Dielectric Energy Loss Research Articles

First-principles study of structural, electronic, optical and thermoelectric properties of rare earth based perovskites XAlO3 (X = Sm, Eu, Gd)

First-principles method based on density functional theory calculations are employed for investigating the electronic, optical and thermoelectric properties of XAlO3 (X = Sm, Eu, Gd) for energy-devices applications. The spin-polarized electronic spectra of XAlO3 depicts their half metallic nature since mere the spin up channel crosses the fermi level. Further, the optical features for instance; the dielectric functions, refractive index, absorption coefficient, extinction coefficient, optical conductivity, reflectivity, and energy loss function are studied which predict that these compounds are supposed to be better materials for the ultraviolet-region based optoelectronic and energy devices. Thermoelectric properties in terms of electrical and thermal conductivity, and figure of merit show higher values of thermoelectric characters which is extremely significant for optoelectronic devices. Interestingly, the positive value of Seebeck coefficient indirectly depict that XAlO3 is a p-type materials.

First-principles calculations to investigate structural, elastic, mechanical, electronic and optical characteristics of RbSrX3(X = Cl, Br)

The inorganic cubic perovskites RbSrCl3 and RbSrBr3 have been studied for structural, phonon, elastic, mechanical, electronic and optical properties using first principles calculations based on Density Functional Theory. The structures are optimized and found stable with lattice constants 5.70 Å and 6.00 Å for RbSrCl3 and RbSrBr3 respectively. The stability is further validated by formation energy and phonon calculations. The bulk modulus, shear modulus, Young’s modulus, Pugh ratio, Poisson ratio, Cauchy pressure and other parameters are calculated using elastic constants to endorse the mechanical stability. The electronic structure revealed that both under study materials are indirect wide band gap material with band gap of 7.74 eV (RbSrCl3) and 6.54eV (RbSrBr3) with TB-mBJ. The density of states are consistent to band structures. The optical parameters such as dielectric constant, refractive index, reflectivity, absorption, optical conductivity and energy loss are calculated in response to incident electromagnetic radiation up to 30eV for their potential use in optoelectronic devices.

First‐principles studies on physical properties for new half‐metallic perovskites AFeO3 (A = Ca, Sr, Ba): Spintronics and energy harvesting applications

AbstractIn this manuscript, structural, electronic, magnetic, and thermoelectric aspects of AFeO3 (A = Ca, Sr, Ba) have been calculated by means of the Full‐Potential Linearized Augmented Plane Wave Method (FP‐LAPW) using spin‐polarized Density Functional Theory (DFT). The calculated structural parameters have been found to be in good resemblance with previously available work. Enthalpy of formation and cohesive energy along with tolerance factor confirms structural stability. Electronic properties by Trans Blaha modified Becke–Johnson potential (TB‐mBJ) suggest metallic behavior in the spin‐up channel and semi‐conducting behavior in the spin‐down channel that supports half‐metallic behavior with mixed covalent and ionic bonding. Density of States (DOS) analysis confirms the major contribution of Fe‐3d‐states in the conduction band and O‐2p states in the valence band. The half‐metallic nature is further confirmed by the integer value of the total magnetic moment. The real and imaginary parts of dielectric functions, optical conductivities, absorption coefficients, reflectivity, and energy loss function have been calculated to evaluate suitability for optical applications. Thermoelectric properties with temperature range 300–900 K against chemical potential including figure of merit, Seebeck coefficient, thermal conductivities, and power factor, were examined using BoltzTraP code. Findings suggest that AFeO3 (A = Ca, Sr, Ba) compounds suitable for spintronic, thermoelectric as well as energy harvesting applications.

Insight into structural stability, electronic, optical and thermoelectric properties of the inverse perovskite Na3SCl compound from first-principles study

In the present work, we give a thorough analysis of the cubic inverse-perovskite Na3SCl's structural, electrical, optical, and thermoelectric properties using the FP-LAPW approach within the context of DFT. PBE-GGA has espoused for exchange-correlation the potential for the evaluation of structural characteristics. A well-known accurate potential for the computation of electronic structures known as TB-mBJ has also been added along with PBE-GGA for the computations of band structures and their density of states. The probe of cohesive energy, formation energy, and elastic aspects demonstrates that the material under study is chemically, and thermodynamically stable. The obtained lattice parameters and other structural data of the investigated Na3SCl are in well agreement with the reported results of similar compounds. A direct band gap of 3.493 eV identified from the band structure for Na3SCl demonstrates the semiconducting character of the examined antiperovskite. Charge density contours analysis reveals that Na3SCl possesses an ionic nature, which is confirmed by electron localization function (ELF) analysis. We additionally assessed optical constants for the Na3SCl, such as the dielectric function, optical reflectivity, refractive index, and electron energy loss, with radiation up to 12 eV. Furthermore, variations in temperature-dependent thermoelectric features in terms of Seebeck coefficient, thermal conductivity, electrical conductivity, power factor, and figure of merit have been determined for the first time using the BoltzTraP code. The perovskite under study has a p-type semiconducting nature, as indicated by the estimated positive Seebeck value, and holes rather than electrons are the predominant charge carriers for conduction. The obtained substantial figure of merit along with the low thermal-to-electrical conductivity ratio for the examined inverse perovskite imply it is suitable for thermoelectric applications in devices. Our examined Na3SCl inverse perovskite offers a fruitful framework for enhancing comprehensive TE efficacy for TE usage and green energy generation.

Modulating opto‐electronic and magnetic responses of Mo‐ and Zn‐adsorbed LiNbO3 (1 1 1) surface for advanced energy harvesting applications: A comprehensive study

AbstractThis study aimed to comprehensively investigate the optoelectronic and magnetic properties of Mo, Zn/LiNbO3 (1 1 1) material. The primary objectives were to understand the potential for manipulating the material's magnetism and to elucidate the origin of spin‐polarized states and magnetic moments, particularly with respect to the unpaired d orbitals of Nb, Mo, and Zn atoms. To achieve these objectives, we employed the Pardew–Burke–Ernzerhof (PBE) method within the Generalized Gradient Approximation (GGA + U) framework. This computational approach allowed us to examine the optoelectronic and magnetic characteristics of the material in detail. Our research yielded several key findings that enhance our understanding of Mo, Zn/LiNbO3 (1 1 1) material. We observed a modest improvement in the material's absorption capacity within the visible spectrum, accompanied by a discernible red‐shift. Notably, our study involved the calculation of the dielectric function and refractive constant of the material, revealing a strong correlation between absorption trends and the dielectric constant. Furthermore, our investigation uncovered that Mo, Zn/LiNbO3 (1 1 1) exhibits distinct conduction and valence bands, with p and d orbitals predominantly contributing to each, respectively. The energy gap of the material falls within a range of 0.30–1.04 eV. A particularly significant finding was the narrower band gap of Mo, Zn/LiNbO3 (1 1 1) material, which can be attributed to the superposition of Mo‐d and Zn‐p orbit energy levels with O‐p orbit energy levels, ultimately forming a covalent bond. Importantly, our research demonstrated the material's heightened optical absorption within the visible spectrum, suggesting its suitability for various photonic and optoelectronic applications. Additionally, we calculated a wide range of optical characteristics, including the dielectric function, absorption coefficient, energy loss, reflectivity, refractive index, extinction coefficient, and optical conductivity, providing a comprehensive assessment of the material's optical properties.

FIRST-PRINCIPLES CALCULATION OF STRUCTURAL, ELECTRONIC, AND OPTICAL PROPERTIES OF InP1-XSbX USING WC-mBJ FOR NANOSCALE IR APPLICATIONS

The structural, electronic, and optical characteristics of cubic InP<sub>1-x</sub>Sb<sub>x</sub>(x = 0, 0.25, 0.50, 0.75, 1) ternary alloys were explored using the full-potential linearized augmented plane wave density functional theory approach. The total energy vs. volume optimization, lattice constants, and density of states were investigated for InP<sub>1-x</sub>Sb<sub>x</sub> alloys using exchange correlation function Wu-Cohen generalized gradient approximation (WC-GGA), available with the WIEN2k code. Band structure of the alloys was calculated using TB-mBJ functional to achieve a higher bandgap accuracy. The results of the mBJ experiment are in close agreement to those of the other experimental studies when compared to WC-GGA. Dielectric function and energy loss function were calculated in order to explore optical properties of the alloys. It was noticed that the estimated lattice parameters exhibit reduction when the Sb content is increased. Furthermore, the compositional dependency of the structural, electronic, and optical properties were also reported. For the InP<sub>1-x</sub>Sb<sub>x</sub> alloys, a band gap of less than 1.6 eVwere observed, making it suitable for usage in infrared optoelectronics devices.

First-principles study of electronic, optical, magnetic, and thermoelectric properties of novel Sr2UXO6 (X = Mn, Zn) double perovskites

Based on Density Functional Theory, the first-principles investigation is carried out to calculate the optoelectronic, magnetic, and thermoelectric transport properties of novel Sr2UXO6 (X = Mn, Zn) double perovskites in their monoclinic structural phase. The electronic band structures and DOS analysis investigations suggest that these materials have a semiconducting nature. To investigate the magnetic behavior spin-polarized calculations have been carried out. The magnetic studies predict the antiferromagnetic (AFM) nature of Sr2UMnO6 and the non-magnetic (NM) nature of Sr2UZnO6. The electrical conductivity analysis demonstrated semiconducting behavior for both materials, with both materials exhibiting n-type conductivity. The Seebeck coefficient indicated the shift in carrier behavior, while thermal conductivity revealed distinct temperature-dependent trends. These results contribute to understanding and optimizing the thermoelectric performance of these materials for energy conversion applications. The optical parameters including both the real and the imaginary part of the complex dielectric function, absorption coefficient, refractive index, energy loss, and reflectivity in the energy 0–14 eV have been calculated and discussed. The optical results show that the materials demonstrate great potential for applications in optoelectronics due to their notable energy absorption characteristics.

The quest for optimal photovoltaics: A theoretical exploration of quasi-one-dimensional tin based chalcogenides XSnS[formula omitted] (X=Ba, Sr)

Structural, mechanical, electronic, and optical properties of alkaline metals (Ba, Sr) tin chalcogenide were investigated by the first principles method based on density functional theory (DFT) implemented in the WEIN2K program. The study found that both materials exhibit a quasi-one-dimensional nature along the b-axis, and the optimized structure agrees with the available experimental data. Mechanical properties revealed that both materials are mechanically stable, exhibit ductility, and have significant anisotropy. BaSnS3 and SrSnS3 exhibit an indirect band gap with the values of 1.55 eV and 1.39 eV, respectively. Which is favorable for photovoltaic solar cell absorber materials. Like many ternary metal chalcogenides, XSnS3 compounds show significant anisotropy in the optical properties due to their quasi-one-dimensional structure. This work determined the degree of optical anisotropy of XSnS3 in terms of the dielectric function, refractive index, optical absorption, reflectivity, optical extinction, birefringence, and energy loss function. The results indicate that BaSnS3 and SrSnS3 materials possess notable optical anisotropy and a high absorption coefficient (α≈106 cm−1), low reflectivity and energy loss function within the visible and ultraviolet energy range. It indicates their potential for use in a range of applications, such as sensors, optoelectronics, and photovoltaic solar cell absorber materials.

Physical properties of Be-based fluoroperovskite compounds XBeF3 (X = K, Rb): a first-principles study

In this study, we used the ab-initio computational tools as implemented in the CASTEP code to explore the effects of pressure on the structural, elastic, electronic, thermodynamic and optical properties of the fluoroperovskite compounds XBeF3 (X = K, Rb) based on Being. Exchange–correlation interactions were modeled using the GGA-PBEsol functional. The ground state of the title materials was characterized by calculating the optimized lattice parameter, the bulk modulus B and its pressure derivative, and the Goldsmith tolerance factor. These materials exhibit structural stability in the cubic structure even when subjected to significant pressure levels, extending up to 18 GPa. The analysis of numerical assessments of single-crystal elastic constants (Cij ), polycrystalline elastic moduli, namely shear modulus (G), Young’s modulus and Poisson’s ratio, as well as the anisotropy factor (A), highlights the mechanical stability, elastic anisotropy and ductility of considered the compounds. The thermodynamic properties of these materials were studied through the Debye quasi-harmonic model. Analysis of energy band structures and density of states spectra shows that XBeF3 (X = K, Rb) is insulating in nature, with band gaps of 7.99 and 7.26 eV, respectively. Additionally, we calculated the linear optical spectra, including dielectric function, absorption coefficient, refractive index, optical reflectivity, and energy loss function. Based on the results obtained, these materials could be used in various optoelectronic devices operating in the UV spectrum and in energy storage devices.

Investigating Electronic, Optical, Thermodynamic, and Thermoelectric Properties of SrO and SrO2 Phases: A Density Functional Theory Approach.

The significance of strontium oxide (SrO) and strontium peroxide (SrO2) is currently being investigated as one of the countless potential uses for green energy. However, few studies have examined the distinctive properties of several phases of SrO and SrO2. In order to fill this research gap, we have conducted a study on their various properties through "density functional theory (DFT)" under ideal conditions. This includes the study of electronic, optical, thermodynamic, and thermoelectric properties of the above-mentioned materials. For this study, the "Quantum Espresso" tool in DFT using Perdew-Burke-Ernzerhof-generalized-gradient approximation (PBE-GGA) as the exchange-correlation functional and "Optimized Norm-Conserving Vanderbilt (ONCV)" as the pseudopotential has been used. The face-centered cubic (FCC), body-centered cubic (BCC), hexagonal-1, and hexagonal-2 phases of SrO and the tetragonal and orthorhombic phases of SrO2 have been selected for the aforesaid study, for which some structural information has already been available. During this study, the energy band gap as an electronic property; the dielectric constant, refractive index, absorption coefficient, reflectivity, and energy loss function as optical properties; entropy, heat capacity, Debye temperature, and Debye sound velocity as thermodynamic properties; and the Seebeck coefficient, thermal conductivity, electrical conductivity, and figure of merit as thermoelectric properties have been investigated. In addition, phonon dispersion curves and formation energies have been used to confirm the dynamical stability and thermodynamic stability, respectively, for all of the materials mentioned above. The curve showed that the FCC, hexagonal-1, and hexagonal-2 phases of "SrO" are dynamically stable. These materials have good optoelectronic properties and can be used in ultraviolet sensors due to their intermediate band gap and highest material response in the ultraviolet range. In terms of thermoelectric property, the maximum value of "figure of merit" for the above material has been achieved up to 0.5. Satisfactory agreement has been found between the current findings and the known theoretical and experimental findings.

In-depth analysis of ternary NaCuX (X = Se and Te) chalcogenides: Bridging structural elastic, electronic, and optical properties

This study employs density functional theory (DFT) using the full potential linearized augmented plane wave plus local orbital (FP-LAPW+1o) approach to investigate the structural, elastic, electronic, and optical properties of NaCuX (X = Se and Te) compounds. Additionally, the modified Becke-Johanson (TB-mBJ) potential is applied to ensure accurate band gap results. Both compounds exhibit semiconducting behavior with a direct band gap at the Γ point. The computed elastic constants confirm mechanical stability for NaCuSe and NaCuTe, as evidenced by their respective bulk modulus, Young modulus, shear modulus, Poisson's ratio, B/G ratio, and elastic anisotropy. The materials display ductile characteristics, indicated by their B/G ratio and Poisson's ratio. The Debye temperature (θD) reveals that NaCuSe possesses the highest thermal conductivity. A decrease in θD is observed from NaCuSe to NaCuTe due to declining elastic constants. Additionally, anisotropy in acoustic velocities is assessed and discussed. The study's equilibrium structural properties align well with experimental data. Optical properties, including frequency-dependent dielectric function, refractive index, extinction coefficient, absorption coefficient, reflectivity, and energy loss function, are calculated and comprehensively analyzed.

Computational insight into the fundamental physical properties of ternary ABCl3 chloroperovskites compounds using the DFT approach

In this research, the ternary non-centrosymmetric chloroperovskites compounds of the form ABCl3 (A = Rb and B = Be, Mg) are investigated extensively to predict the structural, mechanical, and optoelectronic properties with DFT incorporated in WIEN2K code. The crystalline structure of interested chloroperovskites is identified to be cubic, non-centrosymmetric, and stable. The elastic constants Cij, bulk modulus, criteria of Pugh ratio, and the Born criteria confirm the ductility and mechanical stability of ternary RbBeCl3 and RbMgCl3 materials. Electronic properties such as the band structures and density of states are examined with the most widely recognized TB-mBJ potential approximation. RbBeCl3 shows semiconducting behaviour with an indirect wide band gap energy of 3.74 eV from R-Γ symmetries points, while RbMgCl3 is assumed to be an insulator that possesses indirect wide band gap energy of 6.28 eV from R-Γ. It is identified that the ABCl3 (A = Rb and B = Be, Mg) non-centrosymmetric compounds change the behavior from wide band gap semiconductors to perfect insulators when the ‘B’ site in ABCl3 varies from ‘Be’ to ‘Mg’ element. In the electromagnetic range from 0 eV to 40 eV of incident photons energy, several parameters in optical properties that includes the dielectric function, refractive index, absorption coefficient, optical conductivity, extinction coefficient, and energy loss function are investigated for the quest of potential applications of interested non-centrosymmetric cubic systems in modern photovoltaic technologies. These outcomes may add inclusive understanding within ultraviolet ranges for photovoltaic applications.

Study of optical, thermoelectric and mechanical properties of cerium based perovskites CePO3 (P = be, Ca, Mg)

The electronic, optical, thermoelectric, and mechanical characteristics of CePO3 (P=Be, Mg and Ca) perovskites have been investigated by employing density functional theory. The volume versus energy optimized graphs show minimum ground states energy. The studied perovskites have a cubic structure with a space group (221_Pm3‾m). The band structures of CePO3 (P = Be, Mg, Ca) show the semiconductor nature. The narrow band gaps 0.76/0.61/0.1 eV for CeBeO3/CeMgO3/CeCaO3 make them promising for infrared light operating devices. The optical properties of CePO3 (P = Be, Mg and Ca) are analyzed by dielectric constants, refraction, optical conductivity, energy loss, refractive index and reflectivity. The thermoelectric characteristics are investigated by Boltztrap code. Finally, the mechanical characteristics are clarified by elastic constants (C11, C12, C44) and elastic moduli. The Possion and Pugh ratios are addressed ductile nature of studied materials. The comprehensive analysis of studied materials may be helpful for experimental researchers for the fabrication of optoelectronic and thermoelectric devices.

Structural, electronic, optical, and thermoelectric studies on Zintl SrCd2Pn2 (Pn=P/As) compounds for solar cell applications: A First Principle Approach

Strontium-based Zintl materials SrCd2Pn2 (Pn = P/As) have been investigated here for their thermoelectric applications. The fundamental structural, optoelectronics and transport properties of Zintl SrCd2Pn2 (Pn = P/As) compounds were determined by employing the full potential linearized augmented plane wave approach (FP-LAPW). The formation and dynamical stabilities have been confirmed by formation energy and phonon dispersion studies. The established band structures using the modified Becke–Johnson potential (mBJ) reveals a direct energy bandgap (Eg) of 1.58 eV and 1.15 eV for SrCd2P2 and SrCd2As2, respectively. The DOS spectra disclose Pn(P/As) states are present in the valence band while Sr states are present in the conduction band. The optical features of the compounds were analyzed from dielectric constants, refractive index, extinction coefficient, and energy loss function against photon energy (eV) up to 30 eV. We observed that the material absorption by falling the light is fascinating in the visible region, revealing a viable choice for optoelectronics application. We evaluated transport properties like the Seebeck coefficient, electrical and thermal conductivity, power factor versus temperature, carrier concentration, and chemical potential with the classical Boltzmann transport theory. The computed Seebeck coefficients for SrCd2P2 and SrCd2As2 are found to be equal to 242μVK−1 and 239 μVK−1 at 300 K and 255 μVK−1, 257 μVK−1at 1200 K. The highest values of the power factor obtained at 1200 K are 5.88 × 1011 W/K2m.s, 5.21 × 1011W/K2m.s for SrCd2P2 and SrCd2As2, respectively. The tremendous optoelectronic characteristic and outstanding power factor values predicted this group could be favorable for uses in solar and thermoelectric uses.

A first principle investigations for electronic, optical and mechanical response of novel Ba2AgIO6 perovskite

The double perovskite compound, Ba2AgIO6 has been studied through density functional theory to explore its mechanical, electronic, and optical properties. To examine the mechanical stability of the compound, elastic constants, Young’s modulus, bulk modulus and shear modulus have been computed. The computed electronic properties show the direct band gap semiconducting nature of the studied perovskite compound. The optical properties of Ba2AgIO6 are interpreted with the help of energy dependent dielectric tensor, absorption, reflection, refraction, and energy loss spectra. From the present study it is found that Ba2AgIO6 is suitable for the various photovoltaic and optoelectronic applications.

Polarization-independent isotropic metasurface with high refractive index, low reflectance, and high transmittance in the 0.3-THz band

Abstract Metasurfaces substituted for naturally occurring materials make it possible to develop flat optics manipulating terahertz waves. However, the control of unprecedented material properties with metasurfaces frequently produces anisotropic material properties and has yet to be commonly adopted because of the limitation of functionalities as optical components. Here, we demonstrate an isotropic metasurface with polarization-independent material properties with the extremely high refractive index of 14.0 + j0.49, low reflectance of 1.0 %, and high transmittance of 86.9 % at 0.31 THz. Measurements by terahertz time-domain spectroscopy (THz-TDS) verify that the fabricated metasurface with a high refractive index, low reflectance, and high transmittance works for terahertz waves with any polarization direction and results in the unprecedented material characteristics with polarization independence. The relative permittivity and relative permeability are 13.9 – j1.4 and 13.8 + j2.3, respectively. The sum of the dielectric and magnetic energy losses must also be considered to verify the conservation of energy for metasurfaces. The sum of the dielectric and magnetic energy losses is very close to positive values and the conservation of energy is largely satisfied. The proposed metasurface would offer optical components with attractive functionalities such as wavefront control, directivity enhancement, and optical vortices for 6G communications.

DFT Insights into Noble Gold-Based Compound Li5AuP2: Effect of Pressure on Physical Properties.

In this study, the Li5AuP2 compound is investigated in detail due to the unique chemical properties of gold that are different from other metals. Pressure is applied to the compound from 0 to 25 GPa to reveal its structural, mechanical, electronic, and dynamical properties using density functional theory (DFT). Within this pressure range, the compound is optimized with a tetragonal crystal structure, making it mechanically and dynamically stable above 18 GPa and resulting in an increment of bulk, shear, and Young's moduli of Li5AuP2. Pressure application, furthermore, changes the brittle or ductile nature of the compound. The anisotropic elastic and sound wave velocities are visualized in three dimensions. The thermal properties of the Li5AuP2 compound are obtained, including enthalpy, free energy, entropy × T, heat capacity, and Debye temperature. The electronic properties of the Li5AuP2 compound are studied using the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) functionals. The pressure increment is found to result in higher band gap values. The Mulliken and bond overlap populations are also determined to reveal the chemical nature of this compound. The optical properties, such as dielectric functions, refractive index, and energy loss function of the Li5AuP2 compound, are established in detail. To our knowledge, this is the first attempt to study this compound in such detail, thus, making the results obtained here beneficial for future studies related to the chemistry of gold.

High-Entropy Spinel Ferrites with Broadband Wave Absorption Synthesized by Simple Solid-Phase Reaction.

In this work, high-entropy (HE) spinel ferrites of (FeCoNiCrM)xOy (M = Zn, Cu, and Mn) (named as HEO-Zn, HEO-Cu, and HEO-Mn, respectively) were synthesized by a simple solid-phase reaction. The as-prepared ferrite powders possess a uniform distribution of chemical components and homogeneous three-dimensional (3D) porous structures, which have a pore size ranging from tens to hundreds of nanometers. All three HE spinel ferrites exhibited ultrahigh structural thermostability at high temperatures even up to 800 °C. What is more, these spinel ferrites showed considerable minimum reflection loss (RLmin) and significantly enhanced effective absorption bandwidth (EAB). The RLmin and EAB values of HEO-Zn and HEO-Mn are about -27.8 dB at 15.7 GHz, 6.8 GHz, and -25.5 dB at 12.9 GHz, 6.9 GHz, with the matched thickness of 8.6 and 9.8 mm, respectively. Especially, the RLmin of HEO-Cu is -27.3 dB at 13.3 GHz with a matched thickness of 9.1 mm, and the EAB reaches about 7.5 GHz (10.5-18.0 GHz), which covers almost the whole X-band range. The superior absorbing properties are mainly attributed to the dielectric energy loss involving interface polarization and dipolar polarization, the magnetic energy loss referring to eddy current and natural resonance loss, and the specific functions of 3D porous structure, indicating a potential application prospect of the HE spinel ferrites as EM absorbing materials.

Linear and Nonlinear Optical Properties of PVA:SA Blend Reinforced by TiO2 Nanoparticles Prepared by Flower Extract of Aloe Vera for Optoelectronic Applications

In this study, a polyvinyl alcohol–sodium alginate blend, PVA:SA 3:1 (w:w), was doped with different contents of TiO2 nanoparticles (NPs) prepared by aloe vera leaf extract to form the investigated nanocomposites. The nonlinear parameters of third-order susceptibility (χ(3)) and refractive index (n2) were detected by using UV-Vis spectroscopy and Z-scan techniques. Some different optical parameters were also determined, including the refractive index (n), optical dielectric parameters, volume and surface energy loss functions, and some others. The best solar skin protection factor (SSPF) was investigated by 5 wt.% of TiO2 NPs doped in PVA:SA 3:1, which was about 84.6% compared to the corresponding value of the host blend (41%). The studied nanocomposites were examined for their utility in the optical limiting of CUT-OFF laser filters utilizing a continuous He-Ne laser working at 632.2 nm. As a result, our finding demonstrated that TiO2 NPs doped in the host blend of PVA:SA positively influences a laser light blocking for the investigated laser source. Using the estimated gap energies values, different models were used to deduce theoretical values of the linear refractive index (n). The presence of Ti peaks in the EDX spectrum confirmed the doping of TiO2 NPs in the nanocomposites. SEM showed that the TiO2 NPs are homogeneously dispersed through the host blend with some agglomerates. XRD spectra showed that the values of the lattice strain εstr. detected at 2ϴ = 19.78° are 0.058, 0.055, and 0.060, corresponding to 1, 3, and 5 wt.% of TiO2 NPs doped in the PVA:SA blend.

In-doped Aluminum antimonide alloy for optoelectronic applications

First-Principles calculations are made to study the structural electronic and optical properties for indium doped aluminum antimonide. The most appropriate method of density functional theory (DFT) naming Full Potential Linearized Augmented Plane Wave (FP-LAPW) is used. The structural properties like Lattice constant (a), pressure derivative, bulk modulus (B) examined by Local density approximation (LDA) along with generalized gradient approximation (GGA). Generalized gradient approximation along with TB-mBJ is used to determine electronic parameters like band structure along and density of states. According to the computed results the binary compound AlSb is optically inactive and exhibits an indirect (Γ -L) band gap. By increasing the concentration of indium with different percentages, the indirect band gape shifted to direct (Γ – Γ) band gap which shows material is optically active. The optical properties of material including dielectric (Real and imaginary part) constant, reflectivity, refractive index, energy loss, absorption coefficient, and optical conductivity have changed significantly. Electronic and optical properties are modified by (TB-mBJ) approach. The results obtained are examined with experimental data and utilized as a starting point to propose that the material is the superlative choice for optoelectronic devices/applications.