The Effect of Dopants on the Solid State and Optical Parameters of TiO2 / MgO Thin Film

Abstract

The impact of fossil fuel on the environment, coupled with the economic crisis and environmental pollution, which is as a result of the mining of crude oil which is used in the production of fossil fuel, made the researcher to investigate into alternative areas of energy production. This work presents the successful deposition of Titanium Magnesium Oxide [TiO₂ / MgO] doped with Spinacia oleracea, Brassica oleracea and Hibiscus sabdariffa leaf extract on plain glass substrate slides using spray pyrolysis deposition techniques, solvent extraction method was used to extract the dye. This sprayed film properties were characterized for optical properties, the result of the analysis revealed an increase in absorbance within the UV region [300–350 nm], indicating strong photon absorption at shorter wavelengths. A gradual decrease in absorbance across the visible transmittance revealed troughs at the UV regions and crest at Visible and NIR. Crest and troughs observed in the reflectance spectra are attributed to thin film interference effects. The result obtained are attributed to the doping effect of thin-film. The band gap obtained are between 1.1 and 1.3 eV for the doped and 1.9 eV for the undoped. Thin films with band gap range between 1.1 - 1.3 eV corresponds with the ideal single- junction photovoltaic solar spectrum threshold and can be utilized in the manufacturing of commercial solar panels, and concentrator photovoltaics, while optical band gap of I.9 eV is optimized for harvesting high-energy photons. Its band gap suggests potential for photocatalytic and agrivoltaics applications.