Photoreactivity of nanostructured semiconducting oxides

This research will investigate how the fundamental processes of formation of valence band holes and conduction band electrons when oxide semiconductors are irradiated with UV light depend on the crystal structure, morphology and nanostructure of the semiconductor. Improved understanding of these processes is crucial if oxide semiconductors are to be used more widely as photocatalysts, in photovoltaic cells, and in other devices exploiting their photoelectronic properties. The project will draw upon a collaboration between the group of Zhou, at St Andrews, with particular expertise in synthesis and structural characterisation of materials using electron microscopy, and Howe, at Aberdeen, who has experinece of using EPR and FTIR spectroscopy to follow processes occurring in semiconductors and at their surfaces. Different nanostructured forms of TiO2 will be synthesised, and their photoreactivity investigated by a combination of in-situ EPR and FTIR spectroscopies. We will also examine composite semiconductors, using TiO2-WO3 as a model example, in order to understand why such composite semiconductors may show improved performance under visible light excitation.The project will employ two PhD students, one in St-Andrews and one in Aberdeen, who will learn complementary skills in this rapidly evolving area of materials chemistry.