Synthesis and Characterization Cresol Red-Sensitized Cobalt-Doped TiO2 Thin Films Irradiated with Gamma Rays

This study aims to conduct the synthesis process and characterization of titanium dioxide doped cobalt thin films sensitized by cresol red with gamma rays. This study is a pure research by going through two stages of research, namely synthesis and characterization thin film phase. The research materials used include 1). precursor using titanium (IV) dioxide, 2). Doping using Cobalt (II) chloride, 3). Solvents Ethanol (C2H5OH), Sodium Hydroxide (NaOH) and Hydrochloric Acid (HCl), 4) Cresor Red Sensitizing Agent, and 5) media using glass substrates. The results of the study showed that the samples produced in this study are divided into two types, namely in the form of liquid (sol-gel solution) and solid (glass substrate) consisting of five concentrations, namely 0, 5, 10, 15, and 20%. The greater the concentration of cobalt doping used, the color of the sol-gel solution will look darker, which is indicated by the red color. This is compared to the TiO2 solution without doping, which looks white or clear. In the characteristics of the thin layer, it was found that there was a process of shifting the absorption value towards the wavelength of visible light with the highest value in the range of 500-550 nm. In addition to experiencing a shift in the absorption value, there was a decrease in the energy band gap value and activation energy in the TiO₂:Co thin film sample sensitized with cresol red irradiated with gamma rays along with the large concentration of doping given. The morphological structure of the thin layer found with its distribution is very even, the number of particles is large in shape, and the particle size undergoes an agglomeration merging process.