Multi-color fluorescent carbon dots with single wavelength excitation for white light-emitting diodes

Carbon dots (CDs) have been applied in numerous fields by virtue of their excellent features. Multi-color fluorescent carbon dots with high photoluminescence (PL) quantum yield are still the emphases for research. Here, by using 3,5-diaminobenzoic acid and 3,4-diaminobenzoic acid, multi-color-red, green, blue (RGB) emitting CDs (RGB-CDs) were successfully synthesized via a one-pot solvothermal route. The RGB-CDs exhibited stable optical properties and significant photoluminescence characteristics with excitation-independent. Structure and element analysis indicated that conjugated graphite structure of carbon cores and oxygen on surface states were responsible for the RGB color emissions of carbon dots. Moreover, RGB-color and white light-emitting diodes (LEDs) were fabricated by these multi-color fluorescent carbon dots. The LEDs exhibited excellent lighting performance, indicating that these RGB-CDs have the potential to substitute rare elements for solid-state optoelectronic applications .