It is an era when anything that uses electricity—from smartphones and smartwatches to electric vehicles—can be charged wirelessly. Now wireless charging has expanded its stage to the sky. A laser is shined under a drone's wing to recharge even during flight.
Professor Jianhua Han of the School of Aeronautical Engineering at the Civil Aviation University of China and Professor Hong Lin of the Department of Materials Science at Tsinghua University and their team said they "developed a composite device that converts the energy of a laser beam into electricity from a drone's wing," in a paper published on the 30th in Matter & Light, a sister journal of Cell.
The team succeeded in shining a laser from the ground onto a drone's wing to spin its propellers. Han said, "Battery life is the biggest barrier to extending a drone's mission time," adding, "Drones that survey forests or disaster sites or deliver parcels will no longer need to land to replace batteries."
◇ Converting both light and heat into electricity
The team developed a composite device that combines a perovskite solar cell with a thermoelectric device. The perovskite solar cell under the wing generates electricity by receiving laser light from the ground. Perovskite, named after the Russian mineralogist who first discovered calcium titanate (CaTiO₃), has a crystal structure (ABX₃) formed by two cations (A and B) and one anion (X).
The team attached a thermoelectric device, which generates electricity from temperature differences, to a perovskite cell made of cesium lead bromide (CsPbBr₃) crystals to recycle even the energy that would be wasted as waste heat. Where the laser shines, the temperature rises, and the opposite side becomes cooler, allowing the thermoelectric layer to generate electricity. When the team shined a laser on the composite device on the drone's wing, the propeller operated.
Perovskite is drawing attention as a next-generation solar cell. While silicon solar cells are processed at high temperatures, perovskite cells can be made simply and cheaply through solution chemical reactions, and when applied to a plastic film, they become immediately flexible. Thanks to this, it is easy to combine with other devices into a composite device, as in this study.
The problem is that when a high-power laser is fired from the ground, the surface of the cell overheats to 80–90 degrees Celsius. The surface temperature for maximum efficiency in a solar cell is around 17–25 degrees, equivalent to room temperature. Exceeding this reduces power generation efficiency and shortens the device's lifespan. The team noted, "Existing laser wireless charging focused only on the photoelectric conversion efficiency of the solar cell material, but this time we used the problematic heat as an additional power source."
◇ Preventing overheating with airflow paths and nanorods
To prevent the solar cell from overheating, the team inserted antimony selenide (Sb₂Se₃) nanorods, which block heat, between the perovskite layer and the carbon electrode. In effect, they created a kind of thermal barrier. The team explained that electricity flows better along the nanorods and defects in the perovskite crystals are also reduced.
They also changed the wing structure. They attached vertical plate-like fins to the top of the drone's wing to increase the surface area in contact with air. That dissipates heat faster. They also created air channels inside the wing. This not only lowered the temperature of the perovskite layer but also further lowered the temperature on the cold side of the thermoelectric layer. Power generation efficiency increases accordingly, because a larger temperature difference across the thermoelectric layer produces more electricity.
Thanks to the insulating nanorods and the new wing structure, the team said the composite device converted 38.49% of the energy into electricity when a green laser was used. They said this was the highest efficiency among peer technologies operating under the same conditions. A composite device without the insulating nanorods reached only 34.65%.
Han said, "Previous research focused mainly on the materials or the device itself, but we looked beyond the lab to how this system could actually be integrated into an aircraft and made suitable for flight," adding, "This is not a simple materials science issue but an engineering challenge."
However, only ground tests have succeeded so far, and in-flight charging has not yet been tested. For airborne wireless charging to be commercialized, laser beam aiming technology that accurately tracks a moving drone is needed. Light energy losses from clouds, fog, and dust must also be considered. Han said, "This study shows the possibility of refueling aircraft with light," adding, "To go from 1 to 100, many engineering problems must be solved, but this study is a starting point."
References
Matter & Light (2026), DOI: https://doi.org/10.1016/j.matlit.2026.100066