Antimony chalcogenide is a promising yet still not widely used material for solar cell fabrication. Its optoelectronic properties, high absorption coefficient, material availability position the compound for greater utilization, particularly in the development of ultrathin and tandem solar technologies. Its potential was recently bolstered by researchers from the University of New South Wales (Australia) and the University of Science and Technology of China, who set a new performance benchmark for antimony chalcogenide solar cells.

As reported in Nature Energy, the researchers recognized that the major impediment to boosting efficiency of the cells is the way the material is formed during manufacturing. The two key elements, sulfur and selenium, have typically not been evenly distributed as the solar-absorbing layer was deposited, which limited the performance of these cells in the past. The resulting energy barrier formed by this nonuniform pattern formed an energy barrier impeding movement of the electrical charge generated by the sunlight through the solar cell.

The solution: include a small amount of sodium sulfide during fabrication. This addition stabilized the chemical reactions involved in forming the absorber layer, leading to a more uniform distribution of sulfur and selenium. With the internal barrier reduced, electrical charges could move more freely through the material, significantly improving performance.

The result: a solar cell efficiency of 11.02% recorded during laboratory testing, with an independently certified result of 10.7%.

The next goal is to achieve an efficiency of 12%.