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In this study, we employed the density functional theory (DFT) approach using WIEN2k code to study the magnetic and optical behaviors of PbCrO 3 and PbFeO 3 perovskites in both cubic and tetragonal phases. We determined the stability of the ferromagnetic state in terms of the enthalpy of formation, the half-metallic behavior, and spin polarization. The origin and nature of the ferromagnetic state were attributed to John–Teller distortion and a super-exchange mechanism. Comparisons of the calculated crystal field, John–Teller distortion, and exchange energies indicated the stability of the ferromagnetic nature. Due to strong hybridization, the magnetic moment was reduced at the Cr/Fe sites but generated at the nonmagnetic sites. The optical characteristics were explained by in-depth analyses of the polarization, plasmonic resonance, transparency, and other features in terms of the computed parameters.

We have investigated the electronic structure, magnetic and thermoelectric behavior of AV2O4 (A = Zn, Cd, Hg) by using first principle calculations. Various properties are extracted from the computed band structures (BS) and the densities of states (DOS). The studied compounds reveal half-metallic ferromagnetic (HMF) nature. The origin and nature of the observed ferromagnetism is described in terms of the calculated crystal field (ΔCF), John-Teller (ΔJT), direct ΔEX (d) and indirect exchange ΔEX (pd) energies. The strong hybridization of V-3d states with the O-2p state under the influence of octahedral environment reduces magnetic moment of V-atom and generates a fraction of the magnetic moments at Zn/Cd/Hg and O sites. The thermoelectric response is evaluated by calculating electrical conductivity (σ/τ), thermal conductivity (κ/τ), seebeck coefficient (S), power factor (P) and thermal efficiency by using BoltzTraP code.

Using time-resolved laser-scanning confocal microscopy and ultrafast optical pump/THz probe spectroscopy, we measure photoluminescence (PL) and THz-conductivity in perovskite micro-crystals and films. PL quenching and lifetime variations occur from local heterogeneity. Ultrafast THz-spectra measure sharp quantum transitions from excitonic Rydberg states, providing weakly bound excitons with a binding energy of ~13.5 meV at low temperatures. Ab-initio electronic structure calculations give a direct band gap of 1.64 eV, a dielectric constant of ~18, heavy electrons, and light holes, resulting in weakly bound excitons, consistent with the binding energies from the experiment. The complementary spectroscopy and simulations reveal fundamental insights into perovskite light-matter interactions.

Metal-halide perovskites are rapidly emerging crystalline materials that are reasonably preferred as leading aspirant for applications in optoelectronic and thermoelectric devices. In this paper, we have thoroughly reviewed and performed calculations to reveal optoelectronic and transport properties for a potential newcomer, Cs2PdX6 (X = Cl, Br) termed as Cesium Palladium Halides (CPH). Outcome of present computations are compared with available results and a reasonable agreement is recorded. Energy band gap computations performed reveal indirect band gap of 2.29 eV for Cs2PdCl6, which substantially reduces to 1.22 eV when ‘Cl’ is replaced by ‘Br’. Optical absorption spectra investigations performed here, in the energy range from 3 to 5 eV confirms effective utilization of these compounds in solar cells and other optoelectronic applications. In addition, the transport properties computations performed using semi-classical Boltzmann theory, shows constant pattern of thermo power near ambient temperature range (200–500 K), which admits possible utilization of these compounds as low temperature thermoelectric materials. Performed ZT calculations demonstrates reasonably good thermoelectric performance for both materials, as there exist minor variation (0.1) in the values over wide temperature ranges i.e. from 100 to 800 K. Further, detailed analysis of transport properties predicts p-type semiconducting nature of the present series of materials.

Here we report the structural, electronic, optical, and thermoelectric properties of delafossite type 2 H-CuGaO 2 using first principles calculations. The present calculation predict an indirect band gap of 1.20 eV and a direct band gap of 3.48 eV. A detailed analysis of the electronic structure is provided based on atom and orbital projected density of states. Frequency dependent dielectric functions, refractive index, and absorption coefficient as a function of photon energy are discussed. The thermoelectric properties with power factor, and the figure of merit are reported as a function of chemical potential in the region ± 0.195 ( μ − E F ) eV at constant temperature of 300 and 800 K. The thermoelectric properties shows that 2 H-CuGaO 2 could be potential candidate for engineering devises operating at high temperature for the chemical potential in the range of ± 0.055 ( μ − E F ) eV and beyond this range the thermoelectric performance of 2 H-CuGaO 2 get reduced.

We have presented the electronic and thermoelectric properties of d2/do type Heusler compounds TiXSb (X = Ge, Si) using Full Potential Linearized Augmented Plane Wave method (FP-LAPW), based on Density Functional Theory (DFT). For electron exchange, we have considered the most common Generalized Gradient Approximation (GGA), exchange potential. The electronic structure of both TiGeSb and TiSiSb showed overlapping between the valance and the conduction band, indicating their metallic nature. The transport coefficients were calculated by a post DFT treatment which involves the semi-classical Boltzmann Theory as implemented in the code BoltzTraP. The thermoelectric parameters are calculated along perpendicular and parallel directions with respect to chemical potential ( μ ) and temperature. Furthermore, we have also considered the phononic contribution to thermal conductivity ( κ p ) for better understanding of the materials thermodynamics and efficiency (ZT). The calculated ZT values showed TiSiSb as potential thermoelectric candidate at room temperature and under normal conditions, whereas TiGeSb had poor thermoelectric properties.

The oxygen evolution reaction (OER), owing to its sluggish nature, demands efficient and stable catalysts with low production cost, during the electrocatalytic water splitting. In this respect, a series of bimetallic ZnO-Ni(OH)2 composite materials were prepared as electrode materials for OER. The synthetic procedure followed the polyvinylpyrrolidone (PVP) and dopamine (DA) assisted hydrothermal process. The growth modification ability of PVP and adhesive property of polydopamine (from DA) were utilized to attain the 3D interconnected structures. The precursor concentrations were varied to obtain most efficient catalyst, ZNDP-1. In alkaline medium, ZNDP-1 showed a low over potential of 170 mV (@10 mAcm−2 current density) and a Tafel slope of 61 mV dec−1 with significant stability. The surface defects, porosity and synergism within metal centers might cause efficient electrocatalytic activity. Furthermore, DFT studies were performed to understand the mechanistic pathway.

The structural, electronic, magnetic, optical and thermoelectric properties of PrYO 3 (Y=Cr, V) have been studied by using density functional based FP-LAPW+ lo method as implemented into WIEN2k code. The analysis of band structures and density of states confirm the half metallic ferromagnetism in studied compounds. The nature and origin of ferromagnetism has been depicted in terms of crystal field energies, exchange energies involved and exchange constants. Moreover, the reduction of magnetic moment from V/Cr, Pr sites and generation of small magnetic moments on oxygen and interstitials sites leads to negative value of indirect exchange energy Δ x ( pd ) and strong hybridization. Finally, the thermoelectric behavior has been explained by discussing the electrical conductivity, thermal conductivity, Seebeck coefficient, power factor and thermal efficiency. Moreover, evaluation of PrYO 3 on the basis of its magnetic and thermoelectric properties conform that the compounds are much suitable for spintronic and thermoelectric applications.

In this paper, the optoelectronic nature of the CdGa2X4 (X = S, Se) solar cell materials are examined using full potential linear augmented plane wave (FP-LAPW) method as embodied in WIEN2K code. In present computation, we have used most suitable modified Backe-Johnson (mBJ) potential under the framework of density functional theory (DFT). The calculated electronic properties like energy band structure and density of states spectra show that these materials exhibit a direct band gap (Γ–Γ) result of 3.22 eV and 2.36 eV for CdGa2S4 and CdGa2Se4 compounds, respectively. Absorption spectra for CdGa2X4 (X = S, Se) compounds have been studied and it has been found that above the band gap, absorption are taking place and it covers wide visible spectrum energy range. On the basis of calculated band gap, density of states and absorption coefficient spectra, it is found that these compounds can be suitably applicable in optoelectronic devices such as solar cell. The evaluated properties pose well agreement with available experimental data.

In this work, electronic structure and optical properties investigations for defect-chalcopyrite semiconductors ZnGa2Te4 and CdGa2Te4 are presented using full potential linearized augmented plane wave method. Energy bands and density of states (DOS) computations are performed using different flavors of exchange and correlations. The calculations are performed using Wu-Cohen generalized gradient approximation (WC-GGA), Perdew et al. (PBE-sol) and the most accurate modified Becke and Johnson (mBJ) potentials. Our investigations show that energy bands and DOS computed using mBJ potential are in better agreement with the available experimental data. Optical properties such as, dielectric tensor components, absorption spectra, reflectivity, refractivity, dielectric loss, are investigated using mBJ potential. Imaginary peaks of di-electric tensor e 2 ( ω ) , are interpreted by means of inter-band transitions from valence to conduction band. High intensity absorption curves from 3 to 5 eV, energy band gap depicted for ZnGa2Te4 (1.61 eV) and CdGa2Te4 (1.78 eV) materials indicates their applicability for solar photovoltaic and other optoelectronic applications.

Despite serious problems associated with toxicity of lead, lead halide perovskite based solar cells have resulted with remarkable efficiency and hence gained much interest. To overcome this aspect, numerous solutions are attempted by researchers which include the development of new environmental friendly lead free double perovskite (DP) photovoltaic materials. Enlightening on the same line, we report first principle calculations on electronic and optical properties of Cs2AgInCl6 solar photovoltaic materials. Present opto-electronic computations for lead free DP compound, have been performed using the full potential linearized augmented plane wave method. In present investigations, we have adopted exchange and correlation potentials prescribed by Perdew et al. and the most accurate Tran-Blaha modified Becke-Johnson. Both exchange and correlation potential computations are performed with and without spin orbit coupling. Results obtained for electronic and optical properties are validated by systematic comparison with available experimental data. Reasonable reconciliation between investigated results and the available experimental data, endorse accuracy of present computations. To identify the effect of strain on energy gap and hence on the optical properties of Cs2AgInCl6 compound, computations of electronic and optical properties have also been performed under the different values of strain application.

In this paper, electronic and optical properties of Cs2PdCl2Br4 perovskite compound are presented using full potential linearized augmented plane wave (FP-LAPW) method. All computations are performed using most accurate modified Becke Johnson (mBJ) potential within density functional theory. Energy band computations are performed over here to elaborate relationship between energy and wave vector (k). Pattern of occurrence observed for energy bands are analyzed in terms of plotted total and partial density of states. For investigating optical behavior of Cs2PdCl2Br4, we have computed dielectric tensor, absorption spectra, reflectivity and refraction spectra using mBJ potential. Different peaks recorded in the imaginary components of dielectric tensor are interpreted in terms of interband transitions for better understanding. Significant absorption intensity available in desired energy range and suitable band gap indicates effective utilization of this compound in photovoltaic applications.

This paper focusses on the electronic and optical properties of scandium-based silver delafossite ( $$\hbox {AgScO}_2$$ ) semiconductor. The density functional theory (DFT) in the framework of full potential linearized augmented plane wave (FP-LAPW) scheme has been used for the present calculations with local density approximation (LDA) and generalized gradient approximation (GGA). Electronic properties deal with energy bands and density of states (DOSs), while optical properties describe refractive index and absorption coefficient. The energy bands are interpreted in terms of DOSs. The computed value of band gap is in agreement with that reported in the literature. Our results predict $$\hbox {AgScO}_2$$ as indirect band-gap semiconductor. Our calculated value of the refractive index in zero frequency limits is 2.42. The absorption coefficient predicts the applicability of $$\hbox {AgScO}_2$$ in solar cells and flat panel liquid crystal display as a transparent top window layer.