In a groundbreaking advancement, researchers have developed a transparent energy-harvesting device capable of capturing energy from both radio frequency (RF) waves and sunlight to power a wide array of wireless devices. This dual-source approach offers a more reliable and sustainable solution for energy harvesting, addressing the limitations of traditional systems that typically focus on just one energy source.

The new study, published recently, introduces an optically transparent rectifying metasurface system (RMS) that efficiently harvests RF energy while allowing the uninterrupted transmission of visible light. As the researchers explained, “In this paper, an optically transparent rectifying metasurface system is designed and validated for simultaneously harvesting RF energy while enabling the efficient transmission of visible light.”

Traditional energy-harvesting systems have generally focused on a single energy source, such as solar power or radio frequency energy. While effective, these methods are often limited by the unpredictable and intermittent nature of environmental energy sources. The new device, however, tackles these challenges head-on by capturing energy from two abundant sources—radio waves and sunlight—ensuring a more consistent and reliable power supply.

By combining these two energy inputs, the system can maximize energy capture and provide a more stable power output. This dual-source strategy is a significant leap forward in optimizing energy harvesting, particularly in an increasingly wireless, energy-hungry world.

The device’s design is further enhanced by its use of indium tin oxide (ITO), a transparent conductive material that makes the system suitable for integration into various surfaces without sacrificing functionality or aesthetics. According to Liming Si, one of the authors of the study, “The energy harvester is based on indium tin oxide — a material that cannot be seen in visible light.” This transparent feature allows for seamless integration into applications ranging from self-powered windowsdisplays, and building facades to vehicle components.

“Our transparent rectifying metasurface system offers distinct advantages over conventional energy harvesting antennas and metasurfaces, including wide-angle coverage, a low-profile designpolarization insensitivity, and high optical transparency,” Si added.

To maximize the efficiency of energy harvesting, the researchers integrated a voltage-doubling rectifier circuit that specifically targets Wi-Fi bands—2.4 GHz and 5.8 GHz. This innovative approach ensures that energy is captured effectively from common RF sources, such as Wi-Fi signals, while maintaining high optical transparency.

The researchers designed and tested a prototype 3×3 optically transparent metasurface absorber (OTMA) array, which demonstrated impressive results. The system achieved RF to DC efficiencies of 19.64% at 2.4 GHz and 7.92% at 5.8 GHz, while maintaining a remarkable 80% optical transparency.

The integration of this RF energy harvester with a solar cell resulted in a 13.11% increase in maximum power output, showcasing the synergistic potential of combining solar and RF energy harvesting in a single device. This improvement underscores the promise of this hybrid energy harvesting system in meeting the power demands of modern, wireless devices.

The development of this dual-source energy harvesting device marks a major step toward sustainable energy solutions. As energy demands grow in our interconnected world, this transparent, versatile system provides a promising pathway for integrating energy harvesting capabilities into everyday surfaces and devices, paving the way for a more energy-efficient future.

By enabling the seamless capture of energy from both radio waves and sunlight, this technology offers a cost-effectivereliable, and environmentally friendly solution to power the growing number of wireless devices that define our increasingly digital world.

By Impact Lab