Researchers from Tsinghua University and Civil Aviation University of China have developed a perovskite laser cell-thermoelectric (PLC-TE) tandem device that converts an incoming green laser beam into electricity at a power conversion efficiency (PCE) of 38.49%, designed to be embedded in the wing of an unmanned aerial vehicle (UAV) as an in-flight power source.
The work targets laser wireless power transmission (LWPT), an approach to beaming energy over long distances that offers strong directionality, flexible beam-steering and resistance to electromagnetic interference. For UAVs, whose flight time is fundamentally capped by onboard battery capacity, LWPT raises the possibility of a drone that recharges continuously in the air rather than returning to the ground. CsPbBr3 perovskite is a strong candidate receiver material for this application: its broad bandgap absorbs efficiently across the blue-green range (400-550 nm) that aligns with atmospheric transmission windows, and the material remains stable under the high-temperature, high-energy-photon conditions a concentrated laser beam produces.
That stability is nonetheless tested by prolonged high-intensity irradiation, which drives up device temperature and degrades performance through higher Urbach energy and increased electron-phonon scattering. The team's device uses a carbon electrode for the CsPbBr3 layer, which improves durability under sustained high-power laser exposure, but the carbon electrode also acts as the device's main heat source, converting part of the incident light to heat. Rather than treating that heat purely as a loss, the researchers pair the perovskite layer with a thermoelectric (TE) layer that harvests it: through the Seebeck effect, a temperature gradient between the laser-heated perovskite side and the cooler far side of the device generates additional electrical output, on top of the electricity produced by the perovskite's direct photoelectric conversion.
Sustaining that temperature gradient, however, requires keeping heat from simply spreading through the carbon layer and equalizing the two sides. To address this, the team synthesized nanorods of antimony triselenide (Sb2Se3) and doped them into the top interface of the CsPbBr3 layer. Sb2Se3 is a p-type semiconductor with a valence band maximum of -5.35 eV and high hole mobility, and its nanorods are strongly anisotropic: carriers move within covalently bonded (Sb4Se6)n ribbons rather than having to hop between ribbons connected only by weaker van der Waals forces, enabling fast, efficient transport of photogenerated carriers and minimizing non-radiative recombination. The nanorods' low thermal conductivity gives them a second function as a thermal barrier, reducing heat dissipation into the carbon layer below, which helps sustain the temperature gradient the TE layer depends on and keeps the PLC's own operating temperature down.
To confirm the concept would work once built into an actual wing rather than tested in isolation, the team ran ANSYS finite element simulations of the Sb2Se3-enhanced PLC-TE tandem embedded in a UAV wing. The simulations confirmed the device could support both pneumatic actuation and heat dissipation within the wing structure, informing the design of the thermal management approach. In flight, the drone's own propellers provide a further assist, with continuous airflow cooling the thermoelectric layer's cool side and helping maintain the temperature gradient - coupling the aircraft's normal flight operation to the receiver's thermal management.
Under simulated airflow conditions, the champion Sb2Se3-enhanced device reached a PCE of 38.49%, with an open-circuit voltage (VOC) of 2.52 V and a short-circuit current density (JSC) of 260.56 mA·cm⁻², under 520 nm laser irradiation at an incident power density of 1.2 W·cm⁻². According to the secondary writeup, that figure is nearly double the roughly 20% efficiency reported for DARPA's current laser power-beaming receiver, and above the US Department of Energy's 34% benchmark for the best perovskite-silicon tandem solar cells - though the latter comparison spans different operating conditions, since that benchmark reflects performance under the full solar spectrum rather than a narrowband laser source. Incorporating the Sb2Se3 nanorods improved both efficiency and stability, translating into faster propeller rotation, longer operation and higher lift production in the drone testing, and giving the device the ability to handle higher power densities and longer irradiation times.
As Jianhua Han at the Civil Aviation University of China noted in a statement accompanying the publication: "Previous studies largely focused on the materials or the device itself. We wanted to think beyond the laboratory, to how the system could actually be integrated into an aircraft, cooled during operation, and made compatible with flight. It isn't just a materials science problem; it's an engineering one."
The authors describe the work as a strategy for maintaining stable PLC-TE power output in UAV power supplies under high-power-density laser irradiation, addressing thermal management and photo-induced degradation as key barriers to using CsPbBr3 PLCs and their tandem devices for aerospace and other remote power transmission applications. The team's stated next step is testing the device on a real lightweight drone outdoors, a setting that will introduce aerodynamic turbulence, variable ambient lighting and the added complexity of tracking a moving receiver with the laser beam - alongside the beam-path safety questions that outdoor, high-power laser operation raises.
