NREL posts efficiency record for 'quantum dot' solar cells
US researchers have achieved a record 13.4% conversion efficiency for an emerging form of solar-cell technology using quantum dots. The team at the US Department of Energy's National Renewable Energy Laboratory (NREL) said their cell, made from caesium lead tri-iodide and usually around 3 nm and 20 nm, was best used in multi-junction solar cells, according to an article in Science Advances. NREL also speculated that, if paired with perovskite thin-film materials, they could perform as well as niche solar applications found in satellites but at a lower cost than regular silicon cells.
Joey Luther and Erin Sanehira were part of the research team which achieved 13.4% efficiency from a quantum dot solar cell.

Quantum dot solar cells first appeared on NREL’s conversion efficiency chart in 2010, when 2.9% efficient solar cells were created. Since then, better understanding of the technology has greatly increased its efficiency.

Thanks to their very small size – generally between 3 and 20nm according to NREL – quantum dot materials have become a popular area for research in solar. This latest paper from NREL, entitled “Enhanced mobility CsPbI3 quantum dot arrays for record-efficiency, high-voltage photovoltaic cells,” is published in the journal Science Advances.

The researchers state that their cell, made using cesium lead triodide, a material from the halide perovskite family, would best be deployed within multi-junction solar cells. “[The] voltage, coupled with the material’s bandgap, make them an ideal candidate for the top layer in a multijunction solar cell,” said Joseph Luther, project leader in the chemical materials and nanoscience team at NREL.

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The team go on to speculate that their quantum dot cell could be paired with perovskite thin-film materials to achieve efficiencies comparable to niche solar applications such as satellites, at a cost lower than conventional silicon PV technology.

“Often, materials used in space and rooftop applications are completely different,” said PhD Student Erin Sanehira. “It is exciting to see possible configurations that could be used for both situations.”