Abstract
The large-scale use of photovoltaics is becoming a reality, with more than 3 GW of solar cells produced worldwide in 2007. However, it is anticipated that on the order of 100 GW or more of solar cells will be called for within the next few years. For 100 GW of photovoltaic power, the conventional "flat-plate" approach would require ~500 km2 of cells, a daunting challenge. A significant part of the solution is likely to be "concentrator" photovoltaics using optics to focus large areas of light onto much smaller ultrahigh-efficiency solar cells. Recent developments in multijunction cells, which have demonstrated the highest photovoltaic efficiencies ever achieved, have resulted in a surge of development and investment in concentrator technology. This talk will discuss the concentrator approach, focusing on the development of the multijunction cells, from the basic materials requirements through the design and realization of a record-setting 40.8%-efficient cell.
Biography
Daniel Friedman has been at the National Renewable Energy Laboratory since 1990 in the III-V Materials and Devices group, and the Group Manager since 2008. His research topics include studies of materials and design of devices for multijunction solar cells.
Dr. Friedman received his PhD in 1987 from Stanford University, where he was part of the Spicer/Lindau group. His thesis topic was Schottky barriers on HgCdTe. From 1987-1990, he was a postdoctoral scholar in the Fadley group at the University of Hawaii, where he conducted research on photoelectron diffraction studies of surface structure.