Synthesis of multiple-color emissive carbon dots towards white-light emission

Multiple-color emissive carbon dots (C-dots) are gaining increasing attention in various fields. Herein, we report a facile solvothermal method for the synthesis of multiple-color emissive C-dots with the aim of white-light emission. Under single ultraviolet-light excitation, three C-dots emit a easily controlled fluorescent emission wavelength at 440 nm, 500 nm and 610 nm by using different three amines (either ammonium hydroxide, ethylenediamine or p-phenylenediamine, respectively) and pyromellitic dianhydride as molecular precursors while another three C-dots emit a controllable fluorescent emission wavelength at 500 nm, 550 nm and 585 nm by using same three amines and naphthalene-1,4,5,8-tetracarboxylic dianhydride as molecular precursors. The maximum fluorescence wavelength of these C-dots is red-shifted by changing three different amines molecular precursors from ammonium hydroxide, ethylenediamine, to p-phenylenediamine. Furthermore, these C-dots have shown promising applications in the fields of white-light-emitting diodes devices and color printing.