Broadband Metallic Absorber on a Non‐Planar Substrate

Ao, Xianyu; Wang, Xuyue; Yin, Guanbo; Dang, Kangkang; Xue, Yali; He, Sailing

doi:10.1002/smll.201401895

Cited by 24 publications

(14 citation statements)

References 33 publications

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“…The high pumping irradiance, necessary for efficient energy conversion, makes the practice of TC and TPV devices particularly challenging in terms of cost, efficiency and reliability. It is believed that significant improvements in those areas can be made by designing a nearly perfect electromagnetic energy absorber that can achieve broadband, wide-angle and polarization-independent absorption 15 16 17 18 19 20 21 22 23 24 25 26 27 , as well as excellent photothermal properties.…”

mentioning

confidence: 99%

“…With the rapid advent of nanotechnology, design of highly-efficient and compact antireflection coatings or surface absorbers has become viable using nanophotonic techniques: photonic nanostructures 18 19 20 21 22 23 24 25 26 27 28 29 , photonic crystals 30 31 , and metamaterials 15 16 17 . Aiming to facilitate the use of TC and TPV energy conversion devices, here we develop a simple and cost-effective chemical route to prepare a high-performance, large-area absorber constructed using a nanoporous alumina film on top of the commercial 6061-T6 aluminum (Al) substrate.…”

mentioning

confidence: 99%

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Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

Farhat

Cheng²,

et al. 2016

Sci Rep

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We present here a broadband, wide-angle, and polarization-independent nearly perfect absorber consisting of mirror-backed nanoporous alumina. By electrochemically anodizing the disordered multicomponent aluminum and properly tailoring the thickness and air-filling fraction of nanoporous alumina, according to the Maxwell-Garnet mixture theory, a large-area dark alumina can be made with excellent photothermal properties and absorption larger than 93% over a wide wavelength range spanning from near-infrared to ultraviolet light, i.e. 250 nm–2500 nm. The measured absorption is orders of magnitude greater than other reported anodized porous alumina, typically semi-transparent at similar wavelengths. This simple yet effective approach, however, does not require any lithography, nano-mixture deposition, pre- and post-treatment. Here, we also envisage and theoretically investigate the practical use of proposed absorbers and/or photothermal converters in integrated thermoelectronic and/or thermophotovoltaic energy conversion devices, which make efficient use of the entire spectrum of ambient visible to near-infrared radiation.

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confidence: 99%

mentioning

confidence: 99%

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

Farhat

Cheng²,

et al. 2016

Sci Rep

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“…A strong stray light will reduce star image quality and signal to noise ratio. For safeguarding optical instruments present on the satellites and to suppress stray light, various types of black coatings are developed in past few years . Most of these black surfaces are fabricated using surface texturing, optical grating, etching, nano composite or by applying coating of different nanomaterials on the surface of interest.…”

Section: Introductionmentioning

confidence: 99%

“…However, due to their limitations such as narrow bandwidth, complex structure, and costly fabrication routes, these absorbers find limited application. To overcome these issues, efforts have been made to fabricate near perfect optical absorber coating using nanomaterials . Among these, carbon‐based nanomaterials finds huge potential in the fabrication of ultra‐black absorbers due to their exciting combination of properties .…”

Section: Introductionmentioning

confidence: 99%

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

Ghai

Singh

Agnihotri

2019

J of Applied Polymer Sci

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Flexible ultra-black absorber with high thermal/electrical conductivity finds huge applications in the field of stray light attenuation, solar collectors, flexible electronics, and electronic thermal management systems. In this work, we report the fabrication of ultrablack absorber consists of vertically aligned carbon nanotubes (VACNT) in Polydimethylsiloxane (PDMS) having an absorption capacity of more than 98% in UV-Vis wavelength and more than 94% in NIR wavelength range. It is observed that the PDMS-VACNT composite shows ultra-high absorption capacity due to enhanced impedance matching and multiple scattering. In addition to this, the PDMS-VACNT composite shows an emissivity of 0.94 along with a 118% increase in thermal conductivity. Moreover, with the infiltration of VACNT in PDMS, the sheet resistance decrease drastically to 0.08 KΩ/sq, which signify the possible use of ultrablack absorber in electronic skin and flexible sensors etc.

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“…A super absorber should ideally have extremely low reflectance ( R < 0.2%) and very high absorption (A > 99%) over broadband frequency range and angle of incident beam 5 .Various processes as well as materials have been developed to bring down the refractive index of objects to unity and thus increase their absorption capacity 6 – 9 . It is reported that introduction of hierarchal micro-nano structures leads to a near perfect absorber 10 – 12 . The absorbing frequency range of these hierarchal structures depend on the number of factors including refraction index, texture shape, size and their arrangement in the material microstructure 13 .…”

Section: Introductionmentioning

confidence: 99%

Optically Graded Ultra Dark Absorber for Visible and Near-infrared Wavelength Range

Agnihotri

Ghai

Singh

2018

Sci Rep

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Near perfect absorbers find application in many areas including solar cells, energy harvesting and antireflection coatings for space applications. Here we report the use of optical gradation concept to fabricate a near perfect absorber on etched Si wafer. As a proof of concept, 99.4% absorption is achieved in the broad range of 300 nm to 2000 nm. Moreover, absorption capacity of optically graded surface remains higher than 99% up to beam incident angle of 50°. While carbon nanotubes (index ~1.1) are used as top layer, subsequent layers with increasing optical index across the thickness are chosen so as to satisfy zero reflection condition on multilayered assembly. Inward bending of incident beam and total internal reflection of reflected beam caused due to optical index gradient contributes to absorb the incident beam more efficiently. In addition, multiple scattering of incident beam due to the presence of multiscale feature size in graded assembly helps to absorb shorter as well as longer wavelengths of incident light. The graded assembly shows contact angle of 160° with roll-off angle equal to 5° implying that the graded absorber is not only super black but also superhydrophobic and self-cleaning in nature. The combination of properties shown by the super absorber makes it very attractive, especially for next generation solar cells to harness energy in the wavelength range of 1000 nm to 2000 nm.

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Broadband Metallic Absorber on a Non‐Planar Substrate

Cited by 24 publications

References 33 publications

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

Mirror-backed Dark Alumina: A Nearly Perfect Absorber for Thermoelectronics and Thermophotovotaics

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

Optically Graded Ultra Dark Absorber for Visible and Near-infrared Wavelength Range

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