Comparative study of multilayered nanostructures for enhanced solar optical absorption

MRS Advances ◽  
2016 ◽  
Vol 1 (13) ◽  
pp. 839-845 ◽  
Author(s):  
Pabitra Dahal ◽  
Jeffrey Chou ◽  
Yu Wang ◽  
Sang Gook Kim ◽  
Jaime Viegas
Keyword(s):  
Aspect Ratio ◽  
Optical Absorption ◽  
Fdtd Method ◽  
Solar Spectrum ◽  
Finite Domain ◽  
High Aspect Ratio Structure ◽  
Electron Conversion ◽  
Nose Cone ◽  
Multilayered Nanostructures ◽  
Metallic Photonic Crystal

ABSTRACTImproved solar spectrum optical absorption in multilayered nanostructures consisting of metal, semiconductor and dielectric layers increase their potential for efficient photon to electron conversion. In this work, we analyze the influence of different nanostructure shapes and dimensions on the optical absorption in the vacuum wavelength range of 400 nm to 1500 nm based on Finite Domain Time Difference (FDTD) method. A periodic metallic photonic crystal composed of nanorods of gold, titanium oxide, and alumina is proposed by optimizing thickness of Au and TiO2, aspect ratio, sidewall angle, and geometry of the elemental shape. A high aspect ratio structure consisting of elliptical nose cone elements with optimized dimensions is seen to absorb more than 90% of the solar spectrum in the range considered.

scholarly journals Performance simulation of polymer-based nanoparticle and void dispersed photonic structures for radiative cooling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jay Prakash Bijarniya ◽  
Jahar Sarkar ◽  
Pralay Maiti
Keyword(s):  
Fdtd Method ◽  
Solar Spectrum ◽  
Thermal Infrared ◽  
Performance Estimation ◽  
Radiative Cooling ◽  
Slab Thickness ◽  
Slight Variation ◽  
Performance Simulation ◽  
Atmospheric Window ◽  
Substrate Independent

AbstractPassive radiative cooling is an emerging field and needs further development of material. Hence, the computational approach needs to establish for effective metamaterial design before fabrication. The finite difference time domain (FDTD) method is a promising numerical strategy to study electromagnetic interaction with the material. Here, we simulate using the FDTD method and report the behavior of various nanoparticles (SiO2, TiO2, Si3N4) and void dispersed polymers for the solar and thermal infrared spectrums. We propose the algorithm to simulate the surface emissive properties of various material nanostructures in both solar and thermal infrared spectrums, followed by cooling performance estimation. It is indeed found out that staggered and randomly distributed nanoparticle reflects efficiently in the solar radiation spectrum, become highly reflective for thin slab and emits efficiently in the atmospheric window (8–13 µm) over the parallel arrangement with slight variation. Higher slab thickness and concentration yield better reflectivity in the solar spectrum. SiO2-nanopores in a polymer, Si3N4 and TiO2 with/without voids in polymer efficiently achieve above 97% reflection in the solar spectrum and exhibits substrate independent radiative cooling properties. SiO2 and polymer combination alone is unable to reflect as desired in the solar spectrum and need a highly reflective substrate like silver.

Calculated optical absorption of different perovskite phases

2015 ◽  
Vol 3 (23) ◽  
pp. 12343-12349 ◽  
Author(s):  
Ivano E. Castelli ◽  
Kristian S. Thygesen ◽  
Karsten W. Jacobsen
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Solar Spectrum ◽  
Visible Part ◽  
Layered Perovskites

We present calculations of the optical properties of a set of around 80 oxides, oxynitrides, and organometal halide cubic and layered perovskites (Ruddlesden–Popper and Dion–Jacobson phases) with a bandgap in the visible part of the solar spectrum.

An Experimentally Validated Combined Stiffness Formulation for a Finite Domain Considering Volume Fraction, Shape, Orientation, and Location of a Single Inclusion

2018 ◽  
Vol 10 (01) ◽  
pp. 1850011
Author(s):  
Ilige Hage ◽  
Ramsey F. Hamade
Keyword(s):  
Aspect Ratio ◽  
Volume Fraction ◽  
Mathematical Expression ◽  
Ellipsoidal Inclusion ◽  
Finite Domain ◽  
Uniaxial Compression Test ◽  
Numerical Homogenization ◽  
Compression Tests ◽  
The Matrix ◽  
Single Inclusion

This work characterizes the stiffness of a finite domain containing one (biaxial ellipsoidal) void due to the combined effect of inclusion’s attributes: (1) size or volume fraction, VF, (2) shape or aspect ratio, AR, (3) angular orientation, and (4) location (position) within the matrix. The values and ranges of these ellipsoidal inclusion attributes are varied according to a matrix developed using design of experiments (DOE). Modified Mori–Tanaka method combined with dual-eigenstrain method (interior and exterior eigenstrain methods) is used to determine the effective stiffness tensor of the composite domain. Employing the numerically calculated normalized axial modulus [Formula: see text] values in SAS/STAT®, a nonlinear mathematical expression of [Formula: see text] as function of the void’s variables is arrived at Stiffness values found from the numerical homogenization scheme are experimentally corroborated using compression tests conducted on 3D-printed ABS cubes having a single ellipsoidal inclusion of various geometric attributes. In addition, finite element simulations were run of said uniaxial compression test cases to further validate the numerical homogenization results. Corroborated findings suggest that while the location of the inclusions in the matrix have no significant effect on normalized modulus [Formula: see text], the void’s volume fraction has the largest effect where it decreases with VF. The effect of the void’s orientation and elliptical aspect ratio are significant. [Formula: see text] increases with AR at angles ranging from 0–[Formula: see text]; at [Formula: see text][Formula: see text] are almost constant with AR, at angles of 60–[Formula: see text] values of [Formula: see text] decrease with AR. As AR approaches unity, the effect of orientation decreases significantly.

Morphology and Size Dependent Optical Properties of CdS Nanostructures

2006 ◽  
Vol 6 (3) ◽  
pp. 771-776 ◽  
Author(s):  
Soumitra Kar ◽  
S. K. Panda ◽  
B. Satpati ◽  
P. V. Satyam ◽  
S. Chaudhuri
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Aspect Ratio ◽  
Optical Absorption ◽  
Cds Nanoparticles ◽  
Solvothermal Process ◽  
Optical Absorption Spectra ◽  
Size Dependent ◽  
Cds Nanostructures ◽  
Size And Morphology

CdS nanoparticles with different sizes ranging from 2.5 nm to 300 nm and nanorods with aspect ratio ∼32 were synthesized by simple solvothermal process with a view to explore the effect of size and shape on the optical properties of these nanoforms. Solvent, temperature and the Cd source played important role in determining the morphologies and sizes of the nanocrystals. Comparative study of the optical properties of these nanoforms showed systematic changes in the optical absorption spectra with the reduction in particle size. Nanorods showed bulk like properties. Photoluminescence and Raman studies were carried out to explore the size and morphology dependent optical properties of the CdS nanoforms.

Micro hot embossing for high-aspect-ratio structure with materials flow enhancement by polymer sheet

2004 ◽  
Author(s):  
Yoichi Murakoshi ◽  
Xue-Chuan Shan ◽  
Toshio Sano ◽  
Masaharu Takahashi ◽  
Ryutaro Maeda
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Hot Embossing ◽  
Polymer Sheet ◽  
High Aspect Ratio Structure ◽  
Flow Enhancement ◽  
Materials Flow

scholarly journals Optical Absorption in Nano-Structures: Classical and Quantum Models

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Anand Kulkarni ◽  
Durdu Guney ◽  
Ankit Vora
Keyword(s):  
Thin Films ◽  
Optical Absorption ◽  
Classical Model ◽  
Visible Region ◽  
Solar Spectrum ◽  
Electron Interaction ◽  
Structured Materials ◽  
Unit Cells ◽  
Coefficient Versus ◽  
Absorption Characteristics

In the last decade, nano-structured materials have gained a significant interest for applications in solar cells and other optical and opto-electronic devices. Due to carrier confinement, the absorption characteristics in these structures are quite different from the absorption in bulk materials and thin films. Optical absorption coefficients of a silicon nano-wire are obtained based on a semi-classical model where the photon-electron interaction is described by the interaction of an electromagnetic wave with the electrons in the valence band of a semiconductor. The absorption characteristics showed enhanced optical absorption but no resonant peaks. In our modified model, we have identified optically active inter band transitions by performing electronic structure calculations on unit cells of nano-dimensions. The absorption spectrum obtained here shows explicit excitonic processes. This absorption is tunable from the visible region to near UV portion of the solar spectrum. In our previous work on thin films (100 nm) of ITO, we have used classical Drude model to describe free electron absorption. Using the imaginary part of the calculated complex dielectric function, we have plotted the absorption coefficient versus wavelength of the photon and compared with the experimental data showing good agreement between theory and experiment.

Suppression of Frost Propagation With Micropillar Structure Engineered Surface

2016 ◽  
Author(s):  
Yugang Zhao ◽  
Chun Yang
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Aspect Ratio ◽  
Surface Morphology ◽  
Superhydrophobic Surface ◽  
Small Aspect Ratio ◽  
Pattern Design ◽  
Patterned Substrate ◽  
High Aspect Ratio Structure ◽  
Surface Ice

Despite that using surface-roughness-induced superhydrophobic surface as a solution for ice/snow accretion issues has achieved extensive progresses, its icephobicity breaks down in case of condensation frosting, while the high aspect ratio structure brings more concerns on its durability and sustainability. In this work we investigated condensate frosting on substrates fabricated with patterned micropillars having a small aspect ratio, and studied the freezing propagation with different pattern sizes. The results show that a coarse patterned substrate can effectively suppress the freeing propagation while a fine patterned one can drastically promote the freezing propagation. Frost coverage can also be reduced with proper pattern design. A theoretical model was developed to explain the mechanism of surface ice propagation, and agrees well in tendency with experiment measurements. The aim of this study is to provide some new insights on the influence of surface morphology on ice growth.

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