Big leap narrows gap with mainstream solar technology

Scientists at the University of Rochester report a 15× efficiency boost in solar thermoelectric generators, a technology that converts heat differences into electricity. The team used laser-crafted black metal and redesigned thermal interfaces to extract more useful energy from sunlight.

The advance targets a long-standing gap between solar thermoelectrics and conventional photovoltaic panels. By rethinking the device’s hot and cold sides, the researchers raised usable output without changing the semiconductor materials at the core of the generator.

How the laser-made black metal works

The team used femtosecond laser pulses on tungsten to create a nanoscale texture that behaves as a selective solar absorber. This so-called black metal captures solar wavelengths efficiently while reducing off-band thermal losses to preserve heat where it matters.

By tuning surface features, the absorber increases the hot side temperature under the same light, elevating the temperature gradient across the thermoelectric legs. A stronger gradient translates into higher voltage and power from a given device footprint.

Did you know?
Selective solar absorbers can approach high absorptivity in the solar spectrum while emitting less in the infrared, minimizing radiative losses and boosting thermal-to-electric conversion potential.

Making the hot side hotter, the cold side colder

Researchers added a simple plastic cover over the absorber to create a compact greenhouse effect. That layer limits convection and conduction losses to the surrounding air, keeping more heat on the hot side during operation.

The researchers also used laser structuring on the aluminum surface of the cold side to enhance heat rejection. The micro-patterned surface improves air-side cooling, acting like a more effective heat sink and sharpening the temperature difference across the module.

What 15× means for real applications

The efficiency gain enabled the devices to power LEDs at maximum brightness under lower light levels than standard setups. That suggests practical pathways for small power loads where maintenance-free operation is critical.

Potential use cases include autonomous sensors, wearables, and remote units that harvest sunlight or ambient heat. The approach could also pair with waste-heat sources, expanding beyond pure solar into industrial and transportation settings.

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Why it matters for the solar landscape

Conventional residential solar panels convert a notable share of sunlight directly into electricity, but thermoelectrics traditionally lag far behind. A 15× jump does not match photovoltaics, yet it can unlock niches where simplicity and durability outweigh peak efficiency.

Because the method avoids altering the semiconductor legs, it may be easier to integrate into existing thermoelectric platforms. That lowers barriers for prototyping and could speed translation from lab to field pilots.

What to watch next

Scalability and durability will determine the next phase. Manufacturing consistent nanoscale textures and maintaining performance across temperature cycles, humidity, and dust exposure are key engineering hurdles.

Integration with standard module packaging, heat spreaders, and passive cooling elements will shape reliability. Field tests across climates will clarify how the greenhouse layer and textured surfaces age over time.

The forward path

If manufacturing proves repeatable, the combination of selective absorption, greenhouse retention, and enhanced cooling could anchor a new class of compact solar thermoelectric power sources. Modular designs may tailor hot and cold interfaces for different environments.

This approach provides a practical solution for generating useful solar power in locations where traditional panels are impractical or where it is beneficial to combine solar energy with heat harvesting. As refinement continues, the technology could complement mainstream solar rather than compete, filling gaps current solutions leave open.