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Shams M, Guiney LM, Ramesh M, Hersam MC, Chowdhury I. Effects of sunlight on the fate of graphene oxide and reduced graphene oxide nanomaterials in the natural surface water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162427. [PMID: 36841399 DOI: 10.1016/j.scitotenv.2023.162427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 02/19/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
Graphene nanomaterials have been commercialized for use in the electronic and biomedical industries, increasing their dissemination into surface waters and subsequent transformation in natural aquatic environment. While the photodegradation of graphene oxide nanomaterials has been investigated in the past, previous research did not consider actual natural aquatic environment and also focused on primarily graphene oxide nanomaterials. In this study, photodegradation of graphene nanomaterials with varying oxidation levels, including graphene oxide (GO) and partially reduced graphene oxide (rGO-2 h) are evaluated in Columbia River Water and compared with each other. Our results indicate that both direct and indirect photolysis of graphene-based nanomaterials will occur simultaneously in natural surface water. However, environmentally relevant concentrations of photosensitizers in surface water are not capable of producing sufficient ·OH to initiate degradation of GO via indirect photolysis. For all conditions tested, GO showed more rapid photodegradation compared to rGO. Overall, direct and indirect photodegradation of graphene oxide nanomaterials in natural surface water is minimal and slow indicating that phototransformation of graphene-based nanomaterials will be insignificant in natural surface water.
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Utama MIB, Zeng H, Sadhukhan T, Dasgupta A, Gavin SC, Ananth R, Lebedev D, Wang W, Chen JS, Watanabe K, Taniguchi T, Marks TJ, Ma X, Weiss EA, Schatz GC, Stern NP, Hersam MC. Chemomechanical modification of quantum emission in monolayer WSe 2. Nat Commun 2023; 14:2193. [PMID: 37069140 PMCID: PMC10110606 DOI: 10.1038/s41467-023-37892-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 04/04/2023] [Indexed: 04/19/2023] Open
Abstract
Two-dimensional (2D) materials have attracted attention for quantum information science due to their ability to host single-photon emitters (SPEs). Although the properties of atomically thin materials are highly sensitive to surface modification, chemical functionalization remains unexplored in the design and control of 2D material SPEs. Here, we report a chemomechanical approach to modify SPEs in monolayer WSe2 through the synergistic combination of localized mechanical strain and noncovalent surface functionalization with aryl diazonium chemistry. Following the deposition of an aryl oligomer adlayer, the spectrally complex defect-related emission of strained monolayer WSe2 is simplified into spectrally isolated SPEs with high single-photon purity. Density functional theory calculations reveal energetic alignment between WSe2 defect states and adsorbed aryl oligomer energy levels, thus providing insight into the observed chemomechanically modified quantum emission. By revealing conditions under which chemical functionalization tunes SPEs, this work broadens the parameter space for controlling quantum emission in 2D materials.
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Salanne M, Buriak JM, Chen X, Chueh W, Hersam MC, Schaak RE. Best Practices for Simulations and Calculations of Nanomaterials for Energy Applications: Avoiding "Garbage In, Garbage Out". ACS NANO 2023; 17:6147-6149. [PMID: 37038839 DOI: 10.1021/acsnano.3c02368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
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Buriak JM, Akinwande D, Artzi N, Brinker CJ, Burrows C, Chan WCW, Chen C, Chen X, Chhowalla M, Chi L, Chueh W, Crudden CM, Di Carlo D, Glotzer SC, Hersam MC, Ho D, Hu TY, Huang J, Javey A, Kamat PV, Kim ID, Kotov NA, Lee TR, Lee YH, Li Y, Liz-Marzán LM, Mulvaney P, Narang P, Nordlander P, Oklu R, Parak WJ, Rogach AL, Salanne M, Samorì P, Schaak RE, Schanze KS, Sekitani T, Skrabalak S, Sood AK, Voets IK, Wang S, Wang S, Wee ATS, Ye J. Best Practices for Using AI When Writing Scientific Manuscripts. ACS NANO 2023; 17:4091-4093. [PMID: 36848601 DOI: 10.1021/acsnano.3c01544] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
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Jiang S, Lebedev D, Andrews L, Gish JT, Song TW, Hersam MC, Balogun O. Quantitative Characterization of the Anisotropic Thermal Properties of Encapsulated Two-Dimensional MoS 2 Nanofilms. ACS APPLIED MATERIALS & INTERFACES 2023; 15:10123-10132. [PMID: 36753465 DOI: 10.1021/acsami.2c18755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) semiconductors exhibit unique physical properties at the limit of a few atomic layers that are desirable for optoelectronic, spintronic, and electronic applications. Some of these materials require ambient encapsulation to preserve their properties from environmental degradation. While encapsulating 2D semiconductors is essential to device functionality, they also impact heat management due to the reduced thermal conductivity of the 2D material. There are limited experimental reports on in-plane thermal conductivity measurements in encapsulated 2D semiconductors. These measurements are particularly challenging in ultrathin films with a lower thermal conductivity than graphene since it may be difficult to separate the thermal effects of the sample from the encapsulating layers. To address this challenge, we integrated the frequency domain thermoreflectance (FDTR) and optothermal Raman spectroscopy (OTRS) techniques in the same experimental platform. First, we use the FDTR technique to characterize the cross-plane thermal conductivity and thermal boundary conductance. Next, we measure the in-plane thermal conductivity by model-based analysis of the OTRS measurements, using the cross-plane properties obtained from the FDTR measurements as input parameters. We provide experimental data for the first time on the thickness-dependent in-plane thermal conductivity of ultrathin MoS2 nanofilms encapsulated by alumina (Al2O3) and silica (SiO2) thin films. The measured thermal conductivity increased from 26.0 ± 10.0 W m-1 K-1 for monolayer MoS2 to 39.8 ± 10.8 W m-1 K-1 for the six-layer films. We also show that the thickness-dependent cross-plane thermal boundary conductance of the Al2O3/MoS2/SiO2 interface is limited by the low thermal conductance (18.5 MW m-2 K-1) of the MoS2/SiO2 interface, which has important implications on heat management in SiO2-supported and encased MoS2 devices. The measurement methods can be generalized to other 2D materials to study their anisotropic thermal properties.
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Xu DD, Vong AF, Lebedev D, Ananth R, Wong AM, Brown PT, Hersam MC, Mirkin CA, Weiss EA. Conversion of Classical Light Emission from a Nanoparticle-Strained WSe 2 Monolayer into Quantum Light Emission via Electron Beam Irradiation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2208066. [PMID: 36373540 DOI: 10.1002/adma.202208066] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Solid-state single photon emitters (SPEs) within atomically thin transition metal dichalcogenides (TMDs) have recently attracted interest as scalable quantum light sources for quantum photonic technologies. Among TMDs, WSe2 monolayers (MLs) are promising for the deterministic fabrication and engineering of SPEs using local strain fields. The ability to reliably produce isolatable SPEs in WSe2 is currently impeded by the presence of numerous spectrally overlapping states that occur at strained locations. Here nanoparticle (NP) arrays with precisely defined positions and sizes are employed to deterministically create strain fields in WSe2 MLs, thus enabling the systematic investigation and control of SPE formation. Using this platform, electron beam irradiation at NP-strained locations transforms spectrally overlapped sub-bandgap emission states into isolatable, anti-bunched quantum emitters. The dependence of the emission spectra of WSe2 MLs as a function of strain magnitude and exposure time to electron beam irradiation is quantified and provides insight into the mechanism for SPE production. Excitons selectively funnel through strongly coupled sub-bandgap states introduced by electron beam irradiation, which suppresses spectrally overlapping emission pathways and leads to measurable anti-bunched behavior. The findings provide a strategy to generate isolatable SPEs in 2D materials with a well-defined energy range.
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Gamba L, Johnson ZT, Atterberg J, Diaz-Arauzo S, Downing JR, Claussen JC, Hersam MC, Secor EB. Systematic Design of a Graphene Ink Formulation for Aerosol Jet Printing. ACS APPLIED MATERIALS & INTERFACES 2023; 15:3325-3335. [PMID: 36608034 DOI: 10.1021/acsami.2c18838] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Aerosol jet printing is a noncontact, digital, additive manufacturing technique compatible with a wide variety of functional materials. Although promising, development of new materials and devices using this technique remains hindered by limited rational ink formulation, with most recent studies focused on device demonstration rather than foundational process science. In the present work, a systematic approach to formulating a polymer-stabilized graphene ink is reported, which considers the effect of solvent composition on dispersion, rheology, wetting, drying, and phase separation characteristics that drive process outcomes. It was found that a four-component solvent mixture composed of isobutyl acetate, diglyme, dihydrolevoglucosenone, and glycerol supported efficient ink atomization and controlled in-line drying to reduce overspray and wetting instabilities while maintaining high resolution and electrical conductivity, thus overcoming a trade-off in deposition rate and resolution common to aerosol jet printing. Biochemical sensors were printed for amperometric detection of the pesticide parathion, exhibiting a detection limit of 732 nM and a sensitivity of 34 nA μM-1, demonstrating the viability of this graphene ink for fabricating functional electronic devices.
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Shams M, Mansukhani N, Hersam MC, Bouchard D, Chowdhury I. Environmentally sustainable implementations of two-dimensional nanomaterials. Front Chem 2023; 11:1132233. [PMID: 36936535 PMCID: PMC10020365 DOI: 10.3389/fchem.2023.1132233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 02/14/2023] [Indexed: 03/06/2023] Open
Abstract
Rapid advancement in nanotechnology has led to the development of a myriad of useful nanomaterials that have novel characteristics resulting from their small size and engineered properties. In particular, two-dimensional (2D) materials have become a major focus in material science and chemistry research worldwide with substantial efforts centered on their synthesis, property characterization, and technological, and environmental applications. Environmental applications of these nanomaterials include but are not limited to adsorbents for wastewater and drinking water treatment, membranes for desalination, and coating materials for filtration. However, it is also important to address the environmental interactions and implications of these nanomaterials in order to develop strategies that minimize their environmental and public health risks. Towards this end, this review covers the most recent literature on the environmental implementations of emerging 2D nanomaterials, thereby providing insights into the future of this fast-evolving field including strategies for ensuring sustainable development of 2D nanomaterials.
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Yan X, Qian JH, Sangwan VK, Hersam MC. Progress and Challenges for Memtransistors in Neuromorphic Circuits and Systems. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108025. [PMID: 34813677 DOI: 10.1002/adma.202108025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Due to the increasing importance of artificial intelligence (AI), significant recent effort has been devoted to the development of neuromorphic circuits that seek to emulate the energy-efficient information processing of the brain. While non-volatile memory (NVM) based on resistive switches, phase-change memory, and magnetic tunnel junctions has shown potential for implementing neural networks, additional multi-terminal device concepts are required for more sophisticated bio-realistic functions. Of particular interest are memtransistors based on low-dimensional nanomaterials, which are capable of electrostatically tuning memory and learning behavior at the device level. Herein, a conceptual overview of the memtransistor is provided in the context of neuromorphic circuits. Recent progress is surveyed for memtransistors and related multi-terminal NVM devices including dual-gated floating-gate memories, dual-gated ferroelectric transistors, and dual-gated van der Waals heterojunctions. The different materials systems and device architectures are classified based on the degree of control and relative tunability of synaptic behavior, with an emphasis on device concepts that harness the reduced dimensionality, weak electrostatic screening, and phase-changes properties of nanomaterials. Finally, strategies for achieving wafer-scale integration of memtransistors and multi-terminal NVM devices are delineated, with specific attention given to the materials challenges for practical neuromorphic circuits.
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Kuo L, Luijten BJ, Li S, de Moraes ACM, Silvaroli AJ, Wallace SG, Hui J, Downing JR, Shull KR, Hersam MC. Sterilizable and Reusable UV-Resistant Graphene-Polyurethane Elastomer Composites. ACS APPLIED MATERIALS & INTERFACES 2022; 14:53241-53249. [PMID: 36394995 DOI: 10.1021/acsami.2c17791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Shortages of personal protective equipment (PPE) at the start of the COVID-19 pandemic caused medical workers to reuse medical supplies such as N95 masks. While ultraviolet germicidal irradiation (UVGI) is commonly used for sterilization, UVGI can also damage the elastomeric components of N95 masks, preventing effective fit and thus weakening filtration efficacy. Although PPE shortage is no longer an acute issue, the development of sterilizable and reusable UV-resistant elastomers remains of high interest from a long-term sustainability and health perspective. Here, graphene nanosheets, produced by scalable and sustainable exfoliation of graphite in ethanol using the polymer ethyl cellulose (EC), are utilized as UV-resistant additives in polyurethane (PU) elastomer composites. By increasing the graphene/EC loading up to 1 wt %, substantial UV protection is imparted by the graphene nanosheets, which strongly absorb UV light and hence suppress photoinduced degradation of the PU matrix. Additionally, graphene/EC provides mechanical reinforcement, such as increasing Young's modulus, elongation at break, and toughness, with negligible changes following UV exposure. These graphene/EC-PU composites remain mechanically robust over at least 150 sterilization cycles, enabling safe reuse following UVGI. Beyond N95 masks, these UVGI-compatible graphene/EC-PU composites have potential utility in other PPE applications to address the broader issue of single-use waste.
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Franklin AD, Hersam MC, Wong HSP. Carbon nanotube transistors: Making electronics from molecules. Science 2022; 378:726-732. [DOI: 10.1126/science.abp8278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Semiconducting carbon nanotubes are robust molecules with nanometer-scale diameters that can be used in field-effect transistors, from larger thin-film implementation to devices that work in conjunction with silicon electronics, and can potentially be used as a platform for high-performance digital electronics as well as radio-frequency and sensing applications. Recent progress in the materials, devices, and technologies related to carbon nanotube transistors is briefly reviewed. Emphasis is placed on the most broadly impactful advancements that have evolved from single-nanotube devices to implementations with aligned nanotubes and even nanotube thin films. There are obstacles that remain to be addressed, including material synthesis and processing control, device structure design and transport considerations, and further integration demonstrations with improved reproducibility and reliability; however, the integration of more than 10,000 devices in single functional chips has already been realized.
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Chen JS, Dasgupta A, Morrow DJ, Emmanuele R, Marks TJ, Hersam MC, Ma X. Room Temperature Lasing from Semiconducting Single-Walled Carbon Nanotubes. ACS NANO 2022; 16:16776-16783. [PMID: 36121213 DOI: 10.1021/acsnano.2c06419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Miniaturized near-infrared semiconductor lasers that are able to generate coherent light with low energy consumption have widespread applications in fields such as optical interconnects, neuromorphic computing, and deep-tissue optogenetics. With optical transitions at near-infrared wavelengths, diameter-tunable electronic structures, and superlative optoelectronic properties, semiconducting single-walled carbon nanotubes (SWCNTs) are promising candidates for nanolaser applications. However, despite significant efforts in this direction and recent progress toward enhancing spontaneous emission from SWCNTs through Purcell effects, SWCNT-based excitonic lasers have not yet been demonstrated. Leveraging an optimized cavity-emitter integration scheme enabled by a self-assembly process, here we couple SWCNT emission to the whispering gallery modes supported by polymer microspheres, resulting in room temperature excitonic lasing with an average lasing threshold of 4.5 kW/cm2. The high photostability of SWCNTs allows stable lasing for prolonged duration with minimal degradation. This experimental realization of excitonic lasing from SWCNTs, combined with their versatile electronic and optical properties that can be further controlled by chemical modification, offers far-reaching opportunities for tunable near-infrared nanolasers that are applicable for optical signal processing, in vivo biosensing, and optoelectronic devices.
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Murthy AA, Masih Das P, Ribet SM, Kopas C, Lee J, Reagor MJ, Zhou L, Kramer MJ, Hersam MC, Checchin M, Grassellino A, Reis RD, Dravid VP, Romanenko A. Developing a Chemical and Structural Understanding of the Surface Oxide in a Niobium Superconducting Qubit. ACS NANO 2022; 16:17257-17262. [PMID: 36153944 DOI: 10.1021/acsnano.2c07913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Superconducting thin films of niobium have been extensively employed in transmon qubit architectures. Although these architectures have demonstrated improvements in recent years, further improvements in performance through materials engineering will aid in large-scale deployment. Here, we use information retrieved from secondary ion mass spectrometry and electron microscopy to conduct a detailed assessment of the surface oxide that forms in ambient conditions for transmon test qubit devices patterned from a niobium film. We observe that this oxide exhibits a varying stoichiometry with NbO and NbO2 found closer to the niobium film/oxide interface and Nb2O5 found closer to the surface. In terms of structural analysis, we find that the Nb2O5 region is semicrystalline in nature and exhibits randomly oriented grains on the order of 1-3 nm corresponding to monoclinic N-Nb2O5 that are dispersed throughout an amorphous matrix. Using fluctuation electron microscopy, we are able to map the relative crystallinity in the Nb2O5 region with nanometer spatial resolution. Through this correlative method, we observe that the highly disordered regions are more likely to contain oxygen vacancies and exhibit weaker bonds between the niobium and oxygen atoms. Based on these findings, we expect that oxygen vacancies likely serve as a decoherence mechanism in quantum systems.
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Schwinn MC, Rafiq S, Lee C, Bland MP, Song TW, Sangwan VK, Hersam MC, Chen LX. Charge Transfer Dynamics and Interlayer Exciton Formation in MoS2/VOPc Mixed Dimensional Heterojunction. J Chem Phys 2022; 157:184701. [DOI: 10.1063/5.0107791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mixed-dimensional van der Waals heterojunctions involve interfacing materials with different dimensionalities, such as a 2D transition metal dichalcogenide (TMD) and a 0D organic semiconductor. These heterojunctions have shown unique interfacial properties not found in either individual components. Here, we use femtosecond transient absorption to reveal photoinduced charge transfer and interlayer exciton formation in a mixed-dimensional heterojunction between monolayer MoS2 and vanadyl phthalocyanine (VOPc). We find that hole transfer occurs from the MoS2 valence band to VOPc in ~710 fs, while electron transfer occurs from VOPc excited state to MoS2 conduction band in less than 100 fs. This ultrafast electron or hole transfer results in the formation of an interlayer exciton across the interface. Additionally, we observe the emergence of a new absorption band that is formed only in the heterojunction and assign it to the formation of delocalized hybrid states between the VOPc and MoS2 layers. By directly exciting this band, an interlayer exciton forms that is not limited by electron or hole transfer times. These interlayer excitons across the interface lead to longer-lived charge-separated states of up to 2.5 ns, longer than in each individual layer of this heterojunction. Thus, the longer charge-separated state along with ultrafast charge transfer times provide promising results for photovoltaic and optoelectronic device applications.
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Kuo L, Sangwan VK, Rangnekar SV, Chu TC, Lam D, Zhu Z, Richter LJ, Li R, Szydłowska BM, Downing JR, Luijten BJ, Lauhon LJ, Hersam MC. All-Printed Ultrahigh-Responsivity MoS 2 Nanosheet Photodetectors Enabled by Megasonic Exfoliation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2203772. [PMID: 35788996 DOI: 10.1002/adma.202203772] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Printed 2D materials, derived from solution-processed inks, offer scalable and cost-effective routes to mechanically flexible optoelectronics. With micrometer-scale control and broad processing latitude, aerosol-jet printing (AJP) is of particular interest for all-printed circuits and systems. Here, AJP is utilized to achieve ultrahigh-responsivity photodetectors consisting of well-aligned, percolating networks of semiconducting MoS2 nanosheets and graphene electrodes on flexible polyimide substrates. Ultrathin (≈1.2 nm thick) and high-aspect-ratio (≈1 μm lateral size) MoS2 nanosheets are obtained by electrochemical intercalation followed by megasonic atomization during AJP, which not only aerosolizes the inks but also further exfoliates the nanosheets. The incorporation of the high-boiling-point solvent terpineol into the MoS2 ink is critical for achieving a highly aligned and flat thin-film morphology following AJP as confirmed by grazing-incidence wide-angle X-ray scattering and atomic force microscopy. Following AJP, curing is achieved with photonic annealing, which yields quasi-ohmic contacts and photoactive channels with responsivities exceeding 103 A W-1 that outperform previously reported all-printed visible-light photodetectors by over three orders of magnitude. Megasonic exfoliation coupled with properly designed AJP ink formulations enables the superlative optoelectronic properties of ultrathin MoS2 nanosheets to be preserved and exploited for the scalable additive manufacturing of mechanically flexible optoelectronics.
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Lam D, Lebedev D, Kuo L, Sangwan VK, Szydłowska BM, Ferraresi F, Söll A, Sofer Z, Hersam MC. Liquid-Phase Exfoliation of Magnetically and Optoelectronically Active Ruthenium Trichloride Nanosheets. ACS NANO 2022; 16:11315-11324. [PMID: 35714054 DOI: 10.1021/acsnano.2c04888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
α-RuCl3 is a layered transition metal halide that possesses a range of exotic magnetic, optical, and electronic properties including fractional excitations indicative of a proximate Kitaev quantum spin liquid (QSL). While previous reports have explored these properties on idealized single crystals or mechanically exfoliated samples, the scalable production of α-RuCl3 nanosheets has not yet been demonstrated. Here, we perform liquid-phase exfoliation (LPE) of α-RuCl3 through an electrochemically assisted approach, which yields ultrathin, electron-doped α-RuCl3 nanosheets that are then assembled into electrically conductive large-area thin films. The crystalline integrity of the α-RuCl3 nanosheets following LPE is confirmed through a wide range of structural and chemical analyses. Moreover, the physical properties of the LPE α-RuCl3 nanosheets are investigated through electrical, optical, and magnetic characterization methods, which reveal a structural phase transition at 230 K that is consistent with the onset of Kitaev paramagnetism in addition to an antiferromagnetic transition at 2.6 K. Intercalated ions from the electrochemical LPE protocol favorably alter the optical response of the α-RuCl3 nanosheets, enabling large-area Mott insulator photodetectors that operate at telecommunications-relevant infrared wavelengths near 1.55 μm. These photodetectors show a linear photocurrent response as a function of incident power, which suggests negligible trap-mediated recombination or photothermal effects, ultimately resulting in a photoresponsivity of ≈2 mA/W.
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Hyun WJ, Thomas CM, Chaney LE, Mazarin de Moraes AC, Hersam MC. Screen-Printable Hexagonal Boron Nitride Ionogel Electrolytes for Mechanically Deformable Solid-State Lithium-Ion Batteries. NANO LETTERS 2022; 22:5372-5378. [PMID: 35727221 DOI: 10.1021/acs.nanolett.2c01364] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Ionogel electrolytes present several benefits for solid-state lithium-ion batteries including nonflammability, favorable electrochemical properties, and high thermal stability. However, limited processing methods are currently available for ionogel electrolytes, restricting their practical applications. Here, we present a screen-printable ionogel electrolyte formulation based on hexagonal boron nitride (hBN) nanoplatelets. To achieve screen-printable rheological properties, hBN nanoplatelets are mixed with an imidazolium ionic liquid in ethyl lactate. Following screen printing, the resulting spatially uniform and mechanically flexible hBN ionogel electrolytes achieve high room-temperature ionic conductivities >1 mS cm-1 and stiff mechanical moduli >1 MPa. These hBN ionogel electrolytes enable the fabrication of fully screen-printed lithium-ion batteries with high cycling stability, rate performance, and mechanical resilience against flexion and external forces, thus providing a robust energy storage solution that is compatible with scalable additive manufacturing.
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Pola CC, Rangnekar SV, Sheets R, Szydlowska BM, Downing JR, Parate KW, Wallace SG, Tsai D, Hersam MC, Gomes CL, Claussen JC. Aerosol-jet-printed graphene electrochemical immunosensors for rapid and label-free detection of SARS-CoV-2 in saliva. 2D MATERIALS 2022; 9:035016. [PMID: 35785019 PMCID: PMC9245948 DOI: 10.1088/2053-1583/ac7339] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Rapid, inexpensive, and easy-to-use coronavirus disease 2019 (COVID-19) home tests are key tools in addition to vaccines in the world-wide fight to eliminate national and local shutdowns. However, currently available tests for SARS-CoV-2, the virus that causes COVID-19, are too expensive, painful, and irritating, or not sufficiently sensitive for routine, accurate home testing. Herein, we employ custom-formulated graphene inks and aerosol jet printing (AJP) to create a rapid electrochemical immunosensor for direct detection of SARS-CoV-2 Spike Receptor-Binding Domain (RBD) in saliva samples acquired non-invasively. This sensor demonstrated limits of detection that are considerably lower than most commercial SARS-CoV-2 antigen tests (22.91 ± 4.72 pg/mL for Spike RBD and 110.38 ± 9.00 pg/mL for Spike S1) as well as fast response time (~30 mins), which was facilitated by the functionalization of printed graphene electrodes in a single-step with SARS-CoV-2 polyclonal antibody through the carbodiimide reaction without the need for nanoparticle functionalization or secondary antibody or metallic nanoparticle labels. This immunosensor presents a wide linear sensing range from 1 to 1000 ng/mL and does not react with other coexisting influenza viruses such as H1N1 hemagglutinin. By combining high-yield graphene ink synthesis, automated printing, high antigen selectivity, and rapid testing capability, this work offers a promising alternative to current SARS-CoV-2 antigen tests.
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Abstract
Layered van der Waals (vdW) materials have attracted significant attention due to their materials properties that can enhance diverse applications including next-generation computing, biomedical devices, and energy conversion and storage technologies. This class of materials is typically studied in the two-dimensional (2D) limit by growing them directly on bulk substrates or exfoliating them from parent layered crystals to obtain single or few layers that preserve the original bonding. However, these vdW materials can also function as a platform for obtaining additional phases of matter at the nanoscale. Here, we introduce and review a synthesis paradigm, morphotaxy, where low-dimensional materials are realized by using the shape of an initial nanoscale precursor to template growth or chemical conversion. Using morphotaxy, diverse non-vdW materials such as HfO2 or InF3 can be synthesized in ultrathin form by changing the composition but preserving the shape of the original 2D layered material. Morphotaxy can also enable diverse atomically precise heterojunctions and other exotic structures such as Janus materials. Using this morphotaxial approach, the family of low-dimensional materials can be substantially expanded, thus creating vast possibilities for future fundamental studies and applied technologies.
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Schwenker E, Kolluru VSC, Guo J, Zhang R, Hu X, Li Q, Paul JT, Hersam MC, Dravid VP, Klie R, Guest JR, Chan MKY. Ingrained: An Automated Framework for Fusing Atomic-Scale Image Simulations into Experiments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2102960. [PMID: 35384282 DOI: 10.1002/smll.202102960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/20/2021] [Indexed: 06/14/2023]
Abstract
To fully leverage the power of image simulation to corroborate and explain patterns and structures in atomic resolution microscopy, an initial correspondence between the simulation and experimental image must be established at the outset of further high accuracy simulations or calculations. Furthermore, if simulation is to be used in context of highly automated processes or high-throughput optimization, the process of finding this correspondence itself must be automated. In this work, "ingrained," an open-source automation framework which solves for this correspondence and fuses atomic resolution image simulations into the experimental images to which they correspond, is introduced. Herein, the overall "ingrained" workflow, focusing on its application to interface structure approximations, and the development of an experimentally rationalized forward model for scanning tunneling microscopy simulation are described.
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Kotov NA, Akinwande D, Brinker CJ, Buriak JM, Chan WCW, Chen X, Chhowalla M, Chueh W, Glotzer SC, Gogotsi Y, Hersam MC, Ho D, Hu T, Javey A, Kagan CR, Kataoka K, Kim ID, Lee ST, Lee YH, Liz-Marzán LM, Millstone JE, Mulvaney P, Nel AE, Nordlander P, Parak WJ, Penner RM, Rogach AL, Salanne M, Schaak RE, Sood AK, Stevens M, Tsukruk V, Wee ATS, Voets I, Weil T, Weiss PS. Tanks and Truth. ACS NANO 2022; 16:4975-4976. [PMID: 35315638 DOI: 10.1021/acsnano.2c02602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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Eckdahl CT, Ou C, Padgaonkar S, Hersam MC, Weiss EA, Kalow JA. Back electron transfer rates determine the photoreactivity of donor-acceptor stilbene complexes in a macrocyclic host. Org Biomol Chem 2022; 20:6201-6210. [PMID: 35419576 DOI: 10.1039/d2ob00472k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Host-guest 2 : 1 complexation of photoreactive alkene guests improves the selectivity of [2 + 2] photodimerizations by templating alkene orientation prior to irradiation. Host-guest chemistry can also provide 1 : 1 : 1 complexes through the inclusion of electronically complementary donor and acceptor guests, but the photoreactivity of such complexes has not been investigated. We imagined that such complexes could enable selective cross-[2 + 2] photocycloadditions between donor and acceptor stilbenes. In pursuit of this strategy, we investigated a series of stilbenes and found 1 : 1 : 1 complexes with cucurbit[8]uril that exhibited charge-transfer (CT) absorption bands in the visible and near-IR regions. Irradiation of the CT band of an azastilbene, 4,4'-stilbenedicarboxylate, and cucurbit[8]uril ternary complex led to a selective cross-[2 + 2] photocycloaddition, while other substrate pairs exhibited no productive chemistry upon CT excitation. Using transient absorption spectroscopy, we were able to understand the variable photoreactivity of different stilbene donor-acceptor complexes. We found that back electron transfer following CT excitation of the photoreactive complex is positioned deep in the Marcus inverted region due to electrostatic stabilization of the ground state, allowing [2 + 2] to effectively compete with this relaxation pathway. Control reactions revealed that the cucurbit[8]uril host not only serves to template the reaction from the ground state, but also protects the long-lived radical ions formed by CT from side reactions. This protective role of the host suggests that donor-acceptor host-guest ternary complexes could be used to improve existing CT-initiated photochemistry or access new reactivity.
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Liu X, Rahn MS, Ruan Q, Yakobson BI, Hersam MC. Probing borophene oxidation at the atomic scale. NANOTECHNOLOGY 2022; 33:235702. [PMID: 35180715 DOI: 10.1088/1361-6528/ac56bd] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/18/2022] [Indexed: 06/14/2023]
Abstract
Two-dimensional boron (i.e. borophene) holds promise for a variety of emerging nanoelectronic and quantum technologies. Since borophene is synthesized under ultrahigh vacuum (UHV) conditions, it is critical that the chemical stability and structural integrity of borophene in oxidizing environments are understood for practical borophene-based applications. In this work, we assess the mechanism of borophene oxidation upon controlled exposure to air and molecular oxygen in UHV via scanning tunneling microscopy andspectroscopy, x-ray photoelectron spectroscopy, and density functional theory calculations. While borophene catastrophically degrades almost instantaneously upon exposure to air, borophene undergoes considerably more controlled oxidation when exposed to molecular oxygen in UHV. In particular, UHV molecular oxygen dosing results in single-atom covalent modification of the borophene basal plane in addition to disordered borophene edge oxidation that shows altered electronic characteristics. By comparing these experimental observations with density functional theory calculations, further atomistic insight is gained including pathways for molecular oxygen dissociation, surface diffusion, and chemisorption to borophene. Overall, this study provides an atomic-scale perspective of borophene oxidation that will inform ongoing efforts to passivate and utilize borophene in ambient conditions.
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Tafoya RR, Gallegos MA, Downing JR, Gamba L, Kaehr B, Coker EN, Hersam MC, Secor EB. Morphology and electrical properties of high-speed flexography-printed graphene. Mikrochim Acta 2022; 189:123. [DOI: 10.1007/s00604-022-05232-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 02/15/2022] [Indexed: 10/19/2022]
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Kim SM, Kim S, Ling L, Liu SE, Jin S, Jung YM, Kim M, Park HH, Sangwan VK, Hersam MC, Lee HS. Linear and Symmetric Li-Based Composite Memristors for Efficient Supervised Learning. ACS APPLIED MATERIALS & INTERFACES 2022; 14:5673-5681. [PMID: 35043617 DOI: 10.1021/acsami.1c24562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Emerging energy-efficient neuromorphic circuits are based on hardware implementation of artificial neural networks (ANNs) that employ the biomimetic functions of memristors. Specifically, crossbar array memristive architectures are able to perform ANN vector-matrix multiplication more efficiently than conventional CMOS hardware. Memristors with specific characteristics, such as ohmic behavior in all resistance states in addition to symmetric and linear long-term potentiation/depression (LTP/LTD), are required in order to fully realize these benefits. Here, we demonstrate a Li-based composite memristor (LCM) that achieves these objectives. The LCM consists of three phases: Li-doped TiO2 as a Li reservoir, Li4Ti5O12 as the insulating phase, and Li7Ti5O12 as the metallic phase, where resistive switching correlates with the change in the relative fraction of the metallic and insulating phases. The LCM exhibits a symmetric and gradual resistive switching behavior for both set and reset operations during a full bias sweep cycle. This symmetric and linear weight update is uniquely enabled by the symmetric bidirectional migration of Li ions, which leads to gradual changes in the relative fraction of the metallic phase in the film. The optimized LCM in ANN simulation showed that exceptionally high accuracy in image classification is realized in fewer training steps compared to the nonlinear behavior of conventional memristors.
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