Fig. 2
From: Graphene quantum dot nanocomposites: electroanalytical and optical sensor technology perspective
a The shape of GQDs in different types of edges (Reproduce with permission from Reference Facure et al. 2020, Copyright 2020, Royal Society of Chemistry), b Illustration of bandgap energy mechanism of GQDs based on confinement size (Reproduce with permission from Ref. Reshma and Mohanan 2019, Copyright 2019, Elsevier) and surface functional group (Reproduce with permission from Ref. Yan et al. 2018, Copyright 2018, American Chemical Society), c UV–Vis absorption spectra of GQDs, d Photoluminescence spectra of GQDs under different excitation wavelengths (Reproduce with permission from Ref. Zhuo et al. 2012, Copyright 2012, American Chemical Society)