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The exact control of material properties essential for solar applications has been made possible because of perovskites' compositional engineering. However, tackling efficiency, stability, and toxicity at the same time is still a difficulty. Mixed lead-free and inorganic perovskites have lately shown promise in addressing these problems, but their composition space is vast, making it challenging to find good candidates even with high-throughput approaches. We investigated two groups of halide perovskite compound data with the ABX3 formula to investigate the formation energy data for 81 compounds. The structural stability was analyzed over 63 compounds. For these perovskites, we used new library data extracted from a calculation using generalized-gradient approximation within the Perdew–Burke–Ernzerhof (PBE) functional established on density functional theory. As a second step, we built machine learning models, based on a kernel-based naive Bayes algorithm that anticipate a variety of target characteristics, including the mixing enthalpy, different octahedral distortions, and band gap calculations. In addition to laying the groundwork for observing new perovskites that go beyond currently available technical uses, this work creates a framework for finding and optimizing perovskites in a photovoltaic application. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT study of structural, electronic, elastic, mechanical, and thermodynamic properties of V 2 SnX MAX phases. • Computed lattice, elastic constants, moduli; compared with V 2 SnC MAX for comprehensive understanding. • V 2 SnX found elastically, thermodynamically stable; ductile nature confirmed; metallic behavior observed. • V-d states crucial for electrical conductivity, primary contributors around Fermi energy. • Quasi-harmonic Debye model used to analyze temperature, pressure effects on moduli, Debye temp, heat capacity. The M n+1 AX n phases, known for their unique combination of metallic and ceramic properties, have attracted significant attention due to their potential applications in extreme environments. In this study, we use density functional theory to investigate the structural, electronic, elastic, mechanical, and thermodynamic properties of V 2 SnX (X = B and N) compounds. Our results confirm that both compounds are elastically, thermodynamically, and dynamically stable, with a ductile nature. The metallic behavior is further supported by electronic band structures and density of states analysis, with V- d states playing a key role in electrical conductivity. Using the quasi-harmonic Debye model, we also examine the effects of temperature and pressure, finding that the bulk modulus and Debye temperature decrease with rising pressure below 50 GPa. Based on these findings, V 2 SnX compounds are ideal candidates for high-performance applications in harsh conditions, where materials need to maintain stability, conductivity, and resistance to thermal and mechanical stress. [ABSTRACT FROM AUTHOR]

We are attempting to study the properties of new materials based on Diamond-like semiconductors (DLS). Due to broad collection of useful properties, DLS are exciting materials to study. The novel substances Li2MnGeS4 and Li2CoSnS4 result from using a rational and guileless design approach that leads the discovery of DLSs with wide-ranging regions of optical transparency. So here, we have analyzed their applications in atomic devices and system called "optoelectronic" using the FP-APW method and mBJ method. The band gap value for Li2MnGeS4 is 2.911 eV and Li2CoSnS4 is 2.45 eV. The present DLS materials confirm their semiconductor characters. The presence of iron and manganese in these compounds have generated magnetic properties that we explored by the calculation of magnetic moment and spin-densities maps. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT + U + SOC approaches were used to examine structural and optoelectronic properties of pyrochlores Ta 2 A 2 O 7. • Band gap values show Ta 2 A 2 O 7 compounds are semiconductors. • Optical properties report Ta 2 Cd 2 O 7 has a higher value of the refractive index, reflectivity, absorption compared to Ta 2 Ge 2 O 7. • These pyrochlore oxides can effectively absorb photons in the UV energy range. • These pyrochlore oxides have refractive indices that range from 1.0 to 2.0. • These compounds are excellent for photovoltaic device applications if their band gap can be narrowed with the right doping. Due to their stable crystal structure and controllable lattice parameters, rare earth zirconates with pyrochlore type structures have demonstrated a promise for usage in practical applications. We have investigated the electronic and optical properties of pyrochlore oxide compound named Ta 2 A 2 O 7 (A = Cd and Ge) using density functional theory based on spin–orbit coupling and Hubbard (SOC + U) corrections to consider the existence electronic d orbitals of (A) and f elements (Ta). This study focuses on the characterization and investigation of pyrochlore oxides with the A 2 B 2 O 7 composition, which have significant technological applications including quantum spin ices, solid oxide fuel cells, and nuclear waste forms. No evidence regarding magnetic moment is obtained from the first run with spin-polarization setup. Also, from the spectra of TDOS was showing a similar overall profile for both spin channels. The electronic properties (total and partial) densities of states as well as the optical properties such as the complex dielectric function, refractive index, absorption coefficient and reflectivity for wavelengths in the visible spectrum have been reported to explore the potential use of these compounds in technological applications. Consequently, the investigated compounds can be used in optoelectronic device fabrication. [ABSTRACT FROM AUTHOR]

Theoretical simulations were designed by first principles approach of density functional theory to investigate the structural and optoelectronic properties of different structural classes of perylene; isolated perylene, diindeno[1,2,3-cd:1′,2′,3′-lm]perylene (DIP) molecule and DIP molecular crystal. The presence of molecular interactions in DIP crystal proved its structure-dependent behaviours. The herringbone molecular arrangement of DIP crystal has influenced the electronic properties by triggering the intermolecular interactions that reduced the energy gaps between HOMO and LUMO of the crystal. Strong hybridization resulting from dense charges population near zero Fermi energy has pushed valence band maxima in the density of states of all perylene structures to higher energies. Under small energy input, charges are transferred continuously as observed in the spectra of conductivity and dielectric. The existence of strong absorption intensities are consistent with the former works and supported by the obtained polarized reflectivity and loss spectra. [ABSTRACT FROM AUTHOR]

We present a systematic study of the low temperature and hexagonal structure of magnesium borohydride, a crystalline material designed for hydrogen storage purpose. We investigated, using ab-initio calculations, the structural, electronic and optical properties. Our calculated results for structural parameters nicely agree to the experimental measurements. The predicted elastic constants and related mechanical properties demonstrate its profound mechanical stability as well. The analysis of electronic structure reveals an insulator nature with a direct band gap about 6.55 eV in the Γ - Γ direction. This distinguish feature of Mg(BH 4 ) 2 , like many other hydrides, depicts it as suitable substitute for large band gap material. The bonding behavior was also investigated in detail from the charge densities and effective charge populations. The hydrogen (H 2 ) storage capacity is found to be 14.94 wt.% within a reasonable reaction enthalpy of −44.35 kJ mol −1 . This might be easily affordable to consider Mg(BH 4 ) 2 as potential material for practical H 2 storage devices. [ABSTRACT FROM AUTHOR]

In this study, we report investigations of structural and electronic properties of ZnO in wurtzite (WZ), rock salt (RS) and zinc-blende (ZB) phases. Calculations have been done with full-potential linearized augmented plane wave plus local orbital method developed within the frame work of Density Functional Theory (DFT). For structural properties investigations, Perdew and Wang proposed local density approximations (LDA) and Perdew et al. proposed generalized gradient approximations (GGA) have been applied. Where for electronic properties in addition to these, Tran–Blaha modified Becke–Johnson (mBJ) potential has been used. Our computed band gap values of ZnO in WZ and ZB phases with mBJ potential are significantly improved compared to those with LDA and GGA; however, in RS phase, energy gap is significantly overestimated compared to experimental measurements. The Zn-d band was found to be more narrower with mBJ potential than that of LDA and GGA. On the other hand, our evaluated crystal field splitting energy values overestimate the experimental values. [ABSTRACT FROM PUBLISHER]

• Opto-electronic properties of Yb doping BaTiO 3 at the Ba and Ti sites with DFT. • U correction to describe the f states of the Yb dopant. • Band structures and DOS have confirmed the semiconductor nature of BaTiO 3. • Yb doping induces spin-polarized O 2p states for Ti site and Yb 4 f states near the Fermi level. • Dielectric constants for different axes have increased with the Yb doping. Oxide perovskites doped with rare-earth have shown change in optoelectronic properties with high dielectric constants. Herein, the structural, electronic, and optical characteristics of BaTiO 3 doped with ytterbium at the Ba and Ti sites were studied by employing the first-principles density functional calculations. The Tran-Blaha modified Becke-Johnson (TB-mBJ) potential and GGA + U approaches have been used for determining the optoelectronic properties. We probed the impact of the ytterbium incorporation at the Ti and Ba sites into BaTiO 3 by tuning of the structural geometry and electronic structure behavior and dielectric constants. A detailed analysis, of structural properties, reveals that lattice parameters of ytterbium doping shift slightly regarding those of pristine BaTiO 3. The Ba O and Ti O bond lengths were reduced due to the crystalline structure lattice distortion. The band structures demonstrate that ytterbium doping has induced various changes in the electronic nature of BaTiO 3 by creating a magnetism. For both Ba and Ti sites, ytterbium doping has strongly increased the BaTiO 3 dielectric constants. [ABSTRACT FROM AUTHOR]

We used two computational approaches to study hybrid perovskites tin-based photovoltaic solar cells. The first approach is based on electronic transport properties with density functional theory in combination to non-equilibrium Green's function formalism. We have investigated the transmission spectra and density of states. It was observed that the transmission gap decreases when it moves from MASnI 3 to MASnBr 3 exhibiting a larger electronic transport, thanks to delocalization of electronic state. The second approach is based on the drift-diffusion simulation, from which hybrid perovskites tin-based photovoltaic solar cells parameters were found notably dependent on the perovskite absorber layer thickness. The solar cell performance could be improved with surface recombination velocities in the range of 1–101 cm/s and 102–103 cm/s reaching efficiency of 16.07% and 12.52% for MASnIBr 2 and MASnBr 3. • Electronic transport properties of Sn-based perovskites are investigated with DFT and NEGF. • CH 3 NH 3 SnI 3 exhibit larger electronic transport compared to CH 3 NH 3 SnBr 3. • I–V curves illustrate a sensitive response from X = Br to I for CH 3 NH 3 SnX 3 perovskites. • Glass/FTO/PEDOPSS/Perovskite/TiO 2 device is modeled with drift-diffusion models • Solar cell parameters are notably dependent on the perovskite absorber layer thickness. • Solar cell performance improved by quantifying the surface recombination velocities. [ABSTRACT FROM AUTHOR]

We reported first principles calculations of electronic and related optical and thermoelectric properties of two metal-rich palladium–indium selenides Pd 5 InSe and Pd 8 In 2 Se. Both selenides are found to be metallic and their densities of states at the Fermi energy, N (E F), showed an overlap between the Pd- s/p , In -p and Se -p states. Specific heat coefficients were found 0.52 and 0.743 mJ/mol·K2, for Pd 5 InSe and Pd 8 In 2 Se, respectively. Our findings indicate that the linear optical properties have potential use as active photo-catalyst under visible light irradiation. We combined the Boltzmann transport equations with density functional theory to determine the thermoelectric and electrical properties of both compounds. At 300 K, the Seebeck coefficient of Pd 8 In 2 Se is larger than Pd 5 InSe one. Due to their metallic character, both selenides have limited thermoelectric use in their current structures and could be doped to change their electronic structures to narrow semiconductors or semi-metallic materials. Image 1 • DFT calculations of electronic, optical and thermoelectric properties of Pd 5 InSe and Pd 8 In 2 Se. • Both selenides are found metallic. • Linear optical properties have potential use as active photo-catalyst under visible light irradiation. • Boltzmann transport model combined with DFT to determine the thermoelectric properties. [ABSTRACT FROM AUTHOR]

• Europium contributed NiO thin layers were grown on glass substrates via sol-gel spin coating. • The crystal structure, surface topography, optical character of pure NiO sample were investigated. • XRD/AFM observations revealed that NiO:Eu films were nano-sized polycrystalline cubic bunsenite structure with preferential direction. • Ab-initio calculations have elucidated the changes in electronic, magnetic and optical properties. Europium doped NiO thin films were grown onto glass substrates via sol-gel spin coating. The evolution of crystal structure, surface topography, and optical properties of NiO was investigated as a function of Eu doping concentration. AFM observations and XRD analysis revealed that NiO:Eu films composed of nano-sized grains exhibit a polycrystalline cubic bunsenite structure with (200) preferential orientation. Optical study showed that the optical band gap of doped NiO films initially increased with low Eu incorporation ratio then decreased with higher Eu content. However, the Urbach energy increased gradually with Eu doping level. First principle calculations were performed to elucidate the changes on electronic, magnetic and optical properties of NiO due to Eu doping. The incorporation of Eu within NiO host lattice induced a strong hybridization between Eu- f and Ni- d states resulting in important changes of bulk magnetization. [ABSTRACT FROM AUTHOR]

Tailoring the energy gap of ZnO through Cd doping renders Cd:ZnO an intriguing material for photovoltaic and solar cell applications. Unfortunately, the Cd:ZnO blend is unstable, a feature attributed to the structural differences between the parent hexagonal ZnO and cubic CdO. We here report a comparative density functional theory (DFT) study of zinc-blend (ZB) and wurtzite (WZ) ZnO doped with Cd – upto 37.5% of the Zn atoms were substituted by an isovalent Cd. Interestingly, the nearly equivalent total energy of the ZB and WZ Cd:ZnO blends reflects the relative stability of the cubic phase. The formation enthalpies increase linearly with increasing Cd concentration. Cd insertion into ZnO is found to have an insignificant effect on the ZnO structure, with only a slight increase of the lattice constants that follow Vegard׳s formulation. Cd dopants efficiently reduce the electronic band gap of ZnO and in turn the absorption edge and optical energy gap are red-shifted. The Cd:ZnO blends exhibit a lower energy gap in the cubic phase as compared to the hexagonal phase, suggesting that a specific energy gap can be achieved at relatively lower Cd contents in the ZB. The lighter effective free-carrier masses in WZ-Cd:ZnO suggest a higher conductivity and mobility as compared to ZB and the parent ZnO. The narrow energy gaps indicate that both hexagonal and cubic Cd:ZnO systems have potential as material for solar energy applications. [ABSTRACT FROM AUTHOR]

Different concentrations of zirconium with a fixed quantity (4 wt%) of chitosan (CS) doped nickel cobaltite (NiCo 2 O 4) nanorods were synthesized using a co-precipitation approach. This cutting-edge research explores the cooperative effect of Zr-doped CS-NiCo 2 O 4 to degrade the Eriochrome black T (EBT) and investigates potent antibacterial activity against Staphylococcus aureus (S. aureus). Advanced characterization techniques were conducted to analyze structural textures, morphological analysis, and optical characteristics of synthesized materials. XRD pattern unveiled the spinal cubic structure of NiCo 2 O 4 , incorporating Zr and CS peak shifted to a lower 2θ value. UV–Vis spectroscopy revealed the absorption range increased with CS and the same trend was observed upon Zr, showing a decrease in bandgap energy (Eg) from 2.55 to 2.4 eV. The optimal photocatalytic efficacy of doped NiCo 2 O 4 within the basic medium was around 96.26 %, and bactericidal efficacy was examined against S. aureus , revealing a remarkable inhibition zone (5.95 mm). [ABSTRACT FROM AUTHOR]

Abstract We presented a theoretical study of electronic band structure of three compounds ZnAl 2 Te 4 , ZnGa 2 Te 4 and ZnIn 2 Te 4 using pseudo potential method within density functional theory. Calculated band structures show that all band gaps are direct with at Γ with values of 1.639eV for ZnAl 2 Te 4 , 1.026eV for ZnGa 2 Te 4 and 0.836eV ZnIn 2 Te 4. The linear properties based on dielectric function and non-linear optical properties based on second harmonic generation (SHG) were computed. The origin of four critical points (peaks) determined from the second derivative of the imaginary part of the dielectric function is elucidated. The use of individual k-points and individual combination of valence and conduction bands dependent matrix of the dielectric function and the nonlinear optical susceptibility allowed to a precise determination of inter band optical transitions. Indeed, inter-band analysis shows the high intensity of non-linear effect compared to linear effect. Moreover, non-linear inter-band optical transitions involve lower valence bands and higher conduction bands. Graphical abstract Image Highlights • Non-linear optical properties based on second harmonic generation (SHG) were elucidated. • The inter-band analysis shows the high intensity of non-linear effect compared to linear effect. • Non-linear inter-band optical transitions involve both lower valence and higher conduction bands. [ABSTRACT FROM AUTHOR]

In this research, Ag (3 and 6 wt %) and carbon sphere (CS) (3 wt. %) were successfully incorporated into Fe 2 O 3 using a co-precipitation approach. This study aimed to degrade the methylene blue (MB) dye and investigate the bactericidal effect of doping-dependent Fe 2 O 3. The pristine sample has good stability and is less toxic however showed poor degradation potency. To enhance the catalytic activity (CA), CS was introduced as it increases Fe 2 O 3 adsorption capacity and improves metal oxide properties. Ag was incorporated into CS-Fe 2 O 3 , which created additional active sites and might generate reactive oxygen species (ROS). XRD patterns revealed the tetragonal and monoclinic structure of Fe 2 O 3 , and crystallinity was enhanced with dopants (Ag and CS). FTIR was performed to identify vibrational and rotational modes and functional groups of samples. SAED pattern represented the polycrystalline structure of Fe 2 O 3 and (3 & 6 wt%) Ag/CS-Fe 2 O 3. UV–vis spectroscopy depicted that absorption decreased with the increasing amount of Ag/CS and increased band gap energy (E g). PL spectra of doped Fe 2 O 3 represent the reduction in recombination rate resulting in enhanced CA. EDS spectra exhibited the presence of Fe, O, Na, Au, and C, which confirmed the elemental composition of pristine and doped samples. TEM images indicate nanorods (NRs) of Fe 2 O 3 , and HRTEM provides interlayer d-spacing increased upon doping. The nanostructures exhibited excellent CA for the degradation of MB dye in an acidic medium, around 99.44%. Ag/CS-Fe 2 O 3 (6 wt %) nanostructures have shown a significant increase in the inhibition zone (3.65 mm) against Escherichia coli (E. coli) at high-level doses. This study suggests that (3 & 6 wt%) Ag/CS-Fe 2 O 3 nanostructures revealed superior catalytic and antibacterial activity for wastewater treatment. First-principles calculations indicate that the adsorption energies show a relatively strong interaction between MB and (3 & 6 wt%) Ag/CS-Fe 2 O 3. • Fe 2 O 3 and Ag/carbon sphere-doped Fe 2 O 3 were synthesized via co-precipitation. • Better antimicrobial activity was observed with an optimum amount of dopants. • This research elaborates the catalytic behavior of nanocatalysts on MB dye. • Doping host matrix with Ag/Carbon sphere showed lowest photoluminescence intensity. [ABSTRACT FROM AUTHOR]

Highly mismatched alloys (HMAs) are getting a substantial interest of researchers because of holding competence of rapid change in physical properties with minor compositional change and consequently showing their potential for solar energy and photovoltaic applications. In the present density functional theory based work, we design HMAs from the extremely dissimilar GaP (semiconductor) and GaBi (semi-metal). The alloying of the two compounds with unmatched electronic characteristics has triggered a rapid reduction in the energy gap of GaPBi. The energy gap is reduced by 39.3 meV for every 1% increase in Bi composition. The semiconductor behavior of GaPBi based HMAs is found to be transformed to semi-metallic for replacing 64.6% of P atoms by Bi. Unlike the conventional alloys, the variation in the electronic energy gap of GaP 1-x Bi x shows deviation from the Vegard's formalism. Where the optical properties are strongly influenced with the narrowing energy gap of GaPBi. For the Bi-rich GaPBi, the notable red shift is observed in optical dielectric function and absorption spectra. Moreover, the larger atomic size of Bi has enhanced the lattice parameters of Bi-rich GaPBi. The GaPBi based HMAs with tunable energy gap in the span of 2.51 eV–0 eV and the interesting optical properties highlight them prospective materials for optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this study, we investigated the electronic and transport properties of the Vinazene molecular device using the non-equilibrium Green’s function (NEGF) formalism combined to the density functional theory (DFT). Transmission spectrum revealed a high tendency of electrons congregate near to the right gold electrode, resulting in an easy electrons transmission from the right gold electrode to the molecule with bias. Similarly, from the density of states calculations, strong electronic interaction between Vinazene molecule and gold electrodes was observed at the molecular junction. The self consistently obtained I-V characteristics curve demonstrated a continuously increase in current with bias as well. Thus, the achieved sinusoidal conductance curve has proven that the transmission channel of the present Vinazene device possessed a steady opening that led to a stable conducting ability of the device. Our calculated efficiency of the Vinazene single molecule solar device, 0.015%, highlights its promise for organic photovoltaic applications. [ABSTRACT FROM AUTHOR]

The electronic, magnetic and thermoelectric properties of Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 compounds were investigated using the full potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The exchange correlation was treated with the generalized gradient approximation plus optimized effective Hubbard parameter and spin–orbit coupling (GGA+U+SOC). The present uranium selenides show narrow direct energy band gap values of 0.7 and 0.875 eV for Tl 2 Ag 2 USe 4 and Tl 3 Cu 4 USe 6 respectively. For both selenides U- d/f states are responsible for electrical transport properties. Uranium atoms were the most contributors in the magnetic moment compared to other atoms and show ferromagnetic nature. The spin density isosurfaces show the polarization of neighboring atoms of Uranium, such as silver/copper and selenium. Thermoelectric calculations reveal that Tl 3 Cu 4 USe 6 is more suitable for thermoelectric device applications than Tl 2 Ag 2 USe 4 . [ABSTRACT FROM AUTHOR]

III–V compounds containing heavy Bi anion are distinguished from remaining III–V family in terms of their narrower electronic energy gap and potential application for infrared/near infra devices. In the present work, modeling of X–Bi (X = B, Al, Ga and In) compounds and the investigations pertaining to their physical properties were carried out using density functional theory (DFT) based full-potential linearized augmented plane wave plus local orbital, FP-L(APW + lo) approach within various functional of the exchange correlation potentials. The calculated total energies of X–Bi in various geometries reveal that zinc blende phase is the stable ground state structure of BBi, AlBi and GaBi. However, InBi adapts PbO phase at ground state. It was also found that BBi exhibit an electronic structure with an indirect energy gap. However, AlBi, GaBi and InBi are semi-metallic with a narrower or zero band gap. The calculation of the optical properties show that among X–Bi compounds, BBi was found to exhibit higher absorption coefficient values, lower reflectivity and refractive index, enlightening their potential for infrared/near infra devices and other optoelectronic applications as well. [ABSTRACT FROM AUTHOR]

Wurtzite GaInN alloys with flexible energy gaps are pronounced for their potential applications in optoelectronics and solar cell technology. Recently the unwanted built-in fields caused by spontaneous polarization and piezoelectric effects in wurtzite (WZ) GaInN, has turned the focus towards zinc-blende (ZB) GaInN alloys. To comprehend merits and demerits of GaInN alloys in WZ and ZB structures, we performed a comparative study of the structural, electronic and optical properties of Ga1-xInxN alloys with different In concentration using first-principles methodology with density function theory with generalized gradient approximations (GGA) and modified Becke-Johnson (mBJ) potential. Investigations pertaining to total energy of GaInN for the both phases, demonstrate a marginal difference, reflecting nearly equivalent stability of the ZB-GaInN to WZ-GaInN. The larger ionic radii of indium (In), result in larger values of lattice parameters of Ga1-xInxN with higher In concentration. For In deficient Ga1-xInxN, at first, the formation enthalpies increase rapidly as the In content approaches to 45% in WZ and 47% in ZB, and then decreases with the further increase in In concentration. ZB-Ga1-xInxN alloys exhibit comparatively narrower energy gaps than WZ, and get smaller with increase in In contents. The smaller values of effective masses of free carriers, in WZ phase, than ZB phase, reflect higher carrier mobility and electrical conductivity of WZ-Ga1-xInxN. Moreover wide energy gap of WZ-Ga1-xInxN results in large values of the absorption coefficients comparatively and smaller static refractive indices compared to ZB-Ga1-xInxN. Comparable electronic and optical characteristics of the ZB-Ga1-xInxN to WZ-Ga1-xInxN endorses it a material of choice for optoelectronics and solar cell applications besides the WZ-Ga1-xInxN. [ABSTRACT FROM AUTHOR]

Abstract: Stimulation of novel features in ZnO by impurity electrons has attracted a remarkable attention of researchers from the past decade. Consequently, ZnO has found several applications in the field of spintronics and optoelectronics. We report, the effect of 3d-(V, Ag) electrons on the properties of ZnO in stable wurtzite (WZ) and metastable zincblende (ZB) phase using the density functional theory. Introduction of V-3d electrons was found to induce a high magnetic moment value of 5.22 in WZ and 3.26 in the ZB phase, and moreover transform the semiconductor character of ZnO into a metallic nature. Ag-d electrons result in the p-type half-metallic nature of ZnO with a weak ferromagnetic background. Our calculations for ground-state magnetic ordering show that ZnO in the presence of impure 3d-(V, Ag) electrons favors ferromagnetic ordering, and obey the double exchange mechanism. However, impurity atoms have very marginal effect on the lattice parameters of ZnO, thereby exposing its potential to absorb the impurity atoms in high concentration. [Copyright &y& Elsevier]

Abstract: By employing the state of art first principles approaches, comprehensive investigations of a very promising hydrogen storage material, Mg2FeH6 hydride, is presented. To expose its hydrogen storage capabilities, detailed structural, elastic, electronic, optical and dielectric aspects have been deeply analysed. The electronic band structure calculations demonstrate that Mg2FeH6 is semiconducting material. The obtained results of the optical bandgap (4.19eV) also indicate that it is a transparent material for ultraviolet light, thus demonstrating its potential for optoelectronics application. The calculated elastic properties reveal that Mg2FeH6 is highly stiff and stable hydride. Finally, the calculated hydrogen (H2) storage capacity (5.47 wt.%) within a reasonable formation energy of −78kJmol−1, at room temperature, can be easily achievable, thus making Mg2FeH6 as potential material for practical H2 storage applications. [Copyright &y& Elsevier]

Highlights: [•] Mutual alloying of XAs (X=Ga, In, Al) materials is investigated with DFT. [•] XAs materials are suitable for optoelectronic and solar energy applications. [•] Energy gap of Ga1−xAl x As and In1−xAl x As was found to be increased with x. [•] Mutual alloying with different concentrations is useful to tune their properties. [Copyright &y& Elsevier]

The lithium zinc iodate polymorph α-LiZn(IO 3) 3 has been prepared by two different chemical routes using precipitation and heat treatment methods. The optical bandgap of αLiZn(IO 3) 3 was found experimentally to be 4.00 eV confirming the theoretical band gap of 3.93eV as obtained by HSE06-DFT approach. The thermal study of nano mixture lithium zinc iodate has been studied by the non-isothermal simultaneous TG and differential scanning calorimetry. The theoretical and experimental mass loss data are in good agreement for the thermal decomposition. Morphological and compositional analyses were carried out by using scanning electron microscopy and energy-dispersive X-ray measurements. The various phases were studied by powder X-ray diffraction were explored. Density functional theory was used to explore structural and optical properties of two predicted Lithium Zinc iodate polymorphs (LZI-P 21), and (LZI-P 63). The calculated electronic band structure and density of states show that both polymorphs have an indirect band gap an optical birefringence of 0.29 respectively. • The lithium zinc iodate polymorph α-LiZn(IO 3) 3 has been prepared by two different chemical routes. • The optical bandgap of αLiZn(IO 3) 3 was found experimentally to be 4.00 eV. • Morphological and compositional analyses were carried out using SEM and EDX measurements. • DFT was applied to explore optical properties of α-LiZn(IO 3) 3 polymorph. [ABSTRACT FROM AUTHOR]

Abstract: The current study investigates the structural, elastic, electronic and optical properties of CeO2, PrO2 and TbO2 using the full potential (linearized) augmented plane wave plus local orbital method within the Wu–Cohen generalized gradient approximation (GGA) with Hubbard (U) correction and spin–orbit coupling (SOC). The GGA+U implementation lead us to describe correctly the relativistic effect on 4f electrons for CeO2. We clarify that the inclusion of the Hubbard U parameter and the spin–orbit coupling are responsible for the ferromagnetic insulating of PrO2 and TbO2. The magnetic description is achieved by the spin-density contours and magnetic moment calculations, where we show the polarization of oxygen atoms from the rare earth atoms. The mechanical stability is shown via the elastic constants calculations. The optical properties, namely the dielectric function and the reflectivity are calculated for radiation up to 12eV, giving interesting optoelectronic properties to these dioxides. [Copyright &y& Elsevier]

• The ability of PtX{1 1 1} (X = Mo, W) alloys to catalyze the dissociative adsorption reaction of H 2. • Four different sites were investigated: top, bridge, fcc hollow and hcp hollow. • Reducing the cost of proton exchange membrane fuel cells. • Top site is suitable for adsorption and dissociation of the dihydrogen. • The platinum alloy achieves a superior adsorption and dissociation distance from the surface. We reported the density functional theory investigations of the potentiality of platinum alloys with a transition metal PtX {1 1 1} (X = Mo, W) to catalyze the dissociative adsorption reaction of the dihydrogen molecule. We have analyzed the electron density, the density of state (DOS), the Mulliken population, the adsorption energy as well as the adsorption distance. Our aim was to describe the kinetic of the catalysis reactions and see if there is dissociation of the dihyrogen molecule. Also determine the adsorption site position on the upper surface. The most suitable site for dissociation and adsorption of the dihydrogen is the top site. The platinum alloy achieves a significant adsorption and dissociation distance compared to the pure surface. In addition, the most important adsorption energy is attributed to the tungsten alloy, followed by molybdenum alloy and then pure platinum. The initial emitted hypothesis is that the best configuration that favors the dissociation of dihydrogen is the top site in the case of the molybdenum alloy. [ABSTRACT FROM AUTHOR]

We synthesized pure Zn(IO 3) 2 structures employing a chemical method and characterized them using the electron microscopy to understand the effect of acidity on particle size. The average particle size of Zn(IO 3) 2 sample was measured to be 46 nm. We analyzed the results of X-ray diffraction characterization, scanning electron microscopy (SEM), UV–vis absorbance and FTIR spectra. Structural, mechanical, electronic, and related linear optical properties of monoclinic Zn(IO 3) 2 have been explored using density functional theory (DFT) methodology based on pseudo-potential plane wave method approach. The electronic structure shows that Zn(IO 3) 2 has an indirect band gap of 2.59 eV. This value is underestimated, due to DFT shortcoming, compared to the experimental optical band gap that was extracted from the absorbance curve and evaluated at 3.53 eV. The dielectric functions and associated optical responses spectra were calculated. The present zinc iodate could be considered as a promising material for optoelectronics and nonlinear optics applications. • Simple synthesis of Zn (IO 3) 2 using a chemical method at low temperature with lower cost. • Different characterization with XRD, SEM, UV–vis absorbance and FTIR spectra. • Structural, mechanical, electronic, and related linear optical from DFT. • Iodates with indirect band gap of 2.59 eV ideal for laser frequency conversion. [ABSTRACT FROM AUTHOR]

In optoelectronics, the perovskite structures in layered form, also called pyrochlore have been demonstrated to be very largely favorable to the insertion of lanthanides ions, which led them to create new phosphor emitting in a broad spectral range going from visible to near infrared. The pyrochlore oxides such as La 2 Sn 2 O 7 have attained much interest due to their electronic and optical properties. In the present work, we used first-principle calculations to compute the electronic band structure and related optical properties for pure La 2 Sn 2 O 7 and La 2 Sn 2 O 7 doped with europium. Spin orbit coupling (SOC) and electron-electron interaction, both within the generalized gradient approximation plus Hubbard parameter U (SOC ​+ ​GGA ​+ ​U) approximations have been used within the framework of density functional theory (DFT). It was found that La 2 Sn 2 O 7 compound exhibits a direct band gap semiconductor with 2.7 ​eV. Doping of europium further decreases the band gap of pyrochlore of material up to 1.8 ​eV. Optical properties revealed that both compounds are potential materials for optoelectronic device fabrication. Image 1 • For computations of band structure and optoelectronic properties of La 2 Sn 2 O 7 and La 2 Sn 2 O 7 : Eu, GGA ​+ ​U ​+ ​SOC approximation has been used. • La 2 Sn 2 O 7 compound is direct bandgap semiconductor having gap 2.7 ​eV. • Doping of Europium further decreases the bandgap of pyrochlore of material up to 1.8 ​eV. • The results of optoelectronic properties revealed the investigated compounds can be used in optoelectronic device fabrication. [ABSTRACT FROM AUTHOR]

Inorganic halide perovskites especially CsPbI 3 have attracted great attention in optoelectronics and photovoltaic fields due to their good thermal stability and comparable efficiency with organometallic perovskites. CsPbI 3 has two main phases, active black phase at high temperature and inactive yellow phase at low temperature. To obtain the perovskite phase, thin films should be heated above 320 °C, this high temperature can damage the flexible substrates. Recently, it has been suggested that partial or total substitution of iodide by bromide such as CsPbI 3−x Br x , could stabilize the preferred perovskite black phase at lower temperature. Hence, it was very necessary to investigate the electronic and optical characteristics of these materials. The structural, electronic, some carrier transport and optical properties of all-inorganic cesium lead mixed halide perovskite with a low symmetry orthorhombic structure were methodically investigated using density functional theory. • Inorganic halide perovskites especially CsPbI 3 with black phase is explored. • Partial or total substitution of iodide by bromide such as CsPbI 3−x Br x , could stabilize it in black phase. • Electronic and optical characteristics of as CsPbI 3−x Br x are computed with x variation. • The structural and energy stability are enhanced with iodine partial substitution. • Iodine.→ bromine substitution decrease the absorption of mixed halide perovskite. [ABSTRACT FROM AUTHOR]

Cd-doped ZnO nanosheet (ZnO NS) were investigated using a full-potential linearized augmented plane wave method within the generalized gradient approximation (GGA) to calculate the electronic structure and its optical response. The calculated band structures have shown that the Cd-doped ZnO NS is a direct band gap semiconductor at Γ with 1.50 eV band gap. The contribution of each atom/orbital were commented in light of total and partial densities of states. We also derived the optical constants (mainly the dielectric constantsε1(0) andε2(0)), the absorption coefficientI(ω), refractive indexn(ω), extinction coefficientk(ω), and energy-loss functionL(ω). The spectrum of absorption coefficient has revealed to increase rapidly for photon energies higher than 2.5 eV. The absorption spectrum was found to be limited in energy region due to different contributions electronic transitions that occurred within ZnO NS and effect of Cd doping. Reducing the band gap of ZnO NS to low values is suitable process for light-emitting devices and solar cells applications. [ABSTRACT FROM PUBLISHER]