Nexsa surface analysis system

The morphology of the nanostructures was characterized by using field emission scanning electron microscopy (FESEM, FEI Nova Nano SEM-450). The samples were drop casted on a clean silicon wafer and dried in air. The characteristics of the samples were studied further by using transmission electron microscopy (TEM, FEI Tecnai G2 20 S-TWIN) imaging as well as atomic force microscopy (AFM, AFM Dimension ICON, Bruker) imaging. Solid state analysis was carried out using powder X-ray diffraction (PXRD) recorded with Cu Kα used as an X-ray source (λ = 1.54 Å) by using a Smart Lab 9 kW rotating anode X-ray diffractometer. X-ray photoelectron spectroscopy (XPS) analysis was performed using a Thermo Scientific NEXSA SURFACE ANALYSIS System. Inductively coupled plasma mass spectrometry (ICP-MS) analysis was carried out by using an Element XR system (Thermo Fischer Scientific, Germany) coupled to a 7500a ICP mass spectrometer (SAIF, IIT Bombay, India).

XPS data were collected using a Thermo Scientific Nexsa Surface Analysis System equipped with a hemispherical analyser under pressure between 10⁻⁹ and 10⁻⁸ mbar using monochromatic Al K_α X‐ray beam (1486.6 eV) at 72 W (12 kV×6 mA) at an incident angle of 45°. A low‐energy dual‐beam (ion and electron) flood source was used for charge neutralisation. The X‐ray spot size was 400 μm×800 μm. For survey scans, the pass energy, voltage step size and dwell time were 200 eV, 1 eV and 10 ms, respectively. For the high‐resolution scans, these parameters were 50 eV, 0.1 eV and 50 ms, respectively, typically yielding a full width at half maximum (FWHM) value of 0.86–0.87 eV for the Ag 3d_5/2 peak and <1.0 eV for the main C 1s peak in PET during performance tests.
The samples were analysed at a nominal photoelectron emission angle of 0° with respect to the surface normal. Since the actual emission angle is ill‐defined in the case of rough surfaces as in the present case (ranging from 0° to 90°) the sampling depth may range from 0 to approximately 10 nm. Data processing was performed using Avantage software version 5.9902. All elements presented were identified from survey spectra. All binding energies were charge corrected to the adventitious C 1s peak at 284.8 eV. At least two different spots on each sample were probed to ensure the consistency of the results.