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

Figure 5

(a) UV-Vis absorption spectra of N-GQDs with different ethylenediamine content (the ratio of citric acid to ethylenediamine was 1:1, 1:2, 1:3, 1:4, and 1:5, respectively); (b) fluorescence intensity spectra of N-GQDs with different ethylenediamine content at 350nm excitation wavelength (the ratio of citric acid to ethylenediamine was 1:1, 1:2, 1:3, 1:4, and 1:5, respectively); (c) fluorescence intensity spectra at 350nm with different heating temperature and time.

(a)

(b)

(c)