Improvement Of Electrical Properties Research Articles

Collaborative improvement of mechanical and electrical properties of Cu–Ni–Co–P alloys via regulation of nanophase precipitation behavior

Owing to their excellent strength and electrical conductivity, Cu–Ni–Co–P alloys present strong potential as next-generation materials for integrated circuits in electronic information systems. However, these outstanding properties are closely tied to the precise control of nanophase precipitation behavior within Cu-based alloy systems. Herein, the design of alloy composition was combined with aging treatment to regulate the nanoprecipitation process. Furthermore, the effects of P content and aging treatment conditions, including temperature and duration, on the microstructure and the mechanical, and electrical properties of Cu–Ni–Co–P alloys were systematically investigated. The findings reveal that Cu–0.3Ni–0.3Co–0.16P alloys, when aged at 500 °C for 4 h, primarily consist of a Cu-rich matrix interspersed with numerous nanoprecipitates. These nanoprecipitates were identified as the hexagonal CoNiP phase, precipitating in Guinier–Preston (GP) zones and maintaining a coherent relationship with the Cu matrix. The as-annealed Cu–0.3Ni–0.3Co–0.16P alloys demonstrated a tensile strength of 652.9 MPa, a yield strength of 631.2 MPa, a Vickers hardness of 203.2 HV, and an electrical conductivity of 66.4 %IACS. Aberration-corrected scanning transmission electron microscopy revealed that G.P. zones suppressed the coarsening of the CoNiP phase, thereby enhancing the mechanical strength of the Cu–Ni–Co–P alloys. The strength analysis calculations suggest that fine-grain and precipitation strengthening mechanisms are the predominant factors in improving the mechanical strength of these alloys. This study provides valuable insights into the development and manufacturing of high-performance Cu-based alloys for advanced applications in the electronics industry.

First principle investigation of Sr and Eu doped La2NiMnO6: Structural, Electronic, Optical, Magnetic, and Spintronics properties

This study investigates the effects of substituting La₂NiMnO₆ (LNMO) with Strontium (Sr) and Europium (Eu) dopants at the A-site, focusing on changes in material properties. Utilizing Density Functional Theory (DFT) with Local Density Approximation and Hubbard U Correction (LDA + U), we analyze the significant impact of these dopants on LNMO's optical, magnetic, electrical, and spintronic properties. Sr and Eu doping modifies the electronic structure of LNMO, enhancing its dielectric properties, which is crucial for applications requiring a high dielectric constant. The improved optical conductivity of doped LNMO makes it more efficient in light absorption and photoconductivity, beneficial for optoelectronic devices. Doping also enhances the magnetic properties of LNMO, advantageous for spintronics where spin control is essential. These dual improvements in electrical and magnetic properties suggest that Sr and Eu-doped LNMO are highly effective for energy storage technologies. Additionally, the mechanical properties of doped LNMO show improved resilience and stability, key indicators for the durability and longevity of devices. This comprehensive analysis highlights the potential of Sr and Eu-doped LNMO for advancements in spintronics, optoelectronics, and energy storage. The findings provide valuable insights into tuning material properties through doping, paving the way for synthesizing new multifunctional materials. This study not only enhances our understanding of the impact of dopants in double perovskites but also expands possibilities for innovative applications in high-tech fields, offering the potential for creating versatile materials and future innovations.

Design of epoxy composites via molecular orbital modulation and enhanced π-πF interactions achieving synchronous improvement of electrical and mechanical performance

The stacked aromatic rings in bisphenol A epoxy resins provide good mechanical properties and thermal stability while leading to the transport of conjugated delocalized electrons, which dramatically affects the insulation properties of the material. This contradiction leads to performance bottlenecks in epoxy-based encapsulation materials, further limiting the development of high-voltage semiconductor devices. In this study, fluorophenyl-modified epoxy monomers (FPMEPs) are designed to enrich the intermolecular interactions in an aromatic system while inhibiting the charge transport process, thereby solving the contradiction between the electrical and mechanical properties. Firstly, FPMEP with high insulation properties was designed by theoretical calculations and then synthesized by highly selective click chemistry. The fluorophenyl modulates the molecular orbitals of epoxy monomers and acts as a deep trap to inhibit charge injection and transport processes. Further, the π-πF stacking between the aromatic system and fluorophenyl enhances the interaction of the matrix molecules and solves the dispersion problem of fluorinated graphene (FG) fillers. The FPMEP/FG composites thus exhibit a considerable improvement in electrical and mechanical properties (breakdown strength of 39.8 kV/mm, dielectric loss of 0.011@50 Hz, tensile strength of 68.8 MPa, and adhesive strength of 2.15 MPa), and demonstrate good water repellency and aging durability. This matrix-filler synergistic modification strategy provides new insights into the design of insulation material.

The addition of Bi2WO6 nanoparticles to polyvinyl alcohol film: Improvements in optical, mechanical, and electrical properties

This study deals with the influence of adding Bi2WO6 (BWO) nanoparticles on the optical, structural, dielectric, and mechanical properties of polyvinyl alcohol (PVA). BWO nanoparticles synthesized by solvothermal method were characterized by X-Ray diffraction (XRD) and scanning electron microscope (SEM-EDS). The thick film nanocomposites were analyzed by Fourier Transformed Infrared (FTIR) spectrometer, XRD device, SEM, atomic force microscope (AFM), ultraviolet visible (UV–Vis) spectrophotometer, impedance analyzer, and tensile test machine. While FTIR analyses confirmed the formation of composite structure and the presence of BWO in the composites, AFM views indicated the reduced roughness for composites. Additionally, the UV–Vis light absorption spectra revealed a narrowed band gap in the composites. Moreover, with increasing BWO contribution, gradual increases were recorded in Young's modulus, toughness and % breaking strain parameters. The frequency dependent dielectric properties was also shown that the energy storage ability of the PVA matrix enhances 25 % and 50 % due to 2 % and 3 % BWO additives, respectively. However, the composite with higher ε′ and lower ε″ values than the pure PVA in the entire frequency range was the 2 % BWO-doped nanocomposite. Based on the serious and simultaneously improvements in electrical, optical and mechanical properties, it can be suggested that 2 % BWO additive provides the opportunity to expand the application area of PVA synergistically.

A computational study of the effects of graphene additions on electrical properties of polycrystalline copper

The addition of graphene has recently shown promise as a route for the significant improvement of the bulk electrical properties of metallic materials. We explore the effects these additions have on the net electrical conductivity of fabricated copper-graphene (Cu-Gr) nanocomposites as a function of grain structure and grain boundary properties. Synthetic 3D microstructures were generated to represent polycrystalline copper with different average grain diameters and twinned grain boundary fractions. Then, the Poisson equation of electrical transport was solved using a finite difference method in order to predict the net electrical conductivity of each microstructure. In this context, the potential effect of graphene on the conductivity of the composite was evaluated as a function of the number of affected grain boundaries. The results of these calculations indicate that 1.) as supported by literature, net electrical conductivity decreases with decreasing grain size, 2.) the presence of twinned grain boundaries results in smaller loss of conductivity than would otherwise be expected, and 3.) the presence of graphene on the grain boundaries can be expected to lead to improvements in net electrical conductivity. However, we also find that 4.) when the Cu grain structure becomes sufficiently refined, the addition of graphene could conceivably result in significant improvements in electrical conductivity over and above coarse-grained Cu. It is estimated from our calculations that, assuming microstructures with average grain sizes between 100 nm and 100 μm and graphene conductivity 1000 to 10,000 that of a typical Cu grain boundary, an improvement in electrical conductivity of approximately 17 % over that of bulk Cu may be attainable. Therefore, by performing this study we suggest a possible route for the improvement of Cu electrical properties through the addition of graphene.

Enhancement of carrier concentration in chemical bath deposited copper sulfide (CuxS) thin film by post-growth annealing treatment

Copper sulfide thin films (CuxS, 1 ≤ x ≤ 2), owing to their unique optical and electrical properties, have attracted enormous attention in recent research. As one of the chalcogenide semiconductors, CuxS is used in several applications such as chemical sensors, photo-absorbing layers, photovoltaics, and lithium-ion batteries. In this study, copper sulfide thin film (CuxS; where 1 ≤ x ≤ 2) has been deposited by the chemical bath deposition method (CBD) at 27 °C with the molar ratio for copper and sulfur as 1:5, respectively. The structural, compositional, morphological, optical, and electrical properties of as-deposited and annealed CuxS thin films are investigated. From XRD plots, the presence of a mixture of two co-existing polycrystalline phases is observed, i. e. covellite phase with CuS stoichiometry and digenite phase with Cu1.8S stoichiometry up to an annealing temperature of 200 °C. At higher annealing temperatures, i.e. at 300 °C and 400 °C, the phase of CuxS thin film gets completely converted to digenite phase with Cu1.8S stoichiometry and chalcocite phase with Cu2S stoichiometry respectively. There is an enhancement in the crystallinity of CuxS thin film with an increase in annealing temperature as confirmed by XRD and Raman results. The optical bandgap of CuxS thin film is found to be decreased from 2.81 eV to 1.66 eV with an increase in the annealing temperature. The CuxS thin films are found to be p-type in nature, and the film annealed at 400 °C possesses the highest carrier concentration as revealed from the Hall effect measurement. This study aims to investigate the improvement of electrical properties of CuxS thin film with the variation in annealing temperature for optoelectronic applications such as photodetector.

Improvement of Electrical and Thermal Properties of Carbon Nanotube Sheets by Adding Silver Nanowire and Mxene for an Electromagnetic-Interference-Shielding Property Study.

Hybrid carbon nanotube (CNT) sheets were fabricated by mixing CNTs with silver nanowires (AgNWs) and MXene to study their electromagnetic-interference (EMI)-shielding properties. CNT/AgNW and CNT/MXene hybrid sheets were produced by ultrasonic homogenization and vacuum filtration, resulting in free-standing CNT sheets. Three different weight ratios of AgNW and MXene were added to the CNT dispersions to produce hybrid CNT sheets. Microstructure characterization was performed using scanning electron microscopy, and the Wiedemann-Franz law was used to characterize transport properties. The resulting hybrid sheets exhibited improved electrical conductivity, thermal conductivity, and EMI-shielding effectiveness compared to pristine CNT sheets. X-band EMI-shielding effectiveness improved by over 200%, while electrical conductivity improved by more than 1500% in the hybrid sheets due to a higher charge-carrier density and synergistic effects between nanomaterials. The addition of AgNW to CNT sheets resulted in a large improvement in electrical conductivity and EMI shielding; however, this may also result in increased weight and sample thickness. Similarly, the addition of MXene to CNT sheets may result in an increase in weight due to the presence of the denser MXene flakes.

Study on mechanical and electrical properties improvement of insulating paper modified by cellulose nanocrystals

Study on mechanical and electrical properties improvement of insulating paper modified by cellulose nanocrystals

Synthesis and characterization of graphene on copper foil via atmospheric pressure chemical vapor deposition method and its impact on electrical properties

Copper, prized for its exceptional electrical conductivity, thermal conductivity, and mechanical strength, is a staple in electronic applications. The ongoing quest for enhanced performance in miniaturized technologies has led to exploring copper-graphene composites, particularly those integrating bilayer graphene (BLG). This study investigates the enhancement of electrical conductivity in copper through the incorporation of BLG via atmospheric pressure chemical vapor deposition (APCVD). The research highlights the APCVD method's ability to grow high-quality BLG on high-purity oxygen-free copper foil, demonstrating significant improvements in electrical properties. Detailed characterization reveal that the graphene growth process induces structural changes in the copper, promoting ideal crystallographic orientations and larger grain sizes. This process achieves nearly complete graphene coverage and results in a copper/graphene (Cu/GR) composite with minimal defects. The electrical conductivity of the Cu/GR composite significantly increased to 59.32 × 10⁶ S·m⁻1, a 7.83 % improvement over the pristine copper foil. This enhancement is attributed to the increased carrier density and mobility within the composite. These advancements suggest the potential of APCVD-grown graphene for various high-performance electronic applications, providing a promising pathway for further development and optimization of graphene-copper composites.

Effect of Sb2S3 sacrificial layer thickness on structural, optical and electrical properties of CuSbS2 films and investigation of diode parameters of CuSbS2/CdS heterojunctions

The ternary copper chalcogenides CuSbS2 (CAS) is found to have appealing optical and photovoltaic properties to be used as absorber layer in thin film solar cells. However, the difficulty to grow good quality CuSbS2 layer of micrometer thickness by chemical bath deposition method holds a big challenge. In this work, we reported the effect of incorporating Sb2S3 sacrificial layer of different thickness on structural, optical and electrical properties of CAS films. The X-ray diffraction results and Raman spectroscopic analysis confirm the formation of single-phase orthorhombic crystal structure for CuSbS2. The increase of Sb content in CAS films with the increase in deposition time of Sb2S3 layer has been reflected in the change in relative intensity ratio of characteristic Raman peaks as well as in diffraction peak profiles. The magnitude of defect states in terms of Urbach energy is decreased drastically by increasing Sb percentage in the films. A clear improvement in electrical properties of CAS films is observed with the decrease in Cu/Sb ratio. The carrier density is increased by one order of magnitude from 1016 to 1017 cm−3 and hole mobility increases from 1.14 to 4.87 cm2/Vs. The impact of Sb concentration on Scottky diode parameters of CAS/CdS heterojunction was studied by using thermionic emission model. Both the ideality factor and series resistance are decreased with the increase in Sb content. The J-V measurements reveal that the integration of Sb2S3 sacrificial layer improves the PV parameters such as fill factor, open circuit voltage, photocurrent and efficiency. The overall improvement in diode parameters can be ascribed to decrease in defect states, better film quality, absorber layer thickness and improved stoichiometry of CAS films.

Simultaneous electrical and mechanical properties improvement for composite expanded graphite bipolar plate by incorporating surface-activated carbon black paving on the carbonized melamine foam skeleton

The bipolar plate is the critical component that directly impacts the output performance and lifespan of the fuel cell. Composite graphite-based bipolar plates, which can be tailored to exhibit desired properties, are promising candidates for high-performance fuel cells. However, the simultaneous optimization of their electrical and mechanical properties has been a major challenge in the field. This study introduces a foam skeleton made of carbonized melamine foam (CMF) into the graphite bipolar plate to create ample space for subsequent resin impregnation. Carbon black (CB) is added as a filler to form complete conductive paths, which is modified using low-temperature plasma to allow it to be more uniformly adsorbed in the skeleton. The microstructure design of the composite bipolar plate ensures excellent mechanical properties and significantly enhances its electrical conductivity. Moreover, it effectively eliminates the impact of carbon black on the surface roughness of the composite plate. This design also provides superior water management and reduces gas permeability. Practical application tests demonstrate that the developed composite plate exhibits better corrosion resistance and electrochemical stability than metal bipolar plates. Compared to carbonized bipolar plates, it displays better impact resistance and stability.

Fabrication of high-resolution, flexible, laser-induced graphene sensors via stencil masking

The advent of wearable sensing platforms capable of continuously monitoring physiological parameters indicative of health status have resulted in a paradigm shift for clinical medicine. The accessibility and adaptability of such portable, unobtrusive devices enables proactive, personalized care based on real-time physiological insights. While wearable sensing platforms exhibit powerful capabilities for continuously monitoring physiological parameters, device fabrication often requires specialized facilities and technical expertise, restricting deployment opportunities and innovation potential. The recent emergence of rapid prototyping approaches to sensor fabrication, such as laser-induced graphene (LIG), provides a pathway for circumventing these barriers through low-cost, scalable fabrication. However, inherent limitations in laser processing restrict the spatial resolution of LIG-based flexible electronic devices to the minimum laser spot size. For a CO2 laser–a commonly reported laser for device production–this corresponds to a feature size of ∼120 μm. Here, we demonstrate a facile, low-cost stencil-masking technique to reduce the minimum resolvable feature size of a LIG-based device from 120 ± 20 μm to 45 ± 3 μm when fabricated by CO2 laser. Characterization of device performance reveals this stencil-masked LIG (s-LIG) method yields a concomitant improvement in electrical properties, which we hypothesize is the result of changes in macrostructure of the patterned LIG. We showcase the performance of this fabrication method via production of common sensors including temperature and multi-electrode electrochemical sensors. We fabricate fine-line microarray electrodes not typically achievable via native CO2 laser processing, demonstrating the potential of the expanded design capabilities. Comparing microarray sensors made with and without the stencil to traditional macro LIG electrodes reveals the s-LIG sensors have significantly reduced capacitance for similar electroactive surface areas. Beyond improving sensor performance, the increased resolution enabled by this metal stencil technique expands capabilities for scalable fabrication of high-performance wearable sensors in low-resource settings without reliance on traditional fabrication pathways.

Development and characterization of PVA-based nanocomposites with graphene and natural quartz nanoparticles for energy storage applications

This study presents the development and characterization of polymer nanocomposites (PNCs) using polyvinyl alcohol (PVA) as a matrix, incorporating graphene (Gr) and natural quartz nanoparticles (NQNs) as nanofillers. The graphene content was fixed at 1 wt%, while the quartz content was varied at 3 wt%, 7 wt%, and 11 wt%. The NQNs were derived from natural quartz rocks, which were ground and milled to nanosize, emphasizing the utilization of natural materials. Comprehensive characterization was performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–Vis), and extensive electrical and dielectric measurements. SEM and EDS analyses revealed the nearly spherical shape of the NQNs, with sizes ranging from 25 to 88 nm and an average size of 61.2 ± 13.1 nm. XRD patterns indicated a decrease in crystallinity of the polymer matrix with increasing NQNs content, with the PVA/Gr-11 wt% NQNs showing nearly amorphous characteristics. FTIR spectra demonstrated the incorporation of NQNs within the PVA matrix, affecting the chemical bonding and reducing the intensity of characteristic peaks. UV–Vis spectra indicated a significant decrease in the optical bandgap with the addition of NQNs, suggesting enhanced electronic properties. The electrical conductivity measurements, at a frequency range of 50 Hz to 8 MHz and temperature range from 20 °C to 80 °C, showed that the incorporation of Gr, a two-dimensional (2D) material, and NQNs significantly enhanced the conductivity of the nanocomposites, with the optimal performance observed at 7 wt% NQNs. Dielectric measurements revealed that the PVA/Gr-7 wt% NQNs nanocomposite exhibited superior dielectric properties, with higher dielectric constant and lower dielectric loss compared to pure PVA. Nyquist plots indicated reduced bulk resistance and enhanced thermal stability for the PVA/Gr-7 wt% NQNs composite. Capacitance-frequency and conductance-frequency analyses of the fabricated capacitor confirmed this composite's superior performance for dielectric capacitors. The optimized PVA/Gr-7 wt% NQNs nanocomposite, leveraging the unique properties of natural quartz and 2D graphene, demonstrated significant improvements in electrical and dielectric properties, making it a promising candidate for advanced dielectric capacitors in energy storage applications. The study confirms the innovative use of natural and 2D materials to develop energy storage devices.

Improvement of electrical and optoelectronic properties of ZnO thin films by plasma nitridation treatment

Understanding and controlling the effects of trap sites in ZnO semiconductors are crucial for optimizing device performance and enabling various technological applications. To passivate the trap sites, the N atoms are incorporated into polycrystalline ZnO thin films via a plasma nitridation (PN) process using NH3 gas. The results show that the contact resistivity, sheet resistance, and transfer length of the ZnO photodetector are improved after the PN treatment. The photo-to-dark current ratio (PDCR) and responsivity values increase from 42.52 to 103.19 and from 344.36 A/W to 5727.63 A/W, respectively, after the PN treatment. This improvement in photodetector properties is attributed to the introduced N atoms, which effectively reduce the trap sites in the ZnO thin film. This PN treatment technology has the potential to improve device performance in both electronic and optoelectronic applications.

Studying the structural, thermal, mechanical, and dielectric features of PVA/iron oxide@SiO2 polymer nanocomposites for electrical applications

Fe3O4@SiO2 (FS) nanocomposite was synthesized through the co-precipitation method and utilized as a filler material in the polyvinyl alcohol (PVA) matrix to obtain PVA/iron oxide@silica Fe3O4@SiO2 (PFS) films. This study presents the synthesis and characterization of flexible polymer nanocomposites comprising polyvinyl alcohol (PVA) matrices embedded with iron oxide @ silica. Through the analysis of the composite, we observed a significant enhancement in the thermal stability of the nanocomposites with increasing Fe3O4@SiO2 content. X-ray photoelectron spectroscopy (XPS) spectra have been used to provide more information about the chemical state and electronic structure of the polymer film. Dielectric spectroscopy revealed notable improvements in electrical properties, including increased real electric modulus and permittivity. Mechanical investigation showed an improvement in the tensile strength, meanwhile, Young's modulus has improved from 341.2 to 1789.8 MPa, indicating that (PVA) and FS successfully complexed and interacted strongly. These findings underscore the potential of these nanocomposites for high-performance applications in energy storage devices and other fields requiring robust dielectric materials.

Application of nanomaterials in lithium-ion batteries

With the rapid development of society, lithium-ion batteries (LIBs) need higher performance to meet its application in different fields. Nanotechnology has been used in the research of high-performance LIBs for many years, due to its improvement of physical, chemical and electrical properties of materials. The application of nanomaterials in LIBs electrodes is the main research direction, mainly focusing on the structural characterization and electrochemical performance analysis of electrode materials. Therefore, in this research, some recent studies on nanoelectrode materials in LIBs are analzyed, focusing on demonstrating the excellent properties brought about by the unique structure of nanoelectrode materials, and their preparation methods are also briefly introduced. The results show that nanoelectrode materials have a great contribution to improving the cycle performance and rate capacity of LIBs. The prospect is expounded through the role of nanotechnology in the application field of LIBs in the future and the changes it may bring.

Manipulating Pb Vacancies Achieved Ultra‐High Thermoelectrics in Quaternary Pb0.95Na0.04Te1‐xSex via Fine‐Tuning Se Solubility

AbstractOptimizing carrier concentration in PbTe materials can be achieved effectively through the chemical doping of sodium. Nevertheless, the valence balance can lead to the presence of “deleterious defects” in the PbTe matrix, resulting in low sodium solubility at room temperature. Herein, a strategy for fine‐tuning Pb vacancies to improve sodium solubility is developed. By a trace amount of Se‐doping, the solubility of Na in Pb0.99Te1‐xSex through the preservation of Pb vacancies in the matrix is substantially increased. Additionally, a large number of dense dislocations in the grains, which greatly reduced the lattice thermal conductivity is induced. A high power factor of ≈26 mW cm−1 K−2 and low lattice thermal conductivity of ≈0.43 W m−1 K−1 at 823 K in Pb0.95Na0.04Te0.97Se0.03 is achieved. Ultimately, a high figure of merit, ZT ≈2.2, is obtained at 823 K in quaternary PbTe compound. The current findings not only demonstrate that the introduction of trace amounts of Se and Pb vacancies in the PbTe matrix can effectively enhance Na solubility and minimize thermal conductivity, attaining synergistic improvement in electrical and thermal properties, but also indicate that the synergistic effect of Pb vacancies with a specific dopant is an alternative approach for enhancing ZT.

Zirconium doped indium oxide thin films as transparent electrodes for photovoltaic applications

In this work we report on ultra-thin Zirconium doped In2O3 transparent conductive films grown at room temperature via RF-Magnetron co-sputtering. Samples from 15 nm to 90 nm thick, and low Zr atomic concentration (0.6–0.9 at.%), were annealed at T = 200 °C after the deposition. The phase-transition from amorphous to crystalline, confirmed by XRD measurements, leads to an improvement of both electrical and optical properties. The thinnest film (15 nm) shows electrical resistivity as low as 5 × 10−4 Ωcm, with carrier mobility of 20 cm2V−1s−1, and optical transmittance up to 80 % in visible and near-infrared range. IZrO electrode performances were tested through external quantum efficiency (EQE) measurements on a semi-finite Silicon Heterojunction bi-facial solar cell. The EQE values for 90 nm thick film are comparable to that of standard ITO when IZrO films are implemented as front electrodes. These results suggest that ultra-thin IZrO films may be successfully used to reduce costs and the amount of Indium used in Indium-based transparent conductive oxide layers for solar cells.

Theoretical simulation of pre-sintering effect and improvement of electrical transport properties of La0.7Ca0.18Sr0.12MnO3 film prepared by spin coating method

Perovskite manganites Lax(Ca1-ySry)1-xMnO3 have drawn the plentiful attention owing to their distinctive physical properties. Their unique properties make them an ideal candidate for high-sensitivity and uncooled bolometric applications. Optimized La0.7Ca0.18Sr0.12MnO3 (LCSMO) films were grown on (00l) LaAlO3 substrate at different pre-sintering temperature (Tps) via sol–gel spin coating method. According to the test results of microstructure, internal strain, Mn ion valences and surface morphology, electrical transport properties are restricted by MnO6 octahedron distortion and film crystallinity affected by the change in Tps. The microstructure growth was improved and the surface morphology tended to grow in a cross-like structure with high crystallinity by optimizing Tps. Double exchange mechanism and internal strain were enhanced with the increase in Tps. Thereby, due to the enlarging MnOMn bond angle and enhancing MnO covalency, the temperature (Tk) corresponding to temperature coefficient of resistivity (TCR) was increased gradually as Tps increased. The TCR value of LCSMO film reached a maximum value (10.82 %/K) and Tk reached room temperature (302.03 K) at Tps = 1123 K. The theoretical foundation of the pre-sintering effect has been supplemented, helping to understand the influence of pre-sintering on film growth and electrical transport properties.

Enhanced Thermoelectric Performance of Cu2Se Alloys by Simultaneous Engineering of Thermal and Electrical Transport Properties through S and Te Co‐Doping

Cu2Se‐based binary compounds have recently fetched the attention of researchers due to their remarkable electrical and extremely low thermal properties. In addition, Cu2Se‐based quaternary chalcogenides are expected to present exceptional thermoelectric performance. Cu2Se1−x−ySxTey‐like compounds are synthesized via microwave‐assisted hydrothermal method and their respective thermal and electrical transport properties are studied in this research work. The phase purity and homogeneity are examined by X‐ray diffraction and energy‐dispersive X‐ray spectrometry analysis. The introduction of S and Te elements into Cu2Se matrix enhances Seebeck coefficient resulting in improved electrical performance illustrating a maximum power factor of 989.4 μWK−2 m−1 at 673 K. Furthermore, S‐ and Te‐co‐doped samples exhibit reduced total thermal conductivity values with lowest value of 0.808 WK−1 m−1 for Cu2Se0.96S0.02Te0.02 sample in comparison to 1.18 WK−1 m−1 for the pristine sample. The simultaneous improvement in electrical and thermal properties results in enhanced figure of merit of 0.82 for Cu2Se0.96S0.02Te0.02 sample at 673 K.