The influence of process conditions and post-annealing treatments on the ionic transport properties of metakaolin (MK) ceramics prepared by the cold sintering process (CSP) were investigated. Within the temperature range of 120–200 °C, CSP temperature has little influence on densification and microstructure. Impedance spectroscopy revealed that all as-sintered ceramics exhibited significant ionic conduction, with bulk conductivity of approximately 0.001 S/cm at 600 °C. The associated activation energies are confined to a narrow range of 0.63–0.65 eV. In contrast, post-annealing significantly alters the electrical microstructure, giving rise to an additional grain boundary response. Aft... More >

Lead-free (1-$x$)SrTiO$_3$-$x$CaZrO$_3$ solid-solution ceramics ($x$ = 0.05, 0.10, 0.15, 0.20) were synthesized via the conventional solid-state route to investigate structure-microstructure-dielectric relationships. X-ray diffraction patterns of the samples confirmed single-phase formation for all compositions, forming cubic perovskite structure (space group $Pm-3m$). Raman spectra were consistent with the perovskite lattice and local vibrational features, confirming perovskite structure. SEM micrographs revealed noticeable porosity for lower CaZrO$_3$ contents ($x$ = 0.05-0.15) and a more compact morphology at higher CaZrO$_3$ content, with a slight decrease in grain size as $x$ increases... More >

Poly (vinylidene fluoride) (PVDF) composites with high loadings (50-65 wt%) of waste-derived fillers—alum sludge (AS), an inorganic water treatment residue, and wood dust (WD), a lignocellulosic timber by-product—were prepared via melt compounding and compression moulding without compatibilisers. Mechanical, thermal, and dielectric properties were systematically characterised. Increasing filler loading enhanced Young’s modulus but reduced elongation and impact resistance due to restricted chain mobility and stress concentration. Dielectric behaviour differed markedly between the two systems: AS composites exhibited progressive increases in relative permittivity (up to ~70%) attributed... More >

In this work, \((1-x)\text{Ba}_{0.85}\text{Ca}_{0.15}\text{Ti}_{0.9}\text{Zr}_{0.1}\text{O}_{3} - x\text{Sr}_{0.7}\text{Bi}_{0.2}\text{TiO}_{3}\) (BCZT–SBT) ceramics with \( x = 0 \) and \( x = 0.025 \) were prepared through the conventional solid-state route. The samples were calcined at \(1200\,^{\circ}\text{C}\) for \(6\,\text{h}\), then re-milled, pressed into pellets, and sintered at \(1325\,^{\circ}\text{C}\) for \(6\,\text{h}\). XRD patterns indicate the formation of a cubic perovskite structure. A small decrease in lattice parameter is observed upon introducing SBT (\(a\) decreases from \(4.0176\,\text{Å}\) to \(4.0149\,\text{Å}\)), accompanied by a slight reduction in unit-cell... More >

This study focuses on the solid-state processing optimization of SrTi\(_{1-x}\)Fe\(_x\)O\(_3\) (STFO) ceramics with \(0.00 \leq x \leq 0.11\). X-ray diffraction reveals a single-phase cubic structure (space group Pm\(\bar{3}m\)) with lattice constant \(a = b = c = 3.91{Å}\) and a maximum relative density of \(\sim\)94%. SEM confirms well-formed grains in both pure and Fe\(^{3+}\)-doped SrTiO\(_3\). TGA/DSC indicates low weight loss and high thermal stability for the \(x = 0.09\) composition. Electrical conductivity increases with frequency, accompanied by higher dielectric losses for \(x = 0.09\) and \(x = 0.11\). FTIR verifies the Ti-O octahedral stretching frequency at \SI{530}{\cm^{-1}},... More >

Halide double perovskites offer wide compositional flexibility and are being explored for energy-related applications. In this work, the structural, electronic, optical, and thermoelectric properties of Li\(_2\)AgSbX\(_6\) (X = F, Cl, Br, I) were investigated using density functional theory (DFT) within the WIEN2k package. Structural optimization shows a systematic increase in lattice parameter from F → I, accompanied by a decrease in bulk modulus, indicating higher compressibility for the heavier-halide compounds. Electronic-structure calculations within PBE-GGA identify all compositions as indirect-gap semiconductors, with band gaps decreasing across the series: 1.599 eV (F), 1.389 eV (C... More >

Enhancing the energy-storage performance of lead-free dielectric ceramics is essential for developing environmentally sustainable capacitors and power devices. NaNbO$_3$, a promising perovskite, exhibits considerable potential for dielectric applications but is limited by poor densification and high dielectric loss. In this work, the effects of tantalum (Ta) doping at varying concentrations $\text{NaNb}_{1-x}\text{Ta}_x\text{O}_3$, with $x = 0.05, 0.10, \text{and } 0.15$, corresponding to 5%, 10%, and 15% Ta substitution on the crystal structure, microstructure, and electrical properties of NaNbO$_3$ ceramics were systematically investigated. X-ray diffraction (XRD) confirmed phase purity an... More >

This work reports the performance optimization of PTB7:PCBM-based inverted organic solar cells (IOSCs) using the Organic and Hybrid Materials Nano (OghmaNano) simulator. A comprehensive study was carried out by varying the key performance parameters, such as active layer thickness (AL), charge transport layers (CTLs), operating temperature, charge carrier mobilities(CCMs), and incident light intensity. The results showed that the carrier concentrations and mobilities (e.g, electron mobility ($\mu_e$) and hole mobility ($\mu$h)) significantly changed with operating temperature (280 to 400 K), affecting the power conversion efficiency (PCE). Additionally, changing light intensity from 0.1 to 1... More >