The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.
This award will support an eighteen-month research fellowship by Dr. Ryan O'Hayre to work with Dr. Joop Schooman at Technical University in Delft, Netherlands for twelve months, and with Dr. Fritz Prinz at Stanford University in California, for six months.
In recent years, tremendous strides have been made developing promising new classes of solar cells using carefully structured nano-materials. At the Technical University of Delft, in the Netherlands, Ryan O'Hayre is working to improve the efficiency of these devices, exploring new designs that could allow for a robust, cost effective means of converting light into electricity.
Collaborating with Dr. Joop Schoonman and Dr. Albert Goossens, Ryan is investigating a novel solid-state alternative to the Gratzel cell. This all-solid-state, completely inorganic, bulk heterojunction device does not suffer from performance degradation and does not require expensive sealing. It is based on a nanometer-scale interpenetrating network between n-type titanium dioxide and p-type copper indium diselinide. The team uses a relatively new technique, Atomic-Layer Chemical Vapor Deposition (AL-CVD) to fabricate the nanostructured devices.
In addition to improving the efficiency of these nanostructured solar cells, Ryan plans to use a novel Atomic Force Microscope (AFM) impedance microscopy technique that he has developed to study their fundamental behavior. Probing the local properties of solar cells at the nano-scale should produce a better understanding of the basic physical processes at work in the conversion of light to electricity- leading eventually to better solar cells.
As a final aspect of the collaboration, Ryan is working to develop a completely new localized characterization technique, referred to as the AFM intensity-modulated photocurrent imaging technique (in other words, localized IMPS). By applying sinusoidal illumination intensity to the solar cell and measuring the local current response, localized IMPS may be able to address questions about heterogeneous electron lifetime and recombination characteristics in nanostructured solar cells. Extending collaboration between TU Delft and Stanford University, Ryan plans to leverage the AFM impedance imaging facilities at Stanford to implement the AFM-IMPS system.
