Engineers at Florida International University have designed an ultra-thin, dual-purpose solar panel that converts daylight into electricity with an efficiency of 22 percent, then changes polarity to emit near-infrared light.
Designed with the goal of reducing the load on battery packs worn by infantry soldiers, the flexible semiconductor film is envisioned for future integration directly into combat uniforms.
Using one substrate for both power generation and nighttime infrared signaling, researchers hope the dual-purpose solar film will eventually reduce weight burdens while aiding night operations.
Integrating dual-purpose solar films into combat uniforms as a future application
Infantrymen typically have to lug around 20 pounds of lithium batteries in order to fuel their night-vision goggles, radios, and GPS equipment.
Scientists from Florida International University developed a super-thin layer of semiconductor material tested on small laboratory devices, achieving 22.02% efficiency on a 0.12 cm² cell and 20.43% on a 1.1 cm² device.
Future conductive pathways in textiles could potentially harness electricity from such devices to power wearable tactical electronics.
In the future, substituting bulky battery packs with lightweight solar cells could allow for power generation without significantly increasing equipment weight.
If successfully scaled to garment size, wearable solar cells aim to mitigate resupply delays and offer an independent energy source during prolonged tactical operations.
Integrating energy-harvesting materials into military apparel could eventually turn uniform fabric into an energy producer without adding bulk.
Reversal of electrical charge to produce invisible near-infrared light
Normal solar cells produce electricity in the form of DC energy when exposed to sunlight; however, normal solar materials are not able to give off light when they are biased.
The active semiconductor material was modified such that a reversed current will immediately turn the solar cell into a light source.
Reverse current results in narrow-band near-infrared light emission with an 818-nm peak.
This appears as a faint pink glow to the human eye in the dark and can be picked up by night-vision devices.
Infrared lights came to life.
Infrared light signals allow visibility of the terrain to soldiers using night-vision equipment.
Switching electrical bias instantaneously converts the daytime solar cell into a near-infrared light source.
22 percent power conversion efficiency in ultrathin films
Thinned-out solar modules are usually known for their reduced efficiencies in light absorption because of micro-thin absorbers that allow incoming photons to penetrate.
Engineered thin semiconductor layers with increased absorption of the sunlight trapped within micro-thin boundaries helped raise the efficiency.
Laboratory tests showed that under the full spectrum of sunlight illumination, the highest rate of power conversion reached 22 percent.
High efficiency corresponds with regular photovoltaics despite being thinner than one sheet of paper.
The most powerful solar power harvesting across small fabric areas helps provide enough watts to power up tactical equipment.
High-energy output confirms that flexible paper-thin solar modules are suitable replacements for bulky solar generators.
Resistance to mechanical stress and environmental conditions
Wearable military electronics withstand high mechanical stresses, constant folding, and extreme weather conditions in actual field deployment.
The repetitive bending of fabric cracks the brittle silicon semiconductor cells, breaking their electrical connections and making them unable to generate electricity immediately.
The flexible electronics feature an extremely tough polymer base, which can withstand repeated mechanical twisting without cracking.
Encapsulation layers protect the device from water penetration and dust particles, preventing any damage to electrical contacts during heavy rains and mud contamination.
Such rugged construction suggests that ultra-thin solar films could withstand harsh conditions, though operational suitability for wilderness combat has yet to be tested in field deployments, according to Florida International University.
Scale-up of chemical manufacturing for commercial uniform production
Proof-of-concept in the laboratory confirms dual functionality, but scale-up of the synthesis process from small test patches to full military uniforms poses manufacturing challenges.
Engineers depend on unique chemical deposition processes that need accurate temperature control throughout the large, flexible substrate rolls.
Inconsistent chemical deposition in large fabric rolls is likely to result in efficiency losses, with dead spots along the uniform power lines.
Efficiency in large-scale manufacturing will decide how fast defense agencies introduce self-powered and light-emitting combat uniforms for soldiers.
The full study can be found here: Kumar, N., Sahani, R., Lai, C. Y., & Radu, D. R. (2026). Bridging energy harvesting and high-performance electroluminescence in large-area single cation FAPbI3 perovskite devices through Rb⁺/K⁺ dual cation doping. Nano Energy, 148, 111683.
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