Scientists have developed a new type of high-efficiency solar cell that replaces the rare and expensive metal indium with much cheaper tin, an advance that could help lower the cost of future solar panels while making them easier to manufacture on a large scale.
The international research team, whose findings were published in the journal Science, created the world’s first commercial-size tandem solar cell that delivers excellent performance without using indium.
Instead, they used tin oxide, a material that costs only about 1% as much as indium and is much more abundant.
The breakthrough could help speed up the development of next-generation solar panels that produce more electricity from the same amount of sunlight, making renewable energy even more affordable.
Tandem solar cells are considered one of the most promising advances in solar technology. Unlike conventional silicon solar panels, tandem cells combine two different light-absorbing materials that capture different parts of the sunlight spectrum.
This allows them to convert more sunlight into electricity, resulting in much higher efficiency than standard solar panels.
Until now, many high-performance tandem solar cells have relied on indium-based materials. However, indium is relatively scarce and is also widely used in products such as touchscreens, flat-panel displays, and other electronic devices.
As demand for clean energy continues to grow around the world, relying on a limited supply of indium could become a major obstacle to producing large numbers of advanced solar panels.
To solve this problem, the researchers developed a new manufacturing method that replaces indium-based oxide with tin oxide.
They used a technique called reactive plasma deposition, which allows thin layers of tin oxide to be added with minimal damage to the delicate materials inside the solar cell.
The new design achieved impressive results. The researchers first produced a small laboratory device measuring just 1 square centimeter that reached a certified efficiency of 33%.
They then successfully scaled the technology up to a commercial-size mini-module measuring nearly 208 square centimeters while maintaining a certified efficiency of 31%.
Maintaining such high efficiency in a much larger device is an important achievement because many solar technologies lose performance as they are scaled up from laboratory prototypes to practical products.
The researchers also found that the new solar cells were highly durable. The modules continued to perform well after exposure to heat, humidity, and more than three months of outdoor operation, suggesting they could withstand real-world conditions.
Professor Yuan Cheng from Monash University said the work demonstrates, for the first time, that highly efficient, large-area tandem solar cells can be produced without relying on expensive, scarce materials. Because tin is abundant and far less costly than indium, the new approach offers a practical path toward manufacturing next-generation solar panels on a much larger scale.
If the technology can be successfully commercialized, it could help reduce manufacturing costs while delivering solar panels that generate more electricity over their lifetime.
That combination of lower costs, higher efficiency, and improved sustainability could play an important role in expanding clean energy worldwide and supporting the transition to a lower-carbon future.
