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This work deals with the modeling and optimization of the CuInGaSe/CdS based structure, for photovoltaics. In this study we took into consideration the effect of the concentration of the alloy and the temperature on the strain bandgap, the absorption and efficiency of the structure. It has been shown that the gallium concentration x varies the strain bandgap energy, these two parameters significantly...
A new method of achieving mode locking using a gain lever Quantum Dot Mode Locked Laser is proposed as an augment to traditional techniques when striving for higher repetition rates.
We investigated ultrafast dynamics of Dirac electrons under a high electric field in graphene combining strong THz pulses and ultrafast transient absorption spectroscopy. Comparison with semi-classical Boltzmann equation clarifies efficient impact ionization process.
A thin broadband multilayer absorber loaded with fractal frequency selective surface (FSS) by employing micron (80–90 μm) and nano (20–30 nm) sized Ti based Fe3O4 nanoparticles have been presented. The experimentally measured complex permittivity and permeability values have been used for implementation of a two layer absorber in the range of 8.2 to 12.4 GHz. A double layer absorber loaded with Sierpinski...
In this study we report the fabrication of pure CeCO2, ZnO deposited CeCO2 hybrid core-shell nanoparticles by simple and cost effective co precipitation method. The as synthesized samples were characterized by various experimental techniques such as XRD (X-ray diffraction), FTIR (Fourier Transform Infrared Spectroscopy), UV-Vis absorbance and HRTEM (High Field Transmission Tunneling Microscopy) measurements...
We evaluated a data set consisting of 38 different materials — threats and non-threats — to determine whether there are signatures detectable in CT systems equipped with energy-resolving photon-counting detectors that would help the detection task. Data with such detectors was collected in a lab setup using a Compton spectrometer and simple transmission measurements through samples of known material...
A thermo chromic materials named Salicylaldehyde ethanolamine Schiff base was synthesized with ethanolamine and salicylaldehayde derivative in the medium of ethanol, and was characterized by means of UV-Vis absorption, GCMS. The reaction kinetics of Schiff base production was investigated through UV-Vis absorption spectra, and also the thermochromism of Schiff Base Condensed from ethanolamine and...
Solar cells based on II–VI semiconductors are among the leading candidates for low-cost photovoltaic conversion of solar energy due to their high absorption coefficients and therefore the low material consumption for their production. To understand the basics of photovoltaic (PV) cells, several types of simulation software are available. This work reports on the analysis of Zinc Telluride (ZnTe) thin...
Terahertz (THz) spectroscopy is a powerful technique for identification of dangerous materials like drugs and explosives, especially when hidden under optically opaque concealments. Multiple-reflections within such sample systems lead to additional spectral features which could be misinterpreted as artificial material absorption bands. We show that combinations of different chemometric tools help...
The aim of this study is to investigate the impact of the variation of the physical and electrical parameters of a biphasic composite structure on the electromagnetic field transmission, reflection and absorption coefficients. These coefficients are the base for the evaluation of the shielding effectiveness of such materials. A systematic analysis is carried out and the relations between the composite...
We examine the enhancement effects of switching from silver (Ag) nanoparticles (NPs)to nonresonant aluminium (Al) NPs on light absorption in a-Si solar cells. Al nanocubes on ITO spacer increase absorbed power by 24.3% over a cell with Ag nanocubes and 19.4% over a bare cell.
Using absorption materials to reduce RF heating during MRI procedure is studied in this paper. Materials with different electromagnetic absorption characteristics are used to alter the EM and current distributions on the device. Consequently, the RF induced heating behaviors of external fixation devices can be reduced. Numerical and experimental studies are provided to demonstrate the potentials of...
Metrological electromagnetic characterization of materials in the THz frequency range (refractive index and absorption coefficient) is presented in this paper. Our algorithmic models allow us to achieve these characterizations on both monolayer and multilayer materials.
We observe large enhancement of nondegenerate two-photon absorption compared to the degenerate case. We use this to sensitively detect and image mid-IR light with simple uncooled photodiodes. The enhancement also applies to 2-photon emission and gain.
Chlorobenzene, o-dichlorobenzene, and 1,2,4-trichlorobenzene were used as solvents to fabricate active layers of poly(3-hexylthiophene) (P3HT) and fullerene derivatives for polymer solar cells. The fullerene derivatives employed in this study include indene-C60 bisadduct (ICBA) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The microstructural features of P3HT:ICBA and P3HT:PCBM thin films...
In order to elucidate the third-order nonlinear optical (NLO) phenomena of the styrylquinolinium dye (1), the nonlinear absorption parameter (ß) and third-order susceptibility (χ(3)) have been measured using the Z-scan measurements. The one-photon absorption (OPA) and two-photon absorption (TPA) characterizations have been determined by configuration interaction (CI) and time-dependent Hartree-Fock...
THz optical constants were measured for layered clay minerals with different chemical compositions (kaolinite, hectorite and montmorillonite). Corresponding hybrid materials were prepared after chemical modification of parent clays with intercalation (using e.g. alkylamines or amino acids). The THz-TDS spectra showed clearly successful chemical modification of used clay minerals. This can be useful...
In this paper, we apply a recently developed approximation for the full many-body problem of light emission from semiconductors to describe the luminescence of mid infrared dilute nitride materials.
Graphene, a 2D carbon sheet with a honeycomb lattice, is a two-dimensional material with outstanding thermal, mechanical, electronic and optical properties. In particular, graphene is a gapless material with high mobility that exhibits remarkably high absorption values (∼2.3%) for the visible and near-infrared wavelengths. In this paper, we will illustrate some applications of graphene photonics and...
Novel electrical and optical properties of two dimensional (2D) semiconductors highlight their potential applications in optoelectronic devices. Here we report on our experimental investigation into the charge transport and exciton dynamics in some semiconducting 2D crystals such as MoS2 and WSe2.
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