Full-color-emission carbon quantum dots by controlling surface states in a system of solvent

carbon quantum dots (CQDs) have been widely studied due to their outstanding merits. In this article, it is important and interesting that the full-color-emission (blue, green and red light) CQDs are successfully obtained by a simple one step method. They are synthesized from two common precursors, m-phenylenediamines and phosphorus acid, using a one pot solvent engineering strategy. These CQDs can emit bright and stable light under a single-wavelength UV light. Moreover, the alterations of photoluminescence (PL) emission of the blue, green, red are ascribed to the surface states but not the particle size. The redshifted emission of the three CQDs samples is tentatively proposed to result from the contents of sp(2)-hybridized domains, surface C--O and the pyridinic N.