Memristor technology offers a promising route toward energy-efficient computing but faces challenges including resistance drift, variability, and the need for electroforming. Filamentary resistive random-access memory, one of the most studied memristive platforms, typically requires a high-voltage electroforming step to initiate conductive filaments, leading to increased power overhead and reduced endurance. Here we report HfO2-based forming-free memristive devices (PdNeuRAM) that operate at low voltages, support multi-bit functionality, and exhibit reduced variability. Through combined electrical and materials characterization, we identify a Pd-O-Hf interfacial configuration that lowers oxygen-vacancy formation and migration barriers, creating a dense network of shallow defect states. Together with a Ti top electrode acting as an oxygen reservoir and an ultrathin (5 nm) HfO2 layer, this interfacial engineering enables charge redistribution at room temperature and eliminates the need for electroforming. The fabricated devices provide tunable resistance states and reduce programming and read energy by 43% and 38%, respectively, in spiking neural network inference tasks. These results provide mechanistic insight into forming-free resistive switching and demonstrate the potential of Pd/HfO2 devices for energy-efficient neuromorphic computing.

We explore the effect of combining two distinct strain-engineering multilayer regions (designated as L1 and L2) on the structural quality, carrier dynamics, and device optical efficiency of InGaN/GaN multiple quantum well (MQW)-based light-emitting diode (LED) structures. In S1, L2 consists of a single ultrathin InGaN/GaN layer, whereas in the S2 LED structure, L2 contains several superlattice (SL) pairs beneath the MQWs. The incorporation of superlattices in L2 leads to a significant enhancement in the optical performance in the S2 LED structure relative to S1. A detailed structural analysis indicates that the dimensions of V-pits, including their size, depth, and sidewall thickness, are determined by the configuration of the L2 region. The presence of SLs in S2 promotes a more homogeneous indium distribution within the InGaN quantum wells, whereas S1 exhibits In-rich nanosegregation. In S2, a monotonic decrease in indium content from the bottom to the top of the MQWs adjacent to the V-pits is observed, attributed to the fully pseudomorphic strain regime. Photoluminescence (PL) and time-resolved PL measurements show that S2 achieves an internal quantum efficiency exceeding 85% and exhibits distinct drooping characteristics under high carrier injection. These results indicate that carrier overflow and band-filling effects facilitate the transfer of carriers to higher energy states associated with the V-pit sidewalls, followed by repopulation of the main MQWs occurring through regions with gradually varying indium content, resulting in dominant radiative recombination in S2 at room temperature. Electroluminescence measurements confirm that the S2 LED attains an external quantum efficiency 1.6 times greater and an output power approximately 66% higher than those of S1.

Self-powered solar-blind Ga 2 O 3 -based photodetectors (PDs) encounter several challenges, including demanding and complex fabrication processes that substantially increase production costs. However, cost-effective simple device structures based on a single Ga 2 O 3 layer do not exhibit adequate performance due to high dark current. In this report, these challenges are addressed by employing Sn + implantation and post-implantation annealing of β-Ga 2 O 3 epilayers grown by pulsed laser deposition (PLD), enhancing the performance of the resulting metal − semiconductor − metal (MSM) PDs. As-grown β-Ga 2 O 3 film-based PDs are characterized by high dark current, a slow photoresponse (several seconds), and a weak on/off ratio (~ 10). We show that Sn + implantation and post-implantation annealing suppresses the dark current completely as bias increases, yielding an exceptionally superior photocurrent-to-dark current ratio (~ 10 9 ) and faster photoresponse (< 40 ms). We also demonstrate significant detectivity enhancement by a factor of 10 5 , along with a significant solar-blind rejection ratio (~ 10 4 ), a sharp cut-off at 265 nm (UV-C region), as well as excellent self-powered characteristics of implantation-based devices. X-ray photoelectron spectroscopy and density functional theory reveal the possible causes of such improvements. This is the first investigation of self-powered solar-blind DUV PDs based solely on a single Sn + -implanted β-Ga 2 O 3 layer.

High-performance carbon molecular sieve (CMS) membranes present attractive separation properties for energy-intensive gas and vapor separations, but their commercial introduction has been stalled because of their mechanical fragility and fabrication difficulties. Those challenges tend to generally increase for high-temperature (700-900 degrees C) CMS membranes that possess particularly attractive, sharp (sub)microporous microstructures. In this work, we study the application of vapor phase infiltration (VPI) to thin films and membranes from a CMS precursor, 6FDA-DAM polyimide, and the resulting modification of their gas and vapor transport characteristics. The self-limiting nature of sequential (via multiple cycles) VPI allows development of a very steep inorganic dopant gradient (Al2O3) that accumulates predominantly within the first several tens of nanometers of the film surface. In a polymer precursor, prior to conversion to CMS, the VPI quickly leads to a slowdown in methanol vapor sorption kinetics by orders of magnitude highlighting the potential of VPI in moderating the organic vapor transport or improving solvent stability. Progressive heating of the polyimide precursor to 400, 500, and 615 degrees C seems to reduce the impact of VPI on methanol sorption dynamics and facilitate the development of an increasingly accessible microporous structure. For fully developed hybrid CMS membranes, pyrolyzed at a moderate 615 degrees C, VPI increases gas pair selectivities in comparison to the unmodified membranes, e.g., from 5.6 up to 7.7 for O-2/N-2, from similar to 1 up to 23 for H-2/CO2, from 27 up to 430 for H-2/CH4, and from 30 up to 300 for H-2/N-2. At extreme doping levels (>30 cycles), however, gas permeances tend to drop close to or beyond practical levels. The advantageous characteristics of VPI, as well as the relatively easy integration into membrane fabrication or post-treatment, make it a promising approach for designing nanohybrid CMS membranes with high and tunable selectivities while limiting risks of very high pyrolysis temperatures.

Thin-film composite (TFC) carbon molecular sieve (CMS) membranes offer a promising combination of excellent gas separation performance, plasticization resistance, and relative ease of fabrication but their scalable fabrication requires addressing defect formation and mechanical stability issues that are amplified at high pyrolysis temperatures >600 °C. To address these challenges, we focus on employing vapor phase infiltration (VPI) to tighten the surface micropores (within 10-30 nm depth) of mechanically robust selective layers of TFC CMS membranes fabricated at a moderate pyrolysis temperature of 615 °C. We systematically investigated the impact of VPI process temperature (100–200 °C) and reactant vapor pressure (40–200 mTorr) using trimethylaluminum (TMA) and water vapor. While lower process temperatures (100 °C) resulted in a deeper, pressure-dependent infiltration profile, a higher temperature of 200 °C limited the modification to a thin surface skin as a result of faster reaction kinetics and reduced TMA solubility. Although the VPI treatment showed only a minor effect on the glass transition temperature of the rigid precursor, it drastically altered methanol vapor sorption dynamics, reducing the diffusion coefficient by up to three orders of magnitude. After pyrolysis, the nanohybrid CMS structure opened to allow faster methanol transport but maintained significantly enhanced swelling resistance. Gas permeation experiments revealed that the VPI treatment significantly amplified molecular sieving by steepening the kinetic diameter dependence and provided major selectivity enhancements for gas pairs with large size differences (e.g., H2/CH4 selectivities up to >300). These significant boosts in selectivities were, however, accompanied by a large decrease in gas permeance which will need to be addressed to enhance the practicality of the nanohybrid CMS membranes. This work highlights the potential of VPI to precisely tune the ultramicropore structure of mechanically stable, moderate pyrolysis temperature CMS membranes and boost their selectivities for gas separations.

A comprehensive investigation of surface carrier dynamics is indispensable for advancing high-performance optoelectronic and energy-conversion devices, where interfaces critically govern the efficiency, stability, and robustness. In this work, we present an integrated study of tellurium-selenium (Te-Se) nanocomposites using X-ray photoelectron spectroscopy (XPS), femtosecond transient absorption spectroscopy (fs-TA), scanning ultrafast electron microscopy (SUEM), and density functional theory (DFT) to disentangle surface-specific and bulk relaxation pathways. XPS reveals that varying the Te:Se ratio alters the balance between surface oxidation and vacancy density, defining the interfacial landscape. Consistent with this, SUEM uncovers striking composition-dependent surface carrier dynamics: TeSe 1:1 exhibits dark contrast with localized carriers (tau approximate to 378 ps, 4.12 ns), whereas TeSe 1:0.5 displays bright contrast and long-lived diffusion (tau(rise) approximate to 315 ps, tau(2) > 6 ns), despite stronger oxidation. In contrast, fs-TA shows nearly identical bulk relaxation in both compositions, underscoring that the observed differences originate exclusively at the surface. Supported by DFT, these results demonstrate that composition-driven interface engineering provides an effective route to tailor surface carrier lifetimes, offering actionable design guidelines for Te-Se systems in advanced optoelectronic and energy applications.

The replacement or de-bottlenecking of the highly energy-intensive distillation unit operation process for propylene/propane separation has long posed a formidable challenge. Although membrane technology can potentially offer a more energy-efficient alternative, existing materials lack the requisite mixed-gas selectivity for industrial use. Achieving effective separation for propylene and propane with only 0.13Å difference in molecular size requires membranes with superb molecular sieving properties. Here, we report extremely selective carbon molecular sieve (CMS) materials fabricated by utilizing a triptycene-based intrinsically microporous 4,4′-(hexafluoroisopropylidene)diphthalic anhydride-2,6(7)-diamino triptycene (6FDA-DAT1) polyimide precursor and adjusting its microstructure through finely tuned high-temperature pyrolysis. A freshly prepared isotropic CMS membrane pyrolyzed at 800 °C for 2 h displayed a mixed-gas propylene permeability of 56 Barrer combined with a C 3 H 6 /C 3 H 8 selectivity of 66. Notably, after an extended period of continuous mixed-gas testing and aging at 4 bar over 147 days, the CMS membrane exhibited a remarkable increase in mixed-gas propylene/propane selectivity to 152—an unmatched value to date for a CMS material—because of selective tightening of the CMS microstructure by physical aging.

We present a novel approach to significantly boost gas-pair selectivity of thin-film composite (TFC) carbon molecular sieve (CMS) membranes by sputtering platinum on the surface of the CMS precursor polymer prior to pyrolysis. A polyimide of intrinsic microporosity (PIM-PI), 6FDA-HTB, was selected as the CMS precursor which had previously been shown to transform into an excellent CMS membrane material at moderate pyrolysis temperatures (550-600 degrees C). Deposition of Pt at high ion currents combined with subsequent pyrolysis at 550 degrees C leads to the development of an ultrathin (10-20 nm thick) Pt/CMS intermix layer consisting of a CMS matrix with a large volume fraction of embedded, fused Pt nanoparticles. The Pt phase seems to stabilize the micropores of the intermixed CMS phase as well as limit the undesired impact of defects leading to a dramatic enhancement of gas-pair selectivity of the modified TFC CMS membranes (e.g. H-2/CH4 > 1100, CO2/CH4 similar to 100, O-2/N-2 similar to 11) which represent improvements of 3300, 370, and 100 % in comparison to the non-Pt-sputtered CMS control membranes. This novel, simple and effective procedure may be extendable to other types of CMS polymer precursors, membrane supports, alternative sputtering metals and the deposition parameters can be easily tuned to balance the membrane permeance against the desired selectivity.

Continuous long-term evaluation of propylene and propane permeation through narrow slit carbon molecular sieve (CMS) membranes is essential for an in-depth study of their steady-state separation performance. CMS membranes are characterized by finely tuned ultramicroporous structures, exceptional thermal and chemical stability, and hold great promise for the energy-intensive separation of propylene and propane. However, the gradual changes in their performance over time due to penetrant-induced structural chain rearrangements have often been overlooked. In this study, we prepared CMS membranes using a polymer of intrinsic microporosity (PIM) with a highly aromatic tetraphenylethylene (TPE) based building block. The presence of bulky and sterically hindered TPE repeat units renders this polymer an excellent precursor for the fabrication of highperformance CMS membranes. The TPE-PIM-based precursor underwent pyrolysis at temperatures ranging from 550 to 700 degrees C for 1 h. Pure- and mixed-gas permeation tests were accompanied by various characterization techniques to assess the carbonization state of the CMS materials. The CMS pyrolyzed at 700 degrees C exhibited a decline in pure-gas C3H6/C3H8 3 H 6 /C 3 H 8 selectivity from an initial value of 300 to 161 at steady state over a 20-day period. Even more notable, under equimolar mixed-gas feed conditions, the isotropic CMS film displayed a substantial C3H6/C3H8 3 H 6 /C 3 H 8 selectivity reduction from 214 to 62 over a 24-day period. This performance decline can be attributed to competitive sorption and very slow dilation kinetics, which led to moderately reduced propylene permeability while significantly enhancing propane permeability. Our study suggests that long-term, continuously performed mixed-gas permeation experiments are essential to assess the 'steady-state' performance of CMS membranes for mixtures containing highly sorbing feed components, as observed for propylene/propane separation.

There is a growing demand for propylene calls for effective carbon reduction methods. The methanol-to- propylene (MTP) process stands out as a promising solution for meeting global propylene demand sustain- ably. In this study, we identify the mechanistic factors responsible for enhanced reactivity, superior propylene selectivity, and durable catalyst lifespan in the MTP process catalyzed by both unmodified siliceous and Ca-modified ZSM-5 zeolites. By employing advanced characterization techniques like in situ UV-visible and solid-state NMR spectroscopy, along with well-designed control experiments, we highlight the importance of the alkene cycle within the zigzag channel of zeolite ZSM-5 for superior propylene selectivity. Furthermore, our work identifies oxymethylene species as a key intermediate that enhances the lifetime of the alkene cycle and governs MTP catalysis. We also explore the synergistic interaction between Lewis-Br & oslash;nsted acids and their impact on hydrocarbon pool species to deepen our understanding of zeolite catalysis.

Advancements in computing have progressed from near-sensor to in-sensor computing, culminating in the development of multimodal in-memory computing, which enables faster, energy-efficient data processing by performing computations directly within the memory devices. A bio-inspired multimodal in-memory computing system capable of performing real-time low power processing of multisensory signals, lowering data conversion and transmission across several modules in conventional chips is introduced. A novel Cu/MoWS2/VOx/Pt based multimodal memristor is characterized by an ON/OFF ratio as high as 108 with consistent and ultralow operating voltages of ±0.2 surpassing conventional single-mode memory functions. Apart from observing electrical synaptic behavior, photonic depression and humidity mediated optical synaptic learning is also demonstrated. The heterojunction with MoWS2 also enables reconfigurable modulation in both memory and optical synaptic functionalities with changing humidity. This behavior provides tunable conductance modulation capabilities emulating synaptic transmission in biological neurons while showing potential in respiratory detection module for healthcare application. The humidity sensing capability is implemented to demonstrate vision clarity using a convolutional neural network (CNN), with different humidity levels applied as a data augmentation preprocessing method. This proposed multimodal functionality represents a novel platform for developing artificial sensory neurons, with significant implications for non-contact human-computer interaction in intelligent systems.

Traditional electrolytes impose tremendous limitation on the effective operation of lithium-sulfur (Li-S) batteries at elevated temperatures due to insufficient thermal stability and aggravated side reactions, wherein battery failure mechanism and electrolyte design principle remain elusive. Herein, we developed a varied-temperature multimodal nuclear magnetic resonance (VT-mNMR) methodology to elucidate temperature-dependent electrolyte solvation structure and ion dynamics, whereby a thermotolerant bistratal solvation structure electrolyte (BSSE) was formulated to concurrently maintain compact inner solvation sheath and restrict polysulfide shuttling at high temperatures. Cryogenic transmission electron microscopy combined with X-ray photoelectron spectroscopy depth profiling discloses rich inorganic components in the inner layer of solid electrolyte interface. Consequently, Li-S batteries with BSSE can sustain stable operation with a high capacity retention of 90 % at 60 degrees C, which also harvest a stable cycling performance under a wide temperature range within 20-80 degrees C. Our study provides a reliable toolbox for studying liquid electrolyte chemistry in Li-S batteries and beyond, which opens a new avenue for advancing extreme-temperature electrolyte design.

Advancements in computing have progressed from near‐sensor to in‐sensor computing, culminating in the development of multimodal in‐memory computing, which enables faster, energy‐efficient data processing by performing computations directly within the memory devices. A bio‐inspired multimodal in‐memory computing system capable of performing real‐time low power processing of multisensory signals, lowering data conversion and transmission across several modules in conventional chips is introduced. A novel Cu/MoWS 2 /VO x /Pt based multimodal memristor is characterized by an ON/OFF ratio as high as 10 8 with consistent and ultralow operating voltages of ±0.2 surpassing conventional single‐mode memory functions. Apart from observing electrical synaptic behavior, photonic depression and humidity mediated optical synaptic learning is also demonstrated. The heterojunction with MoWS 2 also enables reconfigurable modulation in both memory and optical synaptic functionalities with changing humidity. This behavior provides tunable conductance modulation capabilities emulating synaptic transmission in biological neurons while showing potential in respiratory detection module for healthcare application. The humidity sensing capability is implemented to demonstrate vision clarity using a convolutional neural network (CNN), with different humidity levels applied as a data augmentation preprocessing method. This proposed multimodal functionality represents a novel platform for developing artificial sensory neurons, with significant implications for non‐contact human–computer interaction in intelligent systems.

Clinical studies routinely show that individuals suffer from vitamin D deficiency, which can result in health complications that include cardiovascular disease, autoimmune disorders, neurodegenerative diseases, and different skeletal deformities. Given its integral role in homeostasis and connection to many pathologies, early diagnosis of vitamin D deficiency is crucial. However, monitoring vitamin D levels is challenging, particularly in remote regions, due to the cost, time, and complexity of existing methods. Here, we develop an electrochemical biosensor for vitamin D based on antibody-functionalized MXenes, offering clinically relevant sensitivity, specificity, and amenability for point-of-care testing. Ti3C2Tx MXene nanosheets are amine-functionalized by electrostatically-driven modification with polyethylenimine, whose functionalities are then used for covalent conjugation of anti-vitamin D antibodies via glutaraldehyde chemistry. This platform achieves a detection limit of 1 pg mL−1 with a dynamic range (0.1–500 ng mL−1) that covers clinically relevant deficiency, insufficiency, sufficiency, and toxicity. Low-cost and portable biosensors for vitamin D monitoring could allow early intervention to prevent illnesses associated with vitamin D deficiency. Here, an antibody-functionalized MXene-based biosensor allows for high sensitivity detection of vitamin D, with a 1 pg ml-1 limit of detection.

Organic mixed ionic-electronic conductors (OMIECs) have emerged as essential materials for applications in bioelectronics, neuromorphics, and energy storage, owing to their ability to transport both ions and electrons. While significant progress has been made in understanding their operation, the role of noncompensating ions in polymer redox processes remains underexplored, particularly in the context of their impact on charge compensation and device performance. In this study, we systematically investigate the influence of noncompensating ions on the performance of n-type OMIECs with and without polar side chains, focusing on their interactions with electrolytes containing anions from the Hofmeister series. Our findings reveal a stark contrast in charging behavior and organic electrochemical transistor (OECT) performance based on side-chain chemistry. Polar oligoether side chains promote interactions with anions, resulting in significant performance variations. We demonstrate the critical role of polymer side-chain interactions with the different anions, where polyatomic anions capable of infiltrating the film degrade device performance, particularly in terms of transconductance and operational stability. In contrast, OMIECs without side chains exhibit performance independent of the noncompensating ion nature. Through electrochemical analysis, spectroscopic techniques, and molecular dynamics simulations, we provide a comprehensive understanding of how ion incorporation and polymer-electrolyte interactions shape device behavior. This study highlights the transformative role of side-chain functionality in tailoring the properties of the OMIEC and offers a design framework for high-performance OECTs, enabling advancements in biosensing, neuromorphic computing, and beyond.

Low electrolyte usage is a key to attaining high-energy-density lithium–sulfur (Li–S) batteries. However, this is still a tremendous challenge for traditional ether-based electrolytes that follow a dissolution–precipitation mechanism. Highly solvating electrolytes, which can facilitate polysulfide dissolution and alter reaction pathway, are considered a promising strategy. Nonetheless, mechanistic understanding and kinetic evaluation remain insufficient while the principle of Li2S nucleation and dissociation has not been elucidated. Herein, we unveil the Li-ion solvation and polysulfide speciation in the solvents with different denticity and donicity. The origin of S3•– radical-directed path and three-dimensional Li2S precipitation in high-donicity electrolytes has been uncovered. It is revealed that ammonium ions enable the facile dissolution and dissociation of Li2S via Lewis acid-base interaction and H···S2– binding. Consequently, Li–S batteries with a low electrolyte and sulfur (E/S) ratio of 5 μL·mgs–1 achieve a high capacity of 1092 mAh·g–1. Even at a harsh E/S ratio of 3 μL·mgs–1 and a high sulfur loading of 4 mg·cm–2, they still sustain a stable operation over 30 cycles. Our work sheds light on the underlying reaction mechanism and rationalizes the design of highly solvating electrolytes, which in turn opens a new avenue for achieving pragmatic lean-electrolyte Li–S batteries.

The electrocatalytic synthesis of ammonia (NH3) through the nitrogen reduction reaction (NRR) under ambient temperature and pressure is emerging as an alternative approach to the conventional Haber-Bosch process. However, it remains a significant challenge due to poor kinetics, low nitrogen (N2) solubility in aqueous electrolytes, and the competing hydrogen evolution reaction (HER), which can significantly impact NH3 production rates and Faradaic efficiency (FE). Herein, a rationally designed boron-doped molybdenum sulfide (B-Mo-MoxSy) electrocatalyst is reported that effectively enhances N2 reduction to  NH3 with an onset potential of -0.15 V versus RHE, achieving a FE of 78% and an NH3 yield of 5.83 µg h⁻¹ cm⁻2 in a 0.05 m H2SO4(aq). Theoretical studies suggest that the effectiveness of NRR originates from electron density redistribution due to boron (B) doping, which provides an ideal pathway for nitrogenous species to bind with electron-deficient B sites. This work demonstrates a significant exploration, showing that Mo-based electrocatalysts are capable of facilitating artificial N2 fixation.

Sparsely solvating electrolyte (SSE), which can achieve a quasi-solid-phase sulfur reaction path, stands out as a promising strategy to alleviate the dependence on electrolyte usage and construct lean-electrolyte lithium-sulfur (Li-S) batteries. Nonetheless, its formation relies upon a high dosage of salt and diluent, thereby leading to increased electrolyte cost. To this end, we herein customize a localized SSE (LSSE) featuring a low ratio of salt-to-solvent and diluent-to-solvent through alkyl chain tuning. A multimodal 2D nuclear magnetic resonance technique is developed to unveil the Li-ion solvation sheath reorganization, which is crucial for studying the coordination and dynamics in liquid electrolytes. LSSE affords an anion-derived solid electrolyte interface and effective restriction of the shuttling effect; hence, our Li-S batteries can sustain a steady operation under 4 mu L mgS( -1) and 3 mg cm(-2). Our work opens a new avenue for advancing SSE design in the pursuit of pragmatic lean-electrolyte Li-S batteries.