Nanostructured Fe2O3/TiO2 thick films: Analysis of structural and electronic properties

Thick films using starting nanopowders of TiO2 (anatase 99.7%) and α-Fe2O3 (hematite) mixed in the weight ratios 60:40 and 40:60 for thick film paste were fabricated by screen printing technology on an alumina substrate. Samples were sintered at temperatures of 800–950 °C for 60 min. Structural and electronic properties were analyzed by XRD and SEM analysis, UV/vis spectroscopy and current–voltage analysis in view of potential application as gas sensors and anodes in photoelectrochemical cells for hydrogen generation and water splitting. XRD analysis showed that at 800 °C monoclinic pseudobrookite formed and anatase had transformed into rutile. Increase in sintering temperature lead to a gradual transformation of monoclinic pseudobrookite into the orthorhombic phase. SEM analysis showed that a homogenous small grain structure was obtained especially in the case of thick film samples with the 40:60 ratio of starting anatase and hematite sintered at 850 °C.