Ultrathin Layer Research Articles

One-step preparation of large-size 1.5-μm-thick robust YSZ electrolyte for high CH4 conversion SOFCs at 600 °C

Ultrathin electrolytes can lower the operating temperature of yttria-stabilized zirconia (YSZ)-based solid oxide fuel cells (SOFCs) to below 600 °C, accelerating their commercialization. However, current technologies for fabricating robust electrolytes with large areas and a thickness of a few microns for SOFCs suffer from substantial practical limitations, including high manufacturing costs, intricate technical demands, and multistep fabrication processes. This study introduces a low-cost, high-yield, and facile one-step phase inversion technology to fabricate large-area and shape-variable ultrathin YSZ electrolyte-based SOFCs (disc diameter >12 cm and area of 10 cm × 10 cm). An integrated form of SOFCs with dendritic YSZ microchannels supporting a 1.5-μm-thick dense YSZ thin film was fabricated. The ultrathin electrolyte layer lowered ohmic and polarization losses, enhancing SOFC electrochemical performance. The integrated anode/electrolyte structure overcame the interfacial thermal mismatch, resulting in more than 210 h of long-term stability even with cells operating in rapidly changing environments. The single cell also exhibited a high CH4 conversion efficiency (55%), which was attributed to the fast gas diffusion and excellent catalytic activity within the integrated anode. In addition, our 4 cm × 4 cm flat SOFCs exhibited a high power output (5.1 W) at 600 °C, paving the way for the mass production of ultrathin and robust YSZ electrolytes.

Short-Wave Infrared Colloidal QD Photodetector with Nanosecond Response Times Enabled by Ultrathin Absorber Layers.

Ultrafast short-wavelength infrared (SWIR) photodetection is of great interest for emerging automated vision and spatial mapping technologies. Colloidal quantum dots (QDs) stand out for SWIR photodetection compared to epitaxial (In,Ga)As or (Hg,Cd)Te semiconductors by their combining a size-tunable bandgap and a suitability for cost-effective, solution-based processing. However, achieving ultrafast, nanosecond-level response time has remained an outstanding challenge for QD-based SWIR photodiodes (QDPDs). Here, record 4ns response time in PbS-based QDPDs that operate at SWIR wavelengths is reported, a result reaching the requirement of SWIR light detection and ranging based on colloidal QDs. These ultrafast QDPDs combine a thin active layer to reduce the carrier transport time and a small area to inhibit slow capacitive discharging. By implementing a concentration gradient ligand exchange method, high-quality p-n junctions are fabricated in these ultrathin QDPDs. Moreover, these ultrathin QDPDs attain an external quantum efficiency of 42% at 1330nm, due to a 2.5-fold enhanced light absorption through the formation of a Fabry-Perot cavity within the QDPD and the highly efficient extraction (98%) of photogenerated charge carriers. Based on these results, it is estimated that a further increase of the charge-carrier mobility can lead to PbS QDPDs with sub-nanosecond response time.

Assessing the effects and impacts of the CdSTe interlayer in the performance of the CdTe-CdS thin film solar cells through simulations

CdTe based solar cells have proved to be the most successful thin film PV solar cells with their full industrial production. However, the needed improvement in output efficiency of these cells is constrained by major issues such the poor understanding of the ternary CdSxTe1-x interlayer, formed at the CdS-CdTe interface. While it is believed to have both beneficial and negative effects on the cell performance, its exact mechanism and extent are not fully explored. In this work, the AMPS-1D software was used to model this interlayer, using several of its variables such as thickness, bandgap as well as the thickness of the bounding CdS layer. Results show that the interlayer thickness reduces cell performance, through Jsc, Voc, FF and J-V curves, with best efficiencies of 17.892% (Jsc=27.043mA/cm3, Voc=0.871V, FF=0.8) obtained at zero thickness, falling down by nearly 20% at CdSxT1-x thickness of 100nm. As the bandgap is varied, maximum cell performance of 17.85% (Jsc=27.76, Voc=0.91V and FF=0.81) was found at 1.7eV. Similarly, increasing CdS thickness also reduced cell performance, by reducing the quantum efficiency. The results indicate that if the CdSxTe1-x layer has a thickness of up to 100nm, and a bandgap of around 1.7eV, then cell efficiencies of around 18% were feasible even for ultra-thin CdTe layers of 1μm.

Enhancing ferroelectricity in HfAlOx-based ferroelectric tunnel junctions: A comparative study of MFS and MFIS structures with ultrathin interfacial layers

This study explores the potential advantages of metal–ferroelectric–insulator–semiconductor (MFIS) structures compared with established metal–ferroelectric–semiconductor (MFS) and metal–ferroelectric–metal structures in the context of nonvolatile memory devices. Despite the superior performance of MFS structures in terms of electric field maintenance, switching speed, and power consumption, the presence of interface-related issues between the ferroelectric material and the semiconductor may degrade device performance. We propose an MFIS structure incorporating ultrathin interfacial layers (ILs) of SiO2, HfO2, and ZrO2 to address these issues. These insulator layers enhance device endurance by reducing physical stress and trap density at the interface, thereby improving electrical performance and long-term stability. Moreover, the presence of an IL reduces charge leakage between the ferroelectric layer and semiconductor, contributing to the resolution of the sneak path current problem. An additional feature of MFIS devices is their self-rectifying behavior, simplifying circuit design and manufacturing processes by eliminating the need for an external rectification circuit, consequently reducing costs. Through a series of experiments, this study evaluates the performance of the MFIS structure, investigates the ferroelectric properties of HfAlOx-based FTJs, and examines the conduction mechanism of the MFIS structure. By comparing the o-phase of MFS, SiO2, HfO2, and ZrO2 devices via grazing incidence X-ray diffraction (GIXRD) and using the positive-up-negative-down method to extract polarization and coercive voltage, we provide a comprehensive investigation of the impact of ultrathin ILs on ferroelectric properties. This research aims to offer valuable insights into the advancement of memory device technologies, presenting the MFIS structure as a promising platform for next-generation memory technologies. Further sections will elaborate on the experimental setup, methodology, and detailed study findings.

Stabilization of active ultrathin amorphous ruthenium oxide via constructing electronically interacted heterostructure for acidic water oxidation

Amorphous RuOx (a-RuOx) with disordered atomic arrangement and abundant coordinatively unsaturated Ru sites possesses high intrinsic electrocatalytic activity for oxygen evolution reaction (OER). However, the a-RuOx is prone to fast corrosion during OER in strong acid. Here, we realized the stabilization of an ultrathin a-RuOx layer via constructing heterointerface with crystalline α-MnO2 nanorods array (MnO2@a-RuOx). Benefiting from the strong electronic interfacial interaction, the as-formed MnO2@a-RuOx electrocatalyst display an ultralow overpotential of 128 mV to reach 10 mA cm−2 and stable operation for over 100 h in 0.1 M HClO4. The assembled proton exchange membrane (PEM) water electrolyzer reach 1 A cm−2 at applied cell voltage of 1.71 V. Extensive characterizations indicate the MnO2 substrate work as an electron donor pool to prevent the overoxidation of Ru sites and the OER proceeds in adsorbent evolution mechanism process without involving lattice oxygen. Our work provides a promising route to construct robust amorphous phase electrocatalysts.

Unveiling Enhanced PEC Water Oxidation: Morphology Tuning and Interfacial Phase Change in α-Fe2O3@K-OMS-2 Branched Core-Shell Nanoarrays.

A simple fabrication method that involves two steps of hydrothermal reaction has been demonstrated for the growth of α-Fe2O3@K-OMS-2 branched core-shell nanoarrays. Different reactant concentrations in the shell-forming step led to different morphologies in the resultant composites, denoted as 0.25 OC, 0.5 OC, and 1.0 OC. Both 0.25 OC and 0.5 OC formed perfect branched core-shell structures, with 0.5 OC possessing longer branches, which were observed by SEM and TEM. The core K-OMS-2 and shell α-Fe2O3 were confirmed by grazing incidence X-ray diffraction (GIXRD), EDS mapping, and atomic alignment from high-resolution STEM images. Further investigation with high-resolution HAADF-STEM, EELS, and XPS indicated the existence of an ultrathin layer of Mn3O4 sandwiched at the interface. All composite materials offered greatly enhanced photocurrent density at 1.23 VRHE, compared to the pristine Fe2O3 photoanode (0.33 mA/cm2), and sample 0.5 OC showed the highest photocurrent density of 2.81 mA/cm2. Photoelectrochemical (PEC) performance was evaluated for the samples by conducting linear sweep voltammetry (LSV), applied bias photo-to-current efficiency (ABPE), electrochemical impedance spectroscopy (EIS), incident-photo-to-current efficiency (IPCE), transient photocurrent responses, and stability tests. The charge separation and transfer efficiencies, together with the electrochemically active surface area, were also investigated. The significant enhancement in sample 0.5 OC is ascribed to the synergetic effect brought by the longer branches in the core-shell structure, the conductive K-OMS-2 core, and the formation of the Mn3O4 thin layer formed between the core and shell.

Surface segregation of rigid polyarylene ether amidoxime on polyurethane nanofiber into hierarchical membranes as substrate of flexible SERS nanosensor for sulfamethoxazole detection

Electrospun polymeric nanofibrous membranes are emerging as the promising substrates for preparation of flexible SERS nanosensors due to their intrinsic nanoscale surface roughness, easy scalability as well as rich surface reactivity. Although the nanofiber membranes prepared from high performance thermoplastics exhibit good mechanical stability, the SERS nanosensors based on these substrates normally have lower signal-to-noise ratio because of the interference from background Raman signals of aromatic moieties. Herein, we synthesized an optically transparent polyurethane (PU) and rigid polyarylene ether amidoxime (PEA), which were electrospun into core-shell nanofibers membranes with a “beads-on-web” morphology. Furthermore, the PU-PEA membranes were coated with ultra-thin silver layer and thermally annealed to prepare the flexible SERS nanosensor without any background noises. In addition, the Raman enhancement of SERS nanosensor can be readily improved by tuning of PU-PEA composition, silver thickness as well as thermal annealing temperature. Finally, the optimized SERS nanosensor enables label-free detection of sulfamethoxazole as low as 0.1 nM with a good reproducibility and detection performance in real water sample. Meanwhile, the optimized SERS nanosensor shows long term anti-biofouling capacity. Thanks to its facile fabrication, competitive analytical performance and resistance to biofouling, the current work basically open new way for design of flexible SERS nanosensors for biomedical applications.

Optimization of ultrathin polyamide nanofiltration membranes with sulfonated polyethersulfone interlayers for enhanced performance

The “trade-off” effect of nanofiltration membranes may lead to problems of lower flux and higher energy cost, which limit their applications. In this work, an ultra-thin polyamide selective layer (34 nm in thickness, much lower than the conventional polyamide selective layer) was prepared by constructing a sulfonated polyethersulfone interlayer on the surface of polysulfone ultrafiltration membranes by liquid-phase deposition, taking advantage of the inhibitory effect of sulfonated polyethersulfone nanoparticles on the diffusion of piperazine. The prepared nanofiltration membrane exhibits a water flux per unit pressure of 33.2 L·m−2·h−1·bar−1, which is more than 2.5 times higher than that of the nanofiltration membrane without the introduction of the interlayer (12.2 L·m−2·h−1·bar−1). Additionally, it has a high rejection of 98.8 % for Na2SO4, which surpasses the upper limit of the equilibrium of trade-off. The study also delves into the modulation mechanism of the interfacial polymerization process by the presence of a sulfonated polyethersulfone interlayer and explores the potential reasons for the water flux enhancement. This research will likely provide theoretical support and practical experience for further optimization of nanofiltration membrane performance.

Simultaneously quantitative and qualitative regulation of active sites of Ni-phyllosilicate for enhanced CO2 hydrogenation to methane

To address the problems of low metal utilization rate and poor low-temperature activity of the nickel phyllosilicate catalysts for CO2 methanation, this work prepared ultrathin defect-rich Ni-phyllosilicate through ball milling method in the presence of H2O2 modifier, which simultaneously created active sites with more quantity and higher quality. The instantaneous temperature and high pressure derived from the collision and friction of grinding balls provided driving force for the Ni-phyllosilicate synthesis, and the shear force destroyed the interlayer forces to construct the ultrathin layers. H2O2 molecule could insert the layers and dissociate to O2 bubbles, whose cavitation effect created holes and defects in the nickel phyllosilicate nanosheets and SiO2 spheres. H2O2 amount was crucial for the defect construction and the optimum Ni-AA-1H catalyst possessed the ultrathin nanosheet of 0.68 nm and high Ni dispersion of 15.6 %, whose TOFCO2 reached 3.76 × 10−2 s−1 at 160 °C. The in-situ DRIFTS results confirmed the enhanced low-temperature activity and the HCOO− reaction pathway over Ni-AA-1H for CO2 methanation. Nickel precursor effect was also investigated, and nickel acetylacetonate was determined as the optimal one compared with nickel acetate and nickel chloride, owing to the high steric effect of CH3COCHCOCH3− group and strong basicity environment during ball milling process.

Ultrathin layer TAFC on BiVO4 with ligand-to-metal charge transfer enhances built-in electric field for boosting photoelectrochemical water oxidation

To reveal the mechanism of charge transfer between interfaces of BiVO4-based heterogeneous materials in photoelectrochemical water splitting system, the cocatalyst was grown in situ using tannic acid (TA) as a ligand and Fe and Co ions as metal centers (TAFC), and then uniformly and ultra-thinly coated on BiVO4 to form photoanodes. The results show that the BiVO4/TAFC achieves a superior photocurrent density (4.97 mA cm−2 at 1.23 VRHE). The charge separation and charge injection efficiencies were also significantly higher, 82.0 % and 78.9 %, respectively. From XPS, UPS, KPFM, and density functional theory calculations, Ligand-to-metal charge transfer (LMCT) acts as an electron transport highway in TAFC ultrathin layer to promote the concentration of electrons towards metal center, leading to an increase in the work function, which enhances the built-in electric field and further improves the charge transport. This study demonstrated that the LMCT pathway on TA-metal complexes enhances the built-in electric field in BiVO4/TAFC to promote charge transport and thus enhance water oxidation, providing a new understanding of the performance improvement mechanism for the surface-modified composite photoanodes.

Enhanced stability in InSnO transistors via ultrathin in-situ AlOx passivation

In this study, we present the impact of an ultrathin in-situ AlOx passivation layer on the electrical performance and stability of InSnO (ITO) transistors. Devices incorporating an ultrathin (∼2 nm) AlOx passivation layer demonstrate satisfactory electrical performance and stability, characterized by a decent field-effect mobility, enhancement mode operation, notably reduced subthreshold swing, negligible hysteresis, and, notably, a significantly reduced threshold voltage shift under negative bias stress (NBS) and positive bias stress (PBS), respectively. The total trap density (Ntot), extracted through the sub-threshold slope, and the trap density (Nt), measured using low-frequency noise (LFN) for the AlOx-passivated ITO transistors, are significantly decreased. Those improvements can be attributed to the suppression of oxygen vacancy formation during the reactively-sputtered AlOx and subsequent annealing processes, as demonstrated by comparing the in-depth X-ray photoelectron spectroscopy (XPS) results of the AlOx-passivated and un-passivated ITO films. These results underscore the potential of in-situ reactively-sputtered ultrathin AlOx passivation layers to enhance the stability of thin-film transistors with In-rich channels.

Rapid construction of nickel phyllosilicate with ultrathin layers and high performance for CO2 methanation

The traditional techniques for the synthesis of nickel phyllosilicates usually time-consuming and energy-intensive, which often lead to the formation of layers with excessive thickness due to uncontrolled crystal growth. In order to overcome these challenges, this work introduces a microwave-assisted synthesis strategy to facilitate the synthesis of Ni-phyllosilicate-based catalysts within an exceptionally short duration of only five minutes, attaining a peak temperature of merely 102 °C. To enhance the specific surface area and to increase the exposure of active sites, an investigation was conducted involving three surfactants. The employment of hexadecyl trimethyl ammonium bromide (CTAB) has yielded remarkable results, with an ultrahigh specific surface area reaching 535 m2 g−1 and an ultrathin lamellar thickness of 1.43 nm. The catalyst exhibited an impressive CO2 conversion of 81.7 % at 400 °C, 60 L g−1 h−1, 0.1 MPa. It also demonstrated a substantial turnover frequency for CO2 (TOFCO2) of 5.4 ± 0.1 × 10−2 s−1, alongside a relatively low activation energy (Ea) of 80.74 kJ·mol−1. Moreover, the catalyst maintained its high stability over a period of 100 h and displayed high resistance to sintering. To further elucidate growth temperature gradient of the catalyst and concentration gradient of the materials involved, COMSOL Multiphysics (COMSOL) simulations were effectively utilized. In conclusion, this work breaks the limitation associated with traditional, laborious synthesis methods for Ni-phyllosilicates, which can produce materials with high surface area and thin-layer characteristics.

Building ordered graphene membranes by intermediate layer assisted stacking method for promoted desalination

Laminar separation membranes stacked by graphene and its derivatives hold the merit of controlled mass transfer behaviors. However, precise ion separation is challenged by the disordered assembly of nanosheets on macroporous substrates with complicated surface properties. Herein, we prepare ultrathin ordered graphene membranes by an intermediate layer assisted stacking method. Nanoporous covalent organic framework (COF) nanosheets are first vacuum-filtered on macroporous substrates, followed by deposition and thermal reduction of graphene oxide nanosheets to deliver ultrathin reduced graphene oxide (rGO) layers. The COF-decorated substrates provide a hydrophilic surface with reduced pores and roughness, facilitating the formation of ultrathin rGO layers with ordered stacking patterns and reduced microporous defects. Consequently, the obtained rGO/COF composite membranes can reject ∼90% of Na2SO4, ∼50% of NaCl, and >98% of various organic dyes, which are higher than pure rGO membranes. Meanwhile, the rGO/COF composite membranes can maintain good stability in solutions with different pH values and salt concentrations, and can be long-term operated for at least 10 days. This work is expected to deepen the understanding of the structure of laminar membranes and provides new perspectives to design ordered laminar membranes.

Sub-5 nm ultrathin IGO film transistor printed by micro-doped InGa liquid alloy

In this study, we introduce a novel perspective that the formation of the atomically ultrathin oxide layer on the surface of liquid alloys is primarily governed by thermodynamic laws and is additionally influenced by the surface tension of the liquid alloys. In this case, we control the competition of Gibbs free energy and surface tension to effectively address the severe segregation problem of Ga2O3 and realize the precise doping of Ga2O3 in the preparation process of two dimensional IGO film through the liquid InGa alloy printing approach. Importantly, the Ga2O3 content in the IGO films can be tailored in the full range and a sub-5 nm ultrathin IGO film transistor is innovatively fabricated. The oxidation law, band gap, Fermi level, field-effect mobility, subthreshold swing, and other properties of IGO films in sub-5 nm scale are systemically investigated in detail. It has been demonstrated that the incorporation of Ga2O3 in the doping process dramatically reduced the device's turn-off current and enhanced its ability to resist ultraviolet interference. This novel doping process opens up a significant opportunity for future developments of atomically ultrathin transparent conducting film.

Experimental and ab initio studies of enhance photocatalytic efficiency of La-doped ZnO/g-C3N4 nanocomposites for bromothymol blue dye degradation

The ability of photocatalysis to clean up environmental contamination, notably in the treatment of water and air, has received extensive research. The composite materials synthesized by the coprecipitation method were made of ZnO and graphitic carbon nitride (g-C3N4) with various concentrations of lanthanum doping (La-ZnO). It was discovered that La metal ions were evenly distributed throughout the layered stacking structures of ZnO nanosheet, which had an impact on the band structure and increased the rate of electron-hole separation and visible light absorption. First-principles calculations show that La-doped ZnO-gC3N4 possesses a direct band gap and a type-II band structure with the conduction band minimum and the valence band maximum located in separate layers. A built-in electric field from the gC3N4 to the La-doped ZnO has been established through an analysis of charge density difference, Bader charge, work function, and band alignment. The electron-hole pair becomes spatially separated as a result, which increases the photodegradation activity. High interfacial charge transfer, efficient charge separation and migration, and high visible light optical absorbance were caused by the direct coating of ZnO on an ultra-thin g-C3N4 layer. The 0.6 % La-doped ZnO-gC3N4 degraded 97 % of the bromothymol blue (BB) dye, which was four times higher than the bulk ZnO, which could remove only about 21 % of the dye at the same time. The combined effects of lower photo corrosion, higher solar light usage owing to a hollow structure and heterostructured semiconductor photocatalysis contribute to this increased photocatalytic activity. The capacity of La-doped ZnO/g-C3N4 nanocomposite to effectively break down BB dye via photocatalysis suggests that it has the potential to address the problems associated with dye pollution in water systems.

Asymmetric ionogel electrolyte with an ultrathin metal–organic framework layer for lithium dendrite inhibition in solid-state lithium-metal batteries

Solid-state electrolytes (SSEs) are used to prevent internal short circuits caused by the growth of lithium dendrites in solid-state lithium-metal batteries (SSLMBs). Ionogel electrolytes are new polymeric SSEs with outstanding processability, excellent flexibility, and superior ionic conductivity. Lithium-ion transport in ionogel electrolytes depends on ionic liquid (IL) content; however, increasing the IL content improves ionic conductivity but sharply decreases mechanical properties, thus limiting the ability to resist lithium dendrites. Thus, ionogel electrolytes must strike a balance between ionic conductivity and mechanical properties. Herein, we adopt a new strategy to suppress the growth of lithium dendrites by in situ polymerizing an ultrathin metal–organic framework (MOF) layer (9.8 μm) onto a highly ionic conductive ionogel electrolyte. The ionogel electrolyte provides an asymmetric SSE (ASSE) with a remarkable ionic conductivity of 4.8 × 10−4 S cm−1 (30 °C), whereas the ultrathin MOF layer regulates uniform dissolution/deposition of lithium and inhibits lithium dendrite growth, thereby increasing critical current density of the ASSE to 0.65 mA cm−2. An SSLMB assembled with the ASSE and LiFePO4 exhibits excellent performance and cycling stability, maintaining a specific capacity of 125.4 mAh g−1 after 500 cycles at 0.3C.

Magnetic Nanoparticle Support with an Ultra-Thin Chitosan Layer Preserves the Catalytic Activity of the Immobilized Glucose Oxidase.

Here, we developed magnetically recoverable biocatalysts based on magnetite nanoparticles coated with an ultra-thin layer (about 0.9 nm) of chitosan (CS) ionically cross-linked by sodium tripolyphosphate (TPP). Excessive CS amounts were removed by multiple washings combined with magnetic separation. Glucose oxidase (GOx) was attached to the magnetic support via the interaction with N-hydroxysuccinimide (NHS) in the presence of carbodiimide (EDC) leading to a covalent amide bond. These steps result in the formation of the biocatalyst for D-glucose oxidation to D-gluconic acid to be used in the preparation of pharmaceuticals due to the benign character of the biocatalyst components. To choose the catalyst with the best catalytic performance, the amounts of CS, TPP, NHS, EDC, and GOx were varied. The optimal biocatalyst allowed for 100% relative catalytic activity. The immobilization of GOx and the magnetic character of the support prevents GOx and biocatalyst loss and allows for repeated use.

Large-Area Ultrathin Metal-Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations.

Ultrathin continuous metal-organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic-imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large-area fabrication. Here, we propose a ligand back diffusion-assisted bipolymer-directed metal ion distribution strategy for preparing large-area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross-linked two-dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large-area ultrathin MOF membranes. We report the practical fabrication of three representative defect-free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50-130 nm), including ZIFs and carboxylate-linker MOFs. Among these, the ZIF-8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale-up practicality, MOF membranes were prepared and incorporated into spiral-wound membrane modules with an active area of 4,800 cm2. The ZIF-8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Large‐Area Ultrathin Metal–Organic Framework Membranes Fabricated on Flexible Polymer Supports for Gas Separations

AbstractUltrathin continuous metal–organic framework (MOF) membranes have the potential to achieve high gas permeance and selectivity simultaneously for otherwise difficult gas separations, but with few exceptions for zeolitic‐imidazolate frameworks (ZIF) membranes, current methods cannot conveniently realize practical large‐area fabrication. Here, we propose a ligand back diffusion‐assisted bipolymer‐directed metal ion distribution strategy for preparing large‐area ultrathin MOF membranes on flexible polymeric support layers. The bipolymer directs metal ions to form a cross‐linked two‐dimensional (2D) network with a uniform distribution of metal ions on support layers. Ligand back diffusion controls the feed of ligand molecules available for nuclei formation, resulting in the continuous growth of large‐area ultrathin MOF membranes. We report the practical fabrication of three representative defect‐free MOF membranes with areas larger than 2,400 cm2 and ultrathin selective layers (50–130 nm), including ZIFs and carboxylate‐linker MOFs. Among these, the ZIF‐8 membrane displays high gas permeance of 3,979 GPU for C3H6, with good mixed gas selectivity (43.88 for C3H6/C3H8). To illustrate its scale‐up practicality, MOF membranes were prepared and incorporated into spiral‐wound membrane modules with an active area of 4,800 cm2. The ZIF‐8 membrane module presents high gas permeance (3,930 GPU for C3H6) with acceptable ideal gas selectivity (37.45 for C3H6/C3H8).

Fundamental Origin of Si Surface Defects Caused by Laser Irradiation and Prevention of Suboxide Formation through High Density Ultrathin SiO2

This research investigates surface damage in electronic devices from laser irradiation, particularly focusing on voids, cracks, and vacancies. We discovered that applying a high-density ultrathin SiO2 layer effectively prevents such defects. Atomic Force Microscopy (AFM) analysis showed a significant reduction in surface roughness, with the Rq factor value dropping to 0.158 nm in samples coated with this SiO2 layer. Additionally, X-ray Photoelectron Spectroscopy (XPS) was used to study suboxide formation in the Al2O3/Si structure, revealing insights into defect origins. Electrical tests indicated a substantial decrease in laser-induced damage, evidenced by a leakage current density reduction to 2.4 × 10−6 A/cm2, markedly lower than uncoated samples. Post-metallization annealing (PMA) further improved results, with the interface state density decreasing to 0.63 × 1012 atoms eV−1 cm−2. Our findings highlight the effectiveness of the high-density ultrathin SiO2 layer in mitigating surface defects caused by continuous wave (CW) laser irradiation, promising significant advancements in electronic device manufacturing through potential application in CW laser annealing processes.