Scientists Hit 24% Solar Efficiency Using Cheaper Copper

Solar panels are about to get a lot cheaper without sacrificing power.

A team of US scientists has developed a new type of solar cell that swaps costly silver for copper and still achieves an impressive 24.3% efficiency. That's only 0.2% below traditional silver-based panels, but at a fraction of the cost.

The researchers from Georgia Institute of Technology, the National Renewable Energy Laboratory, and Bert Thin Films created these cells using TOPCon technology, currently one of the most advanced solar cell designs. They printed copper onto the back of the cells using existing manufacturing equipment, meaning solar factories wouldn't need expensive overhauls to adopt this method.

The real innovation came from their LECO process, which uses laser pulses to dramatically improve how copper connects with the silicon underneath. This treatment reduced contact resistance by 97%, solving one of copper's biggest challenges in solar manufacturing.

Copper has always been attractive because it costs far less than silver and works just as well as a conductor. The problem has been keeping copper from migrating into the silicon and ruining the cell's performance. The team tackled this by using a special copper paste that forms a protective oxide layer and firing the cells at carefully controlled temperatures between 500 and 550 degrees Celsius.

Lead researcher Young Woo Ok emphasized that every tool and process used already exists in solar factories today. "It only requires replacing the silver paste with the copper paste," he told PV Magazine, calling it a "plug-and-play alternative."

The team tested their cells under thermal stress at 200 degrees Celsius for over 1,000 hours. The cells showed virtually no degradation in performance, proving copper contacts can last just as long as silver ones.

Why This Inspires

Silver prices have skyrocketed in recent years, making up a significant portion of solar panel costs. This breakthrough arrives at exactly the right moment as the world races to expand renewable energy.

The beauty of this research lies in its practicality. These aren't lab curiosities requiring billion-dollar facilities. Any existing solar manufacturer could implement this technology tomorrow using equipment they already own.

By making solar panels cheaper to produce, this innovation could accelerate adoption worldwide, especially in developing countries where cost remains the primary barrier. More affordable panels mean more rooftops covered, more communities powered, and more carbon emissions avoided.

The researchers published their findings in Solar Energy Materials and Solar Cells, opening the door for manufacturers everywhere to start testing copper-based production. With efficiency losses of just 0.2%, the cost savings could be enormous.

Clean energy just got more accessible for everyone.