Search Results (43)

Flexible oxide electronics require dielectric layers that combine low-temperature processability, low leakage current, high capacitance density, and mechanical reliability. In this work, we prepared ZrAlO_x-PVP hybrid dielectric films through a low-temperature self-combustion solution process at 180 °C and systematically investigated the effect of PVP doping (0–2 wt%). The results show that PVP promotes the formation of M-O-C related bonding environments, suggesting the construction of an organic–inorganic crosslinked structure. Moderate PVP incorporation effectively suppresses leakage pathways, whereas excessive PVP induces polymer aggregation and trap-assisted conduction. Among all samples, the film on flexible PI (polyimide) with a PVP doping concentration of 0.5 wt% exhibits the best overall performance, with a leakage current as low as 1.89 × 10⁻⁸ A/cm² at 1 MV/cm, a dielectric constant of 8.88. After static bending at a radius of 20 mm, the film maintains stable dielectric behavior, indicating improved stress tolerance. Flexible IGZO TFT fabricated with the optimized dielectric shows a mobility of 11.84 cm² V⁻¹ s⁻¹, a threshold voltage of 0.48 V, and a subthreshold swing of 0.24 V dec⁻¹ before bending. This work demonstrates that moderate PVP crosslinking provides an effective balance between defect suppression and stress relaxation, offering a practical interface-engineering strategy for low-temperature flexible high-k dielectrics. Full article

Understanding lithium distribution and transport within Li-ion battery components is critical in improving battery longevity, safety and performance. This study investigates lithium concentration profiles across the interface of an aluminum-doped Li₇La₃Zr₂O₁₂ (Al-LLZO) solid electrolyte and a lithium metal anode using Nuclear Reaction Analysis (NRA), a non-destructive depth-profiling technique. The Al-LLZO electrolyte was synthesized via electrospinning, producing nanofibers, which were subsequently sintered into pellets of average thickness 380 µm. These pellets were integrated into a Li|Al-LLZO|NMC-111 half-cell and cycled at 0.1 C for 1, 3, and 10 cycles, indicating pronounced lithium accumulation at the electrolyte–anode interface. Using NRA, this study provided a clear pathway for better understanding lithium transport and interfacial behavior, by quantitatively measuring the lithium distribution at the Al-LLZO electrolyte–electrode interface, and to look at the changes at this interface over the battery cycles. Full article

The performance and reliability of 4H-SiC Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are largely determined by the material properties of gate dielectric films and the quality of the dielectric/SiC interface. This paper provides a systematic review of recent progress in gate dielectric engineering for 4H-SiC MOSFETs, with emphasis on SiO₂-based gate dielectrics and high-dielectric-constant (high-k) gate dielectrics. First, for conventional thermally grown SiO₂/SiC systems, the effects of interface nitridation, gate oxide doping, and surface pretreatment techniques are comprehensively discussed. The influence mechanisms of these processes on carbon-related interface defects, interface state density and field-effect mobility are analyzed, and the advances in related research are summarized. Second, the application of high-k gate dielectrics, including Al₂O₃, HfO₂, ZrO₂, and stacked dielectric structures, in SiC MOS devices is systematically reviewed. The advantages of these materials in reducing equivalent oxide thickness, increasing gate capacitance, suppressing leakage current, and improving thermal stability are highlighted. In addition, interface defects and electrical characteristics associated with different high-k gate dielectrics are comparatively evaluated. Finally, future research directions are discussed, including in situ interface engineering based on atomic layer deposition, dopant modulation, and heterogeneous gate dielectric structures. These approaches show strong potential for achieving high mobility, low loss, and high reliability in advanced 4H-SiC power MOSFETs. Full article

After reviewing the state of the art of the fluorination of inorganic solid electrolytes, an application of gas/solid fluorination is given and how it can be processed. Garnet-type oxide has been chosen. These oxides with an ideal structure of chemical formula A₃B₂(XO₄)₃ are mainly known for their magnetic and dielectric properties. Certain garnets may have a high enough Li⁺ ionic conductivity to be used as solid electrolyte of lithium ion battery. The surface of LLZO may be changed in contact with the moisture and CO₂ present in the atmosphere that results in a change of the conductivity at the interface of the solid. LiOH and/or lithium carbonate are formed at the surface of the garnet particles. In order to allow for handling and storage under normal conditions of this solid electrolyte, surface fluorination was performed using elemental fluorine. When controlled using mild conditions (temperature lower or equal to 200 °C, either in static or dynamic mode), the addition of fluorine atoms to LLZO with Li_6,4Al_0,2La₃Zr₂O₁₂ composition is limited to the surface, forming a covering layer of lithium fluoride LiF. The effect of the fluorination was evidenced by IR, Raman, and NMR spectroscopies. If present in the pristine LLZO powder, then the carbonate groups disappear. More interestingly, contrary to the pristine LLZO, the contents of these groups are drastically reduced even after storage in air up to 45 days when the powder is covered with the LiF layer. Surface fluorination could be applied to other solid electrolytes that are air sensitive. Full article

A method for generally predicting interface chemical bonding at the metal–oxide interface with the interface reaction considered is reported. So far, the interface between pure metal or alloy and 11 oxides—MgO, Al₂O₃, SiO₂, Cr₂O₃, ZnO, Ga₂O₃, Y₂O₃, ZrO₂, CdO, La₂O₃, and HfO₂—without considering the interface reaction, has been discussed and implemented in the free web-based software product InterChemBond (v2022). Now, the number of oxides available for prediction is 83 in total. Among them, 29 oxides are in one stable valence, and the others are multi-valence. The newly developed prediction method considering the interface reaction is additionally implemented in InterChemBond. The principles and formula for predicting interface bonding while considering interface reactions are provided as well as some screenshots of the software. Full article

This study investigates the synergistic strengthening effects of in situ synthesized nano (ZrB₂ + Al₂O₃) particles and rare earth Er microalloying on the microstructure and mechanical properties of 7085 aluminum alloy. The composite material was prepared through a melt direct reaction combined with rolling and T6 heat treatment, with microstructural evolution characterized by metallurgical microscopy, XRD, and SEM. Results demonstrate that the addition of 3 vol.% in situ nano (ZrB₂ + Al₂O₃) particles optimally enhances both strength and toughness, achieving a tensile strength of 635.4 MPa (16.2% increase) and elongation after fracture of 16.2% (14.9% improvement) compared to the matrix alloy. Excessive particle content (5 vol.%) leads to severe clustering and deteriorated interfacial bonding, causing performance degradation. Introducing 0.3 wt.% Er improves particle distribution uniformity and promotes Al₃(Er,Zr) precipitate formation, refining grains and strengthening interfaces. This further elevates tensile strength to 654.8 MPa (19.7% increase) and elongation to 16.6% (17.7% improvement). The research reveals the synergistic optimization mechanism between particle content and Er addition, providing theoretical support for designing high-performance aluminum matrix composites. Full article

This study attempts to use fly ash as the brazing filler additive to increase the sustainable use of coal-fired power plant by-product materials. The experimental results show that adding 5 wt% fly ash into the Ag paste filler contributes to the interfacial reactions in heterogeneous reactive air brazing (RAB) of the ZrO₂ and Crofer alloy. The Ag-rich phase dominates the brazed zone. The interfacial reaction layers contain oxidation of the Cu-Ti coating layer, Crofer alloy, and the Si/Al-rich oxides from the fly ash particles. The 5% fly ash RAB joint maintained airtightness for 280 h under 2 psig helium at room temperature. When the test temperature was raised to 600 °C for 24 h, the pressure of the joint assembly still did not drop. When the fly ash addition was increased to 10 wt%, the joint assembly was no longer leak-free at room temperature. Many visible voids and cracks exist in the brazed zone and at the ZrO₂/braze and braze/Crofer interfaces. A high volume fraction of the fly ash particles results in many brittle Si/Al-rich oxides in the joint after RAB, and the fracture of these oxides significantly deteriorates the airtightness of the joint. This study shows the feasibility and potential of introducing 5 wt% fly ash particles to the Ag-rich paste filler during the RAB of ZrO₂ and Crofer for airtight applications. Full article

Zr-4 alloy tubes, as the primary cladding material in nuclear reactor cores, face the critical challenge of oxidative attack in 1200 °C steam environments. To address this issue, high-temperature oxidation-resistant coatings fabricated via extreme high-speed laser cladding (EHLA) present a promising mitigation strategy. In this study, Y₂O₃-modified (0.0–5.0 wt.%) Cr/FeCrAl composite coatings were designed and fabricated on Zr-4 substrates using the EHLA process, followed by systematic investigation of Y doping effects on coating microstructures and steam oxidation resistance (1200 °C, H₂O atmosphere). Experimental results demonstrate that Y₂O₃ doping remarkably enhanced the oxidation resistance, with optimal performance achieved at 2.0 wt.% Y₂O₃ (31% oxidation mass gain compared to the substrate after 120-min exposure). Microstructural analysis reveals that the dense grain boundary network facilitates rapid surface diffusion of Al, promoting continuous Al₂O₃ protective film formation. Additionally, Y segregation at grain boundaries suppressed outward diffusion of Cr³⁺ cations, effectively inhibiting void formation at the oxide-coating interface and improving interfacial stability. The developed rare-earth-oxide-doped composite coating via extreme high-speed laser cladding process shows promising applications in surface-strengthening engineering for nuclear reactor Zr-4 alloy cladding tubes, providing both theoretical insights and technical references for the design of high-temperature oxidation-resistant coatings in nuclear industry. Full article

MoS₂ has excellent vacuum lubricating performance. However, it is prone to be oxidized in a high-temperature atmospheric environment, leading to the deterioration of its lubricating performance and even serious space accidents. The high-temperature lubricating performance of MoS₂-based solid lubricating materials can be improved to some extent by the co-compounding of appropriate oxides and Ag. The tribological properties of several common nano-oxides (ZnO, TiO₂, Al₂O₃, and ZrO₂) composited with metal Ag of MoS₂-based composites were compared at 450 °C. The results showed that the comprehensive tribological performance of MoS₂-TiO₂-Ag was the best, an the average friction coefficient of about 0.26, and a wear rate of about 1.2 × 10⁻⁵ mm³/Nm, which was 18% and 43% lower than that of MoS₂-Ag, respectively. The excellent tribological properties of MoS₂-TiO₂-Ag composites were attributed to three aspects: Firstly, with the help of the oxidation resistance of TiO₂ to MoS₂ to some extent and its high ionic potential, its oxidation resistance was improved and its shear strength was reduced to provide low friction. Secondly, relying on the low shear strength and good film-forming tendency of soft metal Ag on the sliding surface, a low shear tribo-film was easily formed on the friction interface, which was helpful for the synergistic lubrication of Ag, MoS₂, and TiO₂.Thirdly, through the matching of hard TiO₂ and soft Ag, the wear resistance and bearing capacity of the composites were improved to some extent. The research results can provide some reference for the selection and design of MoS₂-based high-temperature lubricating materials and the enhancement of their tribological properties. Full article

The lifetime of products made of ceramic materials is related to their mechanical characteristics such as strength, hardness, wear resistance, and fracture toughness. The purpose of this work was to study the effect of sintering temperature on the phase-related peculiarities of the microstructures, causing changes in the flexural strength and fracture toughness of fine-grained ZrO₂–Y₂O₃–Al₂O₃–CoO–CeO₂–Fe₂O₃ ceramics. Flexural strength and fracture toughness tests were carried out using ceramics sintered in three modes (2 h at 1550 °C, 1580 °C, and 1620 °C in argon), and thorough phase, microstructure, and fractographic analyses were performed. For the ceramic sintered at 1550 °C, a mixed mechanism of intergranular fracture of the t-ZrO₂ phase particles and cleavage fracture of the Ce–Al–O phase particles was found, which is reflected in its comparatively low fracture toughness. For the ceramic sintered at 1580 °C, a fracture developed along the boundaries of the aggregates, made of completely recrystallized fine ZrO₂ grains with a high bond strength between adjacent t-ZrO₂ grains; this corresponds to the highest fracture toughness (5.61 ± 0.24 MPa·m^1/2) of this ceramic. For the ceramic sintered at 1620 °C, a transgranular fracture of the t-ZrO₂ phase and Ce–Al–O phase particles and crack propagation along the t-ZrO₂/Ce–Al–O interface were revealed; this caused a decrease in fracture toughness. Full article

In the presented work, the catalytic performance of a nickel catalyst, in CO₂ hydrogenation to methane, within a ZrO₂ open-cell foam (OCF)-based catalyst was studied. Two series of analogous samples were prepared and coated with 100–150 mg of a Mg-Al oxide interface to stabilize the formation of well-dispersed Ni crystallites, with 10–15 wt% of nickel as an active phase, based on 30 ppi foam or 45 ppi foam. The main factor influencing catalytic performance was the geometric parameters of the applied foams. The series of catalysts based on 30 ppi OCF showed CO₂ conversion in the range of 30–50% at 300 °C, while those based on 45 ppi OCF resulted in a significantly enhancement of the catalytic activity: 90–92% CO₂ conversion under the same experimental conditions. Calculations of the internal and external mass transfer limitations were performed. The observed difference in the catalytic activity was primarily related to the radial transport inside the pores, confirmed with the explicitly higher conversions. Full article

The metal-oxide interaction is of significance to the construction of active sites for Cu-catalyzed CO₂ hydrogenation to methanol. This study examines the effect of ZnO and ZrO₂ composition on the Cu/ZnO/ZrO₂ catalyst structure and surface properties to further tune the catalytic activity for methanol synthesis. The ZnO/ZrO₂ ratio can impact the CuZn alloy formation from strong Cu-ZnO interactions and the surface basic sites for CO₂ adsorption at the Cu-ZrO₂ interface. The proportional correlation of the CuZn alloy content and CO₂ desorption amount with the space-time yield (STY) of methanol reveals a synergistic interaction between Cu and oxides (ZnO and ZrO₂) that enhances methanol synthesis. The optimized Cu/ZnO/ZrO₂ catalyst exhibits higher STY relative to the traditional Cu/ZnO/Al₂O₃ catalyst. The obtained results presented herein can provide insight into the catalyst design for methanol synthesis from CO₂. Full article

Carbon-based perovskite solar cells (C-PSCs) have the impressive characteristics of good stability and potential commercialization. The insulating layers play crucial roles in charge modulation at the buried perovskite interface in mesoporous C-PSCs. In this work, the effects of three different tunnel oxide layers on the performance of air-processed C-PSCs are scrutinized to unveil the passivating quality. Devices with ZrO₂-passivated TiO₂ electron contacts exhibit higher power conversion efficiencies (PCEs) than their Al₂O₃ and SiO₂ counterparts. The porous feature and robust chemical properties of ZrO₂ ensure the high quality of the perovskite absorber, thus ensuring the high repeatability of our devices. An efficiency level of 14.96% puts our device among the state-of-the-art hole-conductor-free C-PSCs, and our unencapsulated device maintains 88.9% of its initial performance after 11,520 h (480 days) of ambient storage. These results demonstrate that the function of tunnel oxides at the perovskite/electron contact interface is important to manipulate the charge transfer dynamics that critically affect the performance and stability of C-PSCs. Full article

Intermolecular interactions on inorganic substrates can have a critical impact on the electrochemical and photophysical properties of the materials and subsequent performance in hybrid electronics. Critical to the intentional formation or inhibition of these processes is controlling interactions between molecules on a surface. In this report, we investigated the impact of surface loading and atomic-layer-deposited Al₂O₃ overlayers on the intermolecular interactions of a ZrO₂-bound anthracene derivative as probed by the photophysical properties of the interface. While surface loading density had no impact on the absorption spectra of the films, there was an increase in excimer features with surface loading as observed by both emission and transient absorption. The addition of ALD overlayers of Al₂O₃ resulted in a decrease in excimer formation, but the emission and transient absorption spectra were still dominated by excimer features. These results suggest that ALD may provide a post-surface loading means of influencing such intermolecular interactions. Full article

The tensile strength and fracture properties of the c-ZrO2(001)/α-Al₂O₃($1\overline{1}02$) interfaces were investigated by first-principle tensile simulations. Models with different stacking sequences of c-ZrO₂(001) were examined. The theoretical tensile strength and work of adhesion were present. It was found that the adhesive strength of the interface was strongly influenced by the termination of c-ZrO₂(001), and the c-ZrO₂(001)/α-Al₂O₃($1\overline{1}02$) interfaces adhered weakly. Then, variations of the atomic bonds were observed to clarify the fracture characteristics of the interfaces. Our study indicates that the fracture modes of the O- and Zr-model tend to be ductile fractures, while the fracture mode of the 2O-model is a brittle fracture. Furthermore, all three models were completely separated along the intermediate layer between the initial ZrO₂ and Al₂O₃ slabs. Finally, we compared our results with those available in the published literature, and the potential application of the first-principle results will be further discussed. Full article