This tiny flexible solar cell could power smartwatches of the future

Tiny solar cell may power future smartwatches.
Image: Munash University

Look down at your wrist. If you’re like millions of other people today, you’re probably wearing some version of a smartwatch. Whether it’s an Apple Watch, a Fitbit, or something from Samsung, countless people have adopted the idea of wearing tech on their wrist.

However, packing that much power into such a tiny frame is punishing on batteries. Most smartwatches have to recharge every day to every few days. That’s a problem researchers are hoping to solve with solar power. Thanks to a tiny new solar cell, that might be possible sooner than later.

Harnessing the Sun

Typically, thinking of solar panels conjures up an image of a bulky, large object that sits on a roof. While that’s a common application, it is far from the only one. Many people are quick to forget that calculators are often powered by a tiny solar cell.

That piece of hardware is perfect for supplying enough electricity to power a basic calculator. A smartwatch, on the other hand, is an entirely different story.

Researchers from Monash University in Melbourne, Australia, have developed a solar panel that combines a lightweight frame with tremendous power output. They documented their findings in a blog post on Wednesday.

The solar cell they created is more than 10 times thinner than a human hair. It measures in at just 0.3 micrometers thick. As demonstrated in the photo above, it’s light enough to rest comfortably on the petals of a flower.

Don’t let its tiny size fool you, though. The cell has a power output of 9.9W per gram. That’s enough to power a full-featured smartwatch.

Lasts a Lifetime (Kind of)

One problem with solar cells is that they degrade over time. In consumer devices that don’t charge with a cable, that’s a problem. A dead solar cell means a dead device.

Fortunately, the tiny cell created by the Monash team showed degradation of just 4.8 percent after more than 4,700 hours. They suggest that this means it could last for up to 20,000 hours with “minimal degradation.”

In a consumer device, it would be effective for about 11.5 years according to the researchers.

Dr. Wenchao Huang, a researcher on the project, says, “Currently, silicon solar cells are the dominant technology in the photovoltaic market, which are commonly found in rooftop installations. But, their brittle nature means solar cells exhibit poor performance when bent or stretched.”

He goes on to note that this cell is the organic variety—allowing it to be both flexible and incredibly thin.

Huang says, “Our ultra-flexible solar cells can simultaneously achieve an improved power conversion efficiency, excellent mechanical properties and robust stability. This makes them a very promising candidate as a power source in wearable electronics to realize long-term monitoring of various physiological signals, such as heart and breathing rates.”

The team plans to commercialize the tech in the days to come. However, any real-world applications are likely a long way off.

Nonetheless, the idea of not having to put your smartwatch on the charger is promising. It will certainly be worth the wait.


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