Triple-Junction Solar Cell Efficiencies Above 32%: The Promise and Challenges of Their Application in High-Concentration-Ratio PV Systems

H. L. Cotal, D. R. Lillington, J. H. Ermer, R. R. King, N. H. Karam, S. R. Kurtz, D. J. Friedman, J. M. Olson, J. S. Ward, A. Duda, K. A. Emery, T. Moriarty

Research output: Contribution to conferencePaperpeer-review

54 Scopus Citations

Abstract

Results from Spectrolab-grown Ga0.5In0.5P/GaAs/Ge structures optimized for the AM1.5D spectrum are described along with progress toward developing next-generation multijunction solar cells for high concentration ratios (X). The epitaxially-grown layers were processed into triple junction cells both at Spectrolab and NREL, and I-V tested vs. X. Cells were tested with efficiencies as high as 32.4% near 372 suns. The FF limited the performance with increasing X as a result of the increased role of the series resistance. The Voc vs. X showed its log-linear dependence on Isc over 1000 suns. Based on recent cell improvements for space applications, multijunction cells appear to be ideal candidates for high efficiency, cost effective, PV concentrator systems. Future development of new 1-eV materials for space cells, and further reduction in Ge wafer costs, promises to achieve cells with efficiencies < 40% that cost $0.3/W or less at concentration levels between 300 to 500 suns.

Original languageAmerican English
Pages955-960
Number of pages6
DOIs
StatePublished - 2000
Event28th IEEE Photovoltaic Specialists Conference, PVSC 2000 - Anchorage, United States
Duration: 15 Sep 200022 Sep 2000

Conference

Conference28th IEEE Photovoltaic Specialists Conference, PVSC 2000
Country/TerritoryUnited States
CityAnchorage
Period15/09/0022/09/00

Bibliographical note

Publisher Copyright:
© 2000 IEEE.

NREL Publication Number

  • NREL/CP-520-30356

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