Figure 1From: Cellular distribution and cytotoxicity of graphene quantum dots with different functional groupsUV–Vis absorption spectra and fluorescence spectra of three kinds of GQDs. (a) The UV–Vis absorption spectra of three kinds of GQDs. (b) The fluorescence spectra of aGQDs excited from 320 to 580 nm. (c) The fluorescence spectra of cGQDs independent on the excitation wavelength. (d) The fluorescence spectra of dGQDs.Back to article page