Figure 3
From: Large Scale Synthesis and Light Emitting Fibers of Tailor-Made Graphene Quantum Dots
Chemical composition of GQDs.
(a) FT-IR spectra of GO and GQDs. The IR pattern of GO suggests the presence of oxygen-containing functional groups, such as epoxide, carbonyl and hydroxyl groups. The IR spectra of GQDs contained new peaks corresponding to amine and amide functionalities. (b) XPS N1s spectra of GO and GQDs. Although the XPS spectrum of GO does not show a nitrogen peak, the XPS spectra of GQDs show two new peaks at 399.4 and 400.6 eV, corresponding to primary amine and amide, respectively. (c) Band gaps of GQD-(NH2)n and GQD-(NH2C=O)n as a function of the number of amine and amide functional groups. Gray, white, blue and red colors on the atomic structures represent carbon, hydrogen, nitrogen and oxygen, respectively.
