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Photo of Daniel J. Friedman.

Daniel Friedman

Group Research Manager III-Physics

Daniel.Friedman@nrel.gov | 303-384-6472

Dr. Daniel Friedman is the manager of the High Efficiency Crystalline Photovoltaics Group. He received his doctorate in applied physics from Stanford University in 1987 under the supervision of Professors W. E. Spicer and I. Lindau, studying metal-semiconductor interfaces. His postdoctoral work at the University of Hawaii with Professor C. S. Fadley focused on photoelectron diffraction studies of surface structure. He joined NREL in 1990. His interests at NREL have been in the development of next-generation multijunction high-efficiency solar cells for concentrator systems. One of his early focuses after joining the group was to adapt the GaInP/GaAs multijunction cell technology for concentrator operation, developing the first monolithic two-terminal solar cell to have a verified efficiency greater than 30%. More recently, he has studied novel semiconductor materials for photovoltaics, such as GaInNAs for potential application in a 1-eV-bandgap device on conventional GaAs or Ge substrates, as well as developing concepts for junctions suitable for fabrication on Si. His current work centers on development of future generations of lattice-mismatched multijunction cell structures for ultrahigh-efficiency operation under concentration.

Featured Publications

Daniel J. Friedman, John F. Geisz, and Myles A. Steiner, "Effect of Luminescent Coupling on the Optimal Design of Multijunction Solar Cells," J. Photovolt. 4, 986 (2014).

Daniel J. Friedman, John F. Geisz, and Myles A. Steiner, "Analysis of Multijunction Solar Cell Current-Voltage Characteristics in the Presence of Luminescent Coupling," J. Photovolt., 3, 1429 (2013).

D. J. Friedman, J.M. Olson, and S.R. Kurtz, "High-efficiency III-V multijunction solar cells", Chapter 8 in Handbook of PV Science and Engineering 2nd Edition, edited by A. Luque and S. Hegedus (Wiley, 2011).

D. J. Friedman, "Progress and challenges for next-generation high-efficiency multijunction solar cells," Curr. Opin. Sol. State Mater. Sci 14, 131 (2010).

D.J. Friedman, J.F. Geisz, A.G. Norman, M.W. Wanlass, and S.R. Kurtz, "0.7-eV GaInAs Junction for a GaInP/GaAs/GaInAs(1 eV)/GaInAs(0.7 eV) Four-junction Solar Cell," Proceedings of the 4th World Conference for Photovoltaic Energy Conversion, p. 598 (2006).

View all NREL publications for Daniel J. Friedman.