Highly Fluorescent Nitrogen-Doped Graphene Quantum Dots’ Synthesis and Their Applications as Fe(III) Ions Sensor

Figure 4

(a) Full-scale XPS spectrum of N-GQDs prepared by citric acid: ethylenediamine=1:3; (b) high resolution XPS spectra of C1s; (c) high resolution XPS spectra of N1s.

(a)

(b)

(c)