Title:	New Efficiency Frontiers with Wafer-Bonded Multi-Junction Solar Cells.
Author(s):	T.N.D. Tibbits, P. Beutel, M. Grave, C. Karcher, E. Oliva, G. Siefer, A. Wekkeli, M. Schachtner, F. Dimroth, A.W. Bett, R. Krause, M. Piccin, N. Blanc, M. Muñoz-Rico, C. Arena, E. Guiot, C. Charles-Alfred, C. Drazek, F. Janin, L. Farrugia, B. Hoarau, J. Wasselin, A. Tauzin, T. Signamarcheix, T. Hannappel, K. Schwarzburg, A. Dobrich
Keywords:	Multijunction Solar Cell, Concentrator Cells, III-V Semiconductors, High-Efficiency, Wafer Bonding
Topic:	SOLAR CELLS / ASSEMBLIES / MODULES FOR TERRESTRIAL CONCENTRATOR SYSTEMS AND FOR SPACE SOLAR GENERATORS
Subtopic:	III-V-based Multi-junction Solar Cells, Concentrator Solar Cells and Space Solar Cells
Event:	29th European Photovoltaic Solar Energy Conference and Exhibition
Session:	4CP.2.1
Pages:	1975 - 1978
ISBN:	3-936338-34-5
Paper DOI:	10.4229/EUPVSEC20142014-4CP.2.1
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Triple-junction (3J) solar cells will soon be history. The next generation of multi-junction (MJ) devices are now reaching efficiencies far beyond the record levels of 3J cells on Germanium. In this paper we present results of a 4J wafer-bonded solar cell with bandgaps 1.88 / 1.45 // 1.10 / 0.73 eV measured with an improved efficiency of 46.5% at 324x by Fraunhofer ISE. Design for cost has, from the outset, been a priority with the development of engineered substrates to replace costly and low yielding InP substrates, a product building on Soitec’s proprietary SmartCut® technology. Wafer bonding enables the electro-mechanical combination of lattice and thermal expansion mismatched materials with electrically conductive, transparent bonds, enabling concentrator solar cells to be built from high quality 2J GaInP/GaAs absorbers lattice-matched to GaAs bonded to high quality 2J GaInPAs/GaInAs absorbers lattice matched to InP that operate well at high concentration.