Solar Cells Hit 24.3% Efficiency with Copper Instead of Silver

Solar panels are about to get a lot more affordable thanks to a breakthrough from Georgia Tech researchers who figured out how to swap out pricey silver for copper without sacrificing power.

The team built a solar cell that achieves 24.3% efficiency using copper contacts paired with a clever laser treatment process. That performance nearly matches traditional silver-based cells, which hit 24.5% efficiency, but copper costs a fraction of the price.

Here's why that matters. Silver makes up a significant chunk of solar panel manufacturing costs, and as the world races to expand clean energy, finding cheaper alternatives could accelerate adoption everywhere from rooftops to solar farms.

The Georgia Tech team partnered with Bert Thin Films to develop a special copper paste that can be screen-printed onto solar cells using existing factory equipment. Unlike conventional approaches that require temperatures above 700 degrees Celsius, this copper paste works at just 540 degrees, making it easier and more energy-efficient to manufacture.

The secret sauce comes from a process called laser-enhanced contact optimization, or LECO for short. After applying the copper paste, researchers scan the cell's surface with a laser while applying an electrical current, which creates better connections between the copper and the silicon underneath.

Lead researcher Ruohan Zhong explained that the laser treatment dramatically improves performance. It reduced contact resistance from over 100 units to just 19.7 units, turning poorly conducting cells into high-efficiency devices.

The team confirmed through microscopy that the copper stays confined to the right layer of the solar cell, preventing contamination that could hurt performance. Both the copper and silver cells achieved impressive open-circuit voltages above 730 millivolts.

Why This Inspires

This breakthrough shows how scientific innovation can make clean energy more accessible to everyone. By solving the copper contact challenge that has stumped researchers for years, Georgia Tech created a practical path to cheaper solar panels without compromising quality.

The technology uses a plug-and-play approach that works with existing manufacturing equipment, meaning solar companies could adopt it relatively quickly. That's crucial as global demand for renewable energy continues to surge.

Independent testing confirmed the results, validating that this isn't just a lab curiosity but a commercially viable technology ready for the real world.

Making solar panels more affordable removes one more barrier to widespread clean energy adoption, bringing us closer to a sustainable future powered by the sun.