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Spectrally Dependent Optimization of Multi-Junction Solar Cells
C. Ulbrich, T. Kirchartz, K. Ding, B.E. Pieters, A. Gerber, U. Rau
Multijunction Solar Cell, Tandem, Energy Performance
Thin Films Solar Cells
Subtopic: Amorphous and Microcrystalline Silicon Solar Cells
Event: 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany
Session: 3CO.12.3
2386 - 2389
ISBN: 3-936338-25-6
Paper DOI: 10.4229/24thEUPVSEC2009-3CO.12.3
0,00 EUR
Document(s): paper


Today’s multi-junction solar cell optimization aims at high conversion efficiencies under a standard spectrum. However, depending on the local conditions at the outdoor location this standardized spectrum may not be the optimum. A resulting current mismatch of a series-connected multi-junction solar cell involves losses in the annual yield. We investigate the issue of spectral dependence of the output power of an amorphous silicon-/ microcrystalline silicon (a-Si:H/μc-Si:H) tandem in non-tracked mode on the local spectral conditions. The surprising result is that the optimum junction thicknesses overlap in a wide range for 99 % of the maximum power under the standard AM 1.5g spectrum and for 99 % of the maximum annual yield at both investigated locations. However, a top limitation is predicted to be advantageous for the optimum yield.