Solid-State Carbon Dots with Tunable Fluorescence via Surface Substitution: Effect of Alkyl Moieties on Fluorescence Characteristics

Multicolor solid-state fluorescent CDs were prepared by a one-step solvothermal method using citric acid as the carbon source and six alkyl amines as carbonization solvents. We found that the alkyl chain type of the amine solvent significantly affects the interaction between carbon dots in the solid state and thus affects the fluorescence wavelength and quantum efficiency of the CDs.