According to forecasts, oil will continue to dominate the world energy demand in the next years. The International Energy Agency estimates that over 50% of the technology needed to achieve zero net emissions by 2050 is still under development. Therefore, refineries are currently incorporating renewable energy sources to reduce environmental impact. This article aims to study titanium dioxide films for application in perovskite-based solar cells which have high conversion efficiency and low production cost.
The precursor solution for deposition of titanium dioxide films (TiO2) was prepared by dissolving titanium isopropoxide in a solution of nitric acid and deionized water. TiO2 films were deposited by the spray-pyrolysis technique, which is simple, economical, and feasible for large-scale production. The deposition temperature was fixed at 450°C to achieve the Anastase phase. Deposition parameters such as time, flow and solution concentration were varied to assess their impact upon the morphological, structural, optical, and electrical characteristics of TiO2 films.
The morphology of the spray-pyrolyzed films consisted of homogeneous crowds of small crystals. No cracks were found across film surface. X-ray diffraction analysis confirmed the Anatase crystal structure, necessary for perovskite solar cell applications. The crystallite size ranged from 27.23 to 32.51 nm. The concentration of the precursor solution affected the optical gap energy. The thickness did not show great influence since samples with similar thicknesses, 2.12 and 2.58μm, presented optical gap values of 3.15 and 3.36 eV, respectively. All deposited films exhibited semiconductor characteristics with activation energies for the electrical conduction process between 0.24 and 0.49 eV. The samples deposited from a solution ratio of 450:3.25:37 (H2O: HNO3: Ti(iOPR)4) showed high values of electrical conductivity at room temperature compared to the films deposited from diluted solutions.
This study demonstrates how TiO2 films can be produce by spray-pyrolysis under the deposition conditions needed to improve film characteristics. Thus, it contributes to the development of more efficient and durable perovskite solar cells to make them more accessible and attractive for mass production and industrial use. Additionally, TiO2 films have corrosion resistance and photocatalytic properties that could be of interest to the oil and gas industry.