Researchers from the University of New South Wales have reported a new efficiency record for solar cells based on antimony chalcogenide, a promising semiconductor material for next-generation solar energy devices. They achieved an energy conversion efficiency of over 11% in laboratory conditions, the best result for this class of solar cells.
Antimony chalcogenide, a compound of antimony, sulfur and selenium, has attracted the attention of scientists thanks to a successful combination of properties. It absorbs sunlight well, can be applied in very thin layers, and is produced at relatively low temperatures, which paves the way for low-cost production on a large scale. These qualities make it an especially promising material for future ultra-thin and tandem solar panels, where several solar cells work together to absorb different parts of the solar spectrum.
For a long time, efficiency has remained the biggest limitation for this material: it has not exceeded 10% since 2020. The scientist team has found that this problem stems from the uneven distribution of sulfur and selenium within the material, which occurs during the production process. This chemical imbalance creates energy barriers within the solar cell, preventing electrons from freely moving to the contacts and causing energy losses.
In order to eliminate this effect, the researchers added a small amount of sodium sulfide to the stock solution. This simple addition made it possible to control the reaction more effectively, ensuring a more uniform and layered distribution of the elements across the solar cell’s thickness. As a result, the energy barriers within the material were smoothed out, the number of defects was reduced, and charge transfer became much more efficient. Figuratively speaking, electrons started to flow through the material more freely without getting stuck in defects, meaning that more sunlight was converted into electricity.
These conclusions were confirmed through an independent certification process conducted by specialists at the Commonwealth Scientific and Industrial Research Organisation, Australia’s leading government research center.
The scientists also believe that the material’s potential has not yet been exhausted. Further on, they plan to reduce the number of defects through chemical passivation and increase the efficiency of these solar cells to 12% in the coming years.
This makes antimony chalcogenide a strong candidate for a key material in tandem solar panels of the future, which could provide higher power generation at a lower cost, accelerating the development of affordable solar energy.
