Synthesis of Tin Oxide Thin Films by Sol-gel Spin Coating Method and Study of Their Color Properties Using CIE 1931 and CIE LAB systems

Abstract

The primary objective of the project was to study the color characteristics of tin oxide thin films produced with varying concentrations (0.25M, 0.5M, and 0.75M) by the sol-gel (spin coating) method and 400°C annealing. Using the CIE 1931 system, the color coordinates of the tin oxide (SnO₂) thin films were determined, and three key color attributes (purity, dominant wavelength, and brightness) were measured. The results indicated that the dominant wavelength and brightness values decreased with increasing film concentration, whereas the purity values increased as the film concentration rose. To further differentiate between the colors, the color angle and chrominance were calculated using the CIE LAB system. Additionally, XRD and UV-visible spectrophotometry were employed to analyze the structural and optical characteristics. XRD data revealed that all annealed films exhibited a tetragonal structure. The UV-visible spectrophotometry results showed that transmittance values decreased with increasing film concentration, with the highest transmittance observed at a concentration of 0.25M, reaching approximately 89.9%.