These revolutionary indoor solar panels could power your gadgets

In your home, you probably have a handful of gadgets that rely on batteries: remotes, smoke detectors, wireless keyboards. But instead of having to replace those batteries again and again, those devices could one day be powered by solar panels that harvest energy from your indoor lights.

The idea of an indoor solar panel sounds contradictory; our lamps and overhead lighting aren’t the same as the sun. But indoor solar panels have been in development for years. The problem, though, is they’ve often been “inefficient, expensive, or too unstable to be widely adopted,” says Motjaba Abdi-Jalebi, an associate professor at University College London’s Institute for Materials Discovery. 

“We saw an opportunity to change that,” he adds. Abdi-Jalebi and his research team recently developed new indoor solar cells that are about six times more efficient than today’s commercial indoor photovoltaics, and can be made at low costs.

To do so, they designed solar cells using a material called perovskite. Researchers have developed perovskite solar panels for outdoor use too, though they’re not yet manufactured at scale or competitive with regular photovoltaics.

Perovskite crystal structure often has defects that interrupt the flow of electricity and degrades the material over time, but the material also has its positives: It can actually be turned into an ink, which is then laid down in thin layers. This means it can essentially be printed, like a newspaper. “So in principle,” Abdi-Jalebi says, “you could roll out large sheets of solar cells quickly and cheaply.” That differs from regular silicon solar panels, which require high-temperature, expensive manufacturing processes.

Perovskite can also absorb a wide range of light, even with that thin layer. Abdi-Jalebi’s team used a perovskite material “tuned specifically to absorb indoor light efficiently,” he says. The final result can generate power from any common indoor lighting, from LEDs to fluorescent bulbs.

In their study, the indoor solar cells achieved a power conversion efficiency of 38%, under indoor light of 1000 lux—roughly equivalent to a bright office. That’s a world record for this type of perovskite solar cell, Abdi-Jalebi says. (Outdoor solar panels, on average, convert around 22% of the sunshine into power.) And whereas perovskite panels usually break down, theirs stayed stable; after more than 100 days of testing, the indoor solar panels kept more than 90% of their performance. 

Perovskite panels can be scaled up, but getting them to power more energy-sapping devices like laptops or appliances will take more research. Still, “it’s a very exciting possibility for the future,” Abdi-Jalebi says. Regular solar panels started out really small, with a low efficiency and limited use, too, but now they provide about 7% of the world’s energy—the same as powering all of India. 

With indoor solar panels powering our smart thermostats or indoor sensors, that means less electronic waste because we’re not tossing batteries out every few years. “As homes and workplaces get filled with more connected devices, the impact could be enormous,” Abdi-Jalebi says. “Our vision is to replace billions of disposable batteries—which are a major source of toxic waste—with a clean and recyclable light-harvesting solution.”

Next, his team is going to work with industrial partners to scale up their indoor solar panel production and integrate the cells into real devices. “In the longer term,” he adds, “we see indoor solar cells becoming as common as batteries are today.”

ABOUT THE AUTHOR

Kristin Toussaint is a staff editor for Fast Company’s Impact section, where she covers climate change, labor, shareholder capitalism, and all sorts of innovations meant to improve the world.. On the topic of climate change, she has explained terms including cloud brightening, plastic credits, and renewable natural gas, and told the story of climate solutions, like how Maine got more than 100,000 residents to install heat pumps.

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