Single-chip horticultural LEDs enabled by greenly synthesized red-emitting carbon quantum dots

Light emitting diodes (LEDs) having the emission spectra that match the absorption regions of a target plant are strongly demanded for vertical farming. Herein, we demonstrate the use of red-emitting carbon quantum dots (R-CQDs) as a phosphor to fabricate cost-effective horticultural LEDs. R-CQDs having chlorophyll molecules embedded in a carbogenic matrix were solvothermally synthesized using ethanol extract of bougainvillea leaves as a green carbon source. R-CQDs emit a narrow band maximizing at 670 nm originated from the chlorophyll centers when excited either the carbogenic matrix or embedded chlorophyll. R-CQD phosphor converts partially 410 nm light emitted from a LED chip to red and far red regions, thus offering cheaper, single - chip LEDs for agriculture lighting.