin containing the as-obtained CDs, which exhibit CIE coordinates of (0.33,0.33), a color rendering index (CRI) of 93, and a correlated color temperature (CCT) of 5453 K. The WLEDs show super stability and a high solar spectrum matching degree of 85-114%, protecting the eyesight. This provides a new way to design healthy lighting materials.