Green, low-cost strategy fully recycles perovskite solar cells

Perovskite solar cells are poised to be the next big photovoltaic technology, after silicon. But they usually don’t last more than a couple of years. They also contain toxic lead, which portends heaps of hazardous waste to manage.

Recycling them would help solve that problem. And researchers now report a method to recycle all parts of a perovskite solar cell economically using benign solvents (Nature 2025, DOI: 10.1038/s41586-024-08408-7). The method recovers over 99% of the device materials, and devices made from recycled components are as efficient and stable as the originals even after the materials have been recycled up to five times.

The global solar market is growing, and most of the millions of metric tons of silicon solar panels that reach the end of their life will end up in landfills because recycling them is costly and energy intensive. Researchers want to avoid that fate for perovskite solar cells. So far, though, perovskite recycling approaches have relied on toxic solvents. “We need to figure out how to recycle perovskite solar cells before we put them on the market, and the recycling process should be environmentally friendly,” says Feng Gao, an optoelectronics researcher at Linköping University.

Perovskite solar cells are made of a light-absorbing perovskite layer sandwiched between two layers each of charge-transport materials, conductive metal electrodes, and glass sheets.

Gao, Fengqi You of Cornell University, and colleagues tested their recycling process on solar cells made of a mainstream perovskite, methylammonium lead iodide. After removing the cover glass, the researchers soaked the cell in an ethyl acetate and ethanol solution to dissolve the top charge-transport material, spiro-OMeTAD, and the gold electrode, which they separated and purified for reuse.

Next came recycling the perovskite crystals. For this, the team soaked the cells in an aqueous solution of sodium acetate, sodium iodide, and hypophosphorous acid. Acetate ions bind strongly with the lead iodide in the perovskite, helping to dissolve the perovskite crystals. Sodium iodide provides iodide ions to restore the degraded perovskites, while the acid stabilizes the crystals in solution. When the solution is cooled to room temperature, high-quality perovskite crystals precipitate out.

This left the glass substrate, coated with an indium tin oxide electrode and a charge-transport layer of tin oxide. After drying the substrate, the researchers treated it with ultraviolet light and ozone to remove the defects in the tin oxide. They then remade the solar cell on this substrate layer by layer with the recovered perovskite crystals, spiro-OMeTAD, and gold.

“The question always is ‘is recycling worth doing?’” You says. “We effectively multiplied lifetime by five and lost almost none of the material or the efficiency. From our calculation this recycling technology is amazing.”

Sam Stranks, a professor of optoelectronics at the University of Cambridge, says the work is a very important step toward perovskite solar cell recyclability. “If it can be shown to be effective on full modules and be economically viable, this will help push perovskite solar to be a truly sustainable and impactful technology.”

This study shows that perovskites can be recovered efficiently and cost-effectively using a relatively simple method, says Ian Marius Peters, a photovoltaic researcher at the Jülich Researh Center. He says a good recycling strategy like this one “boosts the long-term economic benefit of the technology.”