Super Black Material from Low-Density Carbon Aerogels with Subwavelength Structures

Abstract

Many scientists have devoted themselves to the study of the interaction between subwavelength structures and electromagnetic waves. These structures are commonly composed of regular arrays of subwavelength protuberances, which can be artificially designed. However, extending from 2D periodic patterns to 3D disordered subwavelength structures has not been studied yet. In this study, we studied the total diffuse reflectivity of carbon aerogels with various 3D networks of randomly oriented particle-like nanostructures by using normally incident visible light (430-675 nm). We observed that the different 3D network nanostructures of carbon aerogels, especially for the structures with the minimum size, reduced the reflectivity effectively. It was found that the key mechanism for the subwavelength-structure-induced ultralow reflectivity property is due to the decrease of the amplitude of electron vibration forced by the electromagnetic wave, which provides a simple method for designing perfect black materials.

Carbon Vesicles: A Symmetry‐Breaking Strategy for Wide‐Band and Solvent‐Processable Ultrablack Coating Materials

“…Ultrablack materials, which are featured by their excellent light‐absorption properties, play important roles in applications, such as high‐resolution optical sensing, [ 1–4 ] solar energy harvesting, [ 5–8 ] infrared light source, [ 9,10 ] and infrared stealth. [ 11,12 ] Various ultrablack structures constructed of carbon, [ 13–17 ] metal, [ 18,19 ] and semiconductor [ 20–23 ] have been reported. Among these structures vertically aligned carbon nanotube arrays (VA‐CNT arrays) exhibit the lowest hemispherical reflectance of 0.045%.…”

“…[ 25,26 ] Manipulating the microstructures of carbon materials is an efficient way to improve their light‐absorbing performance. [ 13–17 ] Low filling ratio and small scatterer size (at least in one dimension) are necessary for realizing ultralow reflectance. [ 24 ] Notably, HCS with a very thin shell is a fairly simple solution to fulfill these two requirements simultaneously.…”

Recyclable Nanoporous Materials with Ordered Tunnels Self‐Assembled from α‐ and γ‐Cyclodextrins

“…The physical properties and applications of the porous materials mostly rely on their pore parameters, [14,15] such as pore size, pore volume, porosity, regularity, and dispersity, [16][17][18] and can be tuned by different synthesis methods. The methods for porous-materials synthesis mainly consist of the sol-gel method, [19,20] template method, [21][22][23][24][25] chemical reaction method, [1][2][3][4] and physical process. [26][27][28][29][30][31][32][33][34] Template method is the most commonly-used technique that can offer an easy way to form porous materials and modulate pore sizes.…”

Near perfect thin film flexible broadband optical absorber with high thermal/electrical conductivity

“…In absence of PDMS layer, the electron transfer from one CNT to another CNT is relatively easier. However, PDMS present between CNT arrays offers restriction to the electron flow . This leads to decrease in the vibrational amplitude of electrons, which ultimately decrease the reflectivity at the interface of PDMS‐VACNTs as per Fresnel equations .…”

“…However, PDMS present between CNT arrays offers restriction to the electron flow . This leads to decrease in the vibrational amplitude of electrons, which ultimately decrease the reflectivity at the interface of PDMS‐VACNTs as per Fresnel equations . The decrease in vibrational amplitude, impedance matching, and multiple scattering together provides ultra‐high optical absorption in broadband wavelength range as schematically shown in Figure (a).…”