Effects of surfaces on photogenerated electron diffusion in zinc oxide nanowires
EMSL Project ID
32698
Abstract
In the context of cost-effectively raising photovoltaic energy conversion efficiency, dye-sensitized solar cells (DSSCs) have emerged as one of the most promising low-cost options. Among them, zinc oxide (ZnO) nanowire-based DSSCs have demonstrated enormous potential in enabling highly efficient energy conversion due to superior charge carrier transport and collection efficiency. Further improvement in the performance of these DSSCs is possible by decreasing the nanowire diameter to provide larger surface areas per unit volume for dye loading. This decrease in the nanowire diameter, however, gives rise to significant surface effects that can play a dominant role in limiting carrier transport. The research proposed here aims to establish a fundamental understanding of the surface effects on photogenerated electron diffusion in ZnO nanowires. To achieve this, investigations on the relationship between surface state characteristics and photogenerated electron diffusion in ZnO nanowires will be conducted. The experiments will be carried out using scanning probe microscopy-based techniques that combine electrical and optical probing capabilities. For the fabrication of simple test devices with single nanowires contacted by two metal electrodes, the access to dual-beam focused ion beam/scanning electron microscope and the wedge wire bonders in the cleanroom at EMSL is requested. The achievement of the proposed objective will greatly contribute to the basic understanding of the limiting factors for solar energy conversion, and will also provide the guide for ongoing photovoltaic material and device engineering efforts.
Project Details
Project type
Exploratory Research
Start Date
2009-08-18
End Date
2010-08-22
Status
Closed
Released Data Link
Team
Principal Investigator