Wafer-Scale Lateral Self-Assembly of Mosaic Ti3C2Tx MXene Monolayer Films

Mojtabavi, Mehrnaz; VahidMohammadi, Armin; Ganeshan, Karthik; Hejazi, Davoud; Shahbazmohamadi, Sina; Kar, Swastik; Duin, Adri C. T. van; Wanunu, Meni

doi:10.1021/acsnano.0c06393

Cited by 59 publications

(35 citation statements)

References 65 publications

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“…[16,17] Few-layer free-standing MXene membranes (films) were assembled and transferred onto silicon chips, each hosting a 30-nm-thick SiN x membrane at its center with a pre-fabricated ≈100 nm aperture, which we have previously developed. [18] Then, following drilling nanopores in the free-standing MXene membrane (the part suspended on the aperture) using a focused electron beam of TEM or STEM, these chips were used in nanopore experiments as we previously reported (see the experimental section for details). [2] Figure 1a shows a schematic of the nanopore experimental setup used in this study.…”

Section: Resultsmentioning

confidence: 99%

“…The 16-layer film was deposited by successive repetition of a monolayer MXene self-assembly method we recently developed. [18] Due to the resolution limit and thermal drift in the AFM measurement, thinner MXene films were not compatible with this method. The 16-layer MXene was selected to ensure the amount of deformation is large enough to overcome the thermal drift.…”

Section: Resultsmentioning

confidence: 99%

“…MXene Nanopore Device Fabrication: To fabricate free-standing MXene membranes, the previously developed lateral interfacial self-assembly method was used. [2,18] In short, an aqueous MXene dispersion was diluted to the desired concentration and then mixed with methanol in a 1:8 volume ratio (1 part methanol), followed by casting on a chloroform bath in a petri dish. Then, a 5 × 5 mm 2 Si/SiO 2 /SiN x chip hosting 50 nm free-standing SiN x membrane with a pre-fabricated ≈100 nm aperture was submerged in the bath and lifted through the droplet and baked on a hot plate at 80°C for about 5 min to dry.…”

Section: Methodsmentioning

confidence: 99%

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Ionically Active MXene Nanopore Actuators

Mojtabavi

Tsai

VahidMohammadi

et al. 2022

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such as oxygen, hydroxyl, and fluorine bound to the transition metal on the basal plane of the MXenes, and n = 1, 2, 3, or 4. [3] An intriguing property of MXenes (e.g., Ti 3 C 2 T x , Ti 2 CT x , and V 2 CT x ) is that protons and different cations (Li + , Na + , Mg 2+ , etc.) can electrochemically (and chemically) intercalate into the interlayer space between individual MXene flakes. [3] This property has enabled the use of MXenes as electrodes in electrochemical energy storage devices such as batteries [4] and supercapacitors; [5,6] tuning MXene films' electronic, [7] optoelectronic [8] and gas sensing properties; [9] and other exciting applications such as electrochemical actuation. [10,11] In most cases, the improved properties and functionality of MXenes as a result of cation intercalation are due to the accompanying change in their interlayer spacing, as well as charge transfer between the cations and the MXene's outer layer transition metal. [8,9,12] To gain more insights and enable tuning and implementing this property of MXenes for different applications, dynamics of cation intercalation between MXene layers have been extensively studied in the past couple of years. Through using various methods such as electrochemical quartz-crystal admittance (EQCA), [13] electrochemical dilatometry, [14] in situ X-ray diffraction (XRD), [5] and electrochemical atomic force micro scopy (AFM) [10] it was shown that upon intercalation of cations into thick multilayered MXene electrodes (films), a significant and reversible volume change (expansion or contraction based on the cation charge density and size) occurs. [14] However, less attention has been given to ion intercalation Reversible electrochemical intercalation of cations into the interlayer space of 2D materials induces tunable physical and chemical properties in them. In MXenes, a large class of recently developed 2D carbides and nitrides, low intercalation energy, high storage capacitance, and reversible intercalation of various cations have led to their improved performance in sensing and energy storage applications. Herein, a coupled nanopore-actuator system where an ultrathin free-standing MXene film serves as a nanopore support membrane and ionically active actuator is reported. In this system, the contactless MXene membrane in the electric field affects the cation movement in the field through their (de)intercalation between individual MXene flakes. This results in reversible swelling and contraction of the membrane monitored by ionic conductance through the nanopore. This unique nanopore coupled to a mechanical actuation system could provide new insights into designing single-molecule biosensing platforms at the nanoscale.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Ionically Active MXene Nanopore Actuators

Mojtabavi

Tsai

VahidMohammadi

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“…[ 19 ] This charge enables various thin‐film processing techniques for device fabrication, such as layer‐by‐layer (LbL) self‐assembly [ 33 ] or interfacial assembly on a wafer scale. [ 34 ] To leverage the inherent charge of Ti 3 C 2 T x , we used an LbL self‐assembly process that we developed previously to form multilayered MXene films. [ 33 ] We chose LbL assembly because this versatile technique allows precise control over the number of bilayers, denoted n , where each bilayer consists of only a few/single flakes of coplanar Ti 3 C 2 T x .…”

Section: Resultsmentioning

confidence: 99%

High‐Speed Ionic Synaptic Memory Based on 2D Titanium Carbide MXene

Melianas

Kang

VahidMohammadi

et al. 2021

Adv Funct Materials

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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.

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“…Moreover, controlled structural organization of NCs can also leverage the strongly anisotropic properties of many NCs, including biomimetics, 2D systems including elemental single-layer materials, di-and tri-metal chalcogenides, and few-layer structures, 1D systems such as nanowires, nanorods, and nanotubes, and 0D structures like colloidal quantum dots and carbon nanodots. [1][2][3][4][5][6][7][8][9] Due to their enhanced functionality and physical properties along one axis, 1D NC systems have become a notable focal point for nanoscale structural ordering. Among 1D systems, singlewall carbon nanotubes (SWCNTs) stand out for their unique and exceptional physical and chemical properties, which are typically realized in ensembles through nanotube individualization via surfactants or DNA wrapping.…”

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confidence: 99%

Dependence of Single‐Wall Carbon Nanotube Alignment on the Filter Membrane Interface in Slow Vacuum Filtration

Walker

Macdermid

Fagan

et al. 2022

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strategies to structurally engineer NCs into ordered ensembles. These bottomup methods minimize disorder and inter-particle energies, which can lead to NC-based superstructures that either have properties that are close to their individualized constituents or exhibit behaviors that are distinctly different. Moreover, controlled structural organization of NCs can also leverage the strongly anisotropic properties of many NCs, including biomimetics, 2D systems including elemental single-layer materials, di-and tri-metal chalcogenides, and few-layer structures, 1D systems such as nanowires, nanorods, and nanotubes, and 0D structures like colloidal quantum dots and carbon nanodots. [1][2][3][4][5][6][7][8][9] Due to their enhanced functionality and physical properties along one axis, 1D NC systems have become a notable focal point for nanoscale structural ordering. Among 1D systems, singlewall carbon nanotubes (SWCNTs) stand out for their unique and exceptional physical and chemical properties, which are typically realized in ensembles through nanotube individualization via surfactants or DNA wrapping. In addition to chirality enrichment, [10][11][12][13] length sorting, [14] handedness selectivity, [15,16] and elemental/molecular insertions, [17][18][19][20][21] aligning SWCNTs on a common axis has enabled researchers to uncover physically rich phenomena at macroscopic scales, such as ultrastrong light-matter coupling, [22][23][24] intersubband plasmons, [25] electric and thermal photoemission, [26,27] terahertz radiation generation, [28,29] and metamaterial physics. [30][31][32] The need for accessible, high-yield, low-cost, facile methods for chemically sorting and physically positioning SWCNTs with identical properties remains the most significant hurdle for the use of nanotubes in high-performance optical, electronic, and mechanical systems.Several techniques for aligning SWCNT ensembles have been used over the past three decades, such as electrical orientation, magnetic orientation, shear strain, oriented growth, templating, inverse dose-controlled, floating evaporative self assembly, and 2D nematic tangential flow interfacial selfassembly. [33][34][35][36][37][38][39][40][41][42][43] Despite the success of several of these methods, nearly all of these protocols cannot be integrated with solution-based chemical processes for chiral enhancement, length sorting, and molecular insertion, which has greatly limited their applicability to fundamental studies and technological integration. Recently, the development of slow vacuum filtration (SVF)The recent introduction of slow vacuum filtration (SVF) technology has shown great promise for reproducibly creating high-quality, large-area aligned films of single-wall carbon nanotubes (SWCNTs) from solution-based dispersions. Despite clear advantages over other SWCNT alignment techniques, SVF remains in the developmental stages due to a lack of an agreed-upon alignment mechanism, a hurdle which hinders SVF optimization. In this work, the filter membrane surface is modified ...

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Wafer-Scale Lateral Self-Assembly of Mosaic Ti₃C₂T_x MXene Monolayer Films

Cited by 59 publications

References 65 publications

Ionically Active MXene Nanopore Actuators

Ionically Active MXene Nanopore Actuators

High‐Speed Ionic Synaptic Memory Based on 2D Titanium Carbide MXene

Dependence of Single‐Wall Carbon Nanotube Alignment on the Filter Membrane Interface in Slow Vacuum Filtration

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