A tandem photovoltaic device embedded with antimony selenide nanorods converted 38.49% of incoming laser energy into electricity while powering a drone propeller blade — a figure its developers at the Civil Aviation University of China describe as among the highest reported for this class of technology under comparable conditions.

The result, published in Matter & Light, addresses the central engineering bottleneck in laser wireless power transmission for uncrewed aerial vehicles: heat. Laser beams heat the photovoltaic cells mounted on a drone's wings, degrading their efficiency and, in the team's early tests, driving device temperatures to 90°C.

"That was much higher than we expected and made us realize that heat buildup was a far more serious problem than we had imagined," said Jianhua Han, who led the study.

A tandem architecture with a thermal problem

The device under test is a perovskite laser cell-thermoelectric (PLC-TE) tandem structure. It pairs a carbon-based CsPbBr3 perovskite laser cell with a bismuth telluride (Bi2Te3) thermoelectric module fixed directly beneath it. A carbon electrode attached to the negative terminal creates a series connection. When laser light strikes the device, the carbon electrode converts part of the incident energy into heat; the thermoelectric layer then harvests that heat and converts it into electricity. Because one side of the device runs warmer than the other, the temperature gradient itself drives additional generation — the larger the gradient, the more electricity the TE layer produces.

Han's team chose perovskites for the laser cell because they are cheap to manufacture, absorb strongly in the visible spectrum and have long charge-carrier diffusion lengths. But the hybrid structure's own carbon, while dissipating some laser-generated heat, still allowed temperatures to climb to 90°C during prolonged illumination.

Sb2Se3 nanorods as a thermal barrier

The fix came from antimony selenide (Sb2Se3), a semiconducting photovoltaic material with low thermal conductivity. The researchers synthesized Sb2Se3 nanorods and incorporated them into the upper portion of the CsPbBr3 layer. Embedded this way, the nanorods act as a thermal barrier: they reduce heat dissipation in the carbon electrode, preserve the temperature gradient the thermoelectric module depends on, and lower the laser cell's overall operating temperature during extended laser exposure.

The team tested the device by mounting it beneath the wing of a stationary drone, carving air channels through the wing to simulate real-world airflow, and illuminating it with high-power green laser light at 520 nm. The measured 38.49% conversion efficiency was sufficient to drive the drone's propeller blade.

From materials research to system design

Han frames the work as a step beyond materials science. "In terms of concept, this is the first time that a system-level scheme of the devices has been applied to a UAV power supply, expanding the work from pure materials research to application-oriented system design," he said. "It demonstrates that powering UAVs with light is not just a theoretical concept, but an engineering pathway that can be practically implemented."

The efficiency figure, however, comes from a stationary drone under simulated airflow in a controlled setting — not from a flying vehicle. Han is explicit about the gap. Before applications such as forest patrol, disaster monitoring and package delivery become realistic, the team must integrate the PLC-TE device into a lightweight drone for outdoor flight testing, assess the technology's safety, and develop a method for accurately tracking moving drones with laser beams.

"Going from the ground-based proof stage to the real flight validation stage will require solving many engineering challenges," said Han, "but our technology is a good starting point and verifying its viability is the core objective for the next phase in our study."