Surface structure and fluorescence characteristics of concentrated carbon point

Abstract The concentration-dependent fluorescence behaviour of carbon dots (CDs) was observed in concentrated CDs solution, and it was found that the excitation-independent fluorescence behaviour gradually transitioned to excitation-dependent fluorescence behaviour with the increase of CDs concentration. The fluorescence characteristics of CDs solution with various concentrations were explained from the perspective of the surface states by using the fluorescence decay spectra of CDs for the first time. A close relationship between the surface microstructures and the optical properties was demonstrated. Mechanism of concentration-dependent generation fluorescence in concentrated CDs solution was presented and a possible aggregation model of CDs was given. This work offers a novel perspective for tuning the emission wavelength of CDs and endowing them with potential various applications.