Recycling Next-Gen Solar Cells With Water

In recent years, solar cells incorporating crystals known as perovskites have repeatedly broken records of how well they convert sunlight to electricity, suggesting they might help revolutionize photovoltaics. Now, a group of scientists have developed a way to recycle all parts of these solar cells in a more environmentally friendly way, compared to current methods. The recycled solar cells work as efficiently as the originals, the new study finds.

The most common solar cells use silicon to convert light to electricity. These silicon photovoltaics, which have been on the market for more than 30 years, are rapidly approaching their theoretical conversion efficiency limit of 29.4 percent. As of October 2024, the best lab cells had achieved efficiencies of more than 27 percent.

As first-generation silicon solar panels now reach the end of their life cycle, problems are mounting when it comes to recycling the panels in an economically viable and ecologically sound way. For instance, in older silicon solar modules, most recycling facilities actually trash the silicon, silver, and copper—their most valuable and least accessible materials—recovering only the aluminum frames and glass panes. Researchers are investigating better recycling methods that can recover at least 90 percent of these materials in the devices. However, these processes are expensive and often involve toxic chemicals.

The Promise of Perovskites

One of the most promising next-generation solar cell technologies involves perovskites. These crystals are not only relatively inexpensive and easy to manufacture, but also lightweight, flexible, and transparent. That transparency means perovskite and silicon can be stacked together in tandem solar cells, which achieved efficiencies of 34.6 percent in 2024.