Table 1.

Results of the characterization of the five carbon dots (CDs), including reaction yield, zeta potential, and atomic composition (carbon, oxygen and nitrogen, obtained by XPS analysis).

CDs	1: Citric Acid (CA) + Urea in H2O	2: CA + Ethylenediamine (EDA) in H2O	3: CA in n,n-Dimethylformamide (DMF)	4: CA in Acetonitrile	5: CA in Pyridine
Reaction yield (%)	7.9	7.3	4.4	7.3	0.4
Zeta potential (mV)	−0.6	−0.2	0.6	2.1	−2.4
C 1s (at.%)	60.9	68.5	70.9	63.1	74.8
O 1s (at.%)	23.7	16.5	22.2	36.4	23.6
N 1s (at.%)	15.4	15.0	6.9	0.6	1.6