Effect of Tin Concentration on The Structure and Color Characteristics of ITO Thin Films Synthesized by Sol–Gel at 400 °C

Annealed at 400 °C. Different tin concentrations were employed. X-ray diffraction revealed a cubic crystal structure with dominant peaks at (222), (400), (320), (622) and (440), With the prevailing trend of growth towards (222). Optical measurements showed that pure indium oxide films exhibited the lowest transmittance in the investigated spectral  range, while the addition of 20% and 40% tin significantly increased the transmittance, exceeding 90% in the wavelength range of 550–700 nm, The results showed that the energy gap values ​​increased with increasing tin concentration. The results of the Hall effect test show that the conductivity is good at a high tin concentration 20%. The highest color  saturation was obtained at 20% Sn with a dominant wavelength of 660 nm and high a color purity of 0.366 according to the CIE 1931 system.