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Raising the Efficiency Ceiling With Multijunction III-V Concentrator Photovoltaics
R. King, A. Boca, K.M. Edmondson, M.J. Romero, H. Yoon, D.C. Law, C. Fetzer, M. Haddad, A. Zakaria, W. Hong, S. Mesropian, D.D. Krut, G.S. Kinsey, P. Pien, R. Sherif, N. Karam
III-V Semiconductor, Gallium Arsenide Based Cells, Multijunction Solar Cell, High Efficiency, Concentrator Cell/s
Advanced Photovoltaics
Subtopic: Terrestrial Concentrator Systems
Event: 23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session: 1BP.2.1
24 - 29
ISBN: 3-936338-24-8
Paper DOI: 10.4229/23rdEUPVSEC2008-1BP.2.1
0,00 EUR
Document(s): paper


In this paper, we look at the question "how high can solar cell efficiency go?" from both theoretical and experimental perspectives. First-principle efficiency limits are analyzed for some of the main candidates for high-efficiency multijunction terrestrial concentrator cells. Many of these cell designs use lattice-mismatched, or metamorphic semiconductor materials in order to tune subcell band gaps to the solar spectrum. Minority-carrier recombination at dislocations is characterized in GaInAs inverted metamorphic solar cells, with band gap ranging from 1.4 to 0.84 eV, by light I-V, electron-beam-induced current (EBIC), and cathodoluminescence (CL). Metamorphic solar cells with a 3-junction GaInP/ GaInAs/ Ge structure were the first cells to reach over 40% efficiency, with an independently confirmed efficiency of 40.7% (AM1.5D, low-AOD, 240 suns, 25°C). The high efficiency of present III-V multijunction cells now in high-volume production, and still higher efficiencies of nextgeneration cells, is strongly leveraging for low-cost terrestrial concentrator PV systems.