Structure and optical properties study of annealed CuO films for development of perovskite-based solar cells

Synthesis and growth of CuO films have been carried out to be used as constituent materials for perovskite-based solar cells. The film was made using a spin-coating and heat treatment sol-gel method with variations in temperatures of 400 °C, 500 °C, and 600 °C, each for one hour. CuO films were then characterized using UV-Vis, XRD, and FTIR. The analysis was carried out to determine the effect of annealing temperature on the absorbance, thickness, gap energy, crystal size, crystallinity, and functional group bonds of compounds found in CuO films. In general, there is a decrease in thickness, and energy bandgap, as the annealing temperature is increased. Conversely, the absorbance, the mean grain size, and crystallinity increased as the annealing temperature was increased. The increase in grain size is one of the causes of decreasing energy bandgap when the annealing temperature is increased. Annealing treatment increases absorbance in the visible and the near-infrared spectrum (photons with lower energy levels). This is very advantageous as solar cell material. CuO film is planned to be used as a tandem for Barium Titanate (BaTiO₃) to form a solar cell system. (paper)