Structural and electronic properties of screen-printed Fe<inf>2</inf>O<inf>3</inf>/TiO<inf>2</inf> thick films and their photoelectrochemical behavior

Abstract

Nanostructured Fe2TiO5 thick films were deposited on fluorine-doped tin oxide glass substrate using screen printing technology. Starting hematite and anatase nanopowders were mixed in molar ratios 1:1 and 1:1.5 and calcined in air at 900°C for 2 h to form pseudobrookite, Fe2TiO5. Functional powders and sintered thick films were analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy and transmission electron microscopy. UV–Vis analysis enabled determination of the band gap. Separation and transfer efficiency of photogenerated charge carriers was confirmed by the photoluminescence and electrochemical impedance spectra. Even though a slightly high onset oxygen evolution potential of photoexcited film electrode samples in NaOH was obtained, photocurrent densities were high, especially in the presence of H2O2 (~12 mA cm−2 at 1.7 V RHE). This work shows promise for practical application due to favorable band positions of pseudobrookite and low-cost screen printing technology.