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Synaptic devices with linear high‐speed switching can accelerate learning in artificial neural networks (ANNs) embodied in hardware. Conventional resistive memories however suffer from high write noise and asymmetric conductance tuning, preventing parallel programming of ANN arrays. Electrochemical random‐access memories (ECRAMs), where resistive switching occurs by ion insertion into a redox‐active channel, aim to address these challenges due to their linear switching and low noise. ECRAMs using 2D materials and metal oxides however suffer from slow ion kinetics, whereas organic ECRAMs enable high‐speed operation but face challenges toward on‐chip integration due to poor temperature stability of polymers. Here, ECRAMs using 2D titanium carbide (Ti3C2Tx) MXene that combine the high speed of organics and the integration compatibility of inorganic materials in a single high‐performance device are demonstrated. These ECRAMs combine the speed, linearity, write noise, switching energy, and endurance metrics essential for parallel acceleration of ANNs, and importantly, they are stable after heat treatment needed for back‐end‐of‐line integration with Si electronics. The high speed and performance of these ECRAMs introduces MXenes, a large family of 2D carbides and nitrides with more than 30 stoichiometric compositions synthesized to date, as promising candidates for devices operating at the nexus of electrochemistry and electronics. [ABSTRACT FROM AUTHOR]

Synaptic devices with linear high‐speed switching can accelerate learning in artificial neural networks (ANNs) embodied in hardware. Conventional resistive memories however suffer from high write noise and asymmetric conductance tuning, preventing parallel programming of ANN arrays. Electrochemical random‐access memories (ECRAMs), where resistive switching occurs by ion insertion into a redox‐active channel, aim to address these challenges due to their linear switching and low noise. ECRAMs using 2D materials and metal oxides however suffer from slow ion kinetics, whereas organic ECRAMs enable high‐speed operation but face challenges toward on‐chip integration due to poor temperature stability of polymers. Here, ECRAMs using 2D titanium carbide (Ti3C2Tx) MXene that combine the high speed of organics and the integration compatibility of inorganic materials in a single high‐performance device are demonstrated. These ECRAMs combine the speed, linearity, write noise, switching energy, and endurance metrics essential for parallel acceleration of ANNs, and importantly, they are stable after heat treatment needed for back‐end‐of‐line integration with Si electronics. The high speed and performance of these ECRAMs introduces MXenes, a large family of 2D carbides and nitrides with more than 30 stoichiometric compositions synthesized to date, as promising candidates for devices operating at the nexus of electrochemistry and electronics. [ABSTRACT FROM AUTHOR]

Spin‐orbit torque (SOT) promises fast and reliable switching of the perpendicular magnetization in spintronic devices, such as magnetic random‐access memory or spin logic devices. To apply the SOT technology to practical devices with low power consumption, it is necessary to reduce the switching current. To this end, most of the research to date in this area has focused on improving the charge‐to‐spin conversion efficiency in heavy metal/ferromagnet structures. In this study, it is reported that the SOT switching current is significantly reduced by modulating magnetic easy‐cone states through voltage‐controlled magnetic anisotropy (VCMA). The introduction of a thin Pt layer at the CoFeB/MgO interface enhances the VCMA effect, allowing a magnetic easy‐cone state of CoFeB to be formed and controlled by the gate voltage. As a result, the SOT switching current density is reduced by up to 50% when the easy‐cone angle is changed from 0° to 58°. Furthermore, the magnetic easy‐cone state is gradually modulated in a reversible and non‐volatile manner, facilitating multilevel spintronic devices. [ABSTRACT FROM AUTHOR]

Spin‐orbit torque (SOT) promises fast and reliable switching of the perpendicular magnetization in spintronic devices, such as magnetic random‐access memory or spin logic devices. To apply the SOT technology to practical devices with low power consumption, it is necessary to reduce the switching current. To this end, most of the research to date in this area has focused on improving the charge‐to‐spin conversion efficiency in heavy metal/ferromagnet structures. In this study, it is reported that the SOT switching current is significantly reduced by modulating magnetic easy‐cone states through voltage‐controlled magnetic anisotropy (VCMA). The introduction of a thin Pt layer at the CoFeB/MgO interface enhances the VCMA effect, allowing a magnetic easy‐cone state of CoFeB to be formed and controlled by the gate voltage. As a result, the SOT switching current density is reduced by up to 50% when the easy‐cone angle is changed from 0° to 58°. Furthermore, the magnetic easy‐cone state is gradually modulated in a reversible and non‐volatile manner, facilitating multilevel spintronic devices. [ABSTRACT FROM AUTHOR]

The development of earth‐abundant and efficient oxygen evolution reaction (OER) electrocatalysts is necessary for green hydrogen production. The preparation of efficient OER electrocatalysts requires both the adsorption sites and charge transfer on the catalyst surface to be suitably engineered. Herein, the design of an electrocatalyst is reported with significantly enhanced water oxidation performance via dual‐phase engineering, which displays a high number of adsorption sites and facile charge transfer. More importantly, a simple chemical etching process enables the formation of a highly metallic transition boride phase in conjunction with the transition metal hydroxide phase with abundant adsorption sites available for the intermediates formed in the OER. In addition, computational simulations are carried out to demonstrate the water oxidation mechanism and the real active sites in this engineered material. This research provides a new material design strategy for the preparation of high‐performance OER electrocatalysts. [ABSTRACT FROM AUTHOR]

1D ferroelectric nanostructures are promising for enhanced ferroelectric and piezoelectric performance on the nanoscale, however, their synthesis at the wafer scale using industrially compatible processes is challenging. In order to advance the nanostructure-based electronics, it is imperative to develop a silicon-compatible growth technique yielding high volumetric density and an ordered arrangement. Here, a major breakthrough is provided in addressing this need and ordered and close-packed single crystalline ferroelectric nanorod arrays, of composition PbZr0.52Ti0.48O3 (PZT), grown on commercial grade 3 in. silicon wafer are demonstrated. PZT nanorods exhibit enhanced piezoelectric and ferroelectric performance compared to thin films of similar dimensions. Sandwich structured architecture utilizing 1D PZT nanorod arrays and 2D reduced graphene oxide thin film electrodes is fabricated to provide electrical connection. Combined, these results offer a clear pathway toward integration of ferroelectric nanodevices with commercial silicon electronics. [ABSTRACT FROM AUTHOR]

Two novel transition metal‐doped tungsten bronze oxides, Pb2.15Li0.85Nb4.85Ti0.15O15 (PLNT) and Pb2.15Li0.55Nb4.85W0.15O15 (PLNW), are synthesized by high‐temperature solid‐state reactions. The Rietveld method using the high‐resolution synchrotron radiation indicates that PLNT and PLNW crystallize in the orthorhombic polar noncentrosymmetric space group, Pmn21 (no. 31). As a class of tungsten bronze oxide, PLNT and PLNW retain a unique rigid framework composed of d0 transition metal cation (Ti4+ or W6+)‐doped highly distorted NbO6 octahedra along with the subsequently generated Pb/LiO12 and PbO15 polyhedra. Interestingly, the d0 transition metal‐doped tungsten bronzes, PLNT and PLNW, exhibit extremely large second‐harmonic generation (SHG) responses of 56 and 67 × KH2PO4, respectively. The observed immeasurably strong SHG is mainly attributed to a net polarization originating from the alignment of highly distorted NbO6 octahedra with doped transition metals in the frameworks. It is believed that doping transition metal cations at the B‐site of the tungsten bronze structures should be an innovative strategy to develop novel high‐performance nonlinear optical materials. [ABSTRACT FROM AUTHOR]

2D materials, analog resistive memories, electrochemical random-access memories, linear switching, mixed ionic-electronic conductors, molecular self-assembly, MXenes, neuromorphic computing High-Speed Ionic Synaptic Memory Based on 2D Titanium Carbide MXene (Adv. Funct. Keywords: 2D materials; analog resistive memories; electrochemical random-access memories; linear switching; mixed ionic-electronic conductors; molecular self-assembly; MXenes; neuromorphic computing EN 2D materials analog resistive memories electrochemical random-access memories linear switching mixed ionic-electronic conductors molecular self-assembly MXenes neuromorphic computing 1 1 1 03/21/22 20220316 NES 220316 B Analog Resistive Memories b In article number 2109970, Armantas Melianas, Armin VahidMohammadi, Alberto Salleo, Mahiar Max Hamedi, and co-workers present the world's first electrochemical transistor memory based on 2D materials (MXene). [Extracted from the article]

In an article published in Advanced Functional Materials, researchers present the world's first electrochemical transistor memory based on 2D materials (MXene). These transistors have the potential to be used in neuromorphic computers and are significantly faster than previous ionic memories and other state-of-the-art technologies. The researchers highlight the potential applications of these transistors in the field of neuromorphic computing. [Extracted from the article]

Natural killer (NK) cells are crucial in the innate immune response and show promise in cancer immunotherapy, but face challenges in activation and targeted gene delivery. In this study, bifunctional lipid nanoparticles (DLNPs) containing 1,2‐dioleoyl‐3‐trimethylammonium‐propane (DOTAP), designed to bolster the antitumor efficacy of chimeric antigen receptor‐modified NK (CAR‐NK) cells by facilitating activation and efficient CAR mRNA delivery are introduced. The DLNPs, created by functionalizing FDA‐approved LNP compositions, exhibit excellent mRNA encapsulation and colloidal stability. NK cells primed with DLNPs show increased cytotoxicity against cancer cells via extracellular signal‐regulated kinase/Mitogen‐Activated Protein Kinase pathway modulation and mitochondrial dynamics changes. The DLNPs enter NK cells predominantly through clathrin‐mediated endocytosis, boosting mRNA delivery and overcoming NK cells' resistance to genetic manipulation. CAR‐NK cells targeting glypican‐3, prevalent in hepatocellular carcinoma, show significant therapeutic effects in an orthotopic mouse model. These findings underscore the potential of DLNPs in enhancing CAR‐NK cell therapy for solid tumors, marking a significant stride in NK cell‐based cancer immunotherapy and broadening prospects for NK cell‐related disease interventions. [ABSTRACT FROM AUTHOR]

Generation of hydrogen fuel via electrochemical water splitting powered by sustainable energy, such as wind or solar energy, is an attractive path toward the future renewable energy landscape. However, current water electrolysis requires desalinated water resources, eventually leading to energy costs and water scarcity. The development of cost‐effective electrocatalysts capable of splitting saline water feeds directly can be an evident solution. Herein, a surface reconstructed nickel‐iron layered double hydroxide (NF‐LDH) is reported as an exceptionally active and durable bifunctional electrocatalyst for saline water splitting without chloride corrosion. The surface reconstructed NF‐LDH consists of Ni3Fe alloy phase interconnected in a 2D network in which an ultrathin (≈2 nm) and low‐crystalline NiFe (oxy)hydroxide phase are formed on the surface. The NiFe (oxy)hydroxide phase draws large anodic current densities, satisfying the level of practical application, while the Ni3Fe alloy phase is simultaneously responsible for the high catalytic activity for cathodic reactions and superior corrosion resistance. The surface reconstructed NF‐LDH electrode can be easily fabricated in a large electrode area (up to 25 cm2) and can successfully produce hydrogen fuels from saline water powered by the laboratory‐made low‐intensity photovoltaic cell. [ABSTRACT FROM AUTHOR]

A multifaceted Mo:BiVO4 (mf‐BVO) photoanode is grown on F‐doped‐SnO2 substrates via achemical bath deposition, and the crystal reconstruction process of mf‐BVO is found to boost the charge transport efficiency significantly for photoelectrochemical (PEC) water splitting. The mf‐BVO exhibits columnar grains with an uncommon (121) texture with high‐index facets such as (112), (020), (132), and (204). The texture and high‐index facets facilitate rapid surface melting and grain fusion during thermal annealing, thus leading to crystal reconstructed micron‐sized BVO grains (cr‐BVO). The cr‐BVO has a photocurrent density ≈50 times larger than that of mf‐BVO. The reason is identified as the significantly improved charge transport efficiency resulting from the dopant activation (increased carrier concentration) and bulky grains (fewer defects). Additionally, the cr‐BVO exhibits improved photocorrosion resistance compared to the nanoparticle‐based BVO. After coating the oxygen evolution catalyst, the photocurrent density of cr‐BVO is further increased to 4.4 mA cm−2 for water oxidation reaction at 1.23 V versus the reversible hydrogen electrode, maintaining a high and stable faradaic efficiency of over 88% for 24 h. These results demonstrate that crystal reconstruction is a facile and effective pathway to improve the charge transport efficiency, opening a new avenue for developing efficient photoelectrodes for PEC water splitting. [ABSTRACT FROM AUTHOR]

The physicochemical properties of nanostructured substrates significantly impact laser desorption/ionization mass spectrometry (LDI‐MS) performance. Fundamental understanding of the substrate properties can provide insights into the design and development of an efficient LDI matrix. Herein, a hybrid matrix of nanoporous Au‐modified TiO2 nanowires (npAu‐TNW) is developed to achieve enhanced LDI‐MS performance. Its origin is investigated based on hybrid matrix properties including photo–thermal conversion and electronic band structure. Notably, further improvement is obtained in the npAu‐TNW than in the pristine TNW and non‐porous Au nanoisland‐modified TNW (Au‐TNW) hybrid, which is attributed to the laser‐induced surface restructuring/melting phenomenon. Noticeable surface restructuring/melting occurs in the npAu by laser exposure through efficient photo–thermal conversion of the highly porous npAu. At this instant of npAu structural changes, internal energy transfer from the npAu to the adsorbed analyte is promoted, which facilitates desorption. Moreover, strain is developed in situ in the TNW adjacent to the restructuring npAu, which distorts the TNW lattice. The strain development reduces recombination rates of charge carriers by introducing shallow trap levels in the bandgap, which enhances the ionization process. Ultimately, the high LDI‐MS performance based on the npAu‐TNW hybrid matrix is demonstrated by analyzing neurotransmitter. [ABSTRACT FROM AUTHOR]

The spin current is significantly limited by the spin‐orbit interaction strength, material quality, and spin‐mixing conductance at material interfaces. Such limitations lead to spin current decay at the interfaces, which severely hinders potential applications in spin‐current‐generating thermoelectric devices. Thus, methodical studies on the enhancement of spin currents are indispensable. Herein, a novel approach for enhancing the spin current injected into a normal metal, Pt, using interface effects with a ferromagnetic insulator, yttrium iron garnet (YIG), is demonstrated. This is accomplished by inserting atomically thin monolayer (ML), tungsten diselenide (WSe2) between Pt and YIG layers. A comparative study of longitudinal spin Seebeck effect (LSSE) measurements is conducted. Two types of ML WSe2 (continuous and large‐area ML WSe2 and isolated ML WSe2 flakes) are used as intermediate layers on YIG film. Notably, the insertion of ML WSe2 between the Pt and YIG layers significantly enhances the thermopower, VLSSE/ΔT by a factor of approximately 5.6 compared with that of the Pt/YIG reference sample. This enhancement in the measured LSSE voltages in the Pt/ML WSe2/YIG trilayer can be explained by the increased spin‐to‐charge conversion at the interface owing to the large spin‐orbit coupling and improved spin mixing conductance with the ML WSe2 intermediate layer. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) or solidified ionic liquids, known as ionogels, have been actively employed in supercapacitors (SCs) owing to their superior electrochemical stabilities to aqueous and organic electrolytes. However, initial efforts of using ILs and ionogels in SCs were not successful because bulky and sluggish ions cannot effectively access tiny pores of conventional microporous carbons. To address this, a strategy is developed to optimize the electrochemically active surfaces of carbonaceous electrodes and thus to improve the energy storage performance by incorporating 3D ordered/interconnected large mesoporous carbons with ionogel electrolytes. Precisely designed large mesopores interconnected via windows promote mass transport of the electrolyte ions within the solid ionogel electrolytes and effectively utilize the surface of the carbon electrodes for capacitive energy storage, giving rise to record‐high energy storage performance that surpasses the upper bound of the Ragone plots of the current state‐of‐the‐art SCs. In addition, all‐solid‐state SCs with outstanding bending/folding durability are successfully demonstrated. Overall, these results provide critical insight into surface utilization of carbon electrodes as well as capacitive energy storage, when viscous and bulky ILs or ionogels are used as electrolytes. [ABSTRACT FROM AUTHOR]

Keywords: chloride corrosion; electrocatalysis; nickel iron layered double hydroxide; seawater splitting EN chloride corrosion electrocatalysis nickel iron layered double hydroxide seawater splitting 1 1 1 05/30/23 20230525 NES 230525 B Seawater Splitting b In article number 2214069, HyukSu Han, Chan-Yeup Chung, Hyeok Kim, and co-workers develop a revolutionary catalyst design strategy to induce chloride blocking materials in nickel iron layered double hydroxide via surface reconstruction enabling excellent overall saline water splitting. Chloride corrosion, electrocatalysis, nickel iron layered double hydroxide, seawater splitting Surface Reconstruction of Ni-Fe Layered Double Hydroxide Inducing Chloride Ion Blocking Materials for Outstanding Overall Seawater Splitting (Adv. Funct. [Extracted from the article]

Ionogels: Optimizing Electrochemically Active Surfaces of Carbonaceous Electrodes for Ionogel Based Supercapacitors (Adv. Funct. Keywords: electrochemically active surfaces; facilitated ion transport; flexible supercapacitors; ionogels; large mesoporous carbons EN electrochemically active surfaces facilitated ion transport flexible supercapacitors ionogels large mesoporous carbons 1 1 1 07/25/20 20200723 NES 200723 In article number 2002053, Keun Hyung Lee, Won Cheol Yoo, and co-workers present a facile strategy to effectively utilize the surface of carbonaceous electrodes using 3D ordered/interconnected large mesoporous carbons and solidified ionic liquid electrolytes, known as ionogels. Electrochemically active surfaces, facilitated ion transport, flexible supercapacitors, ionogels, large mesoporous carbons. [Extracted from the article]