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Zr-based MXenes recently attracted attention because of its experimental preparation showing temperature stability, mechanical strength, and promising energy, sensoric, and electrochemistry applications. However, necessary theoretical predictions at a precise/predictive level are complicated due to essential excitonic features and strong electron correlation (i.e., a necessity to go beyond standard density functional theory, DFT). Contrary to the prevailing focus on oxygen-terminated MXenes and standard predictions of other Zr-based MXenes as conductors, based on the hybrid DFT and GW many-body perturbational theory, we were able to find seven different semiconductors (five of them for their equilibrium geometry and two others under slight tensile biaxial strain) in the case of two- and three-layered Z r 2 C T 2 and Z r 3 C 2 T 2 configurations with various terminations (T = O, F, S, Cl). We observed semiconductor-to-conductor transition induced by strain in the majority of such Zr-based MXenes at an experimentally achievable strain range. Furthermore, using the Bethe–Salpeter equation (BSE), we demonstrated that selected semiconducting Zr-based MXenes possess high optical absorption efficiency (20%–30%) in the visible light range, underscoring their potential in photonic applications. The high sensitivity of Zr-based MXenes to external conditions and functionalization combined with the thermal stability makes the materials promising for applications at operational temperatures in electronic and optical technologies. [ABSTRACT FROM AUTHOR]

Periodic density functional theory was employed to investigate the impact of chemical modifications on the properties of π-conjugated acenedithiophene molecular crystals. Here, we highlight the importance of the β-methylthionation effect, the position of the sulfur atoms of the thiacycle group and their size, and the number of central benzene rings in the chemical modification strategy. Our results show that the introduction of the methylthio groups at the β-positions of the thiophene and the additional benzene ring at the center of the BDT crystal structure are a promising strategy to improve the performance of organic semiconductors, as observed experimentally. We found that β-MT-ADT exhibits large charge carrier mobility, which is in good agreement with the experimental results and comparable to that of rubrene. In addition, the electronic and optical properties of these ambipolar materials suggest promising performances with β-MT-ADT > ADT > β -MT-NDT > NDT > BEDT-BDT > β -MT-BDT > BDT. Moreover, functionalization with thiacycle-fused sulfur atoms of different sizes and numbers improve the properties of BDT but is still less efficient than the methylthionation effect. Overall, our findings suggest a promising molecular modification strategy for possibly high performance ambipolar organic semiconducting materials. [ABSTRACT FROM AUTHOR]

Materials containing mixed anions, particularly, oxyhalides containing asymmetric functional building units, may lead to the discovery of excellent nonlinear optical (NLO) materials. In the present work, the geometric structure, mechanical properties, electronic structure and optical properties of two d 0– d 10 electron transition-metal oxyhalides Cs2CdV2O6Cl2 and Cs3CdV4O12Br have been systematically determined based on density functional theory. The asymmetric functional building units [V2O7], [V4O13], [CdO2Cl4] and [CdO4Br2] exhibit varying degrees of second-order Jahn−Teller distortions, contributing differently to the macroscopic nonlinearity. Mechanical properties reveal that the two oxyhalides are structurally and mechanically stable. Detailed electronic and optical properties of the two oxyhalides are provided. Optical anisotropy character is exhibited along different polarization vectors, giving a large birefringence for satisfying the phase-matching condition. Maximum absolute values of static second harmonic generation (SHG) coefficients are 4.47 pm V−1 for Cs2CdV2O6Cl2 and 3.72 pm V−1 for Cs3CdV4O12Br, suggesting that Cs2CdV2O6Cl2 and Cs3CdV4O12Br are potential NLO crystals with large SHG coefficients. In particular, unique 3D framework structures give a polar structure superposition of individual moments for asymmetric functional building units. Thus, maximum magnitudes of the total microscopic dipole are achieved, having the largest influence on the SHG response. This study elucidates the relationship between the structure and properties of transition-metal oxyhalides, providing valuable insights for designing NLO materials with excellent performance. [ABSTRACT FROM AUTHOR]

Strain engineering is a powerful technique for controlling the performance of semiconductor ceramic systems. In this article, the effect of strain engineering, specifically biaxial compressive and tensile strains, on the bonding characteristics, structure, electronic, and optical properties of nonplanar phosphorene‐like (NPP) ZnS ceramic nanolayers was investigated using density functional theory. It was observed that this ceramic exhibits greater stability under significant tensile strains. The structural stability of NPP‐ZnS ceramic, both with and without biaxial strain, was confirmed by its negative formation energy. Biaxial strain strongly influences the electronic band structure of NPP‐ZnS ceramic nanolayers, leading to a transformation from a direct band gap to an indirect gap under tensile strain. Additionally, the bandgap decreases under compressive strain, while it slightly increases under tensile strain. Various optical properties, including refractive index, extinction coefficient, absorption, reflectivity, optical conductivity, and optical susceptibility, were calculated. Biaxial compressive and tensile strains alter the optical properties, shifting them to higher or lower frequencies. NPP‐ZnS ceramic nanolayers exhibit high optical absorption in the UV range, which can be further enhanced by biaxial strain. Furthermore, under increasing compressive strain, the absorption edge moves toward higher energies. This improvement in optical absorption expands the potential applications of NPP‐ZnS ceramic nanolayers in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Here, using first-principles density functional theory (DFT), we investigated the structure cubic calculations of perovskite RbTaO3: bulk and surface (1 0 0). The Ta and O atoms in the TaO2-(1 0 0) termination appear to have a large atomic displacement (ΔZ) for the top and ninth layers, while the Rb atoms appear to have a minor value of ΔZ. In the RbO-(1 0 0), the Rb and O atoms in the first layer appear to have a large ΔZ, while the Ta atoms appear to have a major value of ΔZ in the second and eighth layers. We describe the thermodynamic formality used to evaluate the stability of RbTaO3 bulk, as well as RbO and TaO2-terminations. Our calculations showed that both the bulk system and the terminations are stable with the surrounding O atoms. The RbTaO3 bulk system appears to have semiconducting behavior with a band gap (Eg) of 2.25 eV. New RbO- and TaO2-terminations appeared half-metallic ferromagnetic (HMF) with a spin magnetic moment of 1.00 μβ. We found the Eg for RbO- and TaO2-terminations to be 2.25 and 2.40 eV, respectively. Also, the atomic populations (Q) and the variation (ΔQ) for (1 0 0)-RbTaO3 terminations were analyzed and compared with the bulk system. We calculated the optical properties of the RbTaO3 alloy and RbO- and TaO2-(1 0 0) surfaces. We found weak reflectivity, excellent optical conductivity, and higher absorption of incident energetic photons. Depending on the above properties, it is possible to use the bulk, RbO and TaO2 terminations in spintronics and optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this groundbreaking study, we unveil the remarkable structural, electronic, and optical Properties of the newly discovered double perovskite material, K2AgBiI6, presenting a paradigm shift in materials science. The unique crystal structure and diverse atomic interactions inherent in this double perovskite make it an up-and-coming candidate for various technological applications, particularly in photovoltaics; owing to its stability and resistance to heat and humidity, we aim to shed light on the extraordinary potential of K2AgBiI6. Our study provides valuable insights for researchers engaged in tailored material design. We anticipate that the exceptional electronic properties of K2AgBiI6 will not only redefine the boundaries of materials engineering but also catalyze unprecedented advances in sustainable technology. Employing the powerful computational tool CASTEP, we conducted detailed electronic structure calculations within the framework of Density Functional Theory (DFT) to unravel the electronic properties of the double perovskite K2AgBiI6. Our investigation thoroughly explored structural properties, band structure, total density of states (DOS), and partial density of states (PDOS). Furthermore, we systematically examined the influence of different exchange-correlation functionals, including LDA, GGA, and m-GGA, on the electronic and optical features of the material by presenting a comparative analysis of these approximations. [ABSTRACT FROM AUTHOR]

In this paper, the geometric configuration, electronic properties, and optical characteristics of an InS/GaTe heterojunction have been computed using the foundational principles of density functional theory. The analysis indicates that when the interlayer distance is 3.88 Å, the binding energy is the most negative, indicating that the structure is the most stable. The bandgap of the two monolayers is larger than that of the heterojunction, which makes the photogenerated electrons of the heterojunction more easily excited. The InS/GaTe heterojunction is a type-II heterojunction that enhances the efficient dissociation of electron–hole pairs. In addition, the InS/GaTe heterojunction demonstrates strong absorption of ultraviolet light, rendering it suitable for applications in ultraviolet detectors and related fields. Furthermore, the bandgap electron transfer direction of the InS/GaTe heterojunction can be controlled by applying electrical force and mechanical pressure. The optical absorption coefficient of the InS/GaTe heterojunction can be adjusted to modify its optical properties. Finally, the possible future applications of the InS/GaTe heterojunction are discussed. [ABSTRACT FROM AUTHOR]

Context: A novel 2D InN/GaN lateral heterostructure (LHT) was simulated by stitching monolayer of 2D InN and monolayer of 2D GaN. The structural stability, electronic structure, and optical properties were systematically investigated using first-principle calculations and by considering the effects of strain. The results indicated that the designed heterostructure has a direct bandgap of 2.26 eV which is further affected by applied biaxial strain. The bandgap of 2D InN/GaN lateral heterostructure decreases with the increase in biaxial strain, and tensile strain triggers a direct-to-indirect energy gap changeover at + 6%. Additionally, under compressive strain, heterostructure remains a direct bandgap semiconductor. Furthermore, the strain significantly affects the optical characteristics of lateral heterostructure. It has been noticed that the first optical absorption peak moves from 2.51 eV (ɛ = − 4%) to 1.40 eV (ɛ = 10%). Therefore, 2D InN/GaN lateral heterostructure provides an approachable way for utilizing in optoelectronic devices through the creation of in-plane lateral heterostructures. Methods: We performed all the computations using a self-consistent method based upon density functional theory. We used the PBEsol functional in the GGA to account for the exchange–correlation effects. We introduced a 10-Å vacuum region in the z-direction to avoid interaction between periodic images. We considered non-negligible weak dispersion correction in the lateral heterostructure using Grimme's DFT-D3 approach. In this study, we also computed the electrical and optical properties employing the local modified Becke-Johnson (lmBJ) exchange potential under meta-GGA functional to obtain more precise results. [ABSTRACT FROM AUTHOR]

Context: The aim of this work is to use first principles calculations to examine the effects of different mechanical strains on the optoelectronic and photocatalytic capabilities of the 2D/2D nanoheterostructure of AlN/GaN. By utilizing the lmBJ (Meta-GGA) and PBEsol (GGA) functional, the bandgap of the nanoheterostructure is calculated and found to be 4.89 eV and 3.24 eV. Simulated 2D AlN/GaN nanoheterostructure exhibits exceptional optical and electronic characteristics under applied biaxial tensile and compressive strains. The band gap changes from 4.89 to 3.77 eV, while the energy gap nature transitions from direct to indirect during tensile strain fluctuations of 0% to 8%. Strain is also found to have a significant effect on the optical absorption peaks. And a 0–8% rise in tensile strain causes the initial absorption peak of the 2D AlN/GaN nanoheterostructure to shift from 4.88 to 4.20 eV, which results in a 14% red shift in photon energy for every 2% change in strain. Furthermore, the optimum bandgap and band edge positions of the 2D AlN/GaN nanoheterostructure enable the water redox process to produce hydrogen and oxygen for wide range of pH. Thus, modification via strain may be an effective method for altering the optical as well as electronic characteristics of a 2D AlN/GaN nanoheterostructure, and this study may pave the way for new applications of this material in optoelectronic devices in the future. Methods: In the current work, density functional theory is used to explore every attribute of the 2D AlN/GaN nanoheterostructure. To characterize the electronic exchange–correlation, we used the PBEsol functional. In order to prevent any interlayer contact between periodicity of images, a vacuum is produced along the z-direction of approximately 10 Å. To increase the precision of bandgap prediction, the electronic and optical characteristics were computed using the meta-GGA lmBJ functional. To account for interlayer van der Waals interactions, nanoheterostructure computations were performed using the DFT-D3 functional. [ABSTRACT FROM AUTHOR]

Graphene nanoribbons (GNRs), categorized into zigzag and armchair types, hold significant promise in electronics due to their unique properties. In this study, optical properties of zigzag and armchair GNRs are investigated using density functional theory (DFT) in conjunction with Kubo–Greenwood formalism. Our findings reveal that optical characteristics of both GNR types can be extensively modulated through the application of a transverse electric field, e.g., the refractive index of the a zigzag GNR is shown to vary in the range of n = 0.3 and n = 9.9 for the transverse electric field values between 0 V/Å and 10 V/Å. Additionally, electrical transmission spectra and the electrical conductivities of the GNRs are studied using DFT combined with non-equilibrium Green's function formalism, again uncovering a strong dependence on the transverse electric field. For example, the conductance of the armchair GNR is shown to vary in the range of G = 6 μA/V and G = 201 μA/V by the transverse electric field. These results demonstrate the potential of GNRs for use in electronically controlled optoelectronic devices, promising a broad range of applications in advanced electronic systems. [ABSTRACT FROM AUTHOR]

Modifying electrical and optical properties in two-carbon materials is essential for electronic devices, energy storage and biosensor applications. We report a comparative study of the effect of systematically intercalated strontium atoms in AA- and AB-stacked bilayer graphene (BG) in the framework of density functional theory (DFT). The electronic band structures, the total and partial electronic density of states and the dielectric function are studied. We show that the intercalation of atoms can influence both electronic properties. Our results show that the Dirac cones, a signature of graphene, are translated into the conduction band. This property may be useful in band-gap tuning applications of nanodevices. The optical properties were calculated parallel and perpendicular to the graphene sheet under polarised electric fields. The calculated optical properties show that the intercalation of Sr in the AA- and AB-stacked BGs promotes IR absorption. The findings provide a basis for developing graphene intercalary compounds, which can be used in optoelectronics to control the absorption of light wavelengths and specifically in biosensor applications. [ABSTRACT FROM AUTHOR]

In this study, the optical properties of porous silicon (PSi), such as the dielectric function, absorption coefficient, bandgap, reflectivity and refractive index, were studied as a function of porosities ranging from 3% to about 40% by using a supercell model in an ab-initio pseudo-potential plane wave (PP-PW) method based on density functional theory (DFT). To validate these theoretical results, various PSi samples were prepared by varying the etching parameters to achieve similar porosities. The PSi samples were subjected to UV–vis spectrophotometry in order to measure their reflectivity. The refractive indexes predicted by DFT were compared to those obtained by the Fresnel equation and the effective medium approximation methods (EMA), particularly Bruggeman's, Looyenga's and del Rio's model (dRZW). These studies showed that the PSi dielectric constant decreases with increasing porosity, which is consistent with a decrease in the refractive index. In addition, as the porosity of PSi rises, the bandgap energy values increase, which is closely related to the decrease in the refractive index. For low porosity, DFT and Looyenga refractive indexes fit better than dRZW or Bruggeman. Furthermore, when the porosity is increased, DFT gives similar results as dRZW and is better than the Bruggeman method. Moreover, at medium porosity (28 or 40%), DFT and EMA models agree well with the experimental refractive indexes of PSi. [ABSTRACT FROM AUTHOR]

Using density functional theory and Boltzmann equations, this study calculates and compares the electronic, optical, thermoelectric, and thermodynamic properties of bulk and single-layer germanium carbide structures. It has been shown that germanium carbide in the bulk structure has an indirect energy band gap of 1.61 eV. In a single layer structure, it is a metal. Thermodynamic properties including specific heat at constant volume have been investigated using the quasi-harmonic approximation (QHA) package in QE. According to the studies conducted on optical properties, this material shows good reflection in the visible region. In addition, this structure has high electrical conductivity and low thermal conductivity, which is essential for thermoelectric materials. Thermoelectric calculations using semi-classical Boltzmann transfer theory show that the performance of two-dimensional compounds with graphene gives good thermoelectric results. At 100 K, the highest figure of merit (ZT) for GeC is 1.00. Our findings evaluate the GeC compound as a suitable thermoelectric material in the temperature gradient from 100 to 900 K. [ABSTRACT FROM AUTHOR]

In this work, we present theoretical calculations of the structural, electronic, optical and thermoelectric properties of the perovskite oxides LaMO3 (M = Ga or In) using density functional theory (DFT) with GGA–PBE approximation, as implemented in the ABINIT code. The cubic crystal structure of LaMO3 (M = Ga or In) compounds changes and its volume increases when the Ga atom is replaced by an In atom. In addition, negative formation energies suggest the thermodynamic stability of the studied compounds. Electron charge densities reveal an ionic bond between La and O, while the bond between M and O appears covalent. Electronic properties showed the indirect semiconducting behavior of LaGaO3 and LaInO3 perovskites. The calculated indirect bandgaps Eg (R–Γ) are found to be 3.34eV for LaGaO3 and 2.08eV for LaInO3. In addition, optical characteristics are determined in terms of real ε1(ω) and imaginary ε2(ω) parts of dielectric constant ε(ω), refractive index n(ω), absorption coefficient α(ω), reflectivity R(ω), energy loss function L(ω), optical conductivity σ(ω) and transmittance T(ω) are also studied. Optical absorption of light energy has been observed in both the visible and ultraviolet ranges, increasing the importance of the studied materials for optoelectronic applications. Finally, the thermoelectric performance of LaMO3 (M = Ga or In) materials has been explored using the Boltzmann transport theory implemented in the BoltzTraP software package. [ABSTRACT FROM AUTHOR]

The change in composition and pressure, both of which lead to new desired properties by altering the structure, is particularly important for improving device performance. Given this, we focused here on the mechanical, elastic, and optoelectronic characteristics of the Cdo.75Zno.25Se alloy using density functional theory at various pressures from 0 GPa to 20 GPa. It is found that the bulk modulus of the material rises with increasing pressure and exhibits mechanical stability as well as cubic symmetry. In addition, the increased pressure leads to a rise in the direct bandgap energy of the material from 2.03 eV to 2.48 eV. The absorption coefficient of the alloy also increases as the pressure increases, where the effective range of absorption covers the broad spectrum of light in the visible range from orange to cyan. This is due to the electronic transitions caused by the altered pressure. The optical parameters, including optical conductivity, extinction coefficient, reflection, and refractive index, are also analyzed under the influence of pressure. Based on this research, effective applications of the Cd substituted Zn-chalcogenides (CdZnSe) alloys in the fields of optoelectronics and photovoltaics are outlined, especially concerning fabricating solar cells, photonic devices, and pressure sensors for space technology. [ABSTRACT FROM AUTHOR]

Tin dioxide (SnO2) is an important transparent conductive oxide (TCO), highly desirable for its use in various technologies due to its earth abundance and non-toxicity. It is studied for applications such as photocatalysis, energy harvesting, energy storage, LEDs, and photovoltaics as an electron transport layer. Elemental doping has been an established method to tune its band gap, increase conductivity, passivate defects, etc. In this study, we apply density functional theory (DFT) calculations to examine the electronic and optical properties of SnO2 when doped with members of the oxygen family, namely S, Se, and Te. By calculating defect formation energies, we find that S doping is energetically favourable in the oxygen substitutional position, whereas Se and Te prefer the Sn substitutional site. We show that S and Se substitutional doping leads to near gap states and can be an effective way to reduce the band gap, which results in an increased absorbance in the optical part of the spectrum, leading to improved photocatalytic activity, whereas Te doping results in several mid-gap states. [ABSTRACT FROM AUTHOR]

Due to their high anisotropic behavior, liquid crystals possess strong nonlinear optical properties. The RM734 liquid crystal is famous for having high anisotropic behaviors compared to traditional liquid crystals. The present work focused on the evaluation of electronic, charge-transport, nonlinear optical, electro-optical, and thermochemical properties of the RM734 liquid crystal. Furthermore, the effect of halogenation on the above properties of RM734 was investigated and is discussed in depth as halogen substitution on the liquid crystal molecule can alter the quantum mechanical properties of any liquid crystal molecule. Density functional theory combined with B3LYP and dispersion correction were used to calculate the properties of RM734. The 6-311G** basis set was used for the estimation of these properties, whereas def2-TZVPD was used to evaluate the nonlinear optical parameters. Due to the halogenation of RM734, its electronic properties vary significantly. By halogenation, a better electron-transport molecule can be converted into a hole-transport molecule. The electro-optical properties were calculated with the application of an external electric field for all molecules. With the help of the order parameter, the nematic phase was observed for all reported molecules. The variation in the birefringence with respect to the external electric field was investigated and discussed in detail. Therefore, the present study reveals the significant impact of halogenation in terms of the nonlinear optical and thermochemical properties of RM734. [ABSTRACT FROM AUTHOR]

A new (C5H14N2)CoCl4 compound was synthesized by slow evaporation at room temperature. Asymmetric unit of this compound consists of one tetrahedral geometry [CoCl4]2- and one diprotonated organic cations. The structure consists of an alternation along the a-axis of organic-inorganic layers parallel to (a, b) plane. The inorganic layers built up of isolated tetrahedral [CoCl4]2-. Crystal packing is stabilized by electrostatic interactions and hydrogen bonds between cations and anions. Hirshfeld surface was conducted to investigate intermolecular interactions. Density Functional Theory (DFT) calculations of geometry optimization, vibrational frequencies, simulated UV-Visible spectrum, Frontier molecular orbitals analysis, nonlinear optical properties were made together with the experimental studies. Good agreement was found between theoretical and experimental results. In fact, the second hyperpolarizability value 〈γ〉 of compound (0.8665 × 10-36 esu) indicates that hydrogen bonds play an important role in the creation of crystal structure, its stability and in the enhancement of polarizability α and hyperpolarizability of crystal. Hence, the large 〈γ〉 value suggests that this compound is a Non-Linear Optical (NLO) material of interest and could be adopted in various optical applications. Energy gap indicates that our compound behaves as a semi-conductor material. In the other hand, the bioassay results showed that this structure exhibits significant antioxidant and antibacterial activities. [ABSTRACT FROM AUTHOR]

Context and results : In this paper, the crystal structure, electronic, optical, and mechanical properties of SrVO3 have been systematically studied by first-principles calculation. The results show that the calculated lattice parameters are in good agreement with the experimental values of X-ray diffraction. The density of states is described in detail in this paper. By analyzing the crystal structure and electronic properties of SrVO3, the magnetic properties of SrVO3 are obtained from the one unpaired electrons of V and the exchange interaction between two V ions. At the same time, a detailed analysis of the optical properties of SrVO3 was conducted, and it was found that it is transparent in the visible light range. Finally, the mechanical properties of SrVO3 are calculated, which can provide some references for future research. Computational method: In this paper, a first-principles method based on density functional theory (DFT) is reported for PBE-GGA analysis using the plane wave-pseudo potential method in a quantum concentrate packet, U value of 7 eV to V-d and a U value of 2 eV to O-p, Grimme correction by DFT-D method. The k points in the Brillouin region are set to 4 × 4 × 4. The energy convergence criterion for self-consistent field calculation is set at 5.0 × 10−6 eV/atom, and the cutoff energy is 1170 eV. In this paper, the force acting on each atom is not more than 0.01 eV/Å, the maximum stress is not more than 0.02GPa, and the maximum atomic displacement is 5 × 10−4 Å. [ABSTRACT FROM AUTHOR]

Context: Density functional theory (DFT) calculations on the ground and the first excited state are performed on the modified and unmodified 4-(methoxyphenyl acetonitrile) monomer (referred to as MPA). The modified monomer named MFA is obtained by Knoevenagel condensation of MPA with dimethylformamide dimethyl acetal (DMF-DMA). DFT computations show that the chemical grafting of the dimethylamino group onto the MPA unit induces a great change in the geometric, electronic, and optical properties. Going from MPA to MFA monomer, a great change in the frontier orbitals of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the ground and the first excited state is observed. Consequently, a reduction in the energy gap HOMO–LUMO and an enhancement in the absorption and emission properties are observed under the chemical modification. The observed modifications in the electronics and optical properties are the result of the charge transfer appearing between the cyano (C≡N) acceptor group and the dimethylamino (DMF-DMA)-grafted group donor ring. Methods: Quantum chemical calculations were performed in the ground and the first excited state using the density functional theory (DFT), and it extends the time-dependent density functional theory (TD-DFT), implemented in the Gaussian 09 software package. The ground state is obtained by optimization of the studied molecular geometries by employing the DFT/M062X/6-31G(d,p) level of theory. The first excited state is obtained by re-optimization of the ground state geometries using the TD-DFT/M062X/6-31G(d,p) level of theory. The contour plots of the frontier orbitals and the molecular electrostatic potential (MEP) maps are obtained from the ground and the first excited state, optimized geometries, and drawn using Gaussview software. [ABSTRACT FROM AUTHOR]

Context: In the renewable industry, pressure-dependent CsPbBr3 perovskite has a lot of potential due to its exceptional properties. Present work revealed the mechanical stability of CsPbBr3 between 0 to 50 GPa. The bandgap of unstressed CsPbBr3 is 2.90 eV, indicating a direct bandgap. Band gap values decrease by increasing external pressure. CsPbBr3 structure showed a direct band gap from 0 to 35 GPa and in-direct from 40 to 50 GPa. The unit cell volume and lattice constants are substantially decreased. Mechanical parameters, i.e., Young's modulus, bulk modulus, anisotropy factor, shear modulus, and poison's ratio are obtained. Under ambient conditions, the mechanical properties of CsPbBr3 showed ductile behavior and with induced pressure, their ductility has significantly improved. By applying stresses ranging from 0 to 50 GPa, the considerable fluctuation in values of dielectric function (imaginary and real), absorption, reflectivity, loss function, refractive index (imaginary and real), and conductivity (imaginary and real), was also identified. When pressure rises, the optical parameters increase and drag in the direction of high energies. Response functions are used to predict the density of states and the phonon lattice dispersion to study the phonon properties. By using the quasi-harmonic Debye model, the thermal effect on the free energy, entropy, enthalpy, and heat capacity were predicted and compared. These results would be useful for theoretical research and indicate how external pressure significantly affects the physical characteristics of CsPbBr3 perovskites, which may open up new possibilities for use in optoelectronic, photonic, and solar cell applications. Methods: The structural, electrical, mechanical, optical, and thermal properties of cesium lead bromide (CsPbBr3) are investigated by applying external pressure from 0 to 50 GPa, using generalized gradient approximations (GGA) and Perdew-Burke-Ernzerhof (PBE) with CASTEP code built-in material studio by density functional theory (DFT). [ABSTRACT FROM AUTHOR]

The present study reports the theoretical investigations of nonlinear optical properties of chalcone derivative namely 4-[(1E)-3-(4-methoxyphenyl)-3-oxoprop-1-en-1-yl]phenyl 4-methylbenzene-1-sulfonate (4MPMS). Density functional theory calculations on the geometry optimization, vibrational spectrum, 1H and 13C NMR chemical shifts, frontier molecular orbitals energies, and nonlinear optical properties are carried out by using B3LYP level in conjunction with 6–311++G(d,p) basis set. The static and frequency-dependent nonlinear optical properties (polarizability (α), anisotropy of polarizability (Δα), first and second-order hyperpolarizabilities (β and γ)) are investigated by using B3LYP level. The static NLO parameters (β(0;0,0) and γ(0;0.0.0)) were calculated as 16.240 × 10−30 and 213.77 × 10−36 esu. The second harmonic generation (SHG) β(-2w,w,w) and γ(-2w,w,w,0) parameters for the title molecule are found to be 213.97 × 10−30 esu and 485.90 × 10−36 esu, respectively. So, the frequency-dependence of β and γ parameters is clear. The obtained results demonstrated that there is a frequency dependence on the nonlinear optical properties of 4MPMS, and the title molecule is a possible candidate for first and second-order nonlinear optical materials. [ABSTRACT FROM AUTHOR]

Physical characteristics of LiXCl3 (X = Sn, Pb) have been reported by a first-principles approach in the CASTEP simulation code. In structural, LiSnCl3 and LiPbCl3 are in the cubic phase and dynamically stable according to the phonan calculation. The electronic properties revealed that LiSnCl3 and LiPbCl3 are semiconductors. The observed energy band gaps are direct band gap in the order of 1.35 eV and 2.29 eV for LiSnCl3, and LiPbCl3, respectively. Additionally, the electronic profile is briefly discussed in terms of the partial and total density of states. The lattice constant and electronic properties are well matched with the previous literature. The partial and total density of states confirms the degree of localization of electrons. Optical properties were examined in the energy range of 0–40 eV. The optical chracteristics such as reflectivity, refractive index, absorption, dielectric function, conductivity, and energy loss function are calculated. The maximum reflectivity is observed in LiPbCl3. Furthermore, the mechanical and elastic characteristics of the materials are estimated to ensure their reliability, stability, and ease of handling in optoelectronic applications. The physical properties reveal that the concerned compounds have direct and narrow energy band gap which are potentially useful in solar cell technology. [ABSTRACT FROM AUTHOR]

Context and results : In this paper, the crystal structure, electronic, optical, and mechanical properties of SrVO3 have been systematically studied by first-principles calculation. The results show that the calculated lattice parameters are in good agreement with the experimental values of X-ray diffraction. The density of states is described in detail in this paper. By analyzing the crystal structure and electronic properties of SrVO3, the magnetic properties of SrVO3 are obtained from the one unpaired electrons of V and the exchange interaction between two V ions. At the same time, a detailed analysis of the optical properties of SrVO3 was conducted, and it was found that it is transparent in the visible light range. Finally, the mechanical properties of SrVO3 are calculated, which can provide some references for future research. Computational method: In this paper, a first-principles method based on density functional theory (DFT) is reported for PBE-GGA analysis using the plane wave-pseudo potential method in a quantum concentrate packet, U value of 7 eV to V-d and a U value of 2 eV to O-p, Grimme correction by DFT-D method. The k points in the Brillouin region are set to 4 × 4 × 4. The energy convergence criterion for self-consistent field calculation is set at 5.0 × 10−6 eV/atom, and the cutoff energy is 1170 eV. In this paper, the force acting on each atom is not more than 0.01 eV/Å, the maximum stress is not more than 0.02GPa, and the maximum atomic displacement is 5 × 10−4 Å. [ABSTRACT FROM AUTHOR]

The absorption spectra of various sizes of nanoparticles of copper (Cu), silver (Ag), and gold (Au) are theoretically investigated. The density functional theory (DFT), time‐dependent DFT (TDDFT), and real‐time TDDFT are used to demonstrate how size and shape affect their optical properties and how these are evolved as the number of atoms increases. For this reason, the focus was turned on almost spherical nanoparticles cut out from the corresponding crystal structure (called 0D), elongated ones (1D), and flattened ones (2D). The nature of the observed absorption peaks is further analyzed with the help of transition contribution maps and induced density plots which help us identify the emergence of probable plasmonic resonances as the size of the nanoparticles increases. [ABSTRACT FROM AUTHOR]

We present a comprehensive investigation of the electronic properties of fluorinated monolayer violet phosphorus using first‐principles calculations. Our results reveal a strong dependence of the electronic properties on the different fluorine coverages of fluorination. As the fluorine coverage increases, monolayer violet phosphorus undergoes a significant transition from a wide direct bandgap semiconductor to a narrow indirect bandgap semiconductor. Moreover, both semi‐fluorinated and fully fluorinated monolayer violet phosphorus exhibit advantageous semiconducting characteristics, with a tunable bandgap of 0.50 ~ 1.04 eV under biaxial strain ranging from −6% to 6%. Notably, the fully fluorinated monolayer violet phosphorus demonstrates a higher coefficient of light absorption within the visible range. Therefore, our findings highlight the tunability of monolayer violet phosphorus properties through the absorption of various fluorine coverages, providing valuable insights for the design and development of novel semiconductor devices based on this material. [ABSTRACT FROM AUTHOR]

A theoretical study of the reported photocatalytic systems based on Zr-based MOF (UiO-67) with biphenyl-4,4′-dicarboxylic acid (bpdc) and 2,2′-bipyridine-5,5′-dicarboxylic acid (bpydc) as linkers was performed. Quantum chemical calculations were carried out to understand the optical properties of the materials and to facilitate the rational design of new UiO-67 derivatives with potentially improved features as photocatalysts under ambient conditions. Hence, the effect of the structural modifications on the optical properties was studied considering different designs based on the nature of the linkers: in 1 only the bpdc linker was considered, or the mixture 1 : 1 between bpdc and bpydc linkers (labeled as 1A). Also, substituents R, –NH2, and –SH, were included in the 1A MOF only over the bpdc linker (labeled as 1A-bpdc-R) and on both bpdc and bpydc linkers (labeled as 1A-R). Thus a family of six isoreticular UiO-67 derivatives was theoretically characterized using Density Functional Theory (DFT) calculations on the ground singlet (S0) and first excited states (singlet and triplet) using Time-Dependent Density Functional Theory (TD-DFT), multiconfigurational post-Hartree–Fock method via Complete Active Space Self-Consistent Field (CASSCF). In addition, the use of periodic DFT calculations suggest that the energy transfer (ET) channel between bpdc and bpydc linkers might generate more luminescence quenching of 1A when compare to 1. Besides, the results suggest that the 1A-R (R: –SH and NH2) can be used under ambient conditions; however, the ET exhibited by 1A, cannot take place in the same magnitude in these systems. These ET can favor the photocatalytic reduction of a potential metal ion, that can coordinate with the bpydc ligand, via LMCT transition. Consequently, the MOF might be photocatalytically active against molecules of interest (such as H2, N2, CO2, among others) with photo-reduced metal ions. These theoretical results serve as a useful tool to guide experimental efforts in the design of new photocatalytic MOF-based systems. [ABSTRACT FROM AUTHOR]

In this study, density functional theory (DFT) as it is implemented in the Quantum Espresso simulation package was employed to investigate the structural, electronic, mechanical and optical properties of RhZrZ (Z = As, Sb) half‐Heusler compounds. Results reveal that both the two compounds are most stable in α phase. Analysis of mechanical properties shows that the compounds are ductile in nature and mechanically stable. Calculations of band structure and density of states indicated that they are semiconductors with RhZrAs direct and RhZrSb indirect band gap. Furthermore, the investigation of the optical properties reveals that there is a high absorption coefficient and low electron energy loss in visible and some ultraviolet energy spectrum indicating that these compounds are potential candidates for optoelectronic applications. [ABSTRACT FROM AUTHOR]

The lack of a bandgap in stanene severely limits its outstanding characteristics in optoelectronic devices. Using first-principles calculations, we systematically investigate the effects of full hydrogenation and shear deformation on the electronic structure and optical properties of stanene. Hydrogenation exerts a remarkable impact on electronic structure of stanene, enabling surface state transition from quasi-metallic to semiconducting. Shear degrades the structural stability of full-hydrogenated stanene (FHstanene). FHstanene exhibits a tunable bandgap of 1.327 eV, which can be further reduced to 0.719 eV through shear deformation. The presence of spin-orbit coupling (SOC) induces band splitting in FHstanene. The maximum optical absorption of FHstanene occurs at 291 nm, while the reflectance peak is observed at 449 nm. The variation in bandgap due to deformation results in a redshift in the absorption coefficient and reflectance, and shear deformation increases the reflectance of FHstanene. These findings broaden the application prospects of stanene in novel nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

Crystals of the family of tetragonal, non‐centrosymmetric melilites have attracted interest as nonlinear optical, piezoelectric, and ferroelectric materials. This work presents an ab initio study of the optical properties of europium melilite, Eu2MgSi2O7. The study includes the calculation of refractive and absorption spectra, with respect to the density of states of the system. The obtained results demonstrate the correlation between the electronic structure of europium melilite and its optical characteristics. [ABSTRACT FROM AUTHOR]

The structural stability, elastic, optoelectronic, and thermoelectric characteristics of anti‐perovskites Na3XO (X = Cu, Ag) have been studied using density functional theory (DFT). The computed formation energy suggests these materials' potential synthesis and thermal stability. The structural and elastic properties of Na3CuO and Na3AgO anti‐perovskite compounds were analyzed using the Perdew–Burke–Ernzerhof (GGA‐PBE) generalized gradient potential approximation. The electronic and thermoelectric properties are calculated using the TB‐mBJ approximation. The materials are identified as direct narrow band gap semiconductors with band gaps of 0.65 and 0.43 eV. The analysis of two‐dimensional charge density contours indicates that Na3CuO and Na3AgO have a mixed bonding character, as validated by the investigation of electron charge density. We analyzed the optical properties of Na3CuO and Na3AgO, including dielectric function, refractive index, absorbance, optical reflectivity, and energy loss, using photon energy up to 6 eV. The investigated thermoelectric characteristics demonstrate figure of merit (ZT) values of 0.58 and 0.56 at room temperature. Consequently, the analyzed anti‐perovskites might address waste heat management requirements and sustainable energy solutions. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive analysis of the orthorhombic CsCuO, focusing on its structural, electronic, mechanical, and optical properties, which uses the first‐principles plane wave pseudopotential technique and local density approximation methods based on density functional theory. The derived structural parameters closely match the previously reported experimental data. The calculated results show that CsCuO is mechanically stable and exhibits a certain toughness. Research on electronic properties shows that CsCuO is a direct‐bandgap semiconductor. Charge density and population analysis show that covalent bonds are formed between O and Cu. The optical property results show that CsCuO has good passability to incident light, indicating that CsCuO is an excellent transparent material. In the visible and infrared light regions, CsCuO has a low absorption coefficient, mainly manifested as ultraviolet absorption. Reflection is mainly distributed in the high‐energy region and does not exceed 25% in the visible light region. It can be used in fields that require less light reflection and the manufacture of medical ultraviolet disinfection equipment. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) is used to study the optical, structural, and electrical aspects of tetragonal tetrahedral compounds AFMgY in space group P4/nmm, where A = Ca–Ba and Y = P, As. The stated results are close to the experimental structural properties. The understudied compounds are visible light active bandgap semiconductors, as shown by the electronic characteristics of AFMgY (where A = Ca–Ba and Y = P, As). The electrical conductivity of the substances under investigation also indicates that they are semiconductors. According to our findings, the bandgap decreases with P, As, and Ca–Ba substitution while it increases from LDA to mBJ. According to the results, the compounds AFMgY (where A = Ca–Ba and Y = P, As) have dynamic optical properties in the visible range, making them promising candidates for optoelectronic devices and solar cell applications. These compounds are promising for thermoelectric material due to their high value of Seebeck coefficients, Power factors and ZT. [ABSTRACT FROM AUTHOR]

This study employs density functional theory, utilizing plane wave ultra-soft pseudopotentials (PW-USPPs) within the generalized gradient approximation (GGA) and incorporating the Hubbard potential (GGA + U), to investigate the structural, electronic, and magnetic characteristics of Mn-doped 2D—WSe2 monolayers. The pristine WSe2 monolayer is identified as a nonmagnetic direct band gap semiconductor with a band gap of 1.55 eV. Upon substituting Mn for W in the WSe2 monolayer, the resulting structure exhibits enhanced stability, indicated by a negative formation energy. The Mn-doped monolayer-WSe2 adopts a semi-metallic nature, deviating from the nonmagnetic characteristics of the pristine 2D—WSe2, showcasing impurity bands dispersion near the Fermi level. The total magnetic moment within the nearest neighboring interactions of the Mn impurity atoms increases notably and it is attributed to the electron-correlation effect in the high spin state under the GGA + U approximation. However, this correlation effect proves insignificant on the total magnetic moment for the second nearest neighboring interactions, yielding consistent outcomes in both GGA and GGA + U approximations. The transition of ferromagnetic to antiferromagnetic states occurs within the temperature range of 400 K–450 K for low Mn-atom concentrations (below 12.5%), indicating long-range ferromagnetic ordering crucial for high-temperature 2D-diluted magnetic semiconductors. However, at high concentrations of impurity atoms, the temperature drops below room temperature (220 K in 22.2%) in the doped monolayer WSe2, showing weak magnetic interaction. Lastly, the optical properties of the doped system is studied by applying polarization in perpendicular and parallel directions to the plane of the monolayer. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study aims to synthesize a novel donor–acceptor dye based on phenothiazine as a donor (D) and nonconjugated spacer was devised and synthesized by condensing of 2,2'-(1H-indene-1,3(2H)-diylidene) dimalononitrile with aldehyde and the practical synthesis methodology as given in Scheme 1. Design/methodology/approach: The prepared phenothiazine dye was systematically experimentally and theoretically examined and characterized using nuclear magnetic resonance spectroscopy (1H,13C NMR), Fourier-transform infrared spectroscopy (IR) and high-resolution mass spectrometry. Density functional theory (DFT) and time-dependent density functional theory DT-DFT calculations were implemented to determine the electronic properties of the new dye Findings: The UV-Vis absorption and fluorescence spectroscopy of the synthesized dye was investigated in a variety of solvents with varying polarities to demonstrate positive solvatochromism correlated with intramolecular charge transfer (ICT). The probe's quantum yields (Фf) are experimentally measured in ethanol, and the Stokes shifts are found to be in the 4846–9430 cm−1 range. Originality/value: The findings depicted that the novel (D-π-A) chromophores may act as a significant factor in the organic optoelectronics. [ABSTRACT FROM AUTHOR]

Thermochromic materials, known for their unique ability to change optical properties with temperature, have broad applications, including in thermochromic light‐emitting diodes (LEDs). However, the scarcity of efficient and stable thermochromic phosphors limits their development. In this study, the development of a novel thermochromic phosphor based on zero‐dimensional (0D) inorganic metal halides is reported. The 0D Cs2ZnBr4:Ag+ phosphors show thermally enhanced self‐trapped exciton (STE) emission across a wide temperature range from 120 to 300 K with the emitted wavelength changing correspondingly. Temperature‐dependent photoluminescence (PL), time‐resolved PL, and density functional theory calculations confirm that the thermally enhanced STE emission originates from the passivated defect/traps in Cs2ZnBr4 and the thermally assisted energy transfer from the host to STEs formed by [AgBr4]3– tetrahedron with matrix phonons complementing the energy mismatch. Furthermore, the reversible thermochromic LEDs based on Cs2ZnBr4:Ag+ phosphors are successfully prepared. Overall, these findings provide a future design of high‐efficiency thermally enhanced luminescent materials and pave a new way for developing thermochromic materials for functional LED illumination. [ABSTRACT FROM AUTHOR]

We explore the effect of crystallographic anisotropy on the optical properties of high-quality β-Ga2O3 thin films by conducting experimental measurements and theoretical simulations. High resolution x-ray diffraction measurements confirm the high-quality and the single crystalline quality, ruling out the effect of defects for all films. Raman spectra reveal the presence of anisotropy, as evident from a stronger B g (2) mode related to GaIO4 chain libration in (100) orientation. Conversely, a stronger A g (10) mode corresponding to tetrahedral bonds is evident in the (010) orientation, while it is suppressed in the (100) orientation. Low-temperature photoluminescence spectra indicate the presence of intrinsic impurity-related emissions in the ultraviolet and blue regions for all films. An anisotropic bandgap is observed, wherein the lowest bandgap value is related to the (010) oriented sample. Spectroscopic ellipsometry measurements confirm different refractive indices and extinction coefficient values depending on crystallographic orientation, which are in good agreement with the theoretical values obtained by density functional theory, confirming the anisotropic characteristics. The theoretical calculations of charge density show that the strength of covalent bonding depends on the β-Ga2O3 orientation, while experimental findings demonstrate that as the covalent bonding character increases, the film bandgap and the refractive index decrease. The anisotropy of β-Ga2O3 with respect to the crystal orientation leads to variations in the extinction coefficient, refractive index, and bandgap energy. [ABSTRACT FROM AUTHOR]

In this research, we studied pristine (PGs) and Al, Ti, and Cr-doped graphene (DGs) via density functional theory calculations for adsorption of OF2 and O3 gas. Changes in the structural, electronic, and optical properties due to Al, Ti, and Cr-doping as well as gas adsorption have been studied. After doping with Al, Ti, and Cr atoms, the cohesive energies were −8.787, −8.754, and −8.768 eV, respectively, where the negative values indicate the structural stability of doped sheets. The OF2 adsorbed on the complexes of PGs, Ti-DGs, Cr-DGs, and Al-DGs showed strong adsorbate–adsorbent interaction with −0.468, −16.369, −11.096, and −9.158 eV adsorption energies, respectively. Similarly, for O3 gas, the adsorption energies of those sheets are −0.444, −10.575, −10.870, and −6.711 eV, respectively. From optical properties analysis, we found that the maximum reflectivity for gas-adsorbed Ti-DGs and Cr-DGs is found in the UV region, whereas the highest reflectivity for Ti-DGs and Cr-DGs is found in the visible range. Our studies reveal that all these DGs are good candidates for the adsorption and dissociation of OF2 and O3 gases. [ABSTRACT FROM AUTHOR]

The full potential linearized augmented plane wave (FP‐LAPW) method is used to compute structural, electronic, and optical properties of III‐V semiconductor ternary alloys GaP1‐xSbx (0≤x≤1) using first‐principle calculations within density functional theory. To calculate the ground state parameters of the structure, the energy exchange‐correlation Wu‐cohen generalized gradient approximation is employed in the wiek2k program. The Tran–Blaha‐modified Becke–Johnson (TB‐mBJ) pseudopotential is employed in addition to the Wu‐Cohen generalised gradient approximation to achieve a precise bandgap. After this, WC‐mBJ is used to examine optical properties such as real and imaginary parts of the dielectric constant, and energy loss. This study illustrates the nonlinear dependency on the various Sb compositions by examining the composition impacts on the bandgap, bulk modulus, and lattice constant. Using WC‐mBJ, the estimated band structures for alloys GaP0.75Sb0.25, GaP0.50Sb0.50, and GaP0.25Sb0.75 show direct energy bandgaps of 2.008 eV (617 nm), 1.482 eV (836 nm), and 1.055 eV (1174 nm), respectively. As a result, this material system has enormous potential for use in applications spanning the visible to infrared spectrum. [ABSTRACT FROM AUTHOR]

Double oxide perovskites have recently attracted immense research interest owing to their excellent structural diversities and tunable functional properties, making them promising candidates for renewable energy applications such as photovoltaics, photocatalysis, and thermoelectric devices. In this study, we systematically computed the structural stability, electronic, optical, and thermoelectric properties of a novel perovskite oxide, Ba2KIO6, using first principles calculations within the PBE-GGA and TB-MBJ exchange-correlation functionals. Our results predicted that Ba2KIO6 crystallizes in a stable cubic double perovskite structure. The electronic structure calculations revealed the indirect band gaps of Ba2KIO6 as 0.81 eV with PBE-GGA and 2.1 eV with TB-MBJ. The calculated optical properties, including the dielectric function and optical conductivity, showed strong light absorption in the UV region, highlighting its potential for optoelectronic applications. Furthermore, our calculations of the thermoelectric performance metrics, including the Seebeck coefficient, electrical conductivity, and thermal conductivity, revealed Ba2KIO6 to possess a decent figure-of-merit, highlighting its potential for efficient thermoelectric applications. Overall, our first-principles study provides useful insights into the diverse functional properties of the novel Ba2KIO6 perovskite oxide and suggests its applicability in thermoelectric generators and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Double perovskite halides Cs2TlGaCl6 and Cs2TlGaBr6 are promising for photovoltaic applications due to their optoelectronic properties. The first-principles density functional theory (DFT) with the HSE06 hybrid functional was applied to systematically investigate their structural stability, electronic structure, optical absorption, and mechanical properties. The calculated tolerance and octahedral factors confirm stable crystal structures. The indirect band gaps of 2.50 eV (Cs2TlGaCl6) and 1.54 eV (Cs2TlGaBr6) are suitable for visible-light harvesting. Strong visible-light absorption and low reflectivity are observed. Elastic constant calculations based on the Voigt–Reuss–Hill approximation validate mechanical stability. The Spectroscopic Limited Maximum Efficiency (SLME) estimates promising photovoltaic efficiencies of 12.41% for Cs2TlGaCl6 and 29.73% for Cs2TlGaBr6 perovskite. These findings highlight the potential of Cs2TlGaCl6 and Cs2TlGaBr6 for low-cost, high-efficiency solar cells, warranting further experimental investigations. [ABSTRACT FROM AUTHOR]

The rare earth-based perovskite oxides are vastly studied for optoelectronic and photovoltaic applications. Here in this manuscript, the structural, mechanical, thermodynamic, electronic, and optical properties of AcXO3 (X = Al, Ga, In) are addressed by density functional theory (DFT) based WIEN2k code. The optimized parameters are reported from the Birch–Murnaghan equation of states in terms of lattice constant and bulk modulus. The elastic constants C11, C12, and C44 for the cubic phase satisfy the Born–Huang stability conditions. The Poisson and Pugh's ratios discriminate that the Ac(Al/Ga)O3 have brittle and AcInO3 ductile nature. The thermodynamic parameters like melting temperature, Debye temperature, and lattice thermal conductivity have also been explained in terms of elastic constants and moduli. The electronic behavior is explained by the band structures and density of states which is mainly contributed by Ac-d, X-p, and O-p states. The replacement of Al with Ga, and In reduces the bandgap from 4.1 to 2.2 eV. The optical characteristics are studied in terms of dielectric constants, absorption coefficient, reflection, refractive index, optical loss, and their dependent parameters. The absorption region shifts from ultraviolet to the visible region making them significant for diverse optoelectronic applications. [ABSTRACT FROM AUTHOR]

A novel allotrope structure of carbon named twin irida graphene composed of 3‐16‐8 carbon rings is proposed. Its structural, mechanical, electronic, and optical characteristics are explored by density functional theory. It is shown that twin irida graphene has an energetically favorable structure. Its dynamical and thermal stabilities at room temperature are also examined and confirmed. The in‐plane stiffness of twin irida graphene is less than graphene. It is a metal and maintains this property even against the external strain and applied electric field. This sheet exhibits an anisotropy response to the incident photon with different polarizations. The potential of sheet for use in energy storage and absorption systems is indicated by its high dielectric constant and optical absorption. The reflection constants as well as the transmission constants of twin irida graphene indicate its transparency, mostly in the high‐energy region. Thus, twin irida graphene is a suitable material for use in optoelectronic applications due to its structural and physical characteristics. [ABSTRACT FROM AUTHOR]

In this study, the pressure‐induced structural, electronic, and optical properties of lead‐free inorganic Ge‐based perovskite materials NaGeX3 (X = F, Cl, Br, and I) through density functional theory (DFT) simulations conducted are explored with CASTEP. This research is driven by identifying perovskite materials with a tunable bandgap that are both efficient and non‐toxic for solar cell applications. The materials under consideration are found to be mechanically and thermodynamically stable, as per the Born stability criteria and formation energy calculations. This band structure analysis indicates these compounds exhibit semiconducting behavior with a tunable bandgap. Under ambient conditions, the Ge─X and Na─X bonds display covalent and ionic characteristics, respectively. Substituting halogens from F to I increases lattice parameters and a more covalent nature of the Ge─X bond. Concurrently, the bandgap narrows, transitioning from indirect (F) to direct (Cl, Br, and I). At the same time, the static dielectric constant rises, and both absorption and conductivity are significantly enhanced with a redshift in the optical spectrum. The application of tensile stress (positive pressure) increases both the lattice constant and bandgap, whereas the dielectric constant, absorption, conductivity, and reflectivity decrease. Conversely, compressive stress (negative pressure) induces the opposite effect. Pressure‐induced variations in the bandgap highlight the potential of NaGeX3 materials to significantly impact the next‐generation solar cells' development, offering a pathway to more sustainable and efficient energy solutions. [ABSTRACT FROM AUTHOR]

Inbuilt high energy band gap and resistivity cause harm to the intrinsic molybdenum trioxide (MoO3) for utilizing it directly in gas sensing and optoelectronic devices. Doping with transition metal ions can be an optimistic solution to these problems. By doping four side of modification of a material is possible. At first, doping can curtail the width of the energy band of semiconductor materials, thereby largely boosting the photo-sensitivity of the material and intensifying the light consumption that is more suitable for anti-laser devices and light source substances. The second is that doping can widen the material's band gap, which can significantly reduce the purities of the substance, improve absorbance, and make it suitable for strong interference semiconductor films and aperture materials. Third, changing the material's charge carrier density and effective mass can significantly improve conductivity. This is mostly relevant for conductive devices and photosensitive materials. Finally, changing the material's valance electron location influences the magnetic moment created by the spin of elementary particles in the entire system, allowing the magnetic characteristics of the substance to be regulated, which is especially useful for diluted magnetic semiconductor (DMS) materials. The investigation report of the structural, electrical, and optical characteristics of Cobalt (Co)-doped orthorhombic-phase MoO3 utilizing plane-wave pseudo-potential technique based on first-principles computation is presented in this paper. The computation has been executed using density a functional theory (DFT)-based CASTEP computer program with the generalized gradient approximation (GGA) together with the Perdue-Burke-Ernzerhof (PBE) exchange–correlation function. Acquired structural parameters present good consistency with the former reported experimental data. The resultant electronic band structure reveals that pure MoO3 shows an indirect energy band gap of 1.873 eV/2.312 eV whereas Co doping causes band narrowing of about 0.94 eV/1.36 eV with PBE/HSE techniques. The total and partial density of states (PDOS) have been studied comparatively, for pure and Co-doped MoO3, respectively. The absorption coefficient, loss function, reflectivity, refractive index, extinction coefficient, dielectric function, along with optical conductivity have also been determined to analyze the optical properties of Co-doped MoO3. Co-doped MoO3 offers higher conductivity while decreasing resistivity, compared to the undoped case. The present study ensures that Co-doped α- MoO3 can be competently employed as a functional material in gas sensing and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Density functional theory has been utilized to compute the electronic and optical characteristics of zBNNRs (w = 6 and 8) doped with lithium. The results suggest that the simulated nanoribbons display properties similar to those of semiconductors. Furthermore, the graphs demonstrate that a 4% lithium doping level decreases the bandgap. The presence of lithium alters the dielectric function of boron nitride nanoribbons (BNNRs) by acting as a donor atom, thereby introducing additional electronic states within the energy bandgap. Additionally, the dopant enhances the static refractive index, particularly in the z-direction. In the energy range of 0–6 eV, both pristine zBNNRs (w = 6) and zBNNRs (w = 8) satisfy the criteria for the transverse-electric mode. Conversely, beyond 3.87 [for Li-doped zBNNRs (w = 6)] and 3.81 eV [for Li-doped zBNNRs (w = 8)], the lithium-doped nanoribbons support the transverse-magnetic plasmons. [ABSTRACT FROM AUTHOR]

The pseudo ab initio ability is based on density function theory (DFT), use of generalized gradient approximation (GGA). In this work we use the Siesta code for the first time in studying this specific FeNi3 and FeNi2Pt alloys and its fcc phase which enabled us to find the structural and optical properties of FeNi3 and FeNi2Pt alloys in its fcc cubic crystal structure. Obtained results showed that the structural properties of the cubic phase structure have lattice constants very close to what was previously found in theoretical and experimental studies, and all the optical properties calculated such as absorption coefficient, reflectivity, refractive index, and the imaginary part of the dielectric constant, show that the FeNi3 and FeNi2Pt alloys They are two electrical conductors, whose valence band is completely overlapped with the conduction band. Through the optical results, it was found that we can use them in the infrared and visible region applications, and this type of work was studied in this research for the first time. [ABSTRACT FROM AUTHOR]

We have explored the electronic and optical properties of the stanene–BeO heterostructure using density functional theory (DFT), including van der Waals interaction using the DFT-D3 correction method of Grimme. The heterostructure exhibits a significant band gap opening, with 93 meV (PBE) and 141 meV (HSE06) values. The impact of spin–orbit coupling (SOC) has also been studied, with PBE + SOC exhibiting a band gap of 55 meV and HSE06 + SOC exhibiting a band gap of 71 meV. Using the DFT-1/2 method, various optical parameters of BeO and Sn monolayer and Sn-BeO heterostructure were studied. The results show a strong red shift in the absorption coefficient, extinction coefficient, and reflectivity, with a prominent absorption peak in the near-UV and visible regions. A significant second harmonic generation peak of 8 × 104 pm V−1 was also obtained. The excellent optical properties of the heterostructure indicate its potential for use in future optoelectronic devices. [ABSTRACT FROM AUTHOR]

BMS (BaMgSiO4) is a promising candidate for inorganic photochromatic materials with excellent opto-electronic properties. Because of its applications in high density optical memory and LEDs, the host matrix BMS has piqued the interest of academics all over the world. In this study, the generalized gradient (GGA and GGA + U) approximations were used to examine the electronic structure and optical properties of BaMgSiO4:Eu, including dielectric function, refractive and extinction coefficients, the optical conductivity, reflectivity, and absorption spectra. It is found that the substitution of Eu ions has reduced the energy band gap of BaMgSiO4. Our findings show that the band gap and optical characteristics of BaMgSiO4 compound are better described by GGA + U method. Future research can use this study as a guide, and it contributes to extending the capabilities of BaMgSiO4 materials to optical applications. The results of this study suggest that phosphide semiconductors could be used in solar cells. [ABSTRACT FROM AUTHOR]