Electronic Materials Letters最新文献

Repeated or sustained bending in flexible displays induces mechanical stress on all components, particularly affecting narrow and thin electronic circuits. There is a lack of research that maintains the bending state during observation of cracks and analyzes electrical properties based on crack parameters. This study aims to observe crack parameters under the bending state and analyze the relationship between crack parameters and electrical properties. The results showed that a smaller bending radius induced greater tensile stress on the specimen surface, which in turn increased both crack density and crack width. Measurement of resistance under bending state also revealed that smaller bending radius resulted in larger crack width and corresponding increases in resistance. We also demonstrated that analyzing cracks in the flat state (after bending state) significantly underestimated the effects of crack width in electrical properties because crack width was almost recovered indicating reversible deformation while crack density remained unchanged, representing irreversible damage after bending state. Therefore, crack analysis under actual bending state is essential for accurately evaluating the mechanical and electrical reliability of flexible electronic components.

Graphical Abstract

The well-known von Neumann bottleneck has emerged as a significant obstacle in computationally demanding AI tasks, as frequent data transfers between logic and memory impair system performance and reduce energy efficiency, thereby motivating the exploration of in-memory and neuromorphic computing as potential solutions. Among emerging material options, halide perovskites (HPs) exhibit a tunable bandgap, rapid ion migration, mechanical pliability, and facile low-temperature processing, making them particularly advantageous for next-generation computing. This article surveys HP-based memristors and synaptic transistors, emphasizing their underlying physical mechanisms, capacity to replicate synaptic behavior, and multilevel memory functionality within novel computing architectures. Additionally, we address integration challenges, particularly regarding stability, variability, and scalability. By examining recent advances, we highlight HPs as a promising materials platform for next-generation AI hardware that can overcome the limitations of traditional von Neumann architectures.

Graphical Abstract

We report the incorporation of 2-(N-morpholino)ethanesulfonic acid potassium salt (MESK) as a multifunctional additive in metal-halide perovskite solar cells to enhance crystallinity and suppress defect formation. The sulfonate (-SO₃⁻) and ether (-O-) groups in MESK act as Lewis bases to promote vertical crystal orientation, while the K⁺ ions mitigate defect formation at grain boundaries and interstitial sites. As a result, the power conversion efficiency (PCE) of the devices improved significantly from 15.09 to 18.03%. To elucidate the underlying mechanism, we performed in-situ grazing-incidence wide-angle X-ray scattering (GIWAXS) during the spin-coating process. The GIWAXS data revealed that MESK induces the formation of intermediate phases prior to the crystallization of the perovskite structure, thereby retarding the crystallization dynamics. This delayed crystallization facilitates crystal growth and the preferential ordering of perovskite films. Our findings highlight the potential of MESK as a versatile additive for improving the performance of perovskite solar cells.

Graphical Abstract

The ongoing development of flexible and wearable devices means that the processes and materials for fabricating stretchable electrodes have been the focus of significant research. We developed a high-performance stretchable conductive film with an elongation of up to 950% by fusing conductive nanofibers and efficient micro-wrinkle-structured films. A large-area micro-wrinkle-structured substrate was fabricated by utilizing the difference in the elastic moduli of Polydimethylsiloxane (PDMS) and Ecoflex. To improve the mechanical performance of the conductive nanofiber film, metal nanofibers were semi-embedded on the surface of the micro-wrinkled structure to strongly bond the film and nanofibers together. The fabrication process of the micro-wrinkle-structured film with the semi-embedded conductive nanofiber network (MWF-SCN) can simply and inexpensively fabricate a large-area micro-wrinkle structure, and the mechanical stability can be significantly improved by semi-embedding highly conductive metal nanofiber networks with an extremely high aspect ratio in the PDMS layer. In addition, the electrical properties were maintained even during repeated bending and stretching. This approach can provide robust conductive networks with improved durability and electrical stability, thus offering promising alternatives for numerous future electronic, optical, display, energy, and sensor devices.

Graphical Abstract

Organometallic perovskite is well known for its excellent optoelectronic properties, which can enable the next generation of optoelectronics. Despite its excellent charge generation, diffusion length, and bandgap properties, the transport mechanism plays a crucial role in device operation. Generated carriers (holes and electrons) move through both the bulk and interfaces, where defects can trap them. Extensive research has shown that quasi-2D, cation/anion engineering, and MACl-modified are widely applied, leading to enhanced stability and device performance. However, modified perovskites often lead to structural disorientation, resulting in recombination or charge accumulation within the perovskite lattice. In this article, quasi-2D and modified 3D perovskite MACl-modified and cation/anion engineering) are compared. Specifically, phenethylammonium iodide (PEAI) is used as a 2D spacer in quasi-2D perovskite, 3D perovskite is modified by methylammonium chloride (MACl) as an additive, along with methylamine (MA), formamidinium (FA), Iodine, and bromine engineering. Both materials exhibit proper optical and electronic characteristics, but the final solar cell performance differs significantly. Devices with quasi-2D perovskite exhibit multiple n-values with distorted perovskite orientation, whereas device of modified 3D perovskite leads to superior device performance, achieving up to 22.6% power conversion efficiency (PCE). Therefore, this article highlights the importance of 3D perovskite continuity in perovskite solar cells (PSCs).

Graphical Abstract

This study compares quasi-2D and MACl-modified 3D perovskites in solar cells, emphasizing structural orientation and charge transport. Quasi-2D perovskites exhibit multiple n-values with lattice distortion, while modified 3D perovskites, engineered via cation/anion tuning and MACl-modification, retain structural integrity, achieving 22.6% power conversion efficiency. These findings underscore the importance of lattice continuity in enhancing performance.

The growing expansion of data-intensive technologies is driving the search for technology capable of brain-like efficiency and adaptability. Among new two-dimensional (2D) systems, MXenes have received attention because their metallic lattices pair strong carrier mobility with surface terminations that enable ion storage. The article covers recent improvements in MXene-based resistive switching memories arranged as artificial synapses. We address the chemical origins of their adjustable conductivity, the fabrication approaches that permit transparent and flexible devices, and the processes that support analog weight modulation at low operating energy. Demonstrations across optoelectronic, gas-responsive, and pressure-sensitive platforms reveal that MXene synapses may reproduce optical, olfactory, and tactile learning within the same material family. Their conductance states remain stable whether devices are bent, folded, or weaved, offering prospects for seamless integration into wearable neural interfaces that incorporate sensing, memory, and logic along a single thread without loss of signal quality. The remaining challenges are examined. Oxidation under atmospheric conditions reduces electrical performance, and batch variation restricts array-level homogeneity. This perspective outlines unmet questions and recommends experimental priorities.

Graphical Abstract

Copper-to-Copper (Cu-to-Cu) bonding with metal passivation addresses fundamental oxidation and thermal budget in Cu-to-Cu bonding, yet thermal transport characterization remains unexplored despite critical importance for thermal management of three-dimensional integration. This study investigates the thermal conductance of Cu-to-Cu bonded interconnects with metal passivation, where quantifying the discrepancy between predicted and experimentally measured thermal transport properties in three-dimensional integrated structures enables design validation and optimization of thermal management strategies under conditions of elevated thermal density where thermal management becomes critical. We developed a time-domain thermoreflectance (TDTR) methodology employing transparent sapphire substrates to optically access the bonded layer. A tantalum (Ta) diffusion barrier is also employed to prevent aluminum-copper interdiffusion during bonding, ensuring measurement integrity. Multilayer thermal modeling incorporating comprehensive sensitivity analysis enables precise determination of the thermal conductance of localized bonded region, overcoming fundamental limitations of conventional approaches that measure bulk thermal properties across entire bonded structures. Systematic optimization of the Cu layer thickness of each side maximizes measurement sensitivity to Cu-to-Cu bonded interconnects while suppressing peripheral contributions that would otherwise compromise measurement fidelity. Comprehensive structural and material characterization via transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) pattern analysis revealed correlation between interfacial structure and measured thermal transport properties in metal-passivated Cu-to-Cu bonded interconnects. The measured conductance values, an order of magnitude below Wiedemann-Franz predictions from electrical resistivity data, indicate dominant electron scattering mechanisms at heterogeneous interfaces, microstructural discontinuities, and oxygen-rich regions within the bonded layer. These findings provide critical thermal management insights for 3D integrated electronic systems employing Cu-to-Cu bonding with metal passivation.

As a promising sustainable energy conversion technology, anion exchange membrane fuel cells (AEMFCs) have attracted substantial research attention due to their eco-friendly characteristics, cost advantages, and potential for high efficiency. The advancement of these systems, however, remains fundamentally limited by the challenge of optimizing the critical trade-off between ionic conductivity and dimensional stability in anion exchange membranes (AEMs). This investigation proposes a novel membrane architecture combining ether-free polymer matrices with piperidinium cationic moieties to address chemical durability concerns. A series of cross-linked poly(p-triphenylpyridine) membranes were successfully fabricated through optimized Friedel-Crafts alkylation processes, incorporating pyridine-derived branching structures alongside conventional quaternary ammonium cross-linkers. The optimized QAPTTP-40% membrane exhibits outstanding electrochemical properties, achieving temperature-enhanced ionic conductivity of 116.2 mS cm⁻¹ at 80 °C through cooperative effects of branched morphology and cross-linked framework. Extended alkaline stability testing (15 days in 2 M NaOH at 80 °C) revealed exceptional chemical resilience with 85.1% conductivity retention. Structural characterization demonstrated advantageous material properties including an elevated ion exchange capacity of 2.94 mmol g⁻¹ coupled with robust mechanical strength (39.4 MPa tensile strength at ambient conditions). The synergistic combination of efficient ion transport pathways, superior alkaline durability, and mechanical robustness establishes this innovative AEM design as a competitive platform for next-generation fuel cell development. These findings provide critical insights into the rational design of high-performance anion exchange membranes through molecular engineering of polymer architectures and cationic group selection.

In this study, we propose an anion vacancy engineering process for CoS₂-based nanomaterials using carbon monoxide (CO) thermal treatment. This process enables precise control over sulfur vacancy formation and phase transitions while preserving structural integrity through the tuning of variables such as temperature, annealing time, and gas composition.

Notably, changes in the oxidation state of cobalt and the chemical state of sulfur were systematically observed as a function of the reaction conditions, confirming that the controlled structural evolution of cobalt sulfides was mediated by selective sulfur extraction. Moreover, the values from thermodynamic calculations were in good agreement with the experimental results, demonstrating that the sulfur extraction process follows a thermodynamically favorable pathway.

The versatility of this approach extends beyond specific materials or processing conditions and can be applied to a wide range of transition metal compounds. Additionally, the process demonstrates excellent scalability, as it is not constrained by sample quantity. The ability to finely control structural and chemical properties highlights the applicability of this method to various fields where defect engineering is critical, such as electrocatalysis and energy storage devices.

In particular, sulfur-deficient CoS₂ demonstrated superior electrocatalytic performance, with an overpotential of only 327 mV at 10 mA cm^− 2 for the oxygen evolution reaction, outperforming conventional noble metal catalysts by approximately 60 mV. This result underscores the practical value and broad applicability of the proposed process.