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SunDrive Uses Copper Instead of Silver in New Solar Cells, Sets World Record for Highest Efficiency.

SunDrive solar cell. Photo: SunDrive

Crystalline silicon solar cells currently dominate the global solar industry, accounting for about 95% of installations. These cells traditionally rely on silver, a precious metal, to generate electricity. But Australian startup SunDrive is pioneering a more sustainable and abundant alternative — copper.

In its latest round of testing, the company’s engineers demonstrated that copper is not only a reliable substitute for silver but also enabled a world-record efficiency of 25.54% for commercial-scale silicon solar cells.

SunDrive began its quest in 2015 to replace silver in silicon solar cells with copper, aiming to make the technology more viable in the long term. Copper, in its raw form, is about 100 times cheaper and far more abundant than silver. From a collaboration with the University of New South Wales, SunDrive unveiled its first copper-based silicon solar cell in 2019 — at the time, the most efficient industrial-scale solar cell ever produced in Australia.

Last year, the company secured government funding to upgrade its technology from industrial-sized cells to commercial modules suitable for rooftop installation. The newest cells underwent testing at Germany’s Solar Energy Research Institute, which officially certified SunDrive’s world-record efficiency earlier this September.

The 25.54% mark surpasses the previous record of 25.26% set by China’s Longi for commercial silicon solar cells. While some lab-scale silicon cells have exceeded these numbers, achieving such efficiency in a commercial-ready copper-based cell represents a major breakthrough for the industry.

“To limit global warming, we need to deploy solar at terawatt scale,” said Alison Lennon, professor at the University of New South Wales and advisor to SunDrive. “That requires huge amounts of metal. Silver is a limited resource and increasingly scarce, which means costs will rise and solar module production will become more expensive. Extracting silver from lower-grade ores also produces more emissions, worsening the problem. Copper, by contrast, is more abundant, cheaper, and easier to recycle. Metals from copper-coated solar modules can be recovered more efficiently than from traditional modules, making future recycling far simpler.”

An Khang (via Interesting Engineering)