<abstract><title style='display:none'>Abstract</title>Zinc aluminate (ZnAl2O4) doped with rare earth metal ions has been investigated most frequently because of the unique luminescent properties resulting from its stability and high emission quantum yields. The present work is devoted to calculate the Judd-Ofelt parameters (Ω2, Ω4 and Ω6) of the trivalent europium doped in ZnAl2O4 spinel, the quality factor (Q) and the branching ratio (<italic>β</italic>).</abstract>

Calculation Of The Judd - Ofelt Parameters Of The ZnAl2O4: Eu3+

<abstract><title style='display:none'>Abstract</title>Fluorides-based perovskites are currently the typical materials being used in spintronic devices, optoelectronic and magneto-resistance colossal fields. Solar cells made of Fluoro-perovskite hold much promise for the future of solar energy. The electronic structure and magnetic properties of KFeF3, KCoF3 and KNiF3 Fluorides are studied using ab initio Calculation. We have analysed the structural phases, total and partial electronic densities and band structures within the (DFT) vs the DFT+U description. We show the Electro-Magnetic Behavior using L(S)DA+U vs L(S)DA in a comparative study of cation effect by integrating three types of crystal structures (Cubic (Pm-3m), Four-Layered Hexagonal (P6/mmc), and Orthorhombic (Pnma)). Equilibrium lattices agree very well with experimental and theoretical data. Magnetic moment of each phase is discussed. The obtained results confirmed that the three crystal structures invested here exhibit Ferromagnetic (FM) behavior. The introduction of the Hubbard’s parameter U increases lattice parameters and magnetic moment. We deduce that the second cation plays an important role in the magnetic effects. L(S)DA+U show correctly that KFeF3, KCoF3 and KNiF3 are insulators.</abstract>

Electro-Magnetic Behavior of Highly Correlated Fluorides KFeF3, KCoF3 and KNiF3: A Comparative <italic>Ab-initio</italic> Study of Cation Effect

<abstract><title style='display:none'>Abstract</title>In this paper, we performed a first principle study for new half-Heusler LiSrX(X= N, P, and As) working with WIEN2k code in the frame work of the density functional theory, and the Boltzmann theory. We estimated the exchange-correlation potential by the generalized gradient approximation (GGA). Energetically, the three compounds show a high stability in structure type2, we notice that the lattice constant increased while bulk modulus decreased in replacing the ions of size increasing. Based on our calculations, LiSrN, LiSrP, and LiSrAs compounds are mechanically stable, and show semiconductor nature with indirect band gaps of 1.21, 1.75 for LiSrN and LiSrAs, and direct band gap of 1.94 eV for LiSrP. The thermoelectric properties are calculated for LiSrX (X=N, P, and As) and they found a high power factor for the p-type doping concentration.</abstract>

Electronic and Thermoelectric Properties in Li-Based Half-Heusler Compounds: A First Principle Study

<abstract>
<title style='display:none'>Abstract</title>
The present work aims to investigate the structural and thermodynamic properties of homogenous tetragonal Cu2ZnSnS4 (CZTS) absorber material in Kesterite phase using first-principle calculations based on density functional theory (DFT). This approach requires only knowledge of the atomic species and crystal structure to predict several physical properties of materials. The Quantum Espresso code within the Ultra Soft pseudopotentials (USPP) and the local density approximation (LDA) were used in the calculations. Equilibrium unit cell volumes, bulk modulus, as well as the pressure derivative of the bulk modulus are predicted. In addition, several thermodynamic properties, especially: the Debye’s vibrational energy, the vibrational free energy, the vibrational entropy, and the constant volume heat capacity at different temperatures <italic>T</italic> of Cu2ZnSnS4 material are calculated and discussed. Our study shows that the vibrational energy, the entropy and the constant volume heat capacity increase with increasing temperature, while the vibrational free energy decreases monotonously with the increase of temperature.
</abstract>

Structural and Thermodynamic Properties oF Cu2ZnSnS4 Material: Theoretical Prediction

<abstract><title style='display:none'>Abstract</title>The need for adequate solar radiation is ever increasing for various applications. However there is an inadequate data of solar radiation in many countries due to the cost of instrument set up. Hence this study investigates two models for estimating solar radiation from routinely measured meteorological parameters. The data were obtained from the International Institute of Tropical Agriculture, Ibadan. The regression coefficients of the quadratic models were determined and used to estimate the global solar radiation for both forward and backward predictions. Their predictive accuracies were compared with four other models and the measured values using standard statistical error indicators. The results showed for forward as compared to backward predictions in bracket root mean square errors 1.2 (1.1); mean bias errors 1.1 (0.8) and mean percentage errors -4.8% (-2.9%) while for backward prediction 1.9 (1.7), 1.7 (1.4) and 7.9% (2.2%) measured in KJm−2day−1 respectively. A positive error value shows an over estimation while a negative value shows an under estimation. The models are versatile for estimating global solar radiation at the horizontal surface, fixing missing data and correcting outliers.</abstract>

Estimating Global Solar Radiation from Routine Meteorological Parameters Over a Tropical City (7.23°N; 3.52°E) Using Quadratic Models

<abstract><title style='display:none'>Abstract</title>Cuprous oxide with different morphologies (3D hierarchical structure consisting of the micrometer dendritic rods and the porous truncated octahedrons) has been successfully synthesized via a facile one-step hydrothermal method using copper (II) acetate and ethyl cellulose as reactants. The p-type dye-sensitized solar cell based on the micrometer porous structure exhibits approximately 15% increase in JSC and VOC than 3D hierarchical structure. This enhancement could be explained by the high dye loading capacity of this porous structure and lowering the recombination process at the oxide/dye/electrolyte interface.</abstract>

Effect of Cu2O Morphology on Photovoltaic Performance of P-Type Dye-Sensitized Solar Cells

<abstract>
<title style='display:none'>Abstract</title>
The effect of high pressures on the mechanical and thermal properties up to phase transition pressure for cubic rock-salt cadmium oxide (CdO) semiconducting compound is presented in this research. The calculations are based on the equation of state (EOS) parameters measured at ambient conditions reported in the literature. The approach used here was previously applied successfully for other materials. Our study shows that the parameters reflect the rigidity of the semiconductor and the melting temperature increases with increasing pressure, while some other parameters decrease gradually for our material of interest. A comparative analysis of some quantities for CdO compound under high pressure was done. Similar behaviors were observed in the literature for particular materials with particular structures. Furthermore, we calculated both the fracture toughness and the fracture surface energy, which are at around 1.23 MPa.m1/2 and 5.14 J.m−2, respectively.
</abstract>

Mechanical and Thermal Behavior of Semiconducting Cadmium Oxide at High-Pressure

<abstract>
<title style='display:none'>Abstract</title>
In this present work, we will study the physical properties of a brand new semiconductor material. the structural stability and the electronic properties of Scandium Arsenide (ScAs) and Aluminum Arsenide (AlAs) semiconductors as well as their ternary alloys (AlxSc1-xAs, 0≤ <italic>x</italic>≤1) in both rocksalt RS (B1) and zincblende ZB (B3). Calculations on both structures are done the method (FPLMTO, <italic>Full Potential Linear Muffin Tin</italic>). In the framework of density functional theory (DFT). The exchange-correlation potential was calculated using both the <italic>Local Density Approximation</italic> and the <italic>Generalized Gradient Approximation</italic>.
The structural parameters of AlxSc1-xAs alloys, such as the lattice constant, the bulk module and its derivative are calculated. The lattice parameter deviates slightly from the line of <italic>Vegard’s Law</italic> in B3 structure, while the deviation was more pronounced in B1 structure.
The calculations showed a phase transition from the ZnS phase (B3) to the RS phase (B1) at pressures (7, 10.5, 14.0 and 23.0 Gpa in LDA and (10.0, 12.5, 10.0 and 25.0 GPa) in GGA for x = 0.25, 0.50, 0.75 and 1.00) respectively.The calculated electronic properties showed that in phase B1, there exists an energy band (X-X) with a direct gap at x = 0.00. On the other hand, in phase B3, there are two kinds of energy bands, of direct gap (Γ-Γ) for x = 0.25, 075 and 1.00, the second band is of indirect gap (Γ-X) for x = 0.50, suggesting the possibility to be used in the long wavelength optoelectronic applications. The deviation of The calculated band gap deviation from linear behavior was significant in both structures. The AlxSc1-xAs alloys were found to be semiconducting at x=0 in the B1 phase and at x=0.25, 0.50, 0.75 and 1 in the B3 phase. Concerning calculations of the optical properties of the ternary AlxSc1-xAs alloy at concentrations x= 0.25, 0.50 and 0.75 in the ZnS (B3) phase, and from our bibliographic research we are sure that no reference exists in the literature. Our work can therefore be used as a reference for future research. Our simulation results are in good agreement with those obtained theoretically and experimentally.
</abstract>

Study of the Phase Transition and Physical Properties of AlAs, ScAs and AlxSc1-XAs Compounds by the FP-LMTO Method

<abstract><title style='display:none'>Abstract</title>
In this paper, we have performed first-principles calculations on the structural and optoelectronic properties of Cu2GeS3 compound in the Cc and Imm2 structures. We have applied the linear augmented plane wave method for all electrons (FPLAPW), which is based on density functional theory (DFT) by using the local density approximation (LDA) and the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA). In addition, the modified Becke Johnson Tran and Blaha potential (TB-mBJ) combined with the Hubbard potential (U), which successfully corrects the band gap problem.
The structural properties such as lattice parameter, compressibility modulus and its derivative for Cu2GeS3-Cc are in good agreement with the available data, but for Cu2GeS3-Imm2 there is no research work in the literature. The band structure results show that the Cu2GeS3-Cc compound has a direct gap (Γ-Γ) and that Cu2GeS3-Imm2 is a metal.
The optical properties are calculated by determining the real and imaginary parts of the dielectric function ε(ω), the absorption coefficient, the reflectivity and the refractive index. These results indicate that these alloys are very useful for UV photo catalysis applications.
</abstract>

Structural, Electronic and Optical Properties of Cu2GeS3. A First Principles Study

<abstract><title style='display:none'>Abstract</title>
This work is a comparative study of the effect of two different annealing methods on copper oxide (CuO) nanoparticle properties obtained previously by direct precipitation method. The prepared samples were annealed in air at various temperatures (300, 400, 500°C) for 1 hour. Then they were characterized by employing scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible, and Fourier Transform Infrared (FT-IR) spectroscopy. The main results revealed an increase in the grain size in both methods as the annealing temperature increases. It reaches 30.93 nm in RTA and 26.75 nm in STA at 500°C. XRD spectra showed, in the case of RTA at 500 °C, a significant decrease in the intensity corresponding to the (002) and (111) orientations. This result indicated that beyond 400 °C, one hour of RTA is not suitable for enhancing CuO nanoparticle crystallinity compared to STA. The optical analysis demonstrated that the energy of the optical band gap in STA is higher than that in RTA. It reaches 2,88 eV at 500°C using RTA which is close to the gap value of CuO in the range of 1.8–2.8 eV. FT-IR results showed, for both methods, the presence of characteristic peaks of the Cu-O bonds in the monoclinic CuO structure without any trace of Cu2O structure. Nevertheless, samples exposed to RTA for one hour are more susceptible to absorbing species of C=O bond (C=O bond is due to the atmospheric CO2 absorption and the presence of organic impurities from the synthesis process) than those of STA. Hence, RTA at 500 °C is far from producing CuO nanoparticles with preferred characteristics; it needs further research to examine the effect of higher temperature by controlling the annealing time.
</abstract>

Effect of Rapid Thermal Annealing on CuO Nanoparticles

<abstract><title style='display:none'>Abstract</title>
The size and shape of solar box cooker is determined by the volume of the vessel, which in turn depends on the number of family members. The primary objective of this study is to overcome the obstacles inhibiting researchers from crafting solar box cookers tailored to their specific research needs, as well as hindrances preventing manufacturers from effectively bringing them to market. This experimental study aims to identify two novel optimal volumetric efficiencies (VE1 and VE2) to minimize cooking time. To achieve this goal, we employed two identical solar box cookers made from the same materials and four vessels. The results obtained clearly show that the absorber temperature reached a maximum value of 124.9 °C and the boiling time was the shortest 02h50 when the first volumetric efficiency VE1 had the least value of 6.2% and the second volumetric efficiency VE2 had the greatest value of 100%. It is concluded that these two volumetric efficiencies could serve as benchmark parameters for future research, providing a standardized reference for developing solar box cookers of varied shapes and sizes under the same climatic conditions.
</abstract>

Experimental Investigation on Two Novel Standard Parameters to Improve the Performance of Solar Box Cookers

<abstract>
<title style='display:none'>Abstract</title>
In today’s world of industrial progress, pollution is a major concern, especially water pollution. Considered a real danger to mankind, this article looks at the treatment of water contaminated by textile dyes, which has become a danger to humans and the environment. As an example, we have chosen the green dye FB (anionic type) which is found in the rejects of a textile factory ENADITEX in the industrial zone of the wilaya of ORAN - ALGERIA, this dye is among the most used in the textile industry. The method adopted for dye removal is adsorption by natural perlite. The Experimental results showed that adsorption of the green dye FB on the porous solid studied: natural perlite, gave a removal rate of 87.51% for 60 minutes. The adsorption isotherms of the adsorbent/adsorbate systems studied are satisfactorily described by the two mathematical models Freundlich and Temkin. All the results obtained show that the adsorption kinetics of the green dye FB by the solid material is well described by the second-order model. The adsorption reaction is a physisorption, as the thermodynamic study demonstrated.
</abstract>

Textile Dye Adsorption By Natural Perlite

<abstract><title style='display:none'>Abstract</title> We consider an application of the tetrad formalism introduced by Cardall et al. [Phys. Rev. D 88 (2013) 023011] to the problem of a rigidly rotating relativistic gas in thermal equilibrium and discuss the possible applications of this formalism to rel- ativistic lattice Boltzmann simulations. We present in detail the transformation to the comoving frame, the choice of tetrad, as well as the explicit calculation and analysis of the components of the equilibrium particle ow four-vector and of the equilibrium stress-energy tensor.</abstract>

Relativistic Rotating Boltzmann Gas Using the Tetrad Formalism

<abstract>
<title style='display:none'>Abstract</title>
The present work aims to predict the elastic constants and other significant properties of ordered BxAl1-xSb (0 ≤ x ≤ 1) ternary semiconducting alloys. We report the initial results of the elastic stiffness constants, the bulk modulus, the aggregate shear modulus, the Cauchy ratio, the aggregate Young’s modulus, the Born ratio, the isotropy factor, the fracture toughness and the longitudinal, transverse and average sound velocities. The Debye temperature and the melting point were also predicted using two different empirical expressions. Except the Cauchy ratio, which decreases with enhancing boron content x, all other physical quantities of BxAl1-xSb alloys increase gradually and monotonically with increasing of boron concentration x in the range 0-1.
Our obtained data for BSb and AlSb binary semiconducting compounds are discussed and analyzed in comparison with experimental and other theoretical values of the literature. Generally, our data for BSb and AlSb are in good agreement with other results reported previously in literature. Indeed, our obtained value (335.82 K) of the Debye temperature for AlSb compound overestimates the result (328.6 K) reported by Salehi et al. by around 2.03%, while that (1520 K) of the melting point for BSb overestimates the result (1500 K) reported recently by Bioud et al. by around 1.34%. Furthermore, to the best of our knowledge, no theoretical or experimental data were reported in the literature on the elastic constants and other properties for BxAl1-xSb alloys to compare with them.
</abstract>

Theoretical Prediction of Mechanical Properties of BxAl1−xSb Ternary Semiconducting Alloys

<abstract>
<title style='display:none'>Abstract</title>
In this work, an ab-initio calculation is used to investigate the elastic constants and some other mechanical and thermal parameters of tetragonal Cu2ZnSnS4 (CZTS) quaternary semiconducting bulk material in Kesterite (KS) and Stannite (ST) phases. The Quantum Espresso code within the Ultra Soft pseudo potentials (USPP) and the local density approximation (LDA) approach were used in the calculation. Firstly,, studies are started with the prediction of the elastic stiffness constants <italic>Cij</italic> and the normal and shear anisotropy factors. Then some other mechanical moduli, especially the isotropic bulk modulus <italic>B</italic>, the shear modulus <italic>G</italic>, the Young modulus <italic>E</italic>, the Poisson’s ratio <italic>ν</italic>, and the Pugh’s criteria (<italic>G</italic>/<italic>B</italic>) are delivered. The analysis of the mechanical stability criteria at equilibrium shows that our elastic stiffness constants <italic>Cij </italic>of CZTS material obey all the stability conditions. Additionally, some other parameters of the CZTS semiconductor, especially: the Vickers hardness <italic>HV</italic>, the sound velocity, the Debye temperature <italic>θD</italic> and the melting temperature <italic>Tm </italic>were also calculated. The obtained values of the elastic constants <italic>Cij</italic> and other mechanical and thermal parameters agree well with experimental and other theoretical results of the literature. The Debye temperature <italic>θD</italic> of the KS phase was found at around 332.7 K, and that of the stannite phase was found equal to 329.1 K, respectively.
</abstract>

Elastic Constants of Tetragonal Cu2ZnSnS4 Semiconductor: AB-Initio Calculation

<abstract>
<title style='display:none'>Abstract</title>
Recently, the lead-free double perovskite compounds have been evinced to be promising candidate for thermoelectric and optoelectronic technologies. In this paper; we have probed a theoretical works on the different physical properties: Structural, electronic, elastic, optical and thermoelectrical properties of the chalcogenide double perovskites A2GaNbS6 (A=Ca, Sr and Ba) within the instructions of density functional theory. The calculations have incorporated using the full potential linearized augmented plane waves (FP-LAPW) method within gradient generalized approximation (GGA) and the modified Becke-Johnson potential (mBJ) to describe the exchange-correlation potential as embodied in the WIEN2K code. The computed structural results show that the non-magnetic structure state is energetically the most stable structure in the cubic <italic>Fm3̄m</italic> (225) configuration, also the elastic and mechanical properties indicate that A2GaNbS6 (A=Ca, Sr and Ba) have a ductile nature. According to the electronic plots the three compounds have a semiconducting behavior with indirect (pseudo-direct) band gap of 1.21, 1.28 and 1.32 eV. Important optical responses of studied chalcogenide double perovskites are found in the visible and ultraviolet energy ranges. Finally, the thermoelectric effectiveness of the three compounds have been probed by computing parameters like Seebeck coefficient, electrical conductivity, thermal conductivity and figure of merit with semi-classical Boltzmann theory and constant relaxation time approximation as implemented in BoltzTrap code, the obtained results show that the chalcogenide double perovskites could be a good candidate for thermoelectric applications.
</abstract>

Structural, Electronic, Elastic, Mechanical, Optical and Thermoelectric Properties of the Chalcogenide Double Perovskites A2GaNbS6 (A = Ca, Sr and Ba): Insights From Density Functional Theory Calculations

<abstract><title style='display:none'>Abstract</title>An investigation of silicon-based tandem solar cells incorporating Al-doped ZnO (AZO) and Cu2O metal oxides, via two of the most efficient methods of optical modeling, specifically ray tracing and transfer matrix algorithms, was performed. The simulations were conducted based on specialized software, namely Silvaco Atlas and MATLAB, as well as on OPAL2 simulation platform. The optical analysis involved the calculation of the spectral curves for reflectance, absorptance and transmittance for different thicknesses of the thin film layers constituting the cell. It was established the optimum thickness of the AZO layer based on the minimum reflectance and maximum transmittance. Moreover, several materials were investigated in order to determine the optimum buffer layer for the tandem solar cell, based on optical modeling. The optical parameters of the ZnO/Cu2O top subcell were optimized, in order to achieve the highest conversion efficiency of such heterojunction solar cell.</abstract>

Optical Modeling and Simulation of Tandem Metal Oxide Solar Cells

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