▎ 摘　　要

Graphene quantum dots (GDQs) were synthesized from citric acid (CA) and coke (C), by using a bottom up and a top-down approach, respectively. The synthesized GQDs were characterized using FTIR, UV-visible, Raman and photo-luminescence (PL) spectroscopies. Substantial variation in their optical emission behavior was observed. All emission spectra of GQDs extracted from CA, were centered at 460 nm, but a red shift was observed with the increase of excitation wavelength, in the emission curves of C-GQDs. So, in this work the comparison of optical behavior of GQDs derived from citric acid and coke has been done and relevant discussion is reported.