Femtosecond laser-produced optical absorbers for solar-thermal energy harvesting

Abstract

Optical absorbers are a key component in all solar-thermal energy technologies. Cermet-based solar absorbers are commonly used in solar-thermal applications. However, due to their multilayered structures, these absorbers have limited thermal conductivity and mechanical stability at the interfaces. Femtosecond laser processing is a single-step, environmentally friendly, and monolithic approach that can directly transform a metal surface to a solar absorber through surface patterning without adding additional weight, hazard, or complexity. In this review, we will focus on femtosecond-laser induced broadband and selective solar absorbers and their utilizations in solar thermoelectric generators and solar-thermal water purification. We will discuss the laser surface patterning and the procedure to control the size, distribution, and composition of the surface structures that are responsible for optical absorbance/emittance. Several multifunctional solar absorber surfaces produced by femtosecond-laser processing and their possible energy applications are also discussed. (Figure presented.).