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We evaluate the structural, optoelectronic, and mechanical characteristics of the novel Rb2CaSnCl6 and Rb2CaSnI6 through density functional theory within the WIEN2K framework. The formation energies and volume optimization provide evidence for the structural stability of these compounds. The optimized lattice constants for Rb2CaSnCl6 and Rb2CaSnI6 are found to be 11.21 Å and 12.45 Å, respectively while their respective formation energies are calculated as − 2.5 Ry and − 1.6 Ry. Similarly, the grounds state energies are calculated − 31,184.32 Ry and − 111,074.60 Ry. We find that Rb2CaSnCl6 is an insulator with a bandgap energy of 3.50 eV when the modified Becke-Johnson (mBJ) approximation is applied and that Rb2CaSnI6 is directly semiconducting with a wide bandgap energy of 2.70 eV. Evaluations of mechanical stability show that both materials are mechanically stable and their constituent atoms are bound together by ionic interactions, indicated by the positive value of Cauchy's pressure: 46. 32 and 21.93 for Rb2CaSnCl6 and Rb2CaSnI6, respectivley. Nevertheless, our investigation showed that Rb2CaSnI6 behaves as a ductile material while Rb2CaSnCl6 is brittle. We also investigate a variety of optical characteristics such as dielectric function, refraction, reflectivity, energy loss function, and extinction coefficient. The static dielectric function was found to be 2.9 and 4.3 for Rb2CaSnCl6 and Rb2CaSnI6, respectively. Rb2CaSnI6 exhibited greater optical conductivity, indicative of it being a better metallic than the Rb2CaSnCl6. The optical investigation suggests that these materials have a great deal of promise for cutting-edge optoelectronic applications, especially in the ultraviolet (UV) spectrum due to their large electronic band gap. These results offer a solid basis for future research into these intriguing materials by experimentalists. [ABSTRACT FROM AUTHOR]

In the twenty-first century, a key focus is the search for materials that hold promise for energy generation and storage. Solar energy, with its abundant availability and minimal impact on the environment, stands out as one of the most important renewable energy sources. Metal halide perovskites have emerged as a fascinating group of materials that offer significant advantages for various photovoltaic and optoelectronic applications. The calculated "τ" values for AgBeX3 (X = F and Cl) metal halide perovskites are found to be 1.007 for AgBeF3 and 0.9 for AgBeCl3, indicating the stability of both materials in the cubic perovskite structure. The band structure and density of states reveal a strong correlation in the electronic properties, indicating that AgBeCl3 is an indirect large band gap semiconductor with a band gap of 3.25 eV from M–Γ. On the other hand, AgBeF3 is an insulator with an indirect band gap of 4.25 eV from X–Γ. Both the AgBeX3 (X = F and Cl) metal halide perovskite compounds were subjected to mechanical analysis, revealing their ductile nature, stability, resistance to scratching, and anisotropic properties. The comprehensive examination of the optical properties reveals that these metal halide perovskites exhibit exceptional characteristics, making them highly suitable for a diverse array of optoelectronic applications. Their unique optical and electronic properties position them as an excellent material family for various optoelectronic devices. Based on the findings from the research, we recognize the potential applications of these selected materials in energy generation and storage devices. [ABSTRACT FROM AUTHOR]

We study the theoretical and simulated shielding properties of 69P2O5–10Gd2O3–10BaO–10ZnO–1Er2O3 and 69P2O5–10GdF3–10BaO–10ZnO-1Er2O3 glasses. We exploit advanced simulation (MCNPX) and Phy-X, an online Photon Shielding and Dosimetry software, in the 0.001–15 MeV energy range, to calculate the linear attenuation coefficient and mass attenuation coefficients of the samples. The obtained mass attenuation coefficient is then used to calculate the critical radiation shielding characteristics, such as the half-value layer, mean free path, tenth value layer, and effective atomic number. The calculated LAC values range from 108.759 to 0.097 and from 84.124 to 0.087 cm−1 while HVL values range from 0.006 to 7.164 and from 0.008 to 8.013 cm, and MFP values vary from 0.009 to 10.335 and from 0.012 to 11.561 cm for ZBaOEr and ZBaFEr, respectively, with energy ranging from 0.015 to 15 MeV. We find that the results obtained from MCNPX and Phy-X are consistent with each other, based on the computed relative difference. The glass sample containing Gd2O3 exhibits better shielding properties than the one with GdF3, over the entire energy range. Our examined glass samples are thick enough to substantially lessen the intensity of incident X-rays and gamma rays. [ABSTRACT FROM AUTHOR]

We present a theoretical comprehensive study which predicts and examines the outcomes of the structural, elastic, electronic, and optical properties of berylliumbased fluoroperovskite BeMF3 (M = Ti and V) compounds which was performed based on DFT (Density Functional Theory). The theoretical computation was done through the simulation package of WIEN2k, in which the implemented method of Full-Potential Linearized Augmented Plane Wave (FP-LAPW) was used. For the treatment of exchange correlation potential, the Generalized Gradient Approximation (GGA) was used for structural and elastic properties while the Modified Becke-Johnson (mBJ) exchange potential was used for a better understanding of the electronic and optical properties. Structural optimization was done with the Birch-Murnaghan equation of state, for the outcomes of fundamental optimized lattice parameters. The optimized 4.0833 Å and 4.0112 Å lattice constants were found for the BeTiF3 and BeVF3, respectively, and we found that both these compounds were structurally stable. For the computation of the elastic constants (ECs) of these crystals the IRelast package was used. Elastically these compounds were found to be mechanically stable because they satisfy the stability criteria, and are anisotropic and ductile in nature. Both the compounds of interest are metallic in nature and have overlapping valence and conduction bands. The TDOS and PDOS (total and partial density of state) plots were used to infer the relevance of the states contributed by each constituent element to the valence and conduction bands. Important optical properties, namely the dielectric function ε(ω), optical conductivity σ(ω), reflectivity R(ω), refractive index η(ω), and extinction coefficient k(ω) were examined and evaluated in a wide energy range (0-40 eV). Both the compounds were found to possess high optical conductivity in the low energy range, and because of these properties both the materials can be deemed to be likely to be of value in many modern electronic devices. To the best of our knowledge, this is the first precise theoretical insight into the some of the physical properties of BeMF3 (M = Ti and V) compounds. These properties are still to be verified experimentally. [ABSTRACT FROM AUTHOR]

Summary: This study presents some physical properties of fluoroperovskite NaQF3 (Q = Ag, Pb, Rh, and Ru) compounds computed with the help of the first‐principle study. Fundamental structural features, ie, basic structural parameters, are investigated and reported, including the lattice constant, bulk modulus, and its pressure derivative. The compounds of interest are founded to be structurally stable. The Goldschmidt's tolerance factor (τ) is an indicator for the stability and distortion of perovskites crystal structures; it is found that τ is 0.951 for NaAgF3, 0.954 for NaPbF3, 0.934 for NaRhF3, and 0.971 for NaRuF3; therefore, NaQF3 (Q = Ag, Pb, Rh, and Ru) are stable fluoroperovskites. Elastic properties are computed, and it is examined that all the compounds are elastically stable, anisotropic, and ductile. For all these materials, the electronic band structure and density of states in both spin‐up and spin‐down schemes are simulated and presented. In the spin‐up scheme of NaAgF3 material, an indirect bandgap of 2.54 (eV) exists from M ‐Γ, while in the spin‐down scheme, NaAgF3 has no bandgap. Bandgap of 1.44 (eV) for NaRhF3 exist in spin‐down configuration and an overlapping pattern in spin‐up case, which confirms the spin‐polarized behavior at the Fermi level. The electronic band's scheme for NaPbF3 and NaRuF3 shows that there is a bandgap in NaRuF3 of 2.37 (eV), which is indirect from M ‐Γ in both (spin‐up and spin‐down) cases, thus depicting a semiconducting nature. In NaPbF3, the spin‐up and ‐down scheme manifests a metallic behavior. In summarizing the electronic band structures, it is noted that NaAgF3 and NaRuF3 show a 100% spin‐polarized nature at the Fermi level, and are half‐metallic. NaPbF3 represents metallic and NaRuF3 represents a semiconducting behavior. Selected studied compounds are found and classified as ferromagnetic because of the total integer value of the magnetic moments. WIEN2k code is employed for these computations, in which the full‐potential linearized augmented plane wave (FP‐LAPW) approach is used within density functional theory (DFT). To treat and perform the total energies calculations, the exchange‐correlation potential of generalized gradient approximation with the additional Hubbard‐U term for indulging on‐site Coulomb interaction (GGA + U) is considered. Based on a precise and good outcome for the reported compounds, beneficial applications in electronic and magnetic technology can be predicted from the electronic and magnetic properties. [ABSTRACT FROM AUTHOR]

In this work, the synthesis of α-MnO2 nanotubes (NTs) via hydrothermal route is reported. XRD investigation confirms the tetragonal crystalline structure of α-MnO2 NTs, where the calculated grain size is equal to 29.3205 ± 4.3227 nm. The observed morphology of α-MnO2 in SEM and TEM images confirm the formation of nanotubes. EDX data confirms that the sample contains Mn and O only. In FTIR, Mn–O stretching mode at 530 cm−1 is observed. In addition, the O–O stretching mode at 715 cm−1 also confirms the presence of MnO6 units. Raman spectrum provides the fingerprints at 569 cm−1 and 635 cm−1 of α-MnO2 originating due to breathing vibrations of MnO6 units. The calculated band gap is 2.7 eV, which is blue-shifted as compared to the bulk (2.1 eV). The PL results indicate prominent emission peaks in blue region (467 nm) and in green region (566 nm). The dielectric constant and dielectric loss of α-MnO2 NTs are high at low frequencies due to conducting grain volume and resistive grain boundaries, while both are low at higher frequencies due to the lagging of charge carriers behind the field. The conductivity of α-MnO2 NTs increases with increasing applied field frequency due to the hopping process between Mn3+/Mn4+ and liberation of trapped charges. Magnetic properties show ferromagnetic nature of α-MnO2 NTs which is attributed to coupling of Mn4+–O2−–Mn4+. The magnetic properties of α-MnO2 are affected by Mn ion interaction which in turn depends upon valence division of Mn in the Mn2O4 framework. [ABSTRACT FROM AUTHOR]

We report the synthesis of tin dioxide/graphene oxide (SnO2/GO) nanocomposite through simple hydrothermal method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirm the rutile tetragonal structure of the nanocomposite with average particle size of 13.37 ± 3.57 nm. The presence of only Sn, O and C in the EDX spectrum confirms the purity of our sample and a large defect density in the composite is found. The 3.7 eV band gap energy, determined by ultra-violet (UV) and photoluminescence (PL), of the nanocomposite is compatible with that of SnO2. Electrochemical measurements have shown that the material has a nice reversible redox process, suggesting its good capacitive behavior as well as a very low internal and charge transfer resistances of 1.43 Ω and 2.12 Ω, respectively. An increase in dielectric constant is observed, which is attributed to small grain size and high defect density. Conduction takes place through hopping process and the rapid increase in conductivity at high frequencies is due to increase in charge density (detached charges from traps + conduction electrons). [ABSTRACT FROM AUTHOR]

We report the fabrication of solid-state dye-sensitized solar cells (ss-DSSCs), using a metal-free organic dye (D102) as a sensitizer. Mesoporous TiO2 acting as a photoanode, is prepared from TiO2 nanopaste followed by drafting light-absorbing dye molecules. Spiro-OMeTAD is used as a hole transport material (HTM), which has a potential role in the energy conversion process of solid-state dye-sensitized solar cells (ss-DSSCs). Here, TiO2 mesoporous films are used with three different thicknesses (∼ 1.5 μm, ∼ 1.7 μm and ∼ 2.0 μm) for the device fabrication. Various characterizations of optimum TiO2 porous film (with the thickness of ∼ 2.0 μm) are performed such as ultraviolet-visible (UV-Vis) transmission, x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and cross-section scanning electron microscopy (SEM). Transmittance analysis reveals that transparency of the TiO2 films ranges from 70% to 80%. The x-ray diffraction (XRD) pattern of TiO2 shows anatase as its major crystalline phase. The porous structure formation of the TiO2 film is confirmed by scanning electron microscopy (SEM) cross section analysis. Photovoltaic performance of the devices was examined in air. Higher power-conversion efficiency (PCE) of 3.5% is obtained with optimum device thickness (∼ 2.3 μm). The device stability test is performed under continuous illumination for 2 h, showing slightly good air and light stability. [ABSTRACT FROM AUTHOR]

The titanium dioxide (TiO2) is synthesized by sol-gel method using titanium-tetra-iso-propoxide (TTIP) as a starting material, and deposited on the pre-cleaned glass substrate using spin coating technique at optimized parameters. Energy dispersive X-ray (EDX) spectroscopy confirms successful TiO2 growth. The optical properties concerning the transmission and absorption spectra show 85% transparency and 3.28 eV wide optical band gap for indirect transition, calculated from absorbance. The exponential behavior of absorption edge is observed and attributed to the localized states electronic transitions, curtailed in the indirect band gap of the thin film. The film reveals decreasing refractive index with increasing wavelength. The photoluminescence (PL) study ascertains that luminescent properties are due to the surface defects. [ABSTRACT FROM AUTHOR]

This work presents in detail the Ab-initio computational research work on the structural, elastic, electronic, and optical properties of Perovskite-type (Halide-Perovskites) barium-based MBaF 3 (M = Ga and In) compounds. The work is based on density functional theory (DFT) within WIEN2K. Structurally both GaBaF 3 and InBaF 3 based on optimization of Birch Murnaghan fit are found to be stable. The IRelast package for the calculations of elastic constants (ECs) is employed for the computation of elastic properties. Mechanically these compounds are identified to be ductile, hard to scratch, anisotropic, mechanically stable, and demonstrate strong resistance to plastic deformation. The precise modified Becke–Johnson (mBJ) potential is employed for electronic properties. Band structures of these compounds possess an insulating nature of direct wide energy band gap of 5 eV for GaBaF 3 and 5.1 eV for InBaF 3 from X-X symmetries points. To know the contribution of different electronic states to the band structures, the TDOS and PDOS i-e (total and partial density of states) are exploited. The insulating direct wide band gap energy nature presented a straightforward direction to study the optical properties of these compounds. The optical properties, of both the compounds, were studied deeply in the energy range from 0 eV to 40 eV. These compounds possess high absorption and optical conduction at high energy ranges. Both materials are transparent to incident photons at low energy ranges. We have concluded from the optical properties investigations that these compounds are suited for high-frequency UV device applications. To our deep knowledge, this is the first systematic theoretical computation of MBaF 3 (M = Ga and In) with structural, elastic, electronic and optical, properties that have yet to be verified experimentally. [ABSTRACT FROM AUTHOR]

Herein, the optoelectronic, structural, thermoelectric, and elastic characteristics of M 2 LiCeF 6 (M = Rb and Cs) double perovskite compounds were investigated using ab initio modeling in the DFT framework. The Birch-Murnaghan fitting curve used for the optimization showed that these two compounds are structurally stable. The elastic properties of the M 2 LiCeF 6 (M = Rb and Cs) double perovskite compounds were examined using the IRelast code. The results showed that these two compounds possess mechanical stability, anisotropy, and toughness, and offer resistance to plastic deformation. The precise and accurate determination of their electronic properties was achieved via the Trans-Blaha-modified Becke-Johnson (TB-mBJ) approximation. The Rb 2 LiCeF 6 and Cs 2 LiCeF 6 compounds are narrow band gap semiconductors with band gaps of 0.6 eV and 0.8 eV at the high symmetrical points from ( Γ - M ), respectively, exhibiting an indirect nature. To further understand how the various states contribute to the different band structures, total and partial density of state (DOS) computations were performed. The optical properties in the energy range of 0-40 eV for Rb 2 LiCeF 6 and Cs 2 LiCeF 6 were explored. The selected materials show transparency in the low incident photon energy range and have large light absorption and transmission at higher photon energies. Thus, it can be concluded that Rb 2 LiCeF 6 and Cs 2 LiCeF 6 can be used in high-frequency UV devices based on their optical characteristics. Both materials exhibit high electrical conductivity, power factors, and figures of merit ( ZT ) and act as effective thermoelectric resources. To the best of our knowledge, this is the first theoretical research on the optoelectronic, structural, thermoelectric, and elastic features of M 2 LiCeF 6 (M = Rb and Cs)., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Coded within Wien2K, we carry out DFT-based calculations for investigations of the structural, elastic, optoelectronic, and thermoelectric properties of BaXF 3 (X = Co, Ir) fluoro-perovskites. The Birch-Murnaghan fit to the energy-vs-volume data and formation energy shows that these fluoro-perovskites are structurally stable. The phonon calculation confirms the thermodynamic stability, while the relation between elastic constants such as C 11 - C 12 > 0, C 11 > 0, C 11 + 2 C 12 > 0, and B > 0 validates the mechanical stability of the compounds. BaIrF 3 exhibits a strong ability to endure compressive and shear stresses. BaCoF 3 shows a weaker capacity of withstanding changes in volume, attributed to a lower bulk modulus. Demonstrating a higher G -modulus of rigidity than the BaIrF 3 , BaCoF 3 demonstrates stronger resistance to change the shape and both compounds are found to be anisotropic and brittle. The determined band structure profiles reveal that both BaCoF 3 and BaIrF 3 demonstrate a metallic nature. In addition, the metallic nature of BaCoF 3 and BaIrF 3 is reinforced by the density-of-states (DOS) study, where Co and F atoms contribute significantly to the total DOS in the valence band in the case of BaCoF 3 , while that of BaIrF 3 is predominated by the Ba and F atoms. The computed values of ε 1 (0) for BaCoF 3 and BaIrF 3 are approximately 30 and 19, respectively, which are in line with Penn's model. The researched materials are confirmed to be strong contenders for optoelectronics by the lack of absorption in the visible range. For their potential use in thermoelectric device applications, thermoelectric parameters such as temperature-dependent Seebeck coefficient, specific heat capacity, thermal conductivity, power factor, and figure of merit are also investigated, which show that these materials are thermally stable and promising for applications in thermoelectric devices., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)