The worldwide adoption of solar photovoltaic (PV) generation has been explosive, increasing by a record 270 TWh (up 26%) in 2022, reaching almost 1,300 TWh. According to the International Energy Agency, solar demonstrated the largest absolute generation growth of all renewable technologies in 2022, surpassing wind for the first time in history. Continued expansion and adoption of PV systems can be expected with the concomitant increase in solar cell component efficiencies, as recently reported for perovskite-on-silicon tandem and quantum dot (QD) solar cells.

A new solar panel world record of 25% efficiency has been claimed Oxford University spinout Oxford PV in the U.K. The PV technology developed combines a thin layer of perovskite, a synthetic solar conversion material, with mainstream silicon solar cells to create more powerful solar panels that can generate around 20% more electricity than silicon-only cell technology.

The solar panel was produced in partnership with Germany’s Fraunhofer Institute for Solar Energy Systems. Using the Institute’s Module-TEC (Technology Evaluation Centre), engineers optimized the existing production line for its tandem technology, producing a silicon perovskite tandem solar panel that delivered an output of 421 W on an area of 1.68 m². Oxford PV claims the 25% efficiency achieved makes it the world’s most efficient perovskite silicon tandem solar module in industrial format.

While the new record marks just a one percentage point rise over the 24% efficiency level commercially available today, it could still exert a marked impact when extrapolated across the rapidly expanding solar industry.

Perovskite QDs, semiconducting nanocrystals with typical dimensions ranging from several to tens of nanometers have garnered significant attention from researchers due to their outstanding photoelectric properties. Their practical use requires a design that reduces the distance between QDs through ligand exchange, a process that binds a large molecule, such as a ligand receptor, to the surface of a QD. Organic perovskite QDs face notable challenges, including defects in their crystals and surfaces during the substitution process and resulting in efficiency limitations.

To overcome this efficiency cap, researchers from Ulsan National Institute of Science and Technology in South Korea employed an alkyl ammonium iodide-based ligand exchange strategy, effectively substituting ligands for organic perovskite QDs with excellent solar utilization. This breakthrough enables the creation of a photoactive layer of QDs for solar cells with high substitution efficiency and controlled defects.

The research published in Nature Energy documents the achievement of a QD solar cell efficiency boost to 18.1%, up from the previous record of 16.6%. The stability of these devices was also improved, as they maintained their efficiency for 1,200 hours under normal conditions, and 300 hours at an elevated temperature of 80° C (176° F). The solar cells also performed just as well after more than two years in storage.