Wavelength-Selective Solar Thermal Absorber With Two-Dimensional Nickel Gratings

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Bong Jae Lee ◽  
Yu-Bin Chen ◽  
Sunwoo Han ◽  
Feng-Cheng Chiu ◽  
Hyun Jin Lee
Keyword(s):  
Solar Radiation ◽  
Near Infrared ◽  
Broad Band ◽  
Sio2 Film ◽  
Solar Thermal ◽  
Local Magnetic Field ◽  
Absorption Enhancement ◽  
Two Dimensional ◽  
Nickel Substrate ◽  
Infrared Spectral

The direct utilization of solar radiation has been considered a promising energy source because of its abundance, sustainability, and cleanness. The conversion of solar radiation into usable heat largely depends on the absorption characteristics of a solar thermal collector. In the present study, we conducted design analysis of a wavelength-selective absorber composed of a two-dimensional Nickel grating, a thin SiO2 film, and a Nickel substrate. Dimensions of the two-dimensional grating were determined with the Taguchi method, which optimized the spectral absorptance for both polarizations. The spectral absorptance demonstrated a broad-band plateau within the visible and the near-infrared spectral region, but it was significantly suppressed at longer wavelengths. Moreover, the absorptance plateau was nearly insensitive to the incident orientation of solar radiation. Physical mechanisms of the absorption enhancement were elucidated with the local magnetic field distribution.

Design a Wavelength-Selective Absorber for Solar Thermal Collectors With Two-Dimensional Nickel Gratings

2013 ◽  
Author(s):  
Yu-Bin Chen ◽  
Sunwoo Han ◽  
Feng-Cheng Chiu ◽  
Hyun Jin Lee ◽  
Bong Jae Lee
Keyword(s):  
Alternative Energy ◽  
Near Infrared ◽  
Broad Band ◽  
Surface Profile ◽  
Radiative Properties ◽  
Solar Thermal ◽  
Solar Irradiation ◽  
Two Dimensional ◽  
Promising Alternative ◽  
Structured Surfaces

The sunlight has been considered a promising alternative energy source because of its abundance and sustainability. A solar thermal collector can turn the solar irradiation into the usable heat, and thus, its performance highly depends on the efficiency of absorber. An ideal absorber should trap most incoming solar radiation in the visible and near-infrared spectral region, and minimize its emitted thermal energy at long wavelengths. One of the promising solutions for satisfying the aforementioned requirements is to employ periodic structured surfaces, whose tunable radiative properties were used in thermophotovoltaic devices and chemical sensors. Two-dimensional subwavelength gratings are thus proposed for the absorber surface profile in the present study. Design objectives are a broad-band peak in the absorption spectrum and a quasi-isotropic angular lobe at the incidence of both linear polarizations. Nickel is selected for its fabrication easiness and low cost. A SiO2 film sandwiched between gratings and a substrate is considered as extra design flexibility to possibly enhance performance without much difficulty. Radiative properties and electromagnetic fields will be obtained from programs based on the rigorous coupled-wave analysis (RCWA). The optimization is then realized with the Taguchi method.

scholarly journals Investigation of optical and photoelectric properties of poly (ohydroxyamide) sensitized by phthalocyanine as a perspective material for solar cells

2020 ◽  
Vol 220 ◽  
pp. 01019
Author(s):  
Elvira Fazalova ◽  
Konstantin Kochunov ◽  
Elena Bodyago ◽  
Georgii Konoplev ◽  
Nikolay Mukhin ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Radiation ◽  
Near Infrared ◽  
Wavelength Region ◽  
Organic Dye ◽  
Glass Substrates ◽  
Photoelectric Properties ◽  
Zinc Phthalocyanines ◽  
Infrared Spectral ◽  
Potential Use

Optical and photoelectric properties of poly (ohydroxyamide) (PHA) sensitized with zinc phthalocyanines were investigated in the visible and near infrared spectral regions. The structures were deposited on glass substrates by centrifugation and subsequent drying of a PHA film without thermal annealing. Optical spectra revealed characteristic absorption peaks of phthalocyanine in the longer wavelength region at 620-640 nm and 680-700 nm; absorption of the PHA matrix monotonously increases to the shorter wavelengths starting from 700 nm. Measurements of the photocurrent under irradiation with a high-power LED at a wavelength 630 nm showed photoconductivity related to the organic dye; photoconductivity also was observed while irradiated at 540 nm, presumably due to the absorption of PHA matrix. For non-sensitized (dye-free) PHA films no detectable photocurrents were produced by 630 nm irradiation. It was shown that introducing of phthalocyanines significantly improves optical absorption and photoconductivity of PHA thin films at the wavelengths, where the maximum in the spectral distribution of solar radiation lies. It was concluded that phthalocyanine-sensitized PHA has the potential use as a photosensitive organic material for solar applications, for example in developing composite organicinorganic structures with ferroelectrics.

scholarly journals Lattice Rayleigh Anomaly Associated Enhancement of NH and CH Stretching Modes on Gold Metasurfaces for Overtone Detection

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1265 ◽  
Author(s):  
Daler R. Dadadzhanov ◽  
Tigran A. Vartanyan ◽  
Alina Karabchevsky
Keyword(s):  
Near Infrared ◽  
Field Enhancement ◽  
Dielectric Substrate ◽  
Square Lattice ◽  
Localized Surface Plasmon ◽  
Absorption Enhancement ◽  
Absorption Bands ◽  
Transparent Dielectric ◽  
Infrared Spectral ◽  
Rayleigh Anomaly

Molecular overtones stretching modes that occupy the near-infrared (NIR) are weak compared to the fundamental vibrations. Here we report on the enhancement of absorption by molecular vibrations overtones via electromagnetic field enhancement of plasmonic nanoparallelepipeds comprising a square lattice. We explore numerically, using finite element method (FEM), gold metasurfaces on a transparent dielectric substrate covered by weakly absorbing analyte supporting N-H and C-H overtone absorption bands around 1.5 μ m and around 1.67 μ m, respectively. We found that the absorption enhancement in N-H overtone transition can be increased up to the factor of 22.5 due to the combination of localized surface plasmon resonance in prolonged nanoparticles and lattice Rayleigh anomaly. Our approach may be extended for sensitive identification of other functional group overtone transitions in the near-infrared spectral range.

scholarly journals Classification by Photoelectric Measurements of Molecular Bands: Current Status and Future Prospects

1979 ◽  
Vol 47 ◽  
pp. 347-373
Author(s):  
Robert F. Wing
Keyword(s):  
Near Infrared ◽  
Narrow Band ◽  
Current Status ◽  
Two Dimensional ◽  
Future Prospects ◽  
Late Type ◽  
Classification Technique ◽  
Cool Stars ◽  
Infrared Spectral ◽  
Photoelectric Measurements

AbstractAs a classification technique, photoelectric narrow-band photometry is especially effective in the case of late-type spectra, in which molecular bands furnish the most sensitive criteria. Measurements of molecular bands with bandpasses of about 50 Å can be made very efficiently, and for normal stars they can be calibrated in terms of temperature and luminosity. In the case of normal late-type giants and supergiants, two-dimensional classifications can be obtained from measurements of TiO and CN; for very cool giants and for dwarfs it is useful siso to measure VO and CaH, respectively. All these molecules have bands in the red and near-infrared spectral regions, where cool stars are relatively bright and where photometric accuracy is highest.

Polarization-independent absorption enhancement in a graphene square array with a cascaded grating structure

2018 ◽  
Vol 25 (2) ◽  
pp. 419-424 ◽  
Author(s):  
Jun Wu
Keyword(s):  
Near Infrared ◽  
Photonic Band Gap ◽  
Absorption Enhancement ◽  
Infrared Range ◽  
Two Dimensional ◽  
Enhanced Absorption ◽  
Guided Mode ◽  
Square Array ◽  
Multilayer Grating ◽  
Polarization Independent

The polarization-independent enhanced absorption effect of graphene in the near-infrared range is investigated. This is achieved by placing a graphene square array on top of a dielectric square array backed by a two-dimensional multilayer grating. Total optical absorption in graphene can be attributed to critical coupling, which is achieved through the combined effect of guided-mode resonance with the dielectric square array and the photonic band gap with the two-dimensional multilayer grating. To reveal the physical origin of such a phenomenon, the electromagnetic field distributions for both polarizations are illustrated. The designed graphene absorber exhibits near-unity polarization-independent absorption at resonance with an ultra-narrow spectrum. Moreover, the polarization-independent absorption can be tuned simply by changing the geometric parameters. The results may have promising potential for the design of graphene-based optoelectronic devices.

Solar Selective Volumetric Receivers for Harnessing Solar Thermal Energy

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Vikrant Khullar ◽  
Himanshu Tyagi ◽  
Todd P. Otanicar ◽  
Yasitha L. Hewakuruppu ◽  
Robert A. Taylor
Keyword(s):  
Thermal Energy ◽  
Near Infrared ◽  
Theoretical Calculations ◽  
Broad Band ◽  
Energy Resource ◽  
Radiative Properties ◽  
Solar Thermal ◽  
Stagnation Temperature ◽  
Solar Thermal Energy ◽  
Surface Absorption

Given the largely untapped solar energy resource, there has been an ongoing international effort to engineer improved solar-harvesting technologies. Toward this, the possibility of engineering a solar selective volumetric receiver (SSVR) has been explored in the present study. Common heat transfer liquids (HTLs) typically have high transmissivity in the visible-near infrared (VIS-NIR) region and high emission in the midinfrared region, due to the presence of intramolecular vibration bands. This precludes them from being solar absorbers. In fact, they have nearly the opposite properties from selective surfaces such as cermet, TiNOX, and black chrome. However, liquid receivers which approach the radiative properties of selective surfaces can be realized through a combination of anisotropic geometries of metal nanoparticles (or broad band absorption multiwalled carbon nanotubes (MWCNTs)) and transparent heat mirrors. SSVRs represent a paradigm shift in the manner in which solar thermal energy is harnessed and promise higher thermal efficiencies (and lower material requirements) than their surface absorption-based counterparts. In the present work, the “effective” solar absorption to infrared emission ratio has been evaluated for a representative SSVR employing copper nanospheroids/MWCNTs and Sn-In2O3 based heat mirrors. It has been found that a solar selectivity comparable to (or even higher than) cermet-based Schott receiver is achievable through control of the cut-off solar selective wavelength. Theoretical calculations show that the thermal efficiency of Sn-In2O3 based SSVR is 6–7% higher than the cermet-based Schott receiver. Furthermore, stagnation temperature experiments have been conducted on a laboratory-scale SSVR to validate the theoretical results. It has been found that higher stagnation temperatures (and hence higher thermal efficiencies) compared to conventional surface absorption-based collectors are achievable through proper control of nanoparticle concentration.

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