Tungsten Based Spectrally Selective Absorbers with Anisotropic Rough Surface Texture.

Area of Science:

• Materials Science
• Optics
• Surface Engineering

Background:

• Spectrally selective absorbers are crucial for thermophotovoltaic devices and solar absorbers.
• High operating temperatures necessitate thermo-mechanically stable and broadband absorbers.

Purpose of the Study:

• To demonstrate anisotropic random rough surfaces for broadband spectral absorption on Tungsten.
• To investigate the impact of surface topography on spectral absorptance.

Main Methods:

• Fabrication of anisotropic random rough surfaces on Tungsten.
• Analysis of spectral absorptance in visible (VIS) and near-infrared (NIR) regions.
• Correlation of absorptance with surface parameters like correlation length and RMS height.

Main Results:

• Optimized random rough surfaces achieve over 95% absorption.
• Anisotropic surfaces broaden the high absorption bandwidth.
• Absorption enhancements of 47% (isotropic) and 52% (anisotropic) were observed in VIS and NIR regions.

Conclusions:

• Anisotropic random rough surfaces offer a viable solution for broadband spectrally selective absorption on Tungsten.
• Surface parameter optimization is key to achieving high absorptance and bandwidth.
• Tungsten surfaces with tailored roughness show promise for demanding thermal applications.