Table 2.

GQDs properties: position of emission center (Em in nm) and colors, PL QY, diameter and height, and main structural characteristics.

GQDs	Em (nm)	QY (%)	Diameter/Height	Structures (Identified Groups in at. % Where It Is Available)
N-GQDs [61]	Near-infrared	35		pyrrolic, pyridinic N, –NH2
N-GQDs [62]	698	62	2.7/0.7 nm	10.8% N, aromatic, –NH2
S,N-GQDs [63]	680	5.4 1	2–6 nm	1.6% N, 5.8 S, 68.2 C, 24.4 O, C–O, C–S, C–N
N-GQDs [59]	528	-	2.45 nm	–NH2
S,N-GQDs [64]	610	-	3 nm
S,N-GQDs [65]	800–850	54.5	4.7 nm	60 C, 5.4 N, 34.6 O
B-GQDs [66]	617 541	17.1 99.8	4 nm
GQDs-PEG [67]	610	6	2.75 nm	GQD–C(O)NH–PEG
N-GQDs [68]	532 to 624	29–35	3.9 ± 0.6 nm	pyridinic, graphitic, pyrrolic N
F-GQDs [69]	455 551	56.7	6.1 nm, 2 to 4 layers	C–F and C–F2 bonds
N-doped (red) S,N-doped green S,N-doped blue [70]	600 540 430	24.2/red 19.7/green 20.2/blue	4.1 nm/r 3.0 nm/g 3.1 nm/b 0.8–0.9 nm height
S-doped [71]	460
GQDs [72]	520–620	1.1 0.89 0.65 0.38	4.5 ± 1.2 16 ± 3.3 41 ± 6.4 70 ± 15 nm	C and O
GQDs GQD- PEI 1800 GQD-PEG600 [73]	550 445 622	-	2.4 6.0 57.3 nm	Csp2, –COOH, –OH, –NH2, –CONH–
GQDs N-doped B-doped [74]	455 465 535	-	4.3 nm	C=C bonds, C=O, C–O, C–N, pyridinic and pyrrolic N, BC3, BC2O, BCO3
N-doped [75]	520	13.8	2.3 nm	Csp2, COOH, COC, C–NH2, CO–NH–
N-doped [76]	451	41.8	3 nm	C=C, C–N, C–O, C–NH2, O=N–C groups
N-doped [77]	447	54	2.65 nm	60.01% C, 36.42 O, 3.57 N
S,N-doped [78]	448	-	3.13 nm	81.1% C, 9.9 N, 4.3 S, 4.7 O, f O–H, N–H, C=O, C–O–C, N=C=S, C–S
GOQDs [79]	400–600	-	10 nm	5.6% C=C, 16.5 C=O, 6.1 C–OOH, 71.8 C–OH
S-doped [80]	450–530	11	3 nm	C–C, C=C, C–S, C=O, –S2− oxidized S species (–SOn−)

¹ Measured using integration sphere.