The LaSrZrFeO6 powder was synthesized using a conventional solid-state reaction process. The qualitative phase analysis through X-ray Diffraction (XRD) and data analysis with Rietveld refinement confirm the single-phase formation of a novel double perovskite. Crystal structure investigation was conducted to determine the lattice parameters, bond lengths, angles, and ions distribution. Additionally, crystallite size, lattice strain, density, and porosity were calculated. Fourier-transform infrared (FTIR) spectroscopy has been performed to examine the vibrational modes and bond formations in the sample. The sample's microstructure, including grain shape and size distribution, and elemental composition, were assessed using Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analysis. The optical energy bandgap of the material, determined to be 2.81 eV, was ascertained through UV–visible absorption spectroscopy. Furthermore, the refractive index was calculated using both the Moss and the Herve and Vandamme methods. The study also delved into the electrical characteristics of the material, such as permittivity (εr), loss tangent (tanδ), and conductivity (σ). These properties were analyzed in relation to changes in frequency and temperature, employing particular formulas and parameters for a comprehensive understanding.

This study presents synthesis by the Pechini method and characterization of Bi1−xGdxFeO3 powders (0.00 ≤ x ≤ 0.20), providing new insights into the effects of gadolinium substitution on the structural, magnetic, and thermal properties of BiFeO3. Unlike previous studies, this work identifies a previously unreported double structural transition, from rhombohedral to cubic symmetry at x = 0.10, and from cubic to orthorhombic symmetry for x ≥ 0.15, demonstrating the critical role of Gd concentration. The magnetization measurements at room temperature exhibited enhanced ferromagnetic-like behavior, with potential implications for improving the material’s photocatalytic and multiferroic performance. Additionally, differential scanning calorimetry emphasized the material’s thermal stability. These findings contribute to a deeper understanding of how Gd substitution modifies the properties of BiFeO3, offering potential for optimizing applications in energy storage, spintronics, and catalysis.

The novel double perovskite oxide SrEuTiFeO6 was synthesized using the solid-state reaction method. X-ray diffraction analysis, complemented by Rietveld refinement, confirmed that this material crystallizes in a cubic double perovskite structure with the Pm3m space group and revealed cationic disorder at both the A (Sr, Eu) and B (Ti, Fe) sites. Crystallite size and lattice strain were determined through various methods. Fourier-transform infrared spectroscopy was utilized to examine vibrational modes and bond distortions within this material. Scanning electron microscopy showed a heterogeneous microstructure, with a wide distribution of grain sizes and shapes, resulting from the kinetics of the solid-state synthesis. Energy dispersive X-ray spectroscopy confirmed the material's homogeneity, stoichiometry, and chemical composition. UV-visible spectroscopy was used to investigate the optical properties of SrEuTiFeO6, identifying several characteristic optical transitions. The band gap energy and refractive index were found to be 2.08 eV and 2.60, respectively, indicating the material's potential for various applications. Additionally, the dielectric properties, including the relative dielectric constant and loss tangent, were thoroughly analyzed as functions of frequency and temperature. The electrical conductivity dispersion phenomenon was also analyzed according to Jonscher's power law, revealing the predominance of overlapping the large polaron tunneling mechanism.

The novel double perovskite oxide material, BaGdTiFeO6 (BGTFO), was synthesized using the solid-state reaction method. The material structure symmetry, morphology, and optical properties were investigated using a variety of techniques. XRD measurements showed that this material crystallizes in a cubic double perovskite structure with a Pm3m space group. The unit cell parameters, atomic positions, crystallite size, and site occupancies were determined using the Rietveld refinement method. Vibrational modes and bond deformations in the sample were examined through FTIR spectroscopy. Scanning electron microscopy revealed irregularly shaped grains with a non-uniform size distribution. The energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the homogeneity, stoichiometry, and chemical formula of this double perovskite oxide. UV–Visible spectroscopy was employed to analyze the material’s absorbance, determining an energy bandgap of 2.05 eV. Additionally, the refractive index of the material was determined using both the Moss as well as the Herve and Vandamme methods, highlighting its potential for use in various application fields, including the optoelectronic industry. The interplay between frequency and temperature in influencing both the dielectric and conductivity characteristics of materials has also been investigated.

Lithium doping improves CsPbBr3 perovskites films by enhancing optical properties and reducing non-radiative recombination for enhanced stability and performance of perovskite thin films based optoelectronic devices.

This research examines distribution networks in detail, both underground and overhead, as well as the layout of distribution pipes. It takes into account both energy and economic aspects. Different installation methods and thermal insulation materials for pipelines are studied, while scientific aspects such as heat and pressure loss modelling, technological advances and strategies for improving cost-effective models are discussed. In addition, regulatory concerns, standards and policies relating to heat distribution are addressed, including Legionella contamination laws and pipe insulation thickness requirements. According to the study’s findings, underground pipes are generally better suited to district heating networks than above-ground pipes and the triple pipes can decrease heat losses by 45% compared to single pipes and by 24% compared to double pipes. This article offers readers a detailed comprehension of the technical, scientific, and regulatory elements of urban heating networks. It highlights the significance of optimizing these networks by employing innovative configurations and adhering to regulatory standards to improve energy efficiency and sustainability in urban areas.

A novel manufacturing process is presented for producing nanopowders and thin films of CuCoO2 (CCO) material. This process utilizes three cost-effective synthesis methods: hydrothermal, sol-gel, and solid-state reactions. The resulting delafossite CuCoO2 samples were deposited onto transparent substrates through spray pyrolysis, forming innovative thin films with a nanocrystal powder structure. Prior to the transformation into thin films, CuCoO2 powder was first produced using a low-cost approach. The precursors for both powders and thin films were deposited onto glass surfaces using a spray pyrolysis process, and their characteristics were examined through X-ray diffraction, scanning electron microscopy, HR-TEM, UV-visible spectrophotometry, and electrochemical impedance spectroscopy (EIS) analyses were conducted to determine the conductivity in the transversal direction of this groundbreaking material for solar cell applications. On the other hand, the sheet resistance of the samples was investigated using the four-probe method to obtain the sheet resistivity and then calculate the in-plane conductivity of the samples. We also investigated the aging characteristics of different precursors with varying durations. The functional properties of CuCoO2 samples were explored by studying chelating agent and precursor solution aging periods using Density Functional Theory calculations (DFT). A complementary Density Functional Theory study was also performed in order to evaluate the electronic structure of this compound. Resuming, this study thoroughly discusses the synthesis of delafossite powders and their conversion into thin films, which hold potential as hole transport layers in transparent optoelectronic devices.

Rare-earth substituted multiferroic Bi1-xRExFeO3 powders with chemical compositions (x = 0.05, 0.15, 0.20 and RE = Nd3+; Eu3+) are synthesized by sol-gel method. The powder X-ray diffraction results manifest that samples are in single phase (R3c) for x < 0.15; the structural phase transformation from the distorted perovskite R3c to the ideal perovskite (Pm3 m) was made for BFO-Nd at x = 0.15 and for BFO-Eu (BEFO) at x = 0.20. Theoretical analyses allowed us to propose & UGamma;4 (k = 0, 0, 0) as the irreducible representation associated to the distortion of the ideal perovskite Pm3 m to the R3c distorted one, where the displacement of Fe atom along [0 0 1] axis is considered as so the parameter order & eta; = (0; 0; & eta;3), which drives the transition Pm3 m -R3c. Dielectric properties of Bi1-xRExFeO3 change noticeably with concentration and nature of RE-doping. The increase of Nd and Eu concentration decreases clearly the dielectric temperature anomalies corresponding to the ferroelectricparaelectric phase transitions, which are more shifting towards lower temperature when the dopant is Eu. Magnetic measurements indicate that antiferromagnetic BFO-Nd (BNFO) powders became ferromagnetic at (0.15 & LE;x & LE; 0.2), while the BFO-Eu (BEFO, x & LE; 0.15) compounds, antiferromagnetic with a small remanant magnetization, become weak ferromagnetic when x = 0.20.

Bi 1-x Eu x FeO 3 micropowders 0 ≤ x ≤ 0.20 were synthesized by sol-gel method. X-ray diffraction shows that the crystal structure changes from rhombohedral to cubic symmetry at x = 0.20 . Dielectric properties and loss factor were investigated as a function of temperature. Neel temperature T N of the compounds was measured by differential scanning calorimetry and found to decrease from 668 K to 646 K for 0 ≤ x ≤ 0.15 and bounce to 667 K for x = 0.20 . The Curie temperature T C which corresponds to the transition from ferroelectric to paraelectric phases was checked out using differential thermal analysis measurements. The T C value increases from 1130 K to 1135 K for 0 ≤ x ≤ 0.15 while no transition was detected for x = 0.20 in accordance with the structural transition from R3c to centrosymmetric Pm3m phase.

In this work, Mg-doped CuCoO2 (CCO) delafossite oxide was synthesized by a low-cost technique, namely spray pyrolysis. We investigated the effects of Mg doping on the structure, morphology, chemical composition, and optical properties of CCO with different percentages (1%, 2%, 3%, 4%, 5%). Using X-ray diffraction analysis, we observed an excellent agreement without any impurities in the Mg-doped CuCoO2 delafossite structure. To analyze the variations caused by doping on the quality, we examined the morphology of the produced films using field emission scanning electron microscopy. The deposited samples exhibited different textures and surfaces that were evenly distributed throughout the substrate. Furthermore, we utilized a transmission electron microscope to examine the Mg-doped CuCoO2 films. The CuCo1-xMgxO2 with x = 0.01 delafossite displayed excellent crystallinity. The results indicated that the fringe distances of 0.23 nm, 0.85 nm, and 0.16 nm corresponded to the spacings of the CuCoO2 lattice planes (110), (222), and (332) respectively. Optical properties were measured using UV-Vis spectroscopy at room temperature, revealing weak visible light absorption. It was found that CuCo1_xMgxO2 could be transparent to photons with energies in the visible range. Additionally, the band gap decreased in parallel with increasing Mg doping until a percentage of 3% (0.03), where a value of Eg = 1.75 eV was obtained.

RFe0.5Cr0.5O3 (R = Nd,Eu) perovskites were synthesized through solid-state reaction. The structural analysis evidences the orthorhombic symmetry of these materials in accordance with their tolerance factor. The lattice parameters, bond lengths, and bond angles, as obtained by Rietveld refinement, vary systematically with the size of R3+ cations. The structural stability and thermally activated expansion of the crystal lattice are affirmed by means of a high-temperature X-ray diffraction (HT-XRD) study. The microstructure of the prepared powders is investigated using scanning electron microscopy (SEM), as well as X-ray diffraction (XRD) through the calculation of the crystallite size. Diffuse reflectance spectra indicate that these materials behave as semiconductors, and the gap energies are calculated. Room-temperature Mossbauer spectroscopy highlights the presence of magnetic frustration phenomenon in both materials. The frequency-dependent dielectric study reveals a colossal dielectric constant in agreement with the Maxwell-Wagner relaxation mechanism resulting from intergrain boundaries, as asserted by impedance spectroscopy. The conductivity mechanism is provided by the correlated barrier hopping model for EuFe0.5Cr0.5O3 perovskite, and the non-overlapping small polaron tunneling mechanism for NdEe(0.5)Cr(0.5)O(3) material. High-temperature dielectric measurements reveal two anomalous features attributed to the magnetodielectric effect and the onset of ferroelectric-paraelectric transition, respectively. Metallic behavior is identified at higher temperatures for both materials.

Conventional solid-state reaction process was adopted to prepare PrFe0.5Cr0.5O3 polycrystalline material. High temperature X-ray diffraction (XRD) patterns confirmed the formation of a single-phase crystallizing in a Pbnm orthorhombic system, with a thermally activated expansion of the crystal lattice. SEM images revealed a morphology consisting of irregularly shaped grains with a size of 0.16-0.40 mu m, while EDX analysis confirms the chemical formula PrFe0.5Cr0.5O3. The infrared (IR) spectrum identified a set of absorption peaks attributed to Cr-O and Fe-O vibrations. Magnetic measurements using Moeurossbauer spectroscopy revealed the onset of a magnetic frustration phenomenon resulting from the random distribution of Fe and Cr atoms. The frequency dependent dielectric study showed a large value of epsilon' in the low-frequency region explained by the Maxwell Wagner model. The dielectric response was associated with heterogeneous conduction in the grains and grain boundaries, as highlighted by impedance spectroscopy, indicating that the material consists of conductive grains separated from each other by poorly conducting grain boundaries. Negative temperature coefficient resistance behavior was also found in the system. High-temperature dielectric measurements were also carried out. The Jonscher's power-law fit to the AC conductivity data confirms that the conduction is dominated by the small polaron hopping mechanism. The optical band gap was evaluated using the Tauc plot and found to be around 2.02 eV, pointing the multifunctionality of this perovskite material.

The pulsed laser deposition (PLD) technique was used to deposit CZTS thin films onto SLG/Mo substrates via the KrF-laser ablation of a composite target consisting of Cu2ZnSnS4 pellet onto which Zn strips were purposely affixed. The effect of the substrate temperature (T-sub) of the PLD-CZTS films on their structure and properties was systematically studied over the 25-500 degrees C temperature range. The Zn content of the films was found to increase mainly when T-sub is raised from 300 to 500 degrees C. While both XRD and Raman analyses confirmed that the films consist of the kesterite-single-phase of which crystallinity improves when T-sub is increased (from RT up to 400 degrees C), the near resonant Raman (at 325 nm) revealed the presence of ZnS phase at high T-sub (> 400 degrees C). The optical energy band gap (Eg) of the PLD-CZTS films was consistently found to decrease from 1.9 to 1.4 eV when T-sub is increased from RT to 500 degrees C. Our results pointed out the T-sub = 400 degrees C as the optimal deposition temperature that meets at best the properties required for the PLD-CZTS films for PV application. The post-annealing (in presence of S and Sn vapors at 560 degrees C) of the PLD-CZTS films has improved further their crystallinity and led to the formation of some ZnS secondary phase at their surface. By appropriately integrating these post-annealed films into SLG/Mo/CZTS/CdS/ZnO/ITO photovoltaic devices, we were able to demonstrate their photoconversion ability with a PCE of 3.3 % (V-oc = 512 mV, J(sc) = 12.5 mA/cm(2) and a FF = 51.5 %). The analysis of their EQE spectrum suggests that the effective carrier collection length in the CZTS absorption layer needs to be extended further to achieve higher photoconversion efficiencies. (C) 2021 Elsevier B.V. All rights reserved.

LaFe0.5Cr0.5O3 (LFCO) perovskite was synthesized by conventional solid-state reaction process in air atmosphere. X-ray powder diffraction data revealed that the sample crystallizes in a Pnma orthorhombic symmetry, with a nearly same shaped grain size of 0.21-0.57 mm as shown from scanning electron microscope (SEM) images. The elemental composition of the sample with nominal stoichiometry is verified by energy-dispersive X-ray spectroscopy (EDS) results. The octahedral coordination of iron and chromium ions in the LaFe0.5Cr0.5O3 system is evidenced by the infrared spectroscopy. Impedance spectroscopy and dielectric measurements are performed in a wide frequency range at various temperatures. The higher values of e0 at low frequencies are explained on the basis of the Maxwell-Wagner (MW) relaxation model arising from the inhomogeneity conduction in the grains and grain boundaries. These findings have been further confirmed by the complex impedance analysis highlighting two electrical responses attributed to grain and grain boundaries effects, respectively. Negative temperature coefficient of resistance (NTCR) effect was also proved on the material. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 3rd International Congress on Materials & Structural Stability.

This study is aimed at developing a low cost lumped model for simulating a Li-ion battery pack with thermal management systems (TMS) under continuous charging/discharging cycles. The considered system is composed of twenty-four commercial Li-ion batteries with phase change material (PCM) and nine aluminium tubes for liquid coolant circulation. A zero-dimensional numerical model is developed based on the transient energy balances and the analogy between heat transfer and electrical transfer using resistances and capacitors. The simulations were carried at 3-C discharging/0.5-C charging rates and obtained results were compared with both three-dimensional computational fluid dynamic (CFD) results and experimental results from the literature. The effect of various system design and operating characteristics such as the cooling method, the coolant temperature and its velocity, the number of coolant pipes and the ambient conditions on the system performance were presented and analysed. Results show that combining both PCM and liquid cooling for battery thermal management leads to reduce the maximal battery temperature by about 38 degrees C and 4 degrees C compared to natural convection thermal management mode and to passive PCM thermal management mode, respectively. Increasing the number of cooling pipes improves the performance of the system and its optimal number in this system is up to 9 pipes. The maximal battery cells temperature is reduced from 31 degrees C to 20 degrees C as the used liquid coolant inlet temperature is reduced from 25 degrees C to 10 degrees C. Finally, the suggested low cost lumped model is a promising tool for simulating, designing and optimising battery pack with thermal management systems under real exploitation conditions.

Finding alternative materials components of lithium ion batteries (LIBs) with high performances is a key factor to improve this technology. The objective of the present study was to investigate the electrochemical performances of tin phosphite (SnHPO 3 ) as anode material for LIBs. SnHPO 3 has been synthesized through a simple hydrothermal method and characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques. The characterization results proved that SnHPO 3 has been successfully synthesized with no impurities. The electrochemical behavior of SnHPO 3 as anode is discussed using cyclic voltammetry and galvanostatic cycling. Interesting performances have been obtained by using carboxymethyl cellulose (CMC) as binder. SnHPO 3 has shown a good reversible capacity thanks to its open-framework with large size channels that buffer volume expansion of tin nanoparticles and to the CMC binder effect.

Transparent conducting oxides (TCOs) are a crucial component of solar cells. Tin-doped indium oxide (ITO) is the most employed TCO, but the scarcity and high price of indium induce a search for lower-cost TCOs with equivalent properties as substitutes. Tin dioxide (SnO2) films have many advantages, such as rich sources of material, low prices, and nontoxicity. SnO2 films present a high visible-light transmittance, near-infrared light reflectivity, and excellent electrical properties. They also have a higher chemical and mechanical stability compared to ITO. The aim of this work is to elaborate SnO2 films by radio frequency (RF)-magnetron sputtering in order to use them as electrodes for organic solar cells (OSCs). The SnO2 films were deposited on glass, SiO2, and quartz substrates in a mixed environment of Ar and O-2. X-ray diffraction (XRD) measurements show that the as-deposited SnO2 films are polycrystalline with a cassiterite tetragonal structure. Scanning electron microscopy (SEM) analysis showed that the films are homogeneous, continuous, and nanostructured. The electrical resistivity and average optical transmittance of the samples are about 10(-3) Omega.cm and over 80%, respectively. The estimated optical band gap (E-g) is around 4.0 eV, while the work function (WF) of the films is around 5.0 eV. The SnO2 films are used as electrodes for inverted OSCs, using poly(3-hexylthiophene-2,5-diyl): [6,6]-phenyl-C60-butryric acid methyl ester (P3HT:PC60BM) as the active layer. The device's open-circuit voltage (V-OC) and short-circuit current density (J(SC)) are similar to those obtained for the inverted OSCs employing ITO as the same electrode. Even if the achieved power conversion efficiency (PCE) is lower compared to the value for the reference OSC with an ITO electrode, these results are promising and place SnO2 TCO as a potential candidate to replace ITO.

Europium-ferrite perovskite EuFeO3 was synthesized basing on standard solid state reaction technique. X-ray diffraction analysis revealed the formation of single phase identified to be crystallizing in a Pbnm orthorhombic structure. X-ray peak broadening was conducted to evaluate the crystallite size and lattice strain. Scanning electron microscopy images showed an agglomerated distribution of grain with an average size ranging between 0.47 and 1.11 mm. The presence iron ions in octahedral environment is highlighted Fourier transform infrared (FT-IR) spectroscopy. Dielectric study was performed as a function of both frequencies (1 kHz-1 MHz) and temperatures (298-300 K). The frequency dependence of dielectric properties revealed a quasi-dc process behavior in the material, typical of carrier dominated systems. Two dielectric anomalies were observed, corresponding to the conduction relaxation dominated by the migration of oxygen vacancies. All observed phenomena were pointed by differential scanning calorimetry (DSC) analysis. Optical absorption studies imply the existence of a direct band gap in the sample. Copyright (C) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 3rd International Congress on Materials & Structural Stability.

Herein, structural, and optical properties of the sprayed Zn1-xFexO (ZFO) thin films, with 0 < x < 0.15, have been investigated, by combining experimental characterizations, and theoretical calculations of the light scattering properties. The X-ray diffraction patterns displays a hexagonal wurtzite structure of the polycrystalline films, with c-axis orientation. The iron ions substitution of Zn2+ ions, was confirmed by XRD, Raman and photoluminescence measurements. Furthermore, an obvious redshift in the near band edge emission peak was also observed by photoluminescence analysis which is attributed to the band structure deformation in ZnO thin films. The resulting optical data indicated a strong correlation between the haze factor, crystalline quality, and the surface morphology feature. The scalar scattering theory within the Rayleigh scattering formula, was used to calculate the simulated haze factor, for the two optimized ZFO thin films, through crystalline quality and surface roughness, namely, the synthetized ZFO film with a 5at% and 7at% iron concentration. A good agreement with the scalar scattering theory is obtained, for the haze factor relative to the transmission.

One of the major perovskites used as a light absorber in perovskite solar cells (PSCs) is methylammonium lead iodide (MAPI). MAPI perovskite shows many optimal optoelectronic properties making it a high-performance solar cell material. Nonetheless, PSCs face some limitations related to stability and degradation against moisture, and toxicity due their lead content. The goal of this work is to study the partial substitution of lead iodide (PbI2) with the inorganic compound copper iodide (CuI) to enhance the solar cell stability thanks to the hydrophobic properties of the latter. XRD showed a tetragonal crystal structure growth for the MAI[(PbI2)1−x(CuI)x] perovskite films. Even for 20 mol%, CuI was well incorporated into the perovskite lattice structure producing a slight change in the lattice parameters. SEM analysis showed a clear improvement of the film’s morphology with the CuI substitution (less pinholes, better uniformity). The optical absorption edges and calculated optical bandgap, around 1.55 eV, remain unchanged with CuI partial substitution. With the increase in CuI/PbI2 ratio photovoltaic properties of the MAI[(PbI2)1−x(CuI)x] devices improved, higher VOC and JSC are observed. Finally, the stability was studied during 150 days in air and an enhancement of PSCs properties was observed for CuI substituted PbI2 PSCs.