Revealing the Structural, Elastic, Electronic, and Optical Properties of K2ScCuCl6 and K2YCuCl6: An In-Depth Exploration Using Density Functional Theory.

The optoelectronic, structural, and elastic properties of K2ScCuCl6 and K2YCuCl6 double perovskite compounds were thoroughly investigated in this study using density functional theory. It is observed that both compounds exhibit exceptional structural and mechanical stability. The structural stability is assessed using Goldsmith's tolerance factor (tG), with values approaching unity indicating a reliable cubic perovskite structure. Phonon stability was ensured by the absence of negative energy formations and only real frequencies in the phonon calculations. Applying the finite displacement method also provided further evidence of the compounds' thermodynamic stability. The electronic properties analysis revealed that K2ScCuCl6 and K2YCuCl6 are narrow band gap semiconductors, with band gap values of 1.8 and 2.5 eV, respectively. This was confirmed by analyzing the density of states. Furthermore, the optical properties exhibited transparency at lower photon energies and significant absorption at higher energies. These exciting findings suggest that K2ScCuCl6 and K2YCuCl6 have promising applications in high-frequency UV devices.

Synthesis of ZnO and PEG-ZnO nanoparticles (NPs) with controlled size for biological evaluation.

The objective of this research was to produce the smallest possible ZnO nanoparticles through an adapted wet chemical process and subsequently, to fabricate a core-shell structure utilizing polyethylene glycol (PEG) as the shell component. The synthesis, size, and shape of the NPs were confirmed using advanced techniques. The resulting clustered NPs were round and had a size of 9.8 nm. Both plain and core-shell NPs were tested for their antibacterial properties against multi-drug resistant bacteria strains (E. cloacae, E. amnigenus, S. flexneri, S. odorifacae, Citrobacter, and E. coli), with concentrations of 500, 1000, and 1500 µg ml-1 used for testing. Both types of NPs demonstrated antibacterial activity against the tested pathogens, with the core-shell NPs being more effective. The synthesized NPs were biocompatible with human red blood cells, with a low level of hemolysis observed. The biocompatibility of the core-shell NPs was significantly enhanced by the presence of the PEG added as the shell. In addition, their effectiveness as photosensitizers for cancer treatment via photodynamic therapy (PDT) was evaluated. MTT assay was used to evaluate the cytotoxicity of ZnO and PEG-ZnO, and the results showed that these NPs were able to generate ROS inside tumor cells upon irradiation, leading to apoptosis and cell death, making them a promising candidate for PDT.

Probing the physical properties for prospective high energy applications of QMnF3 (Q = Ga, In) halide perovskites compounds employing the framework of density functional theory.

We use WIEN2K to conduct density functional theory computations to explore the structural, thermodynamic, optoelectronic, and mechanical properties of fluoroperovskites QMnF3 (Q = Ga, In). The application of the Birch-Murnaghan equation to the energy versus volume, formation energy, and tolerance factor confirms the structural stability of these two QMnF3 (Q = Ga, In) materials. The thermodynamic stability of the compounds is confirmed by the results of the phonon calculation, while the mechanical stability is confirmed from the values of the elastic constants. GaMnF3 demonstrates a high capacity to withstand both compressive and shear stresses. A lower bulk modulus is responsible for the weaker ability of InMnF3 to endure changes in volume. Compared to GaMnF3, InMnF3 possesses rigidity having greater shear modulus, indicating greater resistance to changes in shape. However, both compounds are characterized as mechanically brittle, anisotropic, and ductile. The band structure that was determined indicates that both GaMnF3 and InMnF3 exhibit a metallic character. The density of states analysis further supports the metallic nature of GaMnF3 and InMnF3. In GaMnF3, the "Mn" and "F" atoms in the valence band significantly participate in the total density of states, whereas in InMnF3, both "Mn" and "F" atoms also dominate the total density of states. The values of ε1(0) computed for GaMnF3 and InMnF3 are positive i.e. > 0, and agree with Penn's model. We calculate the optical properties for both GaMnF3 and InMnF3 and the potential of these materials of interest for applications in optoelectronic gadgets including light-emitting diodes is attributed to their absorption in the ultraviolet-visible zone. We believe that this work may provide comprehensive insight, encouraging further exploration of experimental studies.

Probing the physical properties of M2LiCeF6 (M = Rb and Cs) double perovskite compounds for prospective high-energy applications employing the DFT framework.

Herein, the optoelectronic, structural, thermoelectric, and elastic characteristics of M2LiCeF6 (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 M2LiCeF6 (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 Rb2LiCeF6 and Cs2LiCeF6 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 Rb2LiCeF6 and Cs2LiCeF6 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 Rb2LiCeF6 and Cs2LiCeF6 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 M2LiCeF6 (M = Rb and Cs).

Investigating the Physical Properties of Thallium-Based Ternary TlXF3 (X = Be, Sr) Fluoroperovskite Compounds for Prospective Applications.

In the present work, several properties of fluoroperovskites are computed and examined through the approximations of trans- and blaha-modified Becke-Johnson (TB-mBJ) and generalized gradient approximation of Perdew-Burke-Ernzerhof (GGA-PBE) integrated within density functional theory (DFT). The lattice parameters for cubic TlXF3 (X = Be, Sr) ternary fluoroperovskite compounds at an optimized state are examined and their values are used to calculate the fundamental physical properties. TlXF3 (X = Be and Sr) cubic fluoroperovskite compounds contain no inversion symmetry and are thus a non-centrosymmetric system. The phonon dispersion spectra confirm the thermodynamic stability of these compounds. The results of electronic properties clarify that both the compounds possess a 4.3 eV of indirect band gap from M-X for TlBeF3 and a direct band gap of 6.03 eV from X-X for TlSrF3, which display that both compounds are insulators. Furthermore, the dielectric function is considered to explore optical properties like reflectivity, refractive index, absorption coefficient, etc., and the different types of transitions between the bands were investigated by using the imaginary part of the dielectric function. Mechanically, the compounds of interest are computed to be stable and possess high bulk modulus values, and the ratio of "G/B" is higher than "1", which indicates the strong and ductile nature of the compound. Based on our computations for the selected materials, we deem an efficient application of these compounds in an industrial application, which will provide a reference for future work.

First-principles calculations to investigate physical properties of orthorhombic perovskite YBO3 (B = Ti & Fe) for high energy applications.

Orthorhombic oxide perovskite compounds are very promising materials for the applications of optoelectronics and thermal barrier coating. This work represents a numerical simulation of YBO3 compounds through the first-principles ab initio approach. The electronic and magnetic properties are investigated employing the general gradient approximation (GGA) coupled to the integration of the Hubbard U-term which is the GGA + U. The Ti and Fe-based YBO3 perovskite compounds are found to be actively promising within the ferromagnetic configuration and their lattice parameters are consistent with the previous studies. The calculations of formation energy signify that the compounds YBO3 are stable thermodynamically. The electronic properties are computed and evaluated by the band structure and density of states for both compounds and the results depict that these materials are ferromagnetic half-metallic. Mechanically these compounds are stable, ductile, anisotropic, and hard to scratch. The thermal properties are evaluated for YBO3 (B = Ti and Fe) compounds up to a temperature range of 2000 K. This work can open new opportunities for further exploration in this field.

Threshold switching in nickel-doped zinc oxide based memristor for artificial sensory applications.

Electronic devices featuring biomimetic behaviour as electronic synapses and neurons have motivated the emergence of a new era in information and humanoid robotics technologies. In the human body, a nociceptor is a unique sensory neuron receptor that is capable of detecting harmful signals, leading to the central nervous system initiating a motor response. Herein, a nickel-doped zinc oxide (NZO)/Au based memristor is fabricated for the first time and characterized for artificial nociceptor application. For this, the introduction of a nickel-doped zinc oxide (NZO) layer between P++-Si and Au electrodes is used to eliminate the surface effects of the NZO layer, resulting in improved volatile threshold switching performance. Depending on the intensity, duration, and repetition rate of the external stimuli, this newly created memristor exhibits various critical nociceptive functions, including threshold, relaxation, allodynia, and hyperalgesia. The electron trapping/detrapping to/from the traps in the NZO layer is responsible for these nociceptive properties. This kind of NZO-based device produces a multifunctional nociceptor performance that is essential for applications in artificial intelligence systems, such as neural integrated devices with nanometer-sized features.