Abstract: Currently, the low-cost, large-scale synthesis of phosphors for the requirement of modern light-emitting-diode remains a significant challenge. In this work, carbon nanodots (CDs) with concentration-dependent fluorescence were synthesized with citric acid and urea as precursors in N, N-dimethylformamide through solvothermal strategy. When the CDs solution is diluted with deionized water at various ratios, the energy transfer between the CD particles will gradually weaken when the dilution ratio increased, leading to a shift in fluorescence color from red to blue and an enhancement in emission intensity. A systematic investigation on the concentration effects on the fluorescence emission properties of CDs are conducted with a chromatography separation techniques, revealing that the as-prepared CDs solution contains the multicolor components and the fluorescence variations in CDs solutions were attributed to F?rster resonance energy transfer and reabsorption energy transfer. Thus, the precise regulation of multicolor CDs phosphors was further achieved with the starch as confined matrix to regulate the energy transfer between CDs These finding present a new strategy to regulate the optical properties of CDs and pave a new insight the applications of fluorescence labeling and display technology.

Key words: Carbon nanodots, Multicolor, Fluorescence, Aggregation regulation, Phosphors