Near-perfect absorber consisted of a vertical array of single-wall carbon nanotubes and engineered multi-wall carbon nanotubes

Abstract

An extensive study on the optical characteristics of vertically aligned single-wall carbon nanotubes (SWCNTs) and engineered multi-wall carbon nanotubes (MWCNTs) using finite-difference time-domain (FDTD) simulation technique is presented in this work. We investigated absorption characteristics for SWCNTs, MWCNTs, dual-diameter MWCNTs, and cone MWCNTs with the changes in the occupation area and incident angle of light in the visible wavelength range. The enhancement of absorption was achieved by changing the geometrical shapes. Our study suggests that 99.569 % of the total light energy is absorbed in SWCNTs and 99.883 % in cone-shaped-top MWCNTs with an occupation area of 20 % and 50 %, respectively, at 450 nm wavelength and 5000 nm tube height. Moreover, for both SWCNTs and MWCNTs, reflectance increases with the increase of the occupation area due to the larger reflecting top surface area. We found that a drastic reduction of absorption occurs as the angle between the tube axis of aligned carbon nanotubes (CNTs) and the incoming light source increases above 30 °. Our study will be valuable for further investigation of the optical properties of shape-engineered CNTs and will promote CNT-based ultra-broadband absorber devices and systems for multifunctional optoelectronic applications.

A Comprehensive Review on Photoacoustic-Based Devices for Biomedical Applications

“…This is mainly due to the higher thermal conductivity coefficient along the length direction when compared to the diameter direction [ 127 ]. Tahmid et al also demonstrated that the light absorbance is maximized when the direction of light incidence is equal to the length direction of the CNT, as shown in Figure 12 [ 132 ].…”

“… CNTs’ average light absorbance (A avg ) as a function of the light incidence angle. Reproduced with permission from [ 132 ]. …”

Disorder induced absorption enhancement of light in GaAs nanowire array

“…The optimum condition is achieved for 1000-2000 nm variation, where maximum average absorbance (A avg ) is found for both 25% and 50% fillfactors as depicted in figure 4(d). Here, average absorbance is defined as [26]…”

Ultra-broadband near-perfect metamaterial absorber for photovoltaic applications

“…[1][2][3][4][5][6] However, broadband absorbers are essential for photovoltaic cells, 7,8 photodetectors, 9 and thermal emitters. 10,11 Over the years, broadband photon absorbers with various structures such as nanowires, 12 nanopillars, 13 triangular and pyramid gratings, 14 nanocones, 15 plasmonic nanostructures, 16 and nanoholes 17 have been reported theoretically and experimentally for harvesting solar energy. Most of the reported research studies mainly focused on absorbing the visible light spectrum; however, approximately half of the sunlight that reaches the surface of the Earth contains infrared radiation.…”