Studying the structure and optical properties of FeCl₃: ITO prepared by sol–gel dip coating technique

This work used the sol–gel dip coating process to generate thin films of pure indium tin oxide and indium tin oxide film mixing with FeCl₃ at ratios of 50, 100, and 150%. Indium and tin precursors, such as InCl₃ and SnCl₄, were affordable. The produced ITO samples were examined by UV–Vis, SEM, XRD, EDX, and AFM spectroscopy. The primary peak of the (222) plane, according to the thin film XRD patterns, matched a high degree of crystallinity in indium oxide. The elements In, O, Sn, Fe, and Cl are present in the deposited layers, according to the EDX spectrum. According to the SEM pictures, the average diameter of the particles for pure, 50, 100, and 150% were 23.87, 41.12, and 36.27 nm, respectively. From AFM images, the average grain size of pure ITO film was 61 nm. The films with different ratios 50, 100, and 150% had average grain sizes of 96, 36, and 178 nm respectively. The optical band gap of pure ITO was 4.49 eV, while for films ITO + FeCl₃ with different mixing ratios 50, 100, and 150% the energy gap was 2.61, 2.89 and 2.35eV, respectively. From the contact angle found the water contact angles 32.57°, 18.74°, 73.66°, and 43.98° for pure, 50, 100, and 150%, respectively are apparent. It can be found that the contact angle decreases at mixing ratios of 50%, this result indicates that the hydrophilicity of ITO surface at low mixing ratios, this a behavior is due to the reduction of surface roughness.