Features of different processes reported for synthesis of GQDs.

Order	Samples	Reference	Change	Reason
1	B-GQDs	58	High fluorescence toward a blue shift	High reaction temperature and dialyzed solution
2	I-GQDs	59	High fluorescence	Subsequent dialysis
3	G-GQDs	58	High yield	Small amount of oxidizing agent and lower reaction temperature
4	Y-GQDs	60	Improved upconversion properties
5	R-GQDs	61	Low yield and feeble fluorescence	Facile but efficient synthesis with two functionalized groups in GQD solution