Composite Technology Research Articles

Dielectric Regulation in Quasi-vdW Europium Oxysulfur Compounds by Compositional Engineering for 2D Electronics.

Advancing next-generation electronics necessitates precise control of dielectric properties in 2D materials. Here, the first synthesis of novel 2D quasi-van der Waals (vdW) europium oxysulfur (Eu2SOx) compounds, comprising hexagonal Eu₂SO₂ and tetragonal Eu₂SO₆ phases, with composition-tunable dielectric properties, is presented. Using a homodiffusive-controlled epitaxial growth method, materials are achieved with complementary characteristics: the hexagonal Eu₂SO₂ phase exhibits a high dielectric constant (≈30) paired with a moderate bandgap (≈4.56 eV), while the tetragonal Eu₂SO₆ phase offers a wider bandgap (≈5.62 eV) but a lower dielectric constant (≈20). The potential of these materials is demonstrated by integrating ultrathin Eu₂SO₂ nanoplates with molybdenum disulfide (MoS₂) field-effect transistors (FETs) via vdW forces. The resulting devices achieve a near-ideal Ion/Ioff ratio (≈10⁸), minimal hysteresis (≈5.3 mV), a low subthreshold slope (≈63.5 mV dec⁻¹), and ultralow leakage current (≈10⁻¹⁴ A). These results highlight the capacity of europium oxysulfur compounds to address the trade-off between dielectric constant and bandgap, offering tailored solutions for diverse 2D electronic applications. This work underscores the potential of composition engineering to expand the family of rare-earth oxysulfur compounds for nanoelectronics, paving the way for innovative gate dielectrics in next-generation devices.

Fine tuning of supercapacitor performance through compositional and morphological engineering of siloxene-polyaniline composites

Fine tuning of supercapacitor performance through compositional and morphological engineering of siloxene-polyaniline composites

Improved Ferroelectric and Magnetic Properties of Bismuth Ferrite-Based Ceramics by Introduction of Non-Isovalent Ions and Grain Engineering

Single-phase multiferroics exhibiting ferroelectricity and ferromagnetism are considered pivotal for advancing next-generation multistate memories, spintronic devices, sensors, and logic devices. In this study, the magnetic and electric characteristics of bismuth ferrite (BiFeO3) ceramics were enhanced through compositional design and grain engineering. BiFeO3 ceramic was co-substituted by neodymium (Nd) and niobium (Nb), two non-isovalent elements, via the spark plasma sintering process using phase-pure powder prepared via sol-gel as the precursor. The symmetry of the sintered Nd–Nb co-doped samples changed from R3c to Pnma, accompanied by a decrease in the loss tangent, grain size, and leakage current density. The reduction in the leakage current density of the co-doped samples was ~three orders of magnitude. Moreover, ferroelectric, dielectric, and magnetic properties were substantially improved. The remanent polarization and magnetization values of the optimized Nd–Nb co-doped BiFeO3 sample were 3.12 μC cm−2 and 0.15 emu g−1, respectively. The multiferroic properties were enhanced based on multiple factors such as structural distortion caused by co-doping, grain size reduction, suppression of defect charges via donor doping, space-modulated spin structure disruption, and an increase in magnetic ions. The synergistic approach of composition design and grain engineering sets a paradigm for the advancement of multiferroic materials.

Impact of Defect‐Rich Carbon Nanofibers Combined with Magnetic Materials on Broadband Electromagnetic Wave Absorption and Radar Cross‐Section Reduction

Carbon nanofibers (CNFs) exhibit inherent dielectric properties that enhance electromagnetic (EM) wave absorption, yet challenges exist in expanding their effective absorption bandwidth (EAB) and improving flexibility. Many studies fail to adequately consider how structural factors influence performance when combining CNFs with magnetic materials. To address these issues, a 1D carbon nanocomposite is developed by embedding magnetic oxide nanoparticles within CNFs using a simple electrospinning technique. This approach improves membrane flexibility by disrupting rigid alignment and introducing dynamic magnetic interactions, while also creating defect‐rich interfaces that increase the amorphous content (61%) of the CNFsF composite, leading to improved EM wave absorption. The unique macro/mesoporous morphology provides internal interfaces and heterogeneous boundaries that effectively trap and dissipate EM waves. As a result, the flexible CNF composites demonstrate significant EM wave absorption performance, achieving a minimum reflection loss (RLmin) of −39.8 dB at 4.64 GHz and an abroad EAB of up to 7 GHz at only 2.5 mm thickness. Computer simulation technology (CST) simulations indicate a maximum radar cross‐section reduction of 21.1 dB m2, highlighting the material's radar stealth capability. This research advances the development of high‐performance materials and offers new strategies for enhancing absorption properties through composite engineering.

Fabrication of high-performance tin halide perovskite thin-film transistors via chemical solution-based composition engineering.

Metal halide perovskite semiconductors have attracted considerable attention because they enable the development of devices with exceptional optoelectronic and electronic properties via cost-effective and high-throughput chemical solution processes. However, challenges persist in the solution processing of perovskite films, including limited control over crystallization and the formation of defective deposits, leading to suboptimal device performance and reproducibility. Tin (Sn2+) halide perovskite holds promise for achieving high-performance thin-film transistors (TFTs) due to its intrinsic high hole mobility. Nevertheless, reliable production of high-quality Sn2+ perovskite films remains challenging due to the rapid crystallization compared with more extensively studied lead (Pb)-based materials. Recently, composition engineering has emerged as a mature and effective strategy for realizing the high-yield fabrication of Sn2+ halide perovskite thin films. This approach cannot only achieve improved TFT performance with high hole mobilities and current ratios1-6, but also enable reliable device operation with hysteresis-free character and long-term stability7-12. Here we provide the experimental procedure for precursor preparation, film and device fabrication and characterization. The entire process typically takes 20-24 h. This protocol requires a basic understanding of metal halide perovskites, perovskite film coating process, standard TFT fabrication and measurement techniques.

All-perovskite tandem solar cells achieving >29% efficiency with improved (100) orientation in wide-bandgap perovskites.

Monolithic all-perovskite tandem solar cells present a promising approach for exceeding the efficiency limit of single-junction solar cells. However, the substantial open-circuit voltage loss in the wide-bandgap perovskite subcell hinders further improvements in power-conversion efficiency. Here we develop wide-bandgap perovskite films with improved (100) crystal orientation that suppress non-radiative recombination. We show that using two-dimensional perovskite as an intermediate phase on the film surface promotes heterogeneous nucleation along the (100) three-dimensional perovskite facets during crystallization. Preferred (100) orientations can be realized by augmenting the quantity of two-dimensional phases through surface composition engineering, without the need for excessive two-dimensional ligands that otherwise impede carrier transport. We demonstrate an open-circuit voltage of 1.373 V for 1.78 eV wide-bandgap perovskite solar cells, along with a high fill factor of 84.7%. This yields an open-circuit voltage of 2.21 V and a certified power-conversion efficiency of 29.1% for all-perovskite tandem solar cells, measured under the maximum power-point conditions.

Insights into the electronic structure, optical properties, and photocatalytic potential of Gd2CoCrO6 perovskite: a comprehensive theoretical and experimental investigation.

In this study, we present a comprehensive theoretical and experimental investigation into the electronic structure, optical properties, and photocatalytic potential of Gd2CoCrO6 (GCCO) double perovskite. Using first-principles calculations with the generalized-gradient-approximation plus Hubbard U (GGA + U) method, we explored the effects of Coulomb interactions on the electronic properties. Our calculations revealed that GCCO exhibits a half-metallic nature, displaying metallic behavior for up-spin and semiconducting behavior for down-spin states. The optimized U eff value of 4.2 eV accurately reproduces the direct bandgap of 2.25 eV, which aligns closely with experimental results obtained through UV-visible absorption spectroscopy and photoluminescence analysis. Additionally, time-resolved photoluminescence (TRPL) measurements indicate a mean charge carrier lifetime of 2.37 ns, suggesting effective charge separation. Mott-Schottky analysis and valence band X-ray photoelectron spectroscopy (XPS) confirm the n-type semiconducting nature of GCCO with favorable band edge positions for redox reactions. The combination of theoretical insights and experimental characterization indicates that GCCO holds significant promise as a photocatalyst for applications in renewable energy production and environmental remediation, particularly in solar-driven water splitting and pollutant degradation. Our study provides crucial insights into the electronic structure and optical properties of double perovskites like GCCO, highlighting their suitability for photocatalytic applications. Furthermore, the research paves the way for future work in the compositional engineering and defect modulation of double perovskites to optimize their photocatalytic efficiency.

Composition engineering of a Cu2ZnGexSn1−xS4 nanoparticle hole transport layer for carbon electrode-based perovskite solar cells

Composition engineering via alloying Cu2ZnSnS4 and Cu2ZnGeS4 is studied to optimize the properties of a Cu2ZnSn1−xGexS4 hole-transporting layer, which contributes to carbon electrode-based perovskite solar cells with a champion efficiency of 19.8%.

Performance promotion strategies for wide bandgap perovskite solar cells

In this review, we summarize the recent research related to WBG PSCs. Strategies are proposed, including composition engineering, additive engineering, passivation strategies, and interface engineering. Finally, we offer the future prospects.

Single-isomer bis(pyrrolidino)fullerenes as electron-transporting materials for tin halide perovskite solar cells.

Although fullerene bisadducts are promising electron-transporting materials for tin halide perovskite solar cells, they are generally synthesized as a mixture of isomeric products that require a complicated separation process. Here, we introduce a phenylene-bridged bis(pyrrolidino)fullerene, Bis-PC, which forms only a single isomer due to geometrical restriction. When used in a tin perovskite solar cell with a PEA0.15FA0.85SnI3 (PEA: phenylethylammonium and FA: formamidinium) light absorption layer, the resulting open-circuit voltage (V OC) was 0.78 V, a value higher than that of fullerene monoadducts and comparable to that of the commonly used indene-C60 bisadduct (ICBA). The performance could be further improved by the composition engineering of perovskite, where the PEA0.15(FA0.87MA0.13)0.85SnI3 based device (MA: methylammonium) exhibited a photoelectric conversion efficiency of 12.3% with a V OC of 0.86 V. The device with single-isomer Bis-PC shows superior stability to that with mixed-isomer ICBA, retaining its initial performance after 3000 h storage under an inert atmosphere.

Composite engineering structures in seawater − Review of durability and environmental performance

Composite engineering structures in seawater − Review of durability and environmental performance

Engineering of alkali-activated permeable pavement composites with agro-industrial wastes

ABSTRACT This study investigates the development of alkali-activated pervious concrete (PC) composites using industrial and agro-waste as primary constituents. The binder was activated with sodium silicate and sodium hydroxide at an activator modulus (Ms) of 1.25, maintaining a sodium oxide dosage of 4.0% relative to the total binder at a water-to-binder ratio of 0.40. Slag and bagasse ash were used as binders, recycled coarse aggregates (from construction and demolition waste) partially replaced crushed granite and waste-foundry sand served as fine aggregates. Mix proportions were optimised for hydraulic conductivity and compressive strength after 28 days of air curing. Four selected mixes were further evaluated for total porosity, splitting-tensile strength, static flexural strength and flexural fatigue performance. Optimal mechanical properties were observed for the corresponding PC mixes at 10% bagasse ash and 50% recycled aggregates. Statistical analyses of flexural fatigue, including S-N curves and two-parameter Weibull distribution, were conducted, along with Kolmogorov-Smirnov analysis and survival probabilities (95%, 50% and 5%). The findings contribute to understanding the engineering behaviour of alkali-activated PCs, supporting the development of permeable concrete pavement systems through effective utilisation of agro-industrial wastes, thereby promoting sustainability and environmental conservation.

From Wide-Bandgap to Narrow-Bandgap Perovskite: Applications from Single-Junction to Tandem Optoelectronics.

As perovskite solar device is burgeoning photoelectronic device, numerous studies to optimize perovskite solar device have been demonstrated. Amongst various advantages from perovskite light absorbing layer, attractive property of tunable bandgap allowed perovskite to be adopted in many different fields. Easily tunable bandgap property of perovskite opened the wide application and to get the most out of its potential, many researchers contributed as well. By precursor composition engineering, narrow bandgap with bandgap of less than 1.4 eV and wide bandgap with bandgap of more than 1.7 eV were achieved. Optimization of both narrow and wide bandgap perovskite solar cell could pave the way to all-perovskite tandem solar cell which is combination of top cell with wide bandgap and bottom cell with narrow bandgap. This review highlights numerous efforts to advance device performance of both narrow and wide bandgap perovskite solar cell and how they challenged the issues. And finally, efforts to operate and utilize all-tandem perovskite device in real world will be discussed.

Balancing Activity and Stability through Compositional Engineering of Ternary PtNi-Au Alloy ORR Catalysts.

Achieving the optimal balance between cost-efficiency and stability of oxygen reduction reaction (ORR) catalysts is currently among the key research focuses aiming at reaching a broader implementation of proton-exchange membrane fuel cells (PEMFCs). To address this challenge, we combine two well-established strategies to enhance both activity and stability of platinum-based ORR catalysts. Specifically, we prepare ternary PtNi-Au alloys, where each alloying element plays a distinct role: Ni reduces costs and boosts ORR activity, while Au enhances stability. A systematic comparative analysis of the activity-stability relationship for compositionally tuned PtNi-Au model layers, prepared by magnetron co-sputtering, was conducted using a diverse range of complementary characterization techniques and electrochemistry, supported by density functional theory calculations. Our study reveals that a progressive increase of the Au concentration in the Pt50Ni50 alloy from 3 to 15 at % leads to opposing catalyst activity and stability trends. Specifically, we observe a decrease in the ORR activity accompanied by an increase in catalyst stability, manifested in the suppression of both Pt and Ni dissolution. Despite the reduced activity compared to PtNi, the PtNi-Au alloy with 15 at % Au still exhibits nearly three times the activity of monometallic Pt. It also demonstrates a significantly improved dissolution stability relative to that of the PtNi alloy and even monometallic Pt. These findings provide valuable insights into the intricate balance between activity and stability in multimetallic ORR catalysts, paving the way for the design of cost-effective and durable materials for PEMFCs.

OPTIMIZATION OF TENSILE STRENGTH OF EMPTY OIL PALM FRUIT BUNCH FIBER REINFORCED COMPOSITES USING GENETIC ALGORITHMS

The use of natural materials such as oil palm empty fruit bunch fibers can provide a solution to increase value-added and manage plantation waste. Fibers are combined with a matrix to create composite materials. Instead of glass fibers, environmentally friendly natural fibers serve as the reinforcement in the composite material. Implementing natural fiber composites must consider the primary construction requirement, which is tensile strength. Artificial intelligence like genetic algorithms (GA) can simplify and reduce costs in the search for optimal values in composite material engineering. Data is obtained through experimental testing prepared samples and subsequently used as input for GA. The input parameters consist of three variables such as soaking time, volume fraction, and fiber length. The output of the optimization process is tensile strength. The maximum tensile strength has already been achieved with genetic crossover by the 125th generation. Based on GA calculations, the optimal parameters obtained are soaking time of 6.2 hours, volume fraction of 29.6%, and fiber length of 6.9 cm. The predicted optimal tensile strength value is 4.78 MPa.

Compositional engineering of phase-stable and highly efficient deep-red emitting phosphor for advanced plant lighting systems

Inorganic luminescent materials hold great promise for optoelectronic device applications, yet the limited efficiency and poor thermal stability of oxide-based deep-red emitting phosphors hinder the advancement of plant lighting technologies. Herein, a simple compositional engineering strategy is proposed to stabilize the phase, boost external quantum efficiency (EQE) and enhance thermal stability. The chemical modification of the PO4 tetrahedron in NaMgPO4:Eu by incorporating SiO4 lowers the formation energy, leading to the generation of pure olivine phase and increasing the EQE from 27% to 52%, setting a record for oxide deep-red phosphors. In parallel, the introduced deep defect level improves thermal stability at 150 °C from 62.5% to 85.4%. Besides, the excitation and emission peaks shifted to 440 nm and 675 nm, respectively, aligning precisely with the specific spectral absorption requirements of plant phytochromes. Moreover, the luminescent intensity showed nearly no decay after being exposed to 80% relative humidity and 80 oC for 6 h, and the pc-LED utilizing Na1.06MgP0.94Si0.06O4:Eu achieves a high output power of 780 mW at 300 mA. Our research demonstrates a facile method for optimizing the performance of inorganic luminescent materials and provides alternative solutions for low-cost plant lighting.

Proton Storage Chemistry in Aqueous Zinc-Inorganic Batteries with Moderate Electrolytes.

The proton (H+) has been proved to be another important energy storage ion besides Zn2+ in aqueous zinc-inorganic batteries with moderate electrolytes. H+ storage usually possesses better thermodynamics and reaction kinetics than Zn2+, and is found to be an important addition for Zn2+ storage. Thus, understanding, characterizing, and modulating H+ storage in inorganic cathode materials is particularly important. In this review, recent advances regarding the proton storage chemistry in aqueous zinc-inorganic batteries with moderate electrolytes are systematically reviewed. First, the four proton storage reaction patterns of H+ insertion, H+/Zn2+ co-insertion, H+-dependent conversion, and H+-dependent dissolution/deposition reaction are explicitly presented. Meanwhile, the proton storage processes of multi-sites and multi-steps, and the Hopping and Grotthuss proton transport mechanisms are carefully introduced. Second, the characterization techniques of proton storage are systematically classified into four types of electrochemical characterization techniques of batteries, structural characterization techniques of inorganic cathodes, pH characterization technique of electrolyte, and quantitative analysis technologies of H+ storage contribution. Third, the structural engineering of proton storage modulation is preliminarily refined to be interlayer engineering, doping engineering, defect engineering, composite engineering, and other engineering. Finally, the emerging challenges and perspectives about future directions of proton storage chemistry are proposed.

Tailoring Biopolymers for Electronic Skins: Materials Design and Applications.

The past few years have witnessed the rapid exploration of natural and synthetic materials to construct electronic skins (e-skins) to emulate the multisensory functions of human skins driven by promising applications. Among various materials employed in functional e-skins, biopolymers are particularly notable for their exceptional biocompatibility and abundant resources. Despite remarkable progress in engineering biopolymeric materials, a timely and holistic review focusing on the design, synthesis, and modification of biopolymers tailored for biopolymers-derived e-skins (Bp-E-Skins) is lacking. In this review, the key attributes of biopolymers are introducedto establish a fundamental understanding fordeveloping functional Bp-E-Skins. Next, the recent progress in harnessing various natural and synthetic biopolymers as building blocks for constructing Bp-E-Skins is systematically discussed, providing insights into maximizing the distinctive attributes of biopolymers. Subsequently, the benefits of nature-inspired Bp-E-Skins achieved through heterogeneous composite and structural engineering are highlighted, infusing fresh momentum into the advancement of e-skins. Then, the promising applications of Bp-E-Skins in multisensory functions are summarized, including both local monitoring and remote teleoperation, as well as sustainable energy harvesting that empowers e-skins. Finally, the remaining fundamental and technical challenges in advancing Bp-E-Skins are presented to provoke future designs that emulate and even go beyond human skins.

Design Principle and Regulation Strategy of Noble Metal‐Based Materials for Practical Proton Exchange Membrane Water Electrolyzer

AbstractGreen hydrogen holds immense promise in combating climate change and building a sustainable future. Owing to its high power‐to‐gas conversion efficiency, compact structure, and fast response, the proton exchange membrane water electrolyzer (PEMWE) stands out as the most viable option for the widespread production of green hydrogen. However, the harsh operating conditions of PEMWE make it heavily dependent on noble metal‐based catalysts (NMCs) and incur high operational and maintenance costs, which hinder its extensive adoption. Hence, it is imperative to improve the performance and lifespan of NMCs and develop advanced components to reduce the overall costs of integrating PEMWE technology into practical applications. In light of this, the fundamental design principles of NMCs employed in acidic water electrolysis are summarized, as well as recent advancements in compositional and structural engineering to enhance intrinsic activity and active site density. Moreover, recent innovations in stack components of practical PEMWE and their impact on cost‐benefit and lifespan are presented. Finally, the current challenges are examined, and potential solutions for optimizing NMCs and PEMWE in electrocatalytic hydrogen production are discussed.

Towards Novel Generation of Anodes Based on Halide Perovskites for Li-Ion Batteries

The escalating global energy demands require development of clean energy sources and efficient energy storage systems. In this pursuit, a range of energy storage devices, including batteries, fuel cells, and supercapacitors, have been subject to extensive investigation. At this point, lithium-ion cells have been the dominant choice for portable power storage devices for over 30 years. Despite their many advantages, continuous research is being carried out to improve the performance of the cells. There is a need to search for new battery components including electrodes and electrolytes, assuring higher battery capacity, better safety, and enhanced electrochemical stability range. Critical research area involves understanding and controlling the phenomena at the anode-electrolyte interface where energy storage occurs, and the initiation of degradation takes place. The formation of solid electrolyte interphase (SEI) is a crucial property responsible for ensuring cycling stability and extended thermodynamic stability of organic electrolytes in Li-ion batteries.Metal halide perovskites (MHPs) represent a revolutionary class of compounds that can be used in lithium-ion batteries. While metal halide perovskites are predominantly recognized for their applications in energy conversion, their unique structure allowing fast lithium-ion diffusion has prompted exploration in energy storage. The typical preparation of halide perovskites relies on solution-based methods, yet this approach encounters challenges in both compositional engineering and long-term storage. In this context, solid-state chemical reactions induced by mechanical forces have emerged as an effective and straightforward method for solvent free compositional engineering within a relatively short timeframe [1,2].In this work we present the development of a new generation of electrodes using all-inorganic and hybrid inorganic-organic halide perovskites. Different MHPs have been used as the main active material for high-performance electrodes. Beyond serving as anodes, MHPs have also found application as an electrode additive. In this case, the use of another well-known active material as the head component of the anode and MHPs as an additive involved in the formation of the SEI layer is likely to improve the cyclability, capacity and lifetime of the cell.. Our study includes electrochemical and physicochemical characterisation of electrodes based on carbon materials and tailored halide perovskites with electrolytes containing Hückel-type and fluorine free salts [3,4].Acknowledgments:This research was supported by the National Science Centre (NCN) through grant OPUS-21 no. 2021/41/B/ST5/04450.