"Multijunction Solar Cells for Concentrator Photovoltaics"

Location

Elings Hall 1601

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 multi-junction 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 multi-junction cells, from the basic materials requirements through the design and realization of a record-setting 40/8%-efficient cell.

Biography

Dr. Friedman received his Ph.D. in 1987 at Stanford University. He studied under the Spicer/Lindau group, and his thesis focus was Schottky barriers on HgCdTe.
In 1987 to 1990, Dr. Friedman worked as a postdoctoral scholar for the Fadley group as University of Hawaii. There he concentrated on photoelectron diffraction studies of surface structure.

Dr. Friedman has been at NREL since 1990, where he was elected in
2008 to serve as the Group Manager of the III-V Materials and
Devices group. He is studying materials and design of devices for
multi-junction solar cells.