ACS Materials Letters最新文献

Quantum Dots (QDs) with unique electrical and optical properties have wide applications on patterned or pixelated devices such as display devices, integrated photoelectric devices, etc. However, conventional patterning methods have some obvious drawbacks such as complex processing, blurred film boundaries, and degradation on the photophysical properties. Recently, direct photolithographic patterning has appeared as a novel strategy to realize high-resolution patterning solids and high-performance patterned devices. In this review, we summarize the research progress on the direct photolithographic patterning on QDs as well as their applications. We also discuss the current challenges and future development in this field.

Alkaline water electrolysis using non-noble electrocatalysts represents a sustainable method of hydrogen production, but optimizing/maximizing its performance still remains a challenge. While extensive research has focused mainly on the synthesis and design of electrocatalysts, less attention has been given to the structural and interfacial design of electrodes, which critically affects the water-splitting performance. Of particular importance is the interfacial controlled host electrode, which serves as a uniform electrocatalyst reservoir through interfacial interactions and a highly conductive current collector. Its porous structure, in addition to electrocatalyst size and host-electrocatalyst interface, significantly influences the total active surface area and operational stability. Here, we review recent advances in alkaline water electrolysis, highlighting the crucial role of interfacial interactions between host electrode and electrocatalysts, and among adjacent electrocatalysts, as well as the structural design of host electrode. Additionally, we explain how these interactions significantly contribute to operational stability. Commercialization challenges are also discussed.

Overcoming the constraints of single-cation phases and further enhancing structural asymmetry represent critical objectives for optimizing emergent optoelectronic and spin-related properties in two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs). Here, we demonstrate homochiral (S/S) and heterochiral (R/S) cation mixing in 2D HOIPs via a 1:1 mixing of S- and R-4-bromo-α-methylbenzylammonium with S-1-methylhexyammonium. The R/S system achieves an enhanced structural asymmetry, marked by a significant Pb–I–Pb bond angle disparity (Δβ = 9.24°), attributed to the distinctive asymmetric templating effects from mixed cations with distinct molecular structures and opposite absolute configurations. Consequently, spin–orbit-coupled hybrid density functional theory (DFT) calculations indicate a substantial spin splitting (ΔE = 78.5 meV), among the largest reported for PbI₄^2–-based 2D HOIPs. Nonequivalent chiral information from homo- and heterochiral mixing further modulates the Cotton effect for the same elemental composition. Our study demonstrates an important materials design strategy for enhancing structural asymmetry and advancing symmetry-breaking-reliant properties in organic–inorganic hybrids.

Stretchable transparent electrodes are crucial components for deformable electronics. While solid-state electrodes struggle to achieve significant stretchability, liquid metal electrodes have emerged as a potential alternative. However, their widespread application has been limited by their complex fabrication and reduced performance when stretched. This study introduces stretchable transparent electrodes composed of liquid metal in serpentine micromesh patterns. These electrodes are constructed cost-effectively to show high optical transmittance and low sheet resistance. They can endure 800% strain with limited variations in resistance due to the serpentine design. A transparent proximity and touch sensor is combined with soft pneumatic actuators to enable a deformable haptic interface. Additionally, transparent heaters are prepared to conform to the curvilinear body surface, allowing for thermotherapy on subcutaneous tumors while concurrently monitoring the skin’s responses. Liquid metal serpentine micromeshes represent promising transparent electrodes for stretchable devices and systems.

The transition to sustainable energy increasingly relies on hydrogen gas produced by water electrolysis. Current performance metrics for electrolyzers, typically measured in megawatts or kilowatts, inadequately capture the full scope of the system efficiency and hydrogen output rates. The gap between academic and industrial evaluations can distort the perceived effectiveness of these technologies. This Perspective proposes a refined dual-metric evaluation system that integrates both energy efficiency (kWh/kg H₂) and production rate (Nm³/h) to provide a balanced view of performance. A standardized framework similar to that for photovoltaic technologies is suggested to enable transparent comparisons and support advancements in electrolyzer design. Emphasizing the need for consistent testing conditions, the framework aims to ensure that the evaluations of the electrodes, stacks, and overall systems remain reliable across various operational scenarios. Adopting such a comprehensive evaluation approach is essential for accurately communicating the capabilities of water electrolyzers and propelling the widespread use of green hydrogen.

Water splitting for clean hydrogen production is gaining popularity, driving researchers to develop efficient electrocatalysts with minimal energy input, reduced overpotentials, lower Tafel slopes, and enhanced stability. The Tafel slope is an important kinetic parameter to assess an electrocatalyst’s performance. Hence, an accurate determination of the Tafel slope experimentally using appropriate techniques, along with knowledge of multielectron transfer reactions’ kinetics, is of utmost importance. For such reactions, identifying whether the rate-determining step involves an electron transfer or chemical transformation is a key factor. The Tafel slope provides insight into this, revealing the exact equilibrium and mechanism of the reaction. This Perspective explores the theoretical background of the Tafel slope and current experimental techniques for its accurate determination. It discusses the pros and cons of each technique, providing step-by-step guidance for precise Tafel slope calculation, which is essential for assessing electrocatalyst performance in water splitting reactions.

Electrocatalytic water splitting is commonly regarded as a sustainable and clean method to generate hydrogen and oxygen, which is deemed to be efficient for the utilization of renewable energy. Electrocatalysts are essential components to enhance electrochemical efficiency and optimize product yield. Hollow micro/nanostructures possess large specific surface areas, multiple voids, and tunable chemical compositions, making them suitable for use as direct catalysts or as supports for electrochemical reactions. This review summarizes recent advancements in structural and functional designs of micro/nanostructured hollow materials as electrocatalysts for an enhanced water-splitting process. We emphasize ideas and strategies to create various hollow electrocatalysts for oxygen/hydrogen evolution processes. Subsequently, a comprehensive summary of recent studies on hollow borides, carbides, oxides, phosphides, selenides, sulfides, alloys, MXenes, and various heterostructured electrocatalysts containing hollow hosts is provided. Furthermore, we highlight the current challenges and perspectives of hollow micro/nanostructures for electrocatalytic water splitting.

Water electrolysis is a sustainable method of hydrogen production with low levels of CO₂ emissions. However, the problem of high economic costs must be resolved. Hybrid water electrolysis (HWE), derived by replacing the sluggish oxygen evolution reaction, emerges as an alternative method to reduce power consumption. Recent studies on HWEs have focused on reporting cell potential reductions, but their impact on hydrogen production costs is still unclear. In this paper, power consumption and levelized cost of hydrogen (LCOH) were evaluated to understand the economic impact of HWEs. Among various HWEs, HzOR showed an excellent energy consumption reduction (43.3 kWh/kg) resulting in the lowest LCOH ($1.92 kg^–1). These results prove one of the most effective alternatives to water electrolysis in its current state. Although other HWEs show only small reductions in energy consumption and LCOH in their current state, these reactions still show high potential to reduce energy consumption and LCOH.

Here, we report the discovery of the first (8,8)-connected three-dimensional (3D) covalent organic framework (COF), TUS-88, having bcu topology by linking an 8-connected D_4h-symmetric quadrangular prism node to an 8-connected D_2h-symmetric tetragonal prism node. Derived from the π-aromatic conjugated system of pyrene and the abundant aromatic phenyl rings composing the COF scaffold, which promotes stronger π···π interactions with aromatic benzene (Bz) molecules, a superlative Bz uptake of 464 cm³ g^–1 was achieved for TUS-88, coupled with exemplary cyclohexane (Cy) uptake of 224 cm³ g^–1 and ideal Bz/Cy selectivity of 2.07 which are the current benchmark. Breakthrough experiments accomplished using a Bz/Cy (1:1, v/v) mixture corroborated the preferential adsorption of Bz by the COF from the mixture to generate high-purity Cy with a significant time interval of 75.4 min g^–1 and a record-setting Bz/Cy breakthrough selectivity of 2.46.