Six-junction III–V solar cells with 47.1% conversion efficiency under 143 Suns concentration

Single-junction flat-plate terrestrial solar cells are fundamentally limited to about 30% solar-to-electricity conversion efficiency, but multiple junctions and concentrated light make much higher efficiencies practically achievable. Until now, four-junction III–V concentrator solar cells have demon...

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Bibliographic Details
Published in:Nature energy 2020-04, Vol.5 (4), p.326-335
Main Authors: Geisz, John F., France, Ryan M., Schulte, Kevin L., Steiner, Myles A., Norman, Andrew G., Guthrey, Harvey L., Young, Matthew R., Song, Tao, Moriarty, Thomas
Format: Article
Language:English
Subjects:
639/301/299/946
639/4077/909/4101/4096/946
639/638/298/917
Alloys
Economics and Management
Efficiency
Electrical junctions
Energy
Energy gap
Energy Policy
Energy Storage
Energy Systems
Group III-V semiconductors
Photovoltaic cells
Renewable and Green Energy
Solar cells
Threading dislocations
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Summary:Single-junction flat-plate terrestrial solar cells are fundamentally limited to about 30% solar-to-electricity conversion efficiency, but multiple junctions and concentrated light make much higher efficiencies practically achievable. Until now, four-junction III–V concentrator solar cells have demonstrated the highest solar conversion efficiencies. Here, we demonstrate 47.1% solar conversion efficiency using a monolithic, series-connected, six-junction inverted metamorphic structure operated under the direct spectrum at 143 Suns concentration. When tuned to the global spectrum, a variation of this structure achieves a 1-Sun global efficiency of 39.2%. Nearly optimal bandgaps for six junctions were fabricated using alloys of III–V semiconductors. To develop these junctions, it was necessary to minimize threading dislocations in lattice-mismatched III–V alloys, prevent phase segregation in metastable quaternary III–V alloys and understand dopant diffusion in complex structures. Further reduction of the series resistance within this structure could realistically enable efficiencies over 50%. Stacking multiple junctions with different bandgaps and operating under concentrated light allows solar cells to reach efficiencies beyond the limits of standard devices. Geisz et al. present a six-junction solar cell based on III–V materials with a 47.1% efficiency—the highest reported to date.
ISSN:2058-7546
2058-7546
DOI:10.1038/s41560-020-0598-5