Ultrafast Laser Technique Creates Durable 'Super Black' Metals For High-Temperature Energy Applications

A new technique uses ultrafast lasers to transform ordinary metal surfaces into “super black” materials that nearly double the electricity output of heat-to-energy thermophotovoltaic (TPV) systems.

In the journal Joule, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (LBNL) described their novel method of creating “Laser-Blackened Surfaces” (LaBS) by using a femtosecond laser — which pulses in bursts of five ten-trillionths of a second — to carve intricate, microscopic hill-and-valley structures across metallic surfaces.

These laser-carved nano-structures trap incoming light through multiple reflections, dramatically increasing infrared light absorption (thermal emission). High-temperature energy generation systems, like TPV cells, capture heat from hot surfaces and convert it to electricity. “Most metals are poor emitters of thermal radiation after capture,” said Vassilia Zorba, senior scientist at LBNL and lead author of the paper. “But LaBS could effectively transform certain common, inefficient materials into record-setting “near-blackbody” surfaces that almost double electrical power output in TPV systems while remaining durable at extreme temperatures exceeding 1,500 °C.”

LaBS technology shows promise for cost-effective, scalable high-temperature energy applications including TPVs, concentrating solar power (CSP), spacecraft thermal management, and solar water desalination.