High-Efficiency Optical Absorbers Derived from Carbon Nanostructures

摘要

Optical absorbers based on vertically aligned multi-walled carbon nanotubes (MWCNTs), synthesized using electric-field assisted growth, are described here that show an ultra-low reflectance, 100X lower compared to the benchmark, a diffuse metal black - Au-black - from wavelength X ~ 350 nm - 2500 nm. The reflectance of the MWCNT arrays was measured to be as low as 0.02 % at 2 urn. The choice of the starting substrate was deemed to be particularly important in order to synthesize a high-areal density of the MWCNTs using the plasma-based chemical vapor deposition (CVD) process which directly impacts the optical absorption efficiency of the nanoabsorbers. Such high efficiency absorbers are particularly attractive for radiometry, as well as energy harnessing applications.