Figure 3
(a) UV–Vis absorption spectrum of synthesized GQDs (Inset shows the standard curve drawn based on serial dilution results). (b) Photoluminescence spectra of GQDs under different excitation wavelengths of 300–420 nm. The insets are optical images of the solution of GQDs taken under visible light (left) and excited by 360 nm UV light (right). (c) FTIR spectrum of GQDs, arrows on the spectrum indicate characteristic bands of functional groups of GQDs.
