Perovskite solar cell for photocatalytic water splitting with a TiO2/Co-doped hematite electron transport bilayer

Abstract

Hydrogen production using a photoelectrochemical (PEC) route promises to be a clean and efficient way of storing solar energy for use in hydrogen-powered fuel cells. Iron oxide (α-Fe₂O₃) is best suited to be used as a photoelectrode in PEC cells for solar hydrogen production due to its favorable band gap of ∼2.2 eV. Herein, chemical solution deposition was used for the preparation of a series of Co-doped Fe₂O₃ thin films on a titania buffer layer at different doping concentrations (3.0, 7.0 and 10.0 at%). The maximum anodic photocurrent reached up to 3.04 mA cm⁻² by optimizing the balance between the doping concentrations, enhanced donor density, light absorbance, and surface roughness. The optical properties show that the light absorbance tendency switches to the higher wavelength with the further increment of Co beyond 3.0%. Finally, synthesized photosensitive perovskite CH₃NH₃PbI₃ materials were added as a surface treatment agent on the photoelectrode to enhance the photocurrent absolute value. This inorganic nanostructured perovskite CH₃NH₃PbI₃ (MAPbI₃) coated on the Co-doped hematite photoanode achieved an overall solar-to-hydrogen conversion efficiency of 2.46%. Due to its low temperature processing, stability, and enhance efficiency, this perovskite coated TiO₂/Co-doped hematite multilayer thin film solar cell has high potential to be applied in industry for hydrogen production.