Nitrogen-doping carbon dots have attracted broad interest in recent years due to their excellent spectral properties and promising applications. However, the luminescence mechanism of these carbon dots still lacks support from time-resolved spectroscopy. In this work, carbon dots were synthesized using p-phenylenediamine as a precursor (p-CDs), and their excited state dynamics were studied using transient absorption and time-resolved fluorescence spectroscopy. Experimental results reveal the origins of dual fluorescence and the synergistic effect mechanism involving the core state, the surface state, and solvent relaxation. Fluorescence lifetime imaging of p-CDs was performed in cells, highlighting their great potential for applications in biological fields.
