Figure 7.

(a) Photoluminescence spectra taken at 10 K from GQDs with diameters of 12 and 14 nm. A shorter PL peak is observed in 12 nm diameter GQDs. (b) Trend of the PL peak energy depending on the diameter of GQDs. These results are consistent with the results in refs (55−57). Reprinted in part from ref (55) with permission from Kim et al., ACS Nano 2012, 6, 8203–8208. Copyright 2012 American Chemical Society, from ref (56) with permission from Peng et al., Nano Lett. 2012, 12, 844–849. Copyright 2012 American Chemical Society, and from ref (56) with permission from Chhabra et al., RSC. Adv. 2018, 8, 11446–11454. Copyright 2018 Royal Society of Chemistry.