2.2. Instruments
The extinction spectra of silver NP solutions were obtained
using a Varian Cary 3E UV/vis spectrophotometer. Transmission
electron microscopy (TEM) images were obtained using a JEM-
2100 with an acceleration voltage of 200 kV. Scanning electron
microscopy (SEM) measurements were performed with a LEO
1530 field emission SEM. X-ray photoelectron spectroscopy (XPS)
analysis was performed on a Thermo ESCALAB 250 spectrometer
with a Mg Ka (1253.6 eV) achromatic X-ray source. Zeta potential
measurements were carried out using a Malvern Zeta-Sizer-Nano.