Fig. 2: Characterizations of the red emissive CDs.

a Transmission electron microscopy (TEM) images and the size distribution of CDs. b and c High-resolution TEM images of CDs. d Excitation Emission Matrix (EEM) spectra of CDs dissolved in ethanol. e The corresponding UV-vis, PL emission, and PL excitation spectra of CDs dissolved in ethanol. f FT-IR spectra of CDs