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A precise and systematic analysis for A2BCl6 [(A = Cs; B = Se, Sn, Te, Ti, Zr) and (A = K; B = Pd, Pt, Sn)] is performed to investigate structural stability as well as optical and electrical properties using pseudopotential plane wave method. The calculated lattice constants show consistency with the experimental results that ensure their structural stability. From the electronic band structure results, Cs2BCl6 (B = Se, Sn, Te, Ti, Zr) and K2BCl6 (B = Pd, Pt, Sn) are established to be within an energy bandgap that varies between 1.131 and 3.731 eV. The metallic behavior of the materials for Cs2BCl6 (B = Ta, W) and K2BCl6 (B = Ta, W, Mn, Mo, Os, Re, Ru, Ta, Tc) is confirmed showing the presence of conducting characteristics. The dielectric function is large in the near‐ultraviolet region (3.10–4.13 eV). The extinction coefficient of A2BCl6 has the ability to work for implementations like Bragg's reflectors, optical and optoelectronic devices. The optical parameters of A2BCl6 disclose that the working constructions have an elevated dielectric constant. Analysis of the electronic and optical properties demonstrates that these double‐perovskite materials are suitable for photovoltaic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

As part of this study, we elaborated and characterized samples of thin layers of cobalt oxide, doping them with different concentrations of nickel (2%, 4% and 6%). These films were deposited on ordinary glass substrates at a temperature of 400 °C, with a deposition time of 5 min, using the spray pyrolysis technique. The main objective of this research was to explore the influence of nickel doping on the physical properties of cobalt oxide. The results obtained by Raman spectroscopy confirmed the presence of Co+2 cations located in tetrahedral sites and Co+3 in octahedral sites, thus validating the spinel-type cubic structure. Morphological analysis revealed that the incorporation of nickel into the Co3O4 thin films, synthesized by spray pyrolysis, resulted in a significant transformation of the porous surface morphology. This transformation resulted in the transition from a porous structure to a dense and uniform configuration, characterized by nanoflower grains. Analyzes by EDS spectrometry revealed peaks associated with the elements Co and O, thus confirming the composition of the films. An improvement in the durability and overall performance of the solar device in humid environments by obtaining the hydrophobic character (CA = 99°) for the Co3O4/6%Ni film. The transmittance decreased with increased as a function of Ni concentration. Optical studies show direct band gaps Eg1 and Eg2 varying between 1.41 and 1.3 eV and between 2.09 and 1.99 eV respectively. Notably, the electrical resistivity experienced a significant decrease from 28.39 to 0.178 Ω.cm for the undoped and 2% Ni-doped films, respectively. However, for Ni concentrations ≥ 4%, the electrical resistivity increased from 3.47 to 10.2 Ω cm. [ABSTRACT FROM AUTHOR]

Using the projected augmented wave pseudo-potentials (PAW) approach and the generalized gradient approximation (GGA) of Perdew–Burke–Ernzerhof (PBEsol) in the framework of the density functional theory as implemented in the Quantum Espresso code, the mechanical behaviour as well as the thermo-physical properties of LiAl2X (X = Rh, Pd, Ir and Pt) ternary intermetallic compounds under high hydrostatic pressure up to 10 GPa have been predicted. Our finding on the elastic stiffness constants, aggregate elastic modulus, Debye temperature, limiting angular vibrational frequency, vibrational energy as well as the vibrational free energy of LiAl2X (X = Rh, Pd, Ir and Pt) compounds shows that all these quantities increase monotonically with increasing pressure up to 10 GPa; while the elastic compliance constants (except S12), the vibrational entropy and the constant volume heat capacity of LiAl2X (X = Rh, Pd, Ir and Pt) decrease monotonically with increasing pressure. At room-temperature and zero-pressure, the obtained values of the Debye temperature θD are 486.10 K for LiAl2Rh, 462.51 K for LiAl2Pd, 401.36 K for LiAl2Ir and 406.62 K for LiAl2Pt, respectively; while at room-temperature and pressure of 10 GPa, the values obtained of θD are around: 528.29 K for LiAl2Rh, 507.80 K for LiAl2Pd, 428.81 K for LiAl2Ir and 442.88 K for LiAl2Pt, respectively. In addition, the analysing of the generalized mechanical stability criteria under isotropic pressure shows that all our materials of interest are mechanically stable up to 10 GPa. [ABSTRACT FROM AUTHOR]

Spinel thin films Co3O4 have been deposited at a temperature of approximately 400 °C using spray pyrolysis. The testimony process was carried out with different deposition times (4, 5, 6, and 8 min), indicating that the films were grown for varying durations. The objective of varying deposition times of the thin films of Co3O4 was to optimize the fabrication of a hetero-junction between Co3O4 and ZnO. XRD, SEM and Raman investigations showed that pure cubic Co3O4 with an irregular spindle shaped particles have been successfully obtained. The films’ thickness increased under prolonged preparation times leading to a denser surface. The optical measurements revealed that the thin layer with a deposition time of 8 min attained a total absorbance of 98% in the apparent spectrum with a band gap of 1.27 eV. The I–V characteristics recorded of FTO/ZnO/Co3O4/Au cells showed that all devices exhibiting a rectifying behavior with a perfect factor that varies between 3.87 and 1.64. Our results suggest that Co3O4 at 8 min with a carrier density of 2.414 × 1014 cm−3 and high absorbance is potentially a competitive hole transport material in spinel solar cells, and, the recorded characteristics of the photovoltaic phenomenon were noted a short circuit current of 1.302 mA, an open circuit voltage of 369 mV and a fill factor of 32%. [ABSTRACT FROM AUTHOR]