Correlation of growth, structure, optical and electronic properties of novel Nb3O7(OH) and Nb2O5 nanostructures

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One-dimensional single crystalline nanostructured metal oxide electrodes have the advantage of creating efficient pathways for charge carriers. However, defects occurring in these structures and different crystallographic modifications affect their performance in applications such as hybrid and dye-sensitized solar cells, batteries or (photo-)catalysis. This project will focus on novel Nb3O7(OH) and Nb2O5 nanostructures and compare them with the well-established TiO2. The niobium oxide systems have rarely been elaborated, even though they have a high potential for applications. Next to a detailed analysis, special focus will be put on the controlled growth and the influence of the growth conditions on the characteristics of the niobium oxide systems. For the metal oxide nanostructures it will be essential to understand and control the charge carrier mobility in order to allow tailored application in devices. In this regard, this project focusses on the analysis of the effects of grain boundaries and the crystallinity on charge transport and recombination as these processes caused by structural defects might dominate the optical and electronic properties. By varying the growth conditions, better understanding of the mechanisms leading to such defects will allow to control and limit the formation of defects as it has been shown previously by us for TiO2. The combination of high-resolution transmission microscopy studies and optical and electronic characterization methods enables us to obtain a fundamental understanding of the physical phenomena of crystal growth, structure, charge transport, etc. and the correlation between these properties.