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Here in, we study the structural, electronic, mechanical, optical and thermoelectric properties of As based Ba3AsX3 (X = F, Cl) using the density functional theory. The result show that both materials crystallize into cubic structure. The tolerance factor and octahedral factor indicates that both materials have stable perovskite structure. The obtained optimize lattice constant are 6.12 Å and 6.50 Å for Ba3AsF3 and Ba3AsCl3 respectively. The phonon dispersion curves show that both materials are dynamically stable. The electronic study reveals that both materials have semiconductor having band gap of 2.27eV and 1.73eV for Ba3AsF3 and Ba3AsCl3 respectively. Elastic constants are computed and found that both materials are mechanical stable. Furthermore, elastic study presents that both materials are ductile and have anisotropic nature. The optical results show that both materials have excellent optical absorption. It is observed that relaxation time for Ba3AsF3 is longer than that of Ba3AsCl3. Thermoelectric properties such as Seebeck coefficient, electrical conductivity electronic thermal conductivity, power factor and figure of merit are calculated for both materials. It is observed that for both materials Seebeck have almost same maximum value of 1.55 × 10−3 V/K at 300K. The electrical conductivity is found to be greater for Ba3AsF3 than Ba3AsCl3. The figure of merit ZT value is found 1.53 for Ba3AsF3 while 1.23 for Ba3AsCl3 at 700K. From obtained results it is concluded that these materials can be an excellent candidate for thermoelectric and optoelectronic applications.

To identify a promising alternative to lead-based materials for solar cell application, we investigated the different physical properties of K2ScCoX6 (X = F, Cl) perovskites. Both materials have ferromagnetic ground state. The obtained optimize lattice constants are found to be 8.48 Å and 10.04 Å for K2ScCoF6 and K2ScCoCl6 respectively. Our finding indicate that these materials exhibit excellent structural, mechanical, the thermal stability, as evidenced by their Goldsmith's tolerance factor, elastic parameters, and negative formation energies. The formation energy is found to be -2.4 and -2.1 eV/atom for K2ScCoF6 and K2ScCoCl6 respectively. The electronic properties reveals that both materials have semiconducting nature. Notably, we observed low direct bandgap of 0.93 eV for K2ScCoF6 and 1.22 eV for K2ScCoCl6, which contrast with the typically large bandgap values reported for most halide double perovskite. The calculated values of Poisson's and Pugh's ratios, along with positive Cauchy's pressure, suggest a ductile nature for these compounds. Additionally, the optical properties show high absorption and optical conductivity, coupled with low reflectivity and minimal energy loss in lower energy ranges. These results suggest that the halogen-based double perovskite materials have significant potential as photovoltaic absorber materials in solar cell applications. Furthermore, their higher Seebeck coefficients, power factors and low thermal conductivity at room temperature underscore their potential for thermoelectric applications.

To explore a good candidate for solar cell applications as an alternative to lead-independent materials, we calculated the structural and mechanical stability of the Rb2TlSbX6 (X = Cl, Br, I) compounds with PBEsol potential. The optoelectronic and thermoelectric behaviors of these compounds are computed with TB-mBJ potential. Our results indicate that these materials possessed excellent structural, mechanical, and thermal stability on the basic values of their Goldsmith’s, elastic parameters and negative formation energies. The dynamic stability is observed through phonon dispersion curve and found that all materials are dynamically stable. The computed values of Poisson and Pugh ratios and a positive value of Cauchy’s pressure indicate the ductile nature of these materials. We observed the low direct bandgaps for Rb2TlSbCl6, (1.486 eV), Rb2TlSbBr6 (2.07 eV), and Rb2TlSbI6 (1.04 eV) unlike the majority of halide double perovskite family have large bandgap values in literature. In addition, the computed optical and thermoelectric characteristics of the Rb2TlSbX6 (X = Cl, Br, I) materials show large values of absorption and optical conductivity with low reflectivity and energy loss at small energy ranges. According to these findings, all these halogen-based double perovskite materials have the potential to be employed as photovoltaic absorb materials in solar cell applications. Furthermore, the large values of the Seebeck coefficient, high-power factor and figure of merit (ZT) at room temperature also ensured their significance for thermoelectric generators.

Owing to their outstanding performance, environmental friendliness and stability, perovskite materials are becoming very important for solar cells, renewable energy sources and thermoelectric generators. This work uses the first-principles approach to explore the structural, electronic, optical and elastic characteristics of K2ScCuF6 and K2YCuF6 double perovskites. The negative formation energy in Birch-Murnaghan confirms the stability of the compounds in Fm3m (225) space group. The analysis of the electronic properties concluded that both K2ScCuF6 and K2YCuF6 are narrow band gap semiconductors materials, having 1.2 and 2.3 eV of bandgap energies, respectively. This was further verified by the density of states. The mechanical stability, ductility and anisotropic nature of the compounds was shown by analyzing their elastic constants. In addition, the optical properties showed transparency at low energy values but showed both transmission and absorption characteristics at higher energy levels. These interesting results imply that K2ScCuF6 and K2YCuF6 have significant potential in solar cells, light-emitting diodes (LEDs), smart windows, displays and sensors.

The solid solution of pure ZnO nanoparticles and doped Polyvinylepyrrolidone (PVP) green hybrid nanomaterial’s synthesized by using the electro spinning method. The synthetic polymer matrix nonwoven fibrous mats containing innovative properties are shown to shrink and encapsulated the zinc oxide materials to change the surface morphology when the concentration of PVP is increased from 1 % to 2 % dopants. The crystalline nature and morphological studies were examined by using x-ray diffraction and a scanning electron microscope. The average crystallite sizes of easily formed ZnO nanoparticles and nanorods that are 21 nm and 62 nm respectively. Moreover, the electrical and optical properties of the fibrous mesh were determined by using electrical impedance analyzer. The electrical conductivity values were measured in the pure ZnO nanoparticles in contrast to the doped ZnO/PVP. The tangent loss, dielectric constant, capacitance and relaxation time values are revealed in this study. All the characterization has been carried out at room temperature. The relaxation time for 1 %, and 2 % ZnO/PVP is (0.8 ns) and (0.79 ns) respectively which is suitable for the application of trigger using devices. The overall findings of this study implemented in a wide range of technologies i.e. photonics, electronics and super capacitor devices etc.

There are several uses for ultraviolet photodetectors, including in the scientific, military, and industrial sectors. In this sense, UV photodetectors must have high responsiveness, be insensitive to visible light, and be inexpensive to produce. For this purpose, we report the development of Co and Ni based iron oxide nanoparticles via the cost effective low temperature sol–gel auto-combustion process. XRD study approves the cubic crystal structure of iron oxide (Fe2O3) with predominant orientation along (311) direction. A sharp and strong peak is obtained at 583 cm−1 and 594 cm−1 for both samples in FT-IR spectra assigned to metal oxide Fe–O network system which approves the formation of iron oxide. Raman spectroscopy analysis reveals the presence of two A1g and five Eg phonon modes in the case of both samples. Absorption study exhibits the strong absorption peaks for the iron oxide sample doped with cobalt and nickel, while poor absorption was noticed from the pure iron oxide nanoparticles. The large and low energy band gap values are found to be 2.77 eV and 1.68 eV for pure Fe2O3 and cobalt and nickel doped Fe2O3 nanoparticles, respectively. Stone and cloud-like shape morphology was observed from SEM analysis. The EDX spectra reveal the presence of essential elements, like Fe and O in the case of pure iron oxide while Fe, O, Co and Ni in the case of transition metals doped iron oxide nanoparticles. The photoluminescence (PL) spectroscopy technique was recorded the luminescent properties which reveals the decrease in PL intensity that confirms the decline in electron–hole recombination. Therefore, I–V characterization analysis reveals that electrical conductivity increases with the addition of metals due to decrease in electron–hole recombination with the co-doping of metals. These modified opto-electronic properties of the developed Fe2O3 by metals co-doping make it suitable candidate for the use in photodetector application.

This research pursued the effect of various calcination temperatures (300–1000 °C) on developing structural phases and the optical, dielectric, and photodegradation characteristics of cobalt-doped titanium dioxide nanoparticles (TiO2 NPs). The prepared NPs were characterized using X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier transform infrared (FTIR) spectroscopy analysis, ultraviolet–visible light (UV–VIS) spectroscopy, and photodegradation of methylene blue in the presence of visible light. XRD analysis revealed the formation of a tetragonal anatase phase for the samples calcined at 300–600 °C, while the Co-doped samples calcined at 800 °C and 1000 °C displayed a tetragonal rutile phase. The optical band gap analysis indicated that doping in the host matrix produced lower band gap energy for all the prepared samples. Dielectric measurements showed that the rutile phase heated at 800 °C had a larger dielectric constant and dielectric loss than the un-doped TiO2 and the other cobalt-doped samples. Finally, the anatase Co-doped TiO2 exhibited a maximum MB degradation of 93 % in 90 min compared to un-doped TiO2, which only degraded 14 % and rutile-TiO2 NPs (62 % degradation). The underlying mechanism responsible for the diverse photodegradation performance displayed by the anatase and rutile phases of TiO2 NPs is discussed. Overall, these results demonstrate that cobalt doping and the crystalline phase of TiO2 NPs are vital parameters involved in optimizing the photocatalytic activity of TiO2.

Metal sulfides and graphene oxide nanocomposites have recently has garnered considerable attention in the field of electrochemical energy storage devices. In this study, we synthesized a cadmium sulfide/graphene oxide (CdS/GO) nanocomposite using different contents of graphene oxide (0.01, 0.02, 0.03 and 0.04 g) with fixed concentartion of CdS (0.3 g) via Solid-State Reaction (SSR) method. CdS/GO composite were subsequently investigated to be used as electrode materials for supercapacitors. Notably, the optimized electrode CdS/GO-0.04 electrode demonstrated superior capacitive performance compare to individual CdS and their composites with GO. In a symmetric supercapacitor configuration, the CdS/GO-0.04 cathode demonstrated a specific capacitance of 211.5 F g ^−1 at a scan rate of 1.5 A g ^−1 and maintained 93% of its capacitance after 1,000 cycles at a current density of 5 A g ^−1 , indicating excellent cycling stability. The significantly improved capacitive performance of CdS/GO-0.04 can be primarily attributed to the synergistic interaction between CdS and GO particles, enhanced conductivity, and the relatively larger surface area of the composites. These findings suggest that CdS/GO nanocomposites hold great promise as electrode materials for high-performance energy storage applications.

Structural, electronic, optical and elastic properties of Silver based Perovskite AgXCl3 (X = Ca, Sr) are studied by utilizing wien2k package with in DFT. The structural investigation reveals their stability and shows that these compounds are cubic with space group pm-3m 221. For electronic properties the band structure and density of states are computed which indicates the semiconducting nature of both compounds. Elastic constants, Pugh’s ratio, bulk modulus, Poisson’s ratio and anisotropy factor are studied for the analysis of elastic characteristic. The Pugh’s ratio describes the ductile nature of the compounds and ionic nature is determined from the evaluated Cauchy pressure. Optical parameters such as dielectric function, extinction coefficient, refractive index, absorption coefficient, reflectivity and optical conductivity are calculated in the energy range of 0 eV–35 eV. The thermal stability is conformed from the thermal property. The study of these compounds reveals that they can be potential candidates for optoelectronic devices.

A theoretical study on Rb-based fluorperovskites RbXF3(X = Rh, Os, Ir) is performed for the first time to explore their structural, electronic, optical and thermoelectric properties. The compounds are stable in cubic perovskite type structures with lattice spacing in the range of 4.30 4.35 Å. RbRhF3 and RbIrF3 exhibit half-metallic character with indirect band gaps of 4.2 eV and 2.1 eV, respectively, at R-Γ, whereas RbOsF3 possesses entirely semiconducting nature. The calculation of elastic properties revealed that under study compounds are mechanically stable, having ionic bonding. Furthermore, all compounds show ductile nature. Optical properties were also calculated in the broad energy range 0–40 eV.

The Mg-based dielectric ceramics of (Bi0.5Na0.5)(1−x)MgxTiO3, 0.00 ≤ x ≤ 0.04 was successfully synthesized by mixed oxide route at 850 °C for 2 hrs. The XRD result revealed the single phase monoclinic crystal structure without any secondary phases. The SEM image shows the uniform grain size, low porosity and denser microstructure of the samples. The grains size gradually increases from 1.58 µm to 2.70 µm due to mass transportation during the sintering process. The EDX analysis of the spectra of all the samples was investigated and reported the peaks of elemental compositions (i.e. Bi, O, Ti & Mg). The maximum dielectric constant (εr=1291) for the base composition were observed at 200 °C temperature. The abrupt increasing in tangent loss (tanδ) was reported above 200 °C temperature at frequency range (100 Hz–1 MHz). The TGA analysis shows the net loss (∼0.47 % by weight) was observed and the sample was sustained up to 850 °C calcine temperature.

Abstract Sn-doped BaTi4O9 (BT4) dielectric ceramics were prepared by a mixed oxide route. Preliminary X-ray diffraction (XRD) structural study shows that the ceramic samples have orthorhombic symmetry with space group (Pnmm). Scanning electron microscopy (SEM) shows that the grain size of the samples decreases with an increase in Sn4+ content. The presence of the metal oxide efficient group was revealed by Fourier transform infrared (FTIR) spectroscopy. The photoluminescence spectra of the ceramic samples reported red color ~ 603, 604, 606.5 and 605 nm with excitation energy ~ 2.06, 2.05, 2.04 and 2.05 eV for Sn4+ content with x = 0.0, 0.3, 0.5, and 0.7, respectively. The microwave dielectric properties of these ceramic samples were investigated by an impedance analyzer. The excellent microwave dielectric properties i.e. high dielectric constant (εr = 57.29), high-quality factor (Q f = 11,852), or low-dielectric loss (3.007) has been observed.

Manufacturing of energy storage devices with good efficiency and fewer losses has been a distinct topic. A material with good dielectric properties and fewer energy losses is the basic demand of the electronic industry. Barium tetra titanate ceramic material (BaTi4O9) is a prominent dielectric material with average permittivity and low losses. However, we report a Ca2+ substituted Barium tetra titanate (BaTi4O9) with enhancement in dielectric properties and reduction in losses (Ba1-xCax) T4O9 was prepared using the conventional solid-state solution technique. X-ray diffraction analysis confirmed the formation of the orthorhombic phase (with space group = Pnmm). A drastic change in grain size was observed by increasing the Ca2+ substitution. Dielectric properties have been measured at 4 GHz and found maximum dielectric constant = 40 and loss = 0.00014. The optimum electro-caloric response rises from 0.56 to 0.69 k at ΔE = 1.34 Vμm−1. The effect of substitution Ca2+ contents and microstructure on dielectric properties were analyzed using a precision impedance analyzer in a vast frequency range i.e. 4 Hz to 20 MHz. Enhanced dielectric properties with low energy losses made it a prominent material for energy storage devices.

The electrocatalytic hydrogen evolution reaction (HER) is a sustainable energy production route using green chemistry. Transition metal dichalcogenides' application in catalytic hydrogen production is limited due to a lack of solutions that simultaneously address intrinsic activity, increased surface area, electrical conductivity, and stability problems. Herein we address these issues simultaneously by modifying the electronic structure of molybdenum disulfide (MoS2) nanorods using a low content of Pd (1 wt% and 2 wt%) dopant via a facile colloidal solvothermal route. The resulting MoS2 nanorods doped with (1 and 2 wt%) palladium demonstrate current density of 100 mA/cm2 at quit lower over-potentials of 137 mV and 119 mV than 273 mV for pure MoS2 nanorods, accompanied by high stability. This research proposes a strategy for designing high-performance HER electrocatalysts that work in acidic medium. In addition, the Tafel slop calculated for MoS2 is 112 mV/dec whereas for 1 and 2 wt% Pd-MoS2, the Tafel slopes are 70 mV/dec and 46 mV/dec.

In the present work, Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized by the chemical co-precipitation method using Zinc Chloride as the initial chemical, while Nickel and Cobalt chloride as dopants. Phase identification of metal (Ni, Co) doped Zinc Oxide nanoparticles (NPs) was observed using x-ray diffraction (XRD). The small lattice distortion or phase changes appeared due to shifting of diffraction angles peaks towards larger angle in ZnO are corresponded to metal (Ni, Co) dopant. The average crystallite size appears to decrement in NP size from 7.67 nm to 6.52 nm and 5.35 nm to 5.17 nm with increasing 5 % to 80 % of metal (Ni, Co) dopant respectively. The optical characteristics, including the absorption spectra of the prepared sample were observed through UV–Vis spectroscopy, Meanwhile SEM confirmed the observation of composition change in specimen with metal (Ni, Co) dopant concentration. The bandgap value was also found decrement 5.23 eV to 5.05 eV with increment of metal (Ni, Co) dopant concentration. The functional groups were measured by Fourier transformation infrared spectroscopy (FTIR). FTIR peaks found the metal (Ni, Co) doped ZnO with the vibration mode of (Zn2+ –O2−) ions due to the increment of dopant concentrations. Furthermore, electrical results show the ohmic behavior of prepared samples. These findings indicate the possibility of tuning optical, structural and electrical properties of metal (Ni, Co) doped ZnO with various dopant concentrations of Nickel and will have great potential to find application in optoelectronic devices.

Nanoparticles where holmium was substituted with nickel-cadmium Ni0.5Cd0.5HoxFe2-xO4 (X = 0, 0.02, and 0.04) ferrites were synthesized through a sol-gel auto-combustion process to reveal their structural and physical properties. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), a scanning electron microscope (SEM), Fourier transform infrared ray (FTIR) spectroscopy, and impedance spectroscopy techniques. XRD revealed the formation of the cubic crystal structure had a preferential orientation along (311). By including holmium, the lattice constant was reduced, while the average crystallite size was increased. SEM analysis revealed that the nanoparticles exhibited regular shapes, and the average grain size increased with the holmium content. FTIR spectroscopy determined that all the organic and inorganic materials had an absorption range of 400 to 4000 cm−1. The dielectric properties were measured between the frequency ranges of 1 kHz and 2 MHz. This shows that the tangent loss and the dielectric constant were raised when the concentration of holmium was increased.

Low loss Ruddlesden–Popper (RP) series, i.e., (Sr1−xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06, has been synthesized by a mixed oxide route. In this work, the substitution of Ca2+ cation in Sr5Ti4O13 sintered ceramics was chosen to enhance the structural, optical, and dielectric properties of the product. It was found that the Ca2+ content has significant effects on enhancing the dielectric properties as compared to Mn and glass additions. It was observed that the relative density, band gap energy, and dielectric loss (tangent loss) increase while relative permittivity decreases along with Ca2+ content. High relative density (96.7%), low porosity, and high band gap energy (2.241 eV) values were obtained in (Sr1−xCax)5Ti4O13, 0.0 ≤ x ≤ 0.06 sintered ceramics. These results will play a key role in the application of dielectric resonators.

In contrast to austenitic and martensitic stainless steels, ferritic stainless steels have a lower hardness and wear resistance but exhibit excellent corrosion resistance. Due to this fact, their use in the aerospace, automobile, and house construction industries is restricted. Several methods have been utilized to enhance the tribological characteristics of ferritic stainless steels. In this work, titanium nitride coating has been carried out by using a cathodic cage of titanium material, and later on, the titanium cathodic cage is replaced by an AISI-304 cathodic cage in a CCPN chamber to form iron nitride coating on AISI-430 ferritic stainless steel coupons through a plasma nitriding process for 4 h at a fixed temperature of 400 °C. The microstructures and mechanical traits of all processed and control coupons were analyzed using scanning electron microscopy, X-ray diffraction, ball-on-disc wear tester, and microhardness tester techniques. The results showed that hardness increased up to 1489 HV with the titanium cage, which is much higher than the hardness of the base material (270 HV). The titanium cage-treated coupons have high layer thickness, smooth surface morphology, and a minimum crystallite size of 2.2 nm. The wear rate was reduced up to 50% over the base material after the titanium cage plasma treatment. The base coupon exhibited severe abrasive wear, whereas nitrided coupons exhibited dominant adhesive wear. In the iron nitride coatings, this effect is also important, owing to the more influential cleaning process in a glow discharge, and the better adhesion with enhanced interlayer thickness is attributed to the fact that the compliance of the interlayer minimizes shear stresses at the coating–substrate interface. The use of a graded interface improves adhesion compared with the case where no interlayer is used but a titanium interlayer of comparable thickness provides a significant increase in measured adhesion. For both titanium and iron nitride films, there is a reduction in wear volume which is a function of interlayer thickness; this will have a substantial effect on wear lifetime. Thus by careful control of the interlayer thickness and composition, it should be possible to improve coating performance in tribological applications.

In the present work, pure and Cr-doped MoO3 microrods were successfully prepared through the sol gel auto combustion method. The phase evaluation and microstructural, dielectric, and optical properties of synthesized samples were investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and an impedance analyzer (1 MHz–3 GHz). All the samples showed hexagonal structure with space group (P63). According to Vegard’s law, lattice parameters increase with the increase in chromium (Cr3+) contents. In addition, the Williamson–Hall (W–H) plot was drawn for evaluating the micro-strain (εW-H) and crystallite size (DW-H) parameters. From microstructural analysis it was found that the size of microrods increased along with Cr3+ contents. Decreasing band gap energy was observed (from 2.98 to 2.71 eV) with increasing Cr3+ contents. The variation of the dielectric constant and tangent loss of MoO3 microrods with respect to frequency were analyzed.

The single phase Ba _1−x Sr _x TiO _3 (x = 0, 0.4, 0.8) ceramic compositions were fabricated through solid state (mixed oxides) method calcined at 850 °C and sintered at 1200 °C in air. The XRD patterns revealed the single phase BaTiO _3 composition with a space group of pm-3m. The shifting of the (1 0 0) XRD peak to higher 2 θ values is accredited to the substitution of comparatively smaller ion of Sr ^2+ (1.4 Å) for larger Ba ^2+ (1.6 Å) ion following the Braggs diffraction law (2dsin θ = m λ ). The phase transition or Curie point from polar ferroelectric phase to non-polar paraelectric phase of Ba _1−x Sr _x TiO _3 was reported to decrease with increasing Sr ^2+ content in Ba _1−x Sr _x TiO _3 compositions. The value of the dielectric constant decreased with increasing the content of Sr ^2+ , which may be attributed to the substitution of comparatively smaller ion of Sr ^2+ for Ba ^2+ in the perovskite structured Ba _1−x Sr _x TiO _3 .