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The non-toxic nature, low cost, and excellent optical properties make oxide-based perovskites potential candidates for solar cell applications. The full potential linearized augmented plane wave approach is applied to explore the structural, electronic, optical, and thermoelectric properties of Ba2XTiO6 (X = Hf, Ce, and Te) for solar cell applications. As demonstrated by an elastic study, Ba2HfTiO6 is brittle, while Ba2CeTiO6 and Ba2TeTiO6 are ductile. The anisotropic values of Ba2HfTiO6, Ba2CeTiO6 and Ba2TeTiO6 are 1.14, 0.67 and 0.80 respectively. The electronic bandgap values of Ba2HfTiO6, Ba2CeTiO6, and Ba2TeTiO6 are computed as 3.44 eV, 2.96 eV, and 1.26 eV using the Tran-Blaha-modified Becke–Johnson approach. Moreover, the bandgap of Ba2TeTiO6 is compatible for solar cell applications. Optical investigation demonstrates that Ba2TeTiO6 shows maximum absorption in visible light among the studied perovskites. Lastly, the transport properties exhibit figure of merit values of 0.73, 0.77 and 0.81 for Ba2HfTiO6, Ba2CeTiO6, and Ba2TeTiO6 respectively. Consequently, with the bandgap falling in the visible region and high figure of merit among the studied perovskites, Ba2TeTiO6 emerges as the most suitable candidate for solar cell applications based on its electronic, optical, and thermoelectric properties. [ABSTRACT FROM AUTHOR]

The Density Functional Theory (DFT) calculations interpreted the electronic and optical alteration of Ruddlesden–Popper layered perovskite (Sr3Zr2O7) with substitutional doping of Ti‐, Hf‐, and Ti+Hf‐ atoms in place of Zr‐atoms by generating the oxygen vacancies (Vos) defect. Formation energy and phonon calculations confirmed that the studied composites are dynamically stable, and the lattice parameters of the considered RP perovskite with and without vacancy defects did not change by introducing a small concentration of doped elements. The doped Sr3Zr2O7 composites show band gap tuning in the presence and absence of Vos, which was 3.31 eV in pristine form, and localized states near the Fermi line due to dopant and Vos, which confirmed the quantized conductance in all composites and may be beneficial for overcoming uniformity issues in nonvolatile memory devices. Isosurface charge density calculations also verified this result by depicting the physical mechanism of charge accumulation and depletion in the layers of RP perovskite in the vicinity of defects, resulting in residual conducting filaments guiding its growth and leading it to a low resistance state. The photosensitive response of this layered perovskite also confirmed its use for memory storage applications. The valuable outcomes of this study predicted that Sr3Zr2O7+Ti+Hf is the most stable and, hence, the best composite for nonvolatile RRAM device applications. [ABSTRACT FROM AUTHOR]

In this study, calcium titanate (CaTiO3) doped (0, 15, 25 and 35%) polyaniline (PANI) composites in the presence of dodecylbenzene sulphonic acid (DBSA) were successfully synthesized by the means of in-situ emulsion polymerization of aniline monomer. The structural, morphological and optical characterization of as-prepared composites were determined using X-ray diffraction (XRD), field effect scanning electron microscopy, Fourier-transform infrared spectroscopy, UV–vis analysis, and electronic conductivity was determined using two-point probe method. The structural analysis confirms that PANI–DBSA is amorphous, but sharp peaks present in XRD patterns in composites are of crystalline nature. The morphological study reveals efficacious integration of CaTiO3 particles into the PANI–DBSA matrix. Further, the integration of CaTiO3 remarkably reduced the optical bandgap (2.7–2.2 eV) by making composites with PANI–DBSA. Room temperature alternating current conductivity was found to obey universal power law and correlated barrier hopping was found most appropriate model to describe the sample's charge transport mechanism. With the increasing wt% of CaTiO3, the dielectric permittivity and loss both varied according to the interfacial polarization law of Maxwell–Wagner. Moreover, the I–V graphs showed augmented electrical conductivity of composites with an increase in CaTiO3 particle content than that of pure PANI–DBSA. This is a simple way by which PANI–DBSA/CaTiO3 composites having low optical bandgap, high electrical conductivity and permittivity may be fabricated for a widespread technological application. [ABSTRACT FROM AUTHOR]

Water electrolysis is a propitious strategy to overcome the exceeding energy crisis by producing renewable and green hydrogen fuel. However, the practical application of this process is limited due to the inadequacy of earth-rich, economical, and efficient electrocatalysts for carrying out kinetically more sluggish oxygen evolution reactions (OER). In the present research, a simple sol–gel method was employed to produce Co3O4/Pr2O3 nanocomposite material, which provides exceptional electrical conductivity and lesser charge transfer resistance of mixed-valence cations. The fabricated nanomaterials were analyzed using various scientific techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and energy dispersive X-ray spectroscopy (EDX) to determine their crystal structure, morphology, elemental composition, and oxidation states. To investigate the water oxidation capability and steadiness of the modified Co3O4/Pr2O3 electrode material in alkaline conditions, cyclic voltammetry (CV), linear sweep voltammetry (LSV), and constant current chronoamperometry (CA) were utilized. These outcomes revealed that the resultant nanocomposite exhibits a minimal overpotential around 257 mV and a lower Tafel slope around 78 mVdec−1 at a benchmark current density of 10 mAcm−2. In addition, the alkaline solution reliability of the electrocatalysts was examined and confirmed to be steady for 24 h via chronoamperometry. The extraordinary electrocatalytic achievement of Co3O4/Pr2O3 is ascribed to its structural synergistic effect, which encourages the oxygen evolution activity. [ABSTRACT FROM AUTHOR]

We describe a facile approach to fabricate MoS2 and graphene oxide (GO) composites using single-step hydrothermal method to achieve excellent electrochemical properties for energy storage applications, like lithium-ion batteries. Supportive 2D structure of MoS2 material provides direct path for the electron’s flow. MoS2 and graphene oxide (GO) composites provide large surface area for intercalation of ions into/out of active materials due to their layered morphology and also minimize the path for electron transfer. The morphology of samples is studied under XRD, SEM, and TEM. The investigation confirms the formation of composites and increment in crystallinity with doping of MoS2 on graphene oxide (GO) surface. Electrochemical properties are characterized by cyclic voltammogram (CV). As a result, composite MoS2 + GO with 3% weight ratio of graphene oxide (GO) gives best cyclic stability of 740 mAh/g at low current density 100 mA/g just after 160 cycles presenting excellent improvement in electrochemical performance as electrode material in lithium-ion batteries. The structural, electronic, and optical calculations of MoS2/graphene heterostructure have been performed using the density-functional theory. The MoS2/Graphene heterostructure reveals the zero band gap due to high electronic conductivity. The calculated absorption and optical conductivity find to be high in optical properties. [ABSTRACT FROM AUTHOR]

In situ polymerization of aniline was carried out with calcium titanate, in order to synthesize polyaniline/calcium titanate composites by the chemical oxidation in the presence of ammonium persulfate as an oxidizing agent. To study the effect of calcium titanate on the properties of polyaniline (PANI), PANI/calcium titanate (CaTiO3) composites were synthesized with different weight percentages (15, 25, and 35 wt %) of calcium titanate. The structural and morphological analysis was carried out by XRD and SEM, while their electrical properties were studied by temperature-dependent dc conductivity. Thermal properties were also studied, and seebeck coefficient and thermoelectric power studies demonstrated a strong dependence on the weight percentage of calcium titanate in the pure polyaniline. The charge transport mechanism was investigated by temperature-dependent dc electrical conductivity measurements in the temperature range of 303–483 K. Further, an increase in dc conductivity was found on the inclusion of calcium titanate at all temperatures, and the most probable model of charge transport was found to be three-dimensional variable range hopping (3D-VRH) for pure polyaniline while switching to one-dimensional variable range hopping (1D-VRH) in the case of its composites with calcium titanate that has been interpreted in terms of linearization and straightening of polymer chains. The calcium titanate content not only influenced the electrical conductivity but the thermoelectric properties of the resulting composites as well. [ABSTRACT FROM AUTHOR]

Intercalated and exfoliated nanocomposites of insulating polymers poly methyl methacrylate and acrylonitrile butadiene styrene with organically modified montmorillonite (OMMT) was prepared by solution casting method. Formation of polymer nanocomposites was confirmed by X-Ray Diffraction. Fourier transform infrared spectroscopy confirmed the interaction between polymers and cations on the surface of OMMT layers. Dielectric properties of these nanocomposites were examined at room temperature in the frequency range of 100 Hz–1 MHz. The findings of dielectric measurements exhibited higher real and imaginary dielectric permittivity values for exfoliated nanocomposites and lesser real and imaginary dielectric permittivity values for intercalated nanocomposites as compared with pure polymers in the same frequency range. The increase in the permittivity values is attributed to Maxwell Wagner polarization in exfoliated nanocomposites because of increased interfacial area between polymer and the clay layers. Decrease in dielectric permittivity in intercalated polymer nanocomposites is attributed to restricted mobility of polymer chains due to nanoscopic confinement of the polymer with the silicate layers. [ABSTRACT FROM AUTHOR]

We report a facile strategy to synthesize poly-aniline/molybdenum disulfide (PANI/MoS2) nano-composite by in situ chemical polymerization to achieve excellent electrochemical properties for application as super-capacitor electrodes. MoS2 nano-composite is prepared by a hydrothermal method and serves as an excellent 2D conductive skeleton and provides a direct path for electrons. The layered nanostructure of PANI/MoS2 composites provides a larger contact surface area for the intercalation of particles into/out of active materials and shortens the path length for electrolyte ion transport. The structure morphology is characterized by XRD, SEM, TEM and FTIR. Structural and morphological analysis reveals conformation composite formation, increase in crystallinity and particle size increased with doping by rapping of PANI on MOS2 surface. Excellent electrochemical performances of the samples are characterised and are evaluated by cyclic voltammogram, impedance and galvanostatic charge/discharge curve. The maximum specific capacitance of 453 F kg−1 at 1 Ag−1 is observed at the PANI-1%MoS2 electrodes. The energy density of 69 Wh kg−1 is obtained at a power density of 1380 W kg−1, impedance decreased from 5 Ω (PANI) to 2 Ω (1%PANI/MoS2) indicating a positive synergistic effect MoS2 and PANI for the improvement of electrochemical performance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nanocomposite of functionalized CNTs with Fe3O4 nanoparticles is prepared. [•] Good quality interfacial adhesion between CNTs and Fe3O4 matrix. [•] High discharge capacity of 1093mAhg−1 after 50 cycles. [•] 50th Cycle coulombic efficiency of 98.4% at a current density of 100mAg−1. [ABSTRACT FROM AUTHOR]

Atomic Layer Deposition (ALD) was used for a tri-layer structure (HfO 2 /Al 2 O 3 /HfO 2 ) at low temperature over an Indium Tin Oxide (ITO) transparent electrode. First, the microstructure of the fabricated TaN/HfO 2 /Al 2 O 3 /HfO 2 /ITO RRAM device was examined by the cross-sectional High-Resolution Transmission Electron Microscopy (HRTEM). Then, Energy Dispersive X-ray Spectroscopy (EDS) was performed to probe compositional mapping. The bipolar resistive switching mode of the device was confirmed through SET/RESET characteristic plots for 100 cycles as a function of applied biasing voltage. An endurance test was performed for 100 DC switching cycles @0.2 V wherein; data retention was found up to 10 4 s. Moreover, for better insight into the charge conduction mechanism in tri-layer HfO 2 /Al 2 O 3 /HfO 2 , based on oxygen vacancies (V OX ), total density of states (TDOS), partial density of states (PDOS) and isosurface three-dimensional charge density analysis was performed using WEIN2k and VASP simulation packages under Perdew-Burke-Ernzerhof _Generalized Gradient approximation (PBE-GGA). The experimental and theoretical outcomes can help in finding proper stacking of the active resistive switching (RS) layer for resistive random-access memory (RRAM) applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)