Solid-state Reaction Method Research Articles

Synthesis and Characterization of K2Ba3(P2O7)2:VO2+ Nanopowder: Reddish-Orange Emission for LED Applications.

Solid-state reaction method is employed to prepare K2Ba3(P2O7)2:VO2+ nanopowder and studied by using powder x-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, optical absorption spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, and photoluminescence (PL) spectroscopy. XRD studies revealed VO2+ ion doped K2Ba3(P2O7)2 nanopowder have 21 nm crystallite size, orthorhombic phase, and Pmn21 space group. From Williamson-Hall analysis, crystallite size is found as 24 nm. SEM morphology recorded the presence of irregular-sized and round-shaped agglomerates. FT-IR and Raman spectra reveal characteristic bands of phosphate groups. Three characteristic peaks are observed at 848, 695, and 452 nm in optical absorption spectrum. Also, crystal and tetragonal field parameters are calculated as Dq = 1439, Ds = -2789, and Dt = 3422 cm-1. In addition, bandgap energy is found as 3.97 eV. Optical and EPR analyses led to understand the incorporation of vanadyl ions into host lattice. Spin Hamiltonian parameters are evaluated. Basing PL spectrum, Commission Internationale de l'Éclairage's (CIE) chromaticity coordinates are calculated, which are present in reddish-orange region with good color correlated temperature (CCT) and color rendering index (CRI) values facilitating the use in lighting applications and LEDs.

Microstructure And Magnetization Process Due To Cd2+ Doped Ni-mg Spinel Ferrites

The Ni0.5Mg0.5CdxFe2-xO4 ferrites (x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) were prepared by the solid-state reaction method using laboratory-grade oxide materials. Samples from each composition were prepared and then sintered at 1000 °C for 3 hours. The Cd-doped Ni-Mg ferrites' structural and surface morphology effects were analyzed by XRD and SEM. XRD analysis indicated that all the sintered samples crystallized in a single-phase cubic spinel structure. It follows from Vegard's law that, in Ni-Mg-Cd ferrites, the lattice parameter increased linearly with the substitution of Fe³⁺ ions by Cd²⁺. In all the samples, the theoretical density was higher than their bulk densities due to the pores present in them, as the sintering temperature is influenced. SEM images showed that the Cd-doped Ni-Mg ferrites significantly modified the average grain size; thus, the surface morphology appeared to be homogeneous and consisted of well-defined spherical grains. The average grain size decreased while doping with Cd²⁺ in Ni0.5Mg0.5CdxFe2-xO4 up to x = 0.08 and then increased with a further increase in doping concentration. No significant effect on Ms, Hc, and Mr was observed while measuring from the M-H curve by VSM and hysteresis loops. The coercive value Hc was very low, and hence Ni-Mg-Cd ferrites belong to the family of soft ferrites. The Ms value increased in all samples with the content of Cd doping. With these results, it can be asserted that the addition of Cd can make Ni-Mg ferrites more magnetic at the core and change their structure, along with surface appearance; thus, these materials will be useful in many magnetic applications. Bangladesh Journal of Physics, 28(1), 51-58, June 2021

3D nanocomposites of β-TCP-H3BO3-Cu with improved mechanical and biological performances for bone regeneration applications

Recently, 3-D porous architecture of the composites play a key role in cell proliferation, bone regeneration, and anticancer activities. The osteoinductive and osteoconductive properties of β-TCP allow for the complete repair of numerous bone defects. Herein, β-TCP was synthesized by wet chemical precipitation route, and their 3-D porous composites with H3BO3 and Cu nanoparticles were prepared by the solid-state reaction method with improved mechanical and biological performances. Several characterization techniques have been used to investigate the various characteristics of fabricated porous composites. SEM and TEM studies revealed the porous morphology and hexagonal sheets of the β-TCP for the composite THC8 (82TCP-10H3BO3-8Cu). Moreover, the mechanical study showed excellent compressive strength (188 MPa), a high Young’s modulus (2.84 GPa), and elevated fracture toughness (9.11 MPa.m1/2). An in vitro study by MTT assay on osteoblast (MG-63) cells demonstrated no or minimal cytotoxicity at the higher concentration, 100 µg/ml after 24 h and it was found a more pronounced result at 20 µg/ml on increasing the concentration of Cu nanoparticles after incubating 72 h. The THC12 composite showed the highest antibacterial potency exclusively against B. subtilis. S. pyogene, S. typhi and E. coli. at 10 mg/ml, indicating its potential effectiveness in inhibiting all of these pathogens. Genotoxicity and cytotoxicity tests were also performed on rearing Drosophila melanogaster, and these findings did not detect any trypan blue-positive staining, which further recommended that the existence of composites did not harm the larval gut. Therefore, the fabricated porous composites THC8 and THC12 are suitable for bone regrowth without harming the surrounding cells and protect against bacterial infections.

Effects of Electron, Gamma and Neutron Irradiation on the Superconducting Properties of (Bi,Pb)2Sr2Ca2Cu3Ox Bulk Samples

In this study, we explored the potential of irradiation techniques to optimize defect concentration and crystal structure in (Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀ (Bi-2223) superconductors, aiming to enhance their practicality by potentially improving their critical temperature (Tc) in high magnetic fields. Bi-2223 superconductors have higher Tc and less stringent cooling requirements than low-temperature types, yet enhancing Tc under high magnetic fields is still challenging. The study meticulously compared the electrical properties of Bi-2223 samples in bulk form, subjected individually to electron, gamma, and neutron irradiations, prepared via the conventional solid-state reaction method. Subsequent analyses of structural properties through X-ray diffraction revealed changes in cell lattice parameters, while electrical resistance and AC susceptibility measurements provided insights into the critical temperature. Interestingly, a significant decrease in Tc was observed across all irradiated samples instead of an enhancement, challenging our initial hypothesis. Electron and gamma irradiations led to more homogeneously distributed and less porous defects compared to neutron irradiation, which correlated with the observed decrease in Tc—22.9% for neutron, 16.7% for gamma, and 13.5% for electron irradiation. These results highlight the intricate relationship between the type and distribution of defects induced by different irradiations and their varying impacts on superconductor performance. This study illustrates how defects, based on their characteristics, distinctly affect superconducting properties, emphasizing the complexity of defect interactions in superconductors. Our findings highlight the crucial relationship between irradiation-induced defects and the superconducting properties of Bi-2223, suggesting that the impact of Tc reduction on high-temperature superconductor applications needs to be reevaluated.

Tunable photoluminescence and energy transfer in Dy3+ and Eu3+ co-doped NaCaGd(WO4)3 phosphors for pc-WLED applications.

Elevated temperatures can lead to reabsorption and color drift, compromising the quality of phosphor-converted white light-emitting diode (pc-WLED) devices. To ensure the performance of WLEDs under these conditions, it is essential to develop luminescent materials that maintain stable color. Consequently, there is a pressing need for single-phase white-emitting phosphors with robust chromatic stability. In this work, we synthesize a series of color-tunable NaCaGd(WO4)3 (NCGW) phosphors using conventional solid-state reaction method, co-doping with Dy3+ and Eu3+ in varying ratios. X-ray diffraction, Rietveld refinement and scanning electron microscopy analyses are carried out to identify the phase purity and morphology. The photoluminescence (PL) properties are investigated under excitations of 352 nm and 393 nm. The PL emission spectra and fluorescence decay curves reveal efficient energy transfer between the Dy3+ and Eu3+ ions within the NCGW host, demonstrating tunable PL emission properties through manipulation of this energy transfer. At elevated temperatures of up to 200 °C, the positions of the characteristic emission peaks of Dy3+ and Eu3+ in NCGW phosphors remain essentially unchanged. Although the emission band intensities decrease due to thermal quenching, they retain a significant portion of their initial intensity compared to room temperature levels. For proof-of-concept studies, a single-phase NCGW:0.05%Dy3+-0.05%Eu3+ phosphor is combined with a commercial 365 nm UV chip to create a WLED device prototype. This prototype achieves a color rendering index of 81.7, a correlated color temperature of 4862 K and Commission International de I'Eclairage chromaticity coordinates of (0.35, 0.37), exhibiting comparable or superior colorimetric values to those reported in previous research. The results indicate that Dy3+ and Eu3+ co-doped NCGW phosphors, with their high chromaticity stability, have significant potential for full-spectrum WLED applications.

Tunable luminescence in Eu3+/Sm3+ doped Na2YMg2V3O12 for WLEDs and optical thermometry.

In recent years, it has become a development trend to design multi-application luminescent materials with rare earth ion doping. In this work, a series of Eu3+/Sm3+ doped self-activated Na2YMg2V3O12 (NYMVO) phosphors were synthesized through a simple high-temperature solid-state reaction method. Interestingly, due to the energy transfer (ET) from the matrix to the activators, the luminescence color of the phosphors changed from turquoise to orange-red and yellow-green under near-ultraviolet (n-UV) 365nm excitation. Based on the fluorescence intensity ratio of the matrix to Eu3+/Sm3+, the optical thermometry performances of the NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors were described. Notably, the maximum absolute sensitivity (Sa) values for NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors were 0.30K-1 and 0.032K-1, respectively. Correspondingly, the maximum relative sensitivity (Sr) values were 2.17%K-1 and 1.22%K-1, respectively. Moreover, the light-emitting devices based on NYMVO:0.20Eu3+ and NYMVO:0.06Sm3+ phosphors had excellent optical properties, with correlated color temperature (CCT) of 4552 K and 4470 K, and color-rendering index (CRI) of 84.6 and 88.5. These results suggested that the two vanadate phosphors prepared had potential applications in both warm white light-emitting diodes (WLEDs) and optical thermometry.

Structural and luminescent properties of a Cr3+/Sm3+ doped GdAlO3 orthorhombic perovskite for solid-state lighting applications.

The Cr3+ and Sm3+ doped GdAlO3 perovskite with formula Gd0.995Sm0.005Al0.995Cr0.005O3, was synthesized via a solid-state reaction method, and its structure, morphology, and photoluminescence properties were thoroughly investigated. The compound crystallizes in the orthorhombic Pbnm space group, with Cr3+ transition-metal ions substituting Al3+ in the octahedral symmetry site, and Sm3+ lanthanide (rare-earth) ions occupying the tetrahedral site. The material's morphology and chemical composition homogeneity were evaluated through Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis. Photoluminescence excitation (PLE) and emission spectra (PL) were used to shed light on the electronic structure of the Cr3+ cations, through crystal field analysis in the O h symmetry site. Theoretical studies enabled the precise assignment of the Cr3+ 3d-3d transitions. The intra-configurational 4f-4f transitions of Sm3+ resulted in a variety of excitation bands appearing in the high-wavelength range of the PLE spectrum. The photoluminescence studies supported the occurrence of energy transfer in the doped GdAlO3 perovskite between Gd3+, Sm3+ and Cr3+ ions. The obtained results suggest the high potential of the synthesized material for solid state lighting applications.

Exploring Brannerite-Type Mg1−xMxV2O6 (M = Mn, Cu, Co, or Ni) Oxides: Crystal Structure and Optical Properties

Environmentally benign, highly stable oxides exhibiting desirable optical properties and high near-IR reflectance are being researched for their potential application as pigments. Mg1−xMxV2O6 (M = Mn, Cu, Co, or Ni) oxides with brannerite-type structures were synthesized by the conventional solid-state reaction method to study their optical properties. These series exhibit structural transitions from brannerite (C2/m) to distorted brannerite (P1¯) and NiV2O6-type (P1¯) structures. The average color of Mg1−xMxV2O6 compounds varies from reddish-yellow to brown to dark brown. The L*a*b* color coordinates reveal that Mg1−xCuxV2O6 and Mg1−xNixV2O6 show more red hues in color with x = 0.4 and x = 0.5, respectively. The UV–Vis diffuse reflectance spectra indicate a possible origin for these results include the ligand-to-metal charge transfer (O2− 2p-V5+ 3d), metal-to-metal charge transfer (from Mn2+ 3d/Cu2+ 3d/Co2+ 3d/Ni2+ 3d to V5+ 3d), band gap transitions, and d–d transitions. Magnetic property measurements revealed antiferromagnetic behavior for the compounds Mg1−xMxV2O6 (M = Mn, Cu, Co, and Ni), and an oxidation state of +2 for the M ions was deduced from their Curie–Weiss behavior. The system Mg1−xMnxV2O6 has a NIR reflectance in the range between 40% and 70%, indicating its potential to be utilized in the pigment industry.

Mechanical properties of (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composite impacted in seawater

In the present work, the effect of adding Ba0.4Sr0.4Ca0.2Fe12O19 hard nanoparticles and the immersion in seawater for different durations (0, 2, 6, 12, and 24 h) on the mechanical characteristics of the Bi, Pb-2223 superconductor phase were studied. A conventional solid-state reaction method was used to produce the (Ba0.4Sr0.4Ca0.2Fe12O19)x/(Bi1.6, Pb0.4)-2223 composites (0.00 ≤ x < 0.40 wt%). X-ray diffraction (XRD) confirmed the primary phase formation of the tetragonal (Bi1.6, Pb0.4)-2223. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) studies were also carried out to demonstrate the microstructural analyses of the samples during seawater immersion. Compared to the pure (Bi1.6, Pb0.4)-2223 phase, SEM and EDX verified the improvement of the adsorption of seawater elements upon adding the nanoparticles. This resulted in faster grain size reduction in the (Bi1.6, Pb0.4)-2223 phase than in the pure sample before immersion. Vickers microhardness () Measurements were performed for 30 s at room temperature, with applied stresses ranging from 0.49 to 9.80 N after immersion in the seawater for different durations (0, 2, 6, 12, and 24 h). For the sample with x = 0.04 wt%, values enhanced with percentages of 67.72% and 98.44%, before and after immersion in seawater for 24 h, respectively. This suggests that the mechanical properties of the (Bi1.6, Pb0.4)-2223 phase were enhanced by a small addition of these nanoparticles and the salts of seawater adsorbed on the sample’s surface. The modified proportional sample resistance (MPSR) model offered the most accurate theoretical analysis in the plateau limit region, before and after seawater immersions, with a less than 5% variance. Furthermore, the incorporation of Ba0.4Sr0.4Ca0.2Fe12O19 into the superconductor had a positive impact on several mechanical characteristics, including fracture toughness (K), yield strength (Y), and elastic modulus (E). All these mechanical parameter values followed the same trend, increasing with the increase in immersion time. However, they are at their height with the presence of 0.04 wt% of these nanoparticles. The toughness increased by 27.31% of the pure sample at this point. After that, when the immersion time rose from 0 to 24 h, this number increased by 42.59%.

Luminescent Properties of Pr3+-Doped LiBaF3 Crystallites.

Research is ongoing to develop new phosphors capable of emitting light across a broad spectrum, ranging from the ultraviolet (UV) to the infrared region, with potential applications in diverse fields. Using the method of solid-state reactions, a series of LiBaF3:Pr3+ phosphors were obtained, and their luminescent properties in the UV-visible range were studied. The photon cascade emission (PCE) phenomenon has been observed under excitation of the 4f5d bands of Pr3+. The spectral and kinetic luminescent characteristics of LiBaF3:Pr3+ under X-ray excitation (40 keV) were studied. The X-ray excited luminescence spectrum of LiBaF3:Pr3+ consists of the emission of Pr3+ ions, the emission of self-trapped excitons, and the core-valence luminescence of the LiBaF3 host. In addition, the study assessed the optical-thermometric properties of LiBaF3:Pr3+ in the temperature range of 83-563 K, revealing the potential of temperature sensing in the physiological range. This study not only describes the luminescent properties of the newly synthesized LiBaF3:Pr3+ but also explores its potential applications as a fast ultraviolet scintillator and an optical temperature sensor.

High-performance novel anode-supported microtubular protonic ceramic fuel cells via highly efficient and simplified extrusion technology

Protonic ceramic fuel cells (PCFCs) are regarded as efficient energy conversion devices for addressing the challenges of carbon neutrality, which can directly convert the chemical fuel energy into electricity at reduced operating temperatures below 700 °C. However, the insufficient strength and immature preparation processes of PCFCs limit their practical application. In this work, the novel anode-supported microtubular PCFCs with a tube diameter of less than 5 mm were successfully prepared by extrusion technology combined with a dip-coating method. The newly developed BaZr0.4Ce0.4Y0.1Gd0.1O3-δ (BZCYG4411) proton-conducting electrolyte was synthesized using an extremely simple and efficient one-step solid-state reaction method, showing comparable electrical conductivity with BaZr0.4Ce0.4Y0.1Yb0.1O3-δ (BZCYYb4411) and BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb1711) electrolytes, as well as excellent chemical stability. The single cell with Ba2Sc0.1Nb0.1Co1.5Fe0.3O6-δ (BSNCF) cathode exhibited a high peak power density of 906.86 mW cm-2 at 700 °C. Additionally, this microtubular PCFC demonstrated excellent stability after about 103 h durability test at a constant current of 0.5 A cm-2 at 650 °C. This study provides a highly efficient and simplified technology for fabricating high-performance and durable anode-supported microtubular PCFCs.

Excellent Energy Storage and Charge-Discharge Performance in (Pb1-xCax)(Zr0.55Sn0.45)O3 Antiferroelectric Ceramics.

Lead-based antiferroelectric (AFE) ceramics have the advantages of high power density, fast charge and discharge speed, and the electric-field-induced AFE-FE phase transition, making them one of the potential dielectric energy storage materials. However, the energy storage density still needs to be improved. In this work, (Pb1-xCax) (Zr0.55Sn0.45)O3 (PCZS, x = 0.01, 0.02, 0.03 and 0.04) antiferroelectric ceramics were successfully prepared using the solid-state reaction and two-step sintering methods. The results showed that as the Ca2+ content increased, the average grain size decreased from 1.38 ± 0.42 to 1.06 ± 0.35 μm and the dielectric breakdown strength increased from 270 to 325 kV/cm for ceramics with 80 μm in thickness. Two kinds of superlattice structures (F-point with 1/2{ooo} patterns and incommensurate modulation structure (IMS) pattern with 1/n{110} patterns) were observed, indicating the typical octahedral tilting-related AFE structure. The (Pb0.98Ca0.02) (Zr0.55Sn0.45)O3 bulk ceramics, due to the refined polarization-electric field hysteresis loop of the IMS, achieved a maximum recoverable energy storage density (Wrec) of 6.61 J/cm3 with an efficiency (η) of 84.01%. In the circuit of charge-discharge to a load, an ultrahigh power density (PD) of 276.67 MW/cm3 and a discharged energy density (Wdis) of 6.24 J/cm3 were obtained in PCZS2 bulk ceramics at 290 kV/cm. The high Wrec and Wdis indicate that PCZS ceramics offer potential applications in the field of pulse-power electric devices.

Novel high-TC piezo-/ferroelectric ceramics based on a medium-entropy morphotropic phase boundary design strategy

The medium- or high-entropy strategy has emerged as a new paradigm for designing high-performance piezoelectric ceramics. However, the effectiveness of this approach remains unclear to the development of high Curie temperature (TC) piezo-/ferroelectric materials with outstanding performance. To develop high-performance piezo-/ferroelectric materials suitable for high-temperature environments, in this work, we design a novel ceramic system based on a medium-entropy morphotropic phase boundary (ME-MPB) strategy. Piezo-/ferroelectric ceramics of the formula, Pb(Yb1/2Nb1/2)O3–Pb(In1/2Nb1/2)O3–PbTiO3, meeting the medium entropy criteria, were successfully synthesized using the conventional solid-state reaction method. The crystal structure, microstructure, dielectric, piezoelectric, and ferroelectric properties of the ceramics of the ME-MPB compositions were systematically investigated. X-ray diffraction and scanning electron microscopy analyses revealed that these ceramics possess a pure perovskite phase and dense microstructure. Notably, the prepared ceramics exhibited exceptional piezoelectric performance, with a high d33 up to 603 pC/N, a large strain of 0.20%, a high remanent polarization of 44.0 μC/cm2, and a high Curie temperature of 362 °C. This study demonstrates an effective design approach based on the ME-MPB strategy and points out a new pathway for developing high-performance materials for high-temperature applications as sensors, thereby expanding the research perspective on the design of medium-entropy piezo-/ferroelectric ceramics.

Negative Magnetization and Spin-Phonon Coupling in Faceted Nd2FeCrO6 Double Perovskite

The magnetic feature of a faceted double perovskite Nd2FeCrO6, synthesized by the solid-state reaction method, is investigated. Nd2FeCrO6 exhibits an orthorhombic structure with Fe and Cr ions in 3+ oxidation states. These ions are shifted away from the centre of FeO6/CrO6 octahedral sublattice, indicating distortion. The Isomer shift in the Mössbauer spectrum correlates with the 3+ oxidation state of Fe, and the existence of magnetic fraction leading to magnetic frustration in Nd2FeCrO6 is established. The superexchange Fe3+ -O- Fe3+ and Cr3+ -O- Cr3+ interactions favour antiferromagnetic ordering, while Fe3+ -O- Cr3+ interactions promote weak ferromagnetic ordering. The low-temperature magnetic study traces negative magnetization in FC mode for the applied external fields of 100Oe and 1000Oe, attributed to the paramagnetic effect of Nd3+ ions aligning antiparallel to the ferromagnetic component of the |Fe+Cr| sublattice internal field. Also, the negative magnetization of FC mode is found to be field-dependent. The deviation of the B2g phonon around the magnetic ordering temperature TN~250K provides evidence of spin-phonon coupling. This variation in the B2g phonon is analysed in terms of the full width at half maximum (FWHM), peak position, intensity, and height.

Characterization of structure and photoluminescence properties for LiZn(B1-xAlx)O3 (x=0-1) oxides

LiZn(B1-xAlx)O3 (x=0-1) oxide was prepared by calcining at 750 ℃ for 5h using a solid-state reaction method. Due to the difference in the ionic radii of B3+ and Al3+ ions, the lattice is distorted, and a bi-phase composed of ZnO and γ-LiAlO2 oxides are formed for x=1. As the Al3+ ion doping contents increasing, the bi-phase oxide powder particles transform from agglomerated irregular to flaky structure. Under an excitation wavelength of 367nm, two broad luminescence bands located at blue and yellow-green light regions are observed. The CIE chromaticity coordinates are located in the light blue light region for LiZnBO3, whereas the CIE coordinates are located in the white light region (x=0.33, y=0.34) for the bi-phase oxides, and it is quite close to the NTSC standard white light coordinates (x=0.33, y=0.33).

Temperature Dependent Photoluminescence Properties of a Y2Ge2O7:Tb3+ phosphors. A dual band ratiometric luminescent thermometer

A series of green light emitting Y2Ge2O7:xTb3+ phosphors (x = 0.2, 0.5, 1.0, 2.0 and 4.0mol%) were obtained via the solid-state reaction method. The single phase was confirmed by XRD technique. The photoluminescence (PL) excitation spectrum, emission spectra at room and as a function of temperature, decay curves of phosphors were studied in detail. The emission spectra show typical emissions of Tb3+ ions, whose relative intensities change with the ion concentration or UV excitation. A shift of the CIE chromaticity coordinates from blueish to green region was observed. The emission decay curves are compatible with a single type of Tb3+ activator. The obtained internal Quantum Yield (iQY) increase with the terbium concentration, up to 10.0% for sample with 4.0mol%. In addition, the relative sensitivity values (Sr) for samples with 1.0 and 2.0mol% reached 0.97 and 2.02%K-1, respectively. These high thermal sensitivities obtained, in comparison with other Tb3+ based optical temperature sensors, in biophysical temperature range (30–45 °C), illustrates the potential use of Y2Ge2O7:xTb3+ phosphors in the design of efficient FIR luminescent thermometers for biological systems or other industrial applications.

Ga-doping in Li0.33La0.56TiO3: a promising approach to boost ionic conductivity in solid electrolytes for high-performance all-solid-state lithium-ion batteries.

All-solid-state lithium-ion batteries (ASSLBs) are the next advancement in battery technology which is expected to power the next generation of electronics, particularly electric vehicles due to their high energy density and superior safety. ASSLBs require solid electrolytes with high ionic conductivity to serve as a Li-ion battery, driving extensive research efforts to enhance the ionic conductivity of the existing solid electrolytes. Keeping this in view, the B-site of Li0.33La0.56TiO3 (LLTO) solid electrolyte has been partially substituted with Ga and novel Ga-doped LLTO (Li0.33+x La0.56Ti1-x Ga x O3) solid-electrolytes are fabricated using the solid-state reaction method, followed by sintering at 1100 °C for 2 h. The effects of Ga substitution on the structural changes, chemical states, ionic conductivity, and electrochemical stability of LLTO are systematically analyzed. The XRD analysis of the LLTO samples confirms the formation of a tetragonal perovskite structure and increasing bottleneck size up to 3% Ga-doped samples. XPS results have further confirmed the successful substitution of Ti4+ by Ga3+. The Ga3+ substitution has successfully enhanced the conductivity of LLTO solid electrolytes and the highest conductivity of 4.15 × 10-3 S cm-1 is found in Li0.36La0.56Ti0.97Ga0.03O3 (x = 0.03), which is an order of magnitude higher than that of pristine LLTO. This increase in ionic conductivity is a synergistic effect of B-O bond stretching resulting from the size difference between Ga3+ and Ti4+ and the increase in grain size. Moreover, the synthesized solid electrolytes are stable within the range of 2.28 to 3.78 V against Li/Li+, making them potential candidates for all-solid-state lithium-ion batteries.

Impedance spectroscopy and optical properties of lanthanum-modified Bi2FeMnO6 for NTC thermistor applications

The double perovskite Bi1.75La0.25FeMnO6 (BLFMO) ceramic was prepared by solid-state reaction method and characterized by different techniques such as X-ray diffraction, Scanning electron microscope, Energy Dispersive X-ray, Transmission electron microscope,...

Olivine-type germanate phosphors doped with Ln3+ (Ln = Eu, Dy) for solid-state lighting

Olivine-type germanate ceramics doped with Ln3+ ions (where Ln = Eu, Dy) as potential candidates to generate visible luminescence were studied. Analysis of microstructure and phase identification in systems obtained using the solid-state reaction method indicate that ceramics Li2ZnGeO4 and Li2MgGeO4 crystallize in a monoclinic crystal lattice, and samples consist of agglomerates that differ in size and shape. The spectroscopic properties of the ceramics align with the structure, and crucial parameters like the R/O or Y/B ratio and luminescence lifetime strongly depend on the type of ceramic samples. The luminescence spectra for germanate ceramics were recorded depending on the excitation wavelength and analyzed in detail. The Commission Internationale de l’Éclairage (CIE) chromaticity coordinates (x, y) were calculated from the emission spectra. It was observed that the color parameters change when the excitation wavelength and composition are modified. Our results indicate that olivine-type germanate ceramics doped with Eu3+ and Dy3+ ions exhibit red-orange and yellow-white emissions, respectively.

Removal of tetracycline using an ultrastable Pt-decorated-BNCB photocatalyst under efficient solar-driven conditions

The pursuit of optimizing the photocatalytic performance of the novel perovskite-like Bi4NbO8X materials remains a vibrant area of research. In this paper, we report the successful synthesis of the Bi4Nb4O8Cl0.935Br0.065 (BNCB) composite photocatalyst, loaded with Pt nanoparticles, utilizing a combination of solid-state reaction and sodium borohydride reduction methods. Notably, the surface plasmon resonance (SPR) effect exhibited by Pt broadened the spectral response range, while the Schottky junction formed at the Pt/BNCB interface significantly accelerated the separation of photogenerated electron-hole pairs and facilitated the swift migration of photogenerated electrons towards Pt. Experimental outcomes underscore the superior photocatalytic degradation efficacy of the Pt/BNCB composite towards tetracycline (TC), achieving a degradation rate of up to 67%, significantly outperforming pure BNCB. Pt/BNCB exhibits excellent photocatalytic degradation and excellent stability in various pH and ionic environments. Collectively, this work presents a novel approach for designing highly efficient and stable perovskite-type photocatalytic materials, holding immense potential for applications in environmental remediation.