The National Renewable Energy Laboratory (NREL) has announced 39.5% efficiency for a new solar cell it has created calling it the highest efficiency solar cell of any type, measured using standard-1 sun conditions.
This beats the 39.2% efficiency record claimed by the lab in 2020 for a six-junction solar cell using III-V materials, it says.
For the new triple-junction inverter metamorphic multijunction (IMM) architecture-based cell, the NREL scientists developed a quantum well cell with 'unprecedented performance' and implemented it into a device with 3 junctions with different bandgaps. The 3 junctions are made up of gallium indium phosphide (GalnP) on the top, gallium arsenide (GaAs) with quantum wells in the middle, and lattice-mismatched gallium indium arsenide (GalnAs) at the bottom.
To achieve the 39.5% efficiency, the researchers worked on the middle layer, developing optically thick quantum well devices that they claim came without major voltage loss.
Researchers see the cell best suited for low-radiation environments as space applications, but with further development of the cell structure, these cells can be used for high-radiation applications. "The new cell is more efficient and has a simpler design that may be useful for a variety of new applications, such as highly area-constrained applications or low-radiation space applications," said a Senior Scientist in NREL's High-Efficiency Crystalline Photovoltaics (PV) Group and Principal Investigator on the project, Myles Steiner.
Titled Triple-junction solar cells with 39.5% terrestrial and 34.2% space efficiency enabled by thick quantum well superlattices, the research paper has now been published in scientific journal Joule.
Back in April 2020, NREL fabricated a 6-junction solar cell to achieve 47.1% efficiency calling it the highest under concentrated illumination (see NREL Claims Close To 50% Efficiency For 6 Junction Solar Cell).