Electron transport in nanostructured metal-oxide semiconductors

Nanostructured films of metal-oxide semiconductors are the focus of intensive research nowadays due to their applications in the current quest for new sources of clean energy. Metal-oxides like TiO2 and ZnO can be used to make efficient photoanodes for photoelectrochemical solar cells and nanostructured substrates for photocatalytic production of non-polluting fuels. In these applications electron transport through the nanostructure is crucial to achieve a good photon-to-electron quantum efficiency. In this paper the current knowledge of the electron transport mechanisms that take place in these systems is reviewed, highlighting the influence of energy and morphological disorder on the efficacy of the transport process. A special connection is made between the specificity of the electron transport in these systems and their applications in solar cells and photocatalytic devices.

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► Electron transport is determined by both energy and morphological disorder.
► Random Walk simulation is a suitable technique to describe electron transport.
► Coupling between transport and recombination determines collection efficiency.
► Usefulness of nanostructures like nanowires and nanotubes should be reassessed.