FIU engineers develop ultrathin solar device to power soldiers’ gear

A U.S. soldier may carry up to 20 pounds of batteries to power communications equipment and other electronics on missions. New research from Florida International University (FIU) could help lighten that load. 

Backed by a $10 million grant from the Department of War (DoW), a team of FIU engineers led by Daniela Radu, FIU College of Engineering & Computing mechanical and materials engineering interim chair, has developed a dual-use, razor-thin solar device that can harvest sunlight to generate electricity and produce light. 

This innovation, which the researchers call “SOLED” — half solar panel, half light-emitting diode (LED) — can be used as a wearable power system. When stitched into a soldier's uniform or gear, it gives troops working in remote locations a stealthy way to generate power without the noise, heat or bulk of a generator. It can potentially enable new kinds of displays, sensors and other optoelectronic devices, providing warfighters greater flexibility in a contested logistics environment when supply routes are threatened. The research for the device was published in the journal Nano Energy. 

“When you can turn sunlight into power and then use that same panel to produce light, you’re potentially reducing a dependency on batteries, on generators and on resupply,” Radu said. “This is how we can increase energy resilience at the level of individual soldiers.” 

The device is built with a versatile semiconductor material called perovskite, which converts sunlight to electricity at up to 22% efficiency, competitive with commercial solar technology. When that process is reversed, the material can emit light at nearly 11% efficiency, a significant jump over earlier versions of the technology, the research team says. 

The light itself isn’t bright to the naked eye. But that’s still useful: Night-vision sensors, biometric scanners and medical imaging equipment all read wavelengths on a similar frequency. However, the team is currently working to make the panels brighter. 

Their research grows out of the broader DoW grant focused on resilient, quiet energy for troops in the field. Radu leads the Center of Excellence for Integrated Resilient Energy and Energy Storage (CIREES), established with the $10 million investment from the DoW. FIU leads this multiyear project, which includes collaborators from Pennsylvania State University, toward finding new energy solutions that support DoW’s strategic commitment to making warfighter energy resilience a national security priority. 

For Radu and her team, the next step in the development of SOLED is scaling it to a larger platform. In its current state, SOLED is multilayered and thin, which can pose durability challenges for soldiers in the field. In early tests, the team has successfully increased the size of the panels without issue, said Neetesh Kumar, an FIU assistant research professor and lead author of the study.  

“Most solar cells made of these materials are tested at around 0.1 square centimeters in the research phase, because that’s what standard lab equipment is built for,” Kumar said. “We pushed ours to 1.1 and then 2.1 square centimeters and still saw strong performance. Our next goal is to keep scaling toward panel sizes that can go in a product.” 

As the researchers continue scaling the technology, they hope SOLED can eventually provide soldiers with a lightweight, versatile source of power and light that can be integrated directly into uniforms, equipment and other field systems. 

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