Abstract
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%.
Original language | American English |
---|---|
Pages (from-to) | 326-335 |
Number of pages | 10 |
Journal | Nature Energy |
Volume | 5 |
Issue number | 4 |
DOIs | |
State | Published - 1 Apr 2020 |
Bibliographical note
Publisher Copyright:© 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
NREL Publication Number
- NREL/JA-5900-74788
Keywords
- electronic materials
- solar cells
- solar conversion efficiency