201
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Jang H, Wood JD, Ryder CR, Hersam MC, Cahill DG. Anisotropic Thermal Conductivity of Exfoliated Black Phosphorus. Adv Mater 2015; 27:8017-22. [PMID: 26516073 DOI: 10.1002/adma.201503466] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/16/2015] [Indexed: 05/21/2023]
Abstract
The anisotropic thermal conductivity of passivated black phosphorus (BP), a reactive two-dimensional material with strong in-plane anisotropy, is ascertained. The room-temperature thermal conductivity for three crystalline axes of exfoliated BP is measured by time-domain thermo-reflectance. The thermal conductivity along the zigzag direction is ≈2.5 times higher than that of the armchair direction.
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Affiliation(s)
- Hyejin Jang
- Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana, IL, 61801, USA
| | - Joshua D Wood
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Christopher R Ryder
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Chemistry, Department of Medicine, Northwestern University, Evanston, IL, 60208, USA
| | - David G Cahill
- Department of Materials Science and Engineering and Materials Research Laboratory, University of Illinois, Urbana, IL, 61801, USA
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202
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Chan WWC, Glotzer S, Gogotsi Y, Hafner JH, Hammond PT, Hersam MC, Javey A, Kagan CR, Khademhosseini A, Kotov NA, Lee ST, Möhwald H, Mulvaney PA, Nel AE, Nordlander PJ, Parak WJ, Penner RM, Rogach AL, Schaak RE, Stevens MM, Wee ATS, Willson CG, Tierney HL, Weiss PS. Grand Plans for Nano. ACS Nano 2015; 9:11503-11505. [PMID: 26689337 DOI: 10.1021/acsnano.5b07280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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203
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McMorrow JJ, Walker AR, Sangwan VK, Jariwala D, Hoffman E, Everaerts K, Facchetti A, Hersam MC, Marks TJ. Solution-Processed Self-Assembled Nanodielectrics on Template-Stripped Metal Substrates. ACS Appl Mater Interfaces 2015; 7:26360-26366. [PMID: 26479833 DOI: 10.1021/acsami.5b07744] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The coupling of hybrid organic-inorganic gate dielectrics with emergent unconventional semiconductors has yielded transistor devices exhibiting record-setting transport properties. However, extensive electronic transport measurements on these high-capacitance systems are often convoluted with the electronic response of the semiconducting silicon substrate. In this report, we demonstrate the growth of solution-processed zirconia self-assembled nanodielectrics (Zr-SAND) on template-stripped aluminum substrates. The resulting Zr-SAND on Al structures leverage the ultrasmooth (r.m.s. roughness <0.4 nm), chemically uniform nature of template-stripped metal substrates to demonstrate the same exceptional electronic uniformity (capacitance ∼700 nF cm(-2), leakage current <1 μA cm(-2) at -2 MV cm(-1)) and multilayer growth of Zr-SAND on Si, while exhibiting superior temperature and voltage capacitance responses. These results are important to conduct detailed transport measurements in emergent transistor technologies featuring SAND as well as for future applications in integrated circuits or flexible electronics.
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Affiliation(s)
| | | | | | | | | | | | - Antonio Facchetti
- Polyera Corporation , 8045 Lamon Avenue, Skokie, Illinois 60077, United States
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204
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Hyun WJ, Secor EB, Rojas GA, Hersam MC, Francis LF, Frisbie CD. All-Printed, Foldable Organic Thin-Film Transistors on Glassine Paper. Adv Mater 2015; 27:7058-7064. [PMID: 26439306 DOI: 10.1002/adma.201503478] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 08/28/2015] [Indexed: 06/05/2023]
Abstract
All-printed, foldable organic thin-film transistors are demonstrated on glassine paper with a combination of advanced materials and processing techniques. Glassine paper provides a suitable surface for high-performance printing methods, while graphene electrodes and an ion-gel gate dielectric enable robust stability over 100 folding cycles. Altogether, this study features a practical platform for low-cost, large-area, and foldable electronics.
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Affiliation(s)
- Woo Jin Hyun
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455, USA
| | - Ethan B Secor
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Geoffrey A Rojas
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
- Department of Chemistry, Department of Medicine, Evanston, IL, 60208, USA
| | - Lorraine F Francis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455, USA
| | - C Daniel Frisbie
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, MN, 55455, USA
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205
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Kiraly B, Jacobberger RM, Mannix AJ, Campbell GP, Bedzyk MJ, Arnold MS, Hersam MC, Guisinger NP. Electronic and Mechanical Properties of Graphene-Germanium Interfaces Grown by Chemical Vapor Deposition. Nano Lett 2015; 15:7414-7420. [PMID: 26506006 DOI: 10.1021/acs.nanolett.5b02833] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Epitaxially oriented wafer-scale graphene grown directly on semiconducting Ge substrates is of high interest for both fundamental science and electronic device applications. To date, however, this material system remains relatively unexplored structurally and electronically, particularly at the atomic scale. To further understand the nature of the interface between graphene and Ge, we utilize ultrahigh vacuum scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) along with Raman and X-ray photoelectron spectroscopy to probe interfacial atomic structure and chemistry. STS reveals significant differences in electronic interactions between graphene and Ge(110)/Ge(111), which is consistent with a model of stronger interaction on Ge(110) leading to epitaxial growth. Raman spectra indicate that the graphene is considerably strained after growth, with more point-to-point variation on Ge(111). Furthermore, this native strain influences the atomic structure of the interface by inducing metastable and previously unobserved Ge surface reconstructions following annealing. These nonequilibrium reconstructions cover >90% of the surface and, in turn, modify both the electronic and mechanical properties of the graphene overlayer. Finally, graphene on Ge(001) represents the extreme strain case, where graphene drives the reorganization of the Ge surface into [107] facets. From this work, it is clear that the interaction between graphene and the underlying Ge is not only dependent on the substrate crystallographic orientation, but is also tunable and strongly related to the atomic reconfiguration of the graphene-Ge interface.
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Affiliation(s)
- Brian Kiraly
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Robert M Jacobberger
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Andrew J Mannix
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Gavin P Campbell
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael J Bedzyk
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Department of Physics and Astronomy, Northwestern University , Evanston, Illinois 60208, United States
| | - Michael S Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States
| | - Nathan P Guisinger
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
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206
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Pal PP, Jiang N, Sonntag MD, Chiang N, Foley ET, Hersam MC, Van Duyne RP, Seideman T. Plasmon-Mediated Electron Transport in Tip-Enhanced Raman Spectroscopic Junctions. J Phys Chem Lett 2015; 6:4210-4218. [PMID: 26538036 DOI: 10.1021/acs.jpclett.5b01902] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We combine experiment, theory, and first-principles-based calculations to study the light-induced plasmon-mediated electron transport characteristics of a molecular-scale junction. The experimental data show a nonlinear increase in electronic current perturbation when the focus of a chopped laser beam moves laterally toward the tip-sample junction. To understand this behavior and generalize it, we apply a combined theory of the electronic nonequilibrium formed upon decoherence of an optically triggered plasmon and first-principles transport calculations. Our model illustrates that the current via an adsorbed molecular monolayer increases nonlinearly as more energy is pumped into the junction due to the increasing availability of virtual molecular orbital channels for transport with higher injection energies. Our results thus illustrate light-triggered, plasmon-enhanced tunneling current in the presence of a molecular linker.
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Affiliation(s)
- Partha Pratim Pal
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Nan Jiang
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Matthew D Sonntag
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Naihao Chiang
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Edward T Foley
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Richard P Van Duyne
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
| | - Tamar Seideman
- Department of Chemistry, ‡Department of Materials Science and Engineering, and ⊥Applied Physics Graduate Program, Northwestern University , Evanston, Illinois 60208, United States
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207
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Jang S, Kim B, Geier ML, Hersam MC, Dodabalapur A. Short Channel Field-Effect-Transistors with Inkjet-Printed Semiconducting Carbon Nanotubes. Small 2015; 11:5505-5509. [PMID: 26312458 DOI: 10.1002/smll.201501179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/10/2015] [Indexed: 06/04/2023]
Abstract
Short channel field-effect-transistors with inkjet-printed semiconducting carbon nanotubes are fabricated using a novel strategy to minimize material consumption, confining the inkjet droplet into the active channel area. This fabrication approach is compatible with roll-to-roll processing and enables the formation of high-performance short channel device arrays based on inkjet printing.
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Affiliation(s)
- Seonpil Jang
- Microelectronic Research Center, The University of Texas at Austin, 10110 Burnet Road, MER Bldg 160, Austin, TX, 78758, USA
| | - Bongjun Kim
- Microelectronic Research Center, The University of Texas at Austin, 10110 Burnet Road, MER Bldg 160, Austin, TX, 78758, USA
| | - Michael L Geier
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Ananth Dodabalapur
- Microelectronic Research Center, The University of Texas at Austin, 10110 Burnet Road, MER Bldg 160, Austin, TX, 78758, USA
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208
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Geier ML, McMorrow JJ, Xu W, Zhu J, Kim CH, Marks TJ, Hersam MC. Solution-processed carbon nanotube thin-film complementary static random access memory. Nat Nanotechnol 2015; 10:944-8. [PMID: 26344184 DOI: 10.1038/nnano.2015.197] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/31/2015] [Indexed: 05/07/2023]
Abstract
Over the past two decades, extensive research on single-walled carbon nanotubes (SWCNTs) has elucidated their many extraordinary properties, making them one of the most promising candidates for solution-processable, high-performance integrated circuits. In particular, advances in the enrichment of high-purity semiconducting SWCNTs have enabled recent circuit demonstrations including synchronous digital logic, flexible electronics and high-frequency applications. However, due to the stringent requirements of the transistors used in complementary metal-oxide-semiconductor (CMOS) logic as well as the absence of sufficiently stable and spatially homogeneous SWCNT thin-film transistors, the development of large-scale SWCNT CMOS integrated circuits has been limited in both complexity and functionality. Here, we demonstrate the stable and uniform electronic performance of complementary p-type and n-type SWCNT thin-film transistors by controlling adsorbed atmospheric dopants and incorporating robust encapsulation layers. Based on these complementary SWCNT thin-film transistors, we simulate, design and fabricate arrays of low-power static random access memory circuits, achieving large-scale integration for the first time based on solution-processed semiconductors.
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Affiliation(s)
- Michael L Geier
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Julian J McMorrow
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Weichao Xu
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Jian Zhu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Chris H Kim
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Tobin J Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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209
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Secor EB, Ahn BY, Gao TZ, Lewis JA, Hersam MC. Rapid and Versatile Photonic Annealing of Graphene Inks for Flexible Printed Electronics. Adv Mater 2015; 27:6683-8. [PMID: 26422363 DOI: 10.1002/adma.201502866] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 08/20/2015] [Indexed: 05/28/2023]
Abstract
Intense pulsed light (IPL) annealing of graphene inks is demonstrated for rapid post-processing of inkjet-printed patterns on various substrates. A conductivity of ≈25,000 S m(-1) is achieved following a single printing pass using a concentrated ink containing 20 mg mL(-1) graphene, establishing this strategy as a practical and effective approach for the versatile and high-performance integration of graphene in printed and flexible electronics.
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Affiliation(s)
- Ethan B Secor
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Bok Y Ahn
- Harvard School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Cambridge, MA, 02138, USA
| | - Theodore Z Gao
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
| | - Jennifer A Lewis
- Harvard School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Cambridge, MA, 02138, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, IL, 60208, USA
- Department of Chemistry, Department of Medicine, Northwestern University, Evanston, IL, 60208, USA
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210
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Cui S, Pu H, Wells SA, Wen Z, Mao S, Chang J, Hersam MC, Chen J. Ultrahigh sensitivity and layer-dependent sensing performance of phosphorene-based gas sensors. Nat Commun 2015; 6:8632. [PMID: 26486604 PMCID: PMC4639804 DOI: 10.1038/ncomms9632] [Citation(s) in RCA: 274] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 09/11/2015] [Indexed: 12/24/2022] Open
Abstract
Two-dimensional (2D) layered materials have attracted significant attention for device applications because of their unique structures and outstanding properties. Here, a field-effect transistor (FET) sensor device is fabricated based on 2D phosphorene nanosheets (PNSs). The PNS sensor exhibits an ultrahigh sensitivity to NO2 in dry air and the sensitivity is dependent on its thickness. A maximum response is observed for 4.8-nm-thick PNS, with a sensitivity up to 190% at 20 parts per billion (p.p.b.) at room temperature. First-principles calculations combined with the statistical thermodynamics modelling predict that the adsorption density is ∼10(15) cm(-2) for the 4.8-nm-thick PNS when exposed to 20 p.p.b. NO2 at 300 K. Our sensitivity modelling further suggests that the dependence of sensitivity on the PNS thickness is dictated by the band gap for thinner sheets (<10 nm) and by the effective thickness on gas adsorption for thicker sheets (>10 nm).
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Affiliation(s)
- Shumao Cui
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
| | - Haihui Pu
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
| | - Spencer A Wells
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Zhenhai Wen
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
| | - Shun Mao
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
| | - Jingbo Chang
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Junhong Chen
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 N Cramer Street, Milwaukee, Wisconsin 53211, USA
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211
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Zhu J, Kang J, Kang J, Jariwala D, Wood JD, Seo JWT, Chen KS, Marks TJ, Hersam MC. Solution-Processed Dielectrics Based on Thickness-Sorted Two-Dimensional Hexagonal Boron Nitride Nanosheets. Nano Lett 2015; 15:7029-7036. [PMID: 26348822 DOI: 10.1021/acs.nanolett.5b03075] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Gate dielectrics directly affect the mobility, hysteresis, power consumption, and other critical device metrics in high-performance nanoelectronics. With atomically flat and dangling bond-free surfaces, hexagonal boron nitride (h-BN) has emerged as an ideal dielectric for graphene and related two-dimensional semiconductors. While high-quality, atomically thin h-BN has been realized via micromechanical cleavage and chemical vapor deposition, existing liquid exfoliation methods lack sufficient control over h-BN thickness and large-area film quality, thus limiting its use in solution-processed electronics. Here, we employ isopycnic density gradient ultracentrifugation for the preparation of monodisperse, thickness-sorted h-BN inks, which are subsequently layer-by-layer assembled into ultrathin dielectrics with low leakage currents of 3 × 10(-9) A/cm(2) at 2 MV/cm and high capacitances of 245 nF/cm(2). The resulting solution-processed h-BN dielectric films enable the fabrication of graphene field-effect transistors with negligible hysteresis and high mobilities up to 7100 cm(2) V(-1) s(-1) at room temperature. These h-BN inks can also be used as coatings on conventional dielectrics to minimize the effects of underlying traps, resulting in improvements in overall device performance. Overall, this approach for producing and assembling h-BN dielectric inks holds significant promise for translating the superlative performance of two-dimensional heterostructure devices to large-area, solution-processed nanoelectronics.
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Affiliation(s)
- Jian Zhu
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Joohoon Kang
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Junmo Kang
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Deep Jariwala
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Joshua D Wood
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Jung-Woo T Seo
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Kan-Sheng Chen
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Tobin J Marks
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States
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212
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Wang X, Mansukhani ND, Guiney LM, Ji Z, Chang CH, Wang M, Liao YP, Song TB, Sun B, Li R, Xia T, Hersam MC, Nel AE. Differences in the Toxicological Potential of 2D versus Aggregated Molybdenum Disulfide in the Lung. Small 2015; 11:5079-87. [PMID: 26237579 PMCID: PMC4600460 DOI: 10.1002/smll.201500906] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/04/2015] [Indexed: 05/19/2023]
Abstract
2D molybdenum disulfide (MoS2 ) has distinct optical and electronic properties compared to aggregated MoS2 , enabling wide use of these materials for electronic and biomedical applications. However, the hazard potential of MoS2 has not been studied extensively. Here, a comprehensive analysis of the pulmonary hazard potential of three aqueous suspended forms of MoS2 -aggregated MoS2 (Agg-MoS2 ), MoS2 exfoliated by lithiation (Lit-MoS2 ), and MoS2 dispersed by Pluronic F87 (PF87-MoS2 )-is presented. No cytotoxicity is detected in THP-1 and BEAS-2B cell lines. However, Agg-MoS2 induces strong proinflammatory and profibrogenic responses in vitro. In contrast, Lit- and PF87-MoS2 have little or no effect. In an acute toxicity study in mice, Agg-MoS2 induces acute lung inflammation, while Lit-MoS2 and PF87-MoS2 have little or no effect. In a subchronic study, there is no evidence of pulmonary fibrosis in response to all forms of MoS2 . These data suggest that exfoliation attenuates the toxicity of Agg-MoS2 , which is an important consideration toward the safety evaluation and use of nanoscale MoS2 materials for industrial and biological applications.
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Affiliation(s)
- Xiang Wang
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute; University of California, Los Angeles, CA 90095, United States
| | - Nikhita D. Mansukhani
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Linda M. Guiney
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Zhaoxia Ji
- California NanoSystems Institute; University of California, Los Angeles, CA 90095, United States
| | - Chong Hyun Chang
- California NanoSystems Institute; University of California, Los Angeles, CA 90095, United States
| | - Meiying Wang
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
| | - Yu-Pei Liao
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
| | - Tze-Bin Song
- Department of Materials Science and Engineering, University of California, Los Angeles, CA 90095, United States
| | - Bingbing Sun
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
| | - Ruibin Li
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
| | - Tian Xia
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute; University of California, Los Angeles, CA 90095, United States
| | - Mark C. Hersam
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - André E. Nel
- Division of NanoMedicine, Department of Medicine; University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute; University of California, Los Angeles, CA 90095, United States
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213
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Hersam MC, Lee ST, Nel AE, Rogach A, Buriak JM, Weiss PS. Big Roles for Nanocenters. ACS Nano 2015; 9:8639-8640. [PMID: 26391441 DOI: 10.1021/acsnano.5b05779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Mark C Hersam
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
| | - Shiut-Tong Lee
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
| | - Andre E Nel
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
| | - Andrey Rogach
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
| | - Jillian M Buriak
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
| | - Paul S Weiss
- Editorial Advisory Board Member and Chemistry of Materials Editor-in-Chief
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214
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Chowdhury I, Mansukhani ND, Guiney LM, Hersam MC, Bouchard D. Aggregation and Stability of Reduced Graphene Oxide: Complex Roles of Divalent Cations, pH, and Natural Organic Matter. Environ Sci Technol 2015; 49:10886-10893. [PMID: 26280799 DOI: 10.1021/acs.est.5b01866] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aggregation and stability of graphene oxide (GO) and three successively reduced GO (rGO) nanomaterials were investigated. Reduced GO species were partially reduced GO (rGO-1h), intermediately reduced GO (rGO-2h), and fully reduced GO (rGO-5h). Specifically, influence of pH, ionic strength, ion valence, and presence of natural organic matter (NOM) were studied. Results show that stability of GO in water decreases with successive reduction of functional groups, with pH having the greatest influence on rGO stability. Stability is also dependent on ion valence and the concentration of surface functional groups. While pH did not noticeably affect stability of GO in the presence of 10 mM NaCl, adding 0.1 mM CaCl2 reduced stability of GO with increased pH. This is due to adsorption of Ca(2+) ions on the surface functional groups of GO which reduces the surface charge of GO. As the concentration of rGO functional groups decreased, so did the influence of Ca(2+) ions on rGO stability. Critical coagulation concentrations (CCC) of GO, rGO-1h, and rGO-2h were determined to be ∼ 200 mM, 35 mM, and 30 mM NaCl, respectively. In the presence of CaCl2, CCC values of GO and rGO are quite similar, however. Long-term studies show that a significant amount of rGO-1h and rGO-2h remain stable in Call's Creek surface water, while effluent wastewater readily destabilizes rGO. In the presence NOM and divalent cations (Ca(2+), Mg(2+)), GO aggregates settle from suspension due to GO functional group bridging with NOM and divalent ions. However, rGO-1h and rGO-2h remain suspended due to their lower functional group concentration and resultant reduced NOM-divalent cation bridging. Overall, pH, divalent cations, and NOM can play complex roles in the fate of rGO and GO.
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Affiliation(s)
- Indranil Chowdhury
- Department of Civil and Environmental Engineering, Washington State University , Pullman, Washington 99164, United States
| | - Nikhita D Mansukhani
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Linda M Guiney
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Mark C Hersam
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois 60208, United States
| | - Dermont Bouchard
- National Exposure Research Laboratory, Ecosystems Research Division, United States Environmental Protection Agency , Athens, Georgia 30605, United States
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215
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Jacobberger RM, Kiraly B, Fortin-Deschenes M, Levesque PL, McElhinny KM, Brady GJ, Rojas Delgado R, Singha Roy S, Mannix A, Lagally MG, Evans PG, Desjardins P, Martel R, Hersam MC, Guisinger NP, Arnold MS. Direct oriented growth of armchair graphene nanoribbons on germanium. Nat Commun 2015; 6:8006. [PMID: 26258594 PMCID: PMC4918381 DOI: 10.1038/ncomms9006] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Accepted: 07/03/2015] [Indexed: 12/21/2022] Open
Abstract
Graphene can be transformed from a semimetal into a semiconductor if it is confined into nanoribbons narrower than 10 nm with controlled crystallographic orientation and well-defined armchair edges. However, the scalable synthesis of nanoribbons with this precision directly on insulating or semiconducting substrates has not been possible. Here we demonstrate the synthesis of graphene nanoribbons on Ge(001) via chemical vapour deposition. The nanoribbons are self-aligning 3° from the Ge〈110〉 directions, are self-defining with predominantly smooth armchair edges, and have tunable width to <10 nm and aspect ratio to >70. In order to realize highly anisotropic ribbons, it is critical to operate in a regime in which the growth rate in the width direction is especially slow, <5 nm h−1. This directional and anisotropic growth enables nanoribbon fabrication directly on conventional semiconductor wafer platforms and, therefore, promises to allow the integration of nanoribbons into future hybrid integrated circuits. Semiconducting armchair graphene nanoribbons with sub-10 nm width are of great technological importance but yet to realize. Here, the authors report growth of such nanoribbons on germanium and controlled crystallographic orientation and well-defined armchair edges are obtained.
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Affiliation(s)
- Robert M Jacobberger
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Brian Kiraly
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Matthieu Fortin-Deschenes
- Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Québec, Canada H3C 2A7
| | - Pierre L Levesque
- Department of Chemistry, Université de Montréal, Montréal, Québec, Canada H3C 3JT
| | - Kyle M McElhinny
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Gerald J Brady
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Richard Rojas Delgado
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Susmit Singha Roy
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Andrew Mannix
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.,Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Max G Lagally
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Paul G Evans
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Patrick Desjardins
- Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Québec, Canada H3C 2A7
| | - Richard Martel
- Department of Chemistry, Université de Montréal, Montréal, Québec, Canada H3C 3JT
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.,Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Nathan P Guisinger
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Michael S Arnold
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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216
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Affiliation(s)
- Mark C Hersam
- Department of Materials Science and Engineering, Department of Chemistry, and Department of Medicine, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
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217
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Nel AE, Parak WJ, Chan WCW, Xia T, Hersam MC, Brinker CJ, Zink JI, Pinkerton KE, Baer DR, Weiss PS. Where Are We Heading in Nanotechnology Environmental Health and Safety and Materials Characterization? ACS Nano 2015; 9:5627-30. [PMID: 26100220 DOI: 10.1021/acsnano.5b03496] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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218
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Kim B, Park J, Geier ML, Hersam MC, Dodabalapur A. Voltage-Controlled Ring Oscillators Based on Inkjet Printed Carbon Nanotubes and Zinc Tin Oxide. ACS Appl Mater Interfaces 2015; 7:12009-14. [PMID: 25966019 DOI: 10.1021/acsami.5b02093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
A voltage-controlled ring oscillator is implemented with double-gate complementary transistors where both the n- and p-channel semiconductors are deposited by inkjet printing. Top gates added to transistors in conventional ring oscillator circuits control not only threshold voltages of the constituent transistors but also the oscillation frequencies of the ring oscillators. The oscillation frequency increases or decreases linearly with applied top gate potential. The field-effect transistor materials system that yields such linear behavior has not been previously reported. In this work, we demonstrate details of a material system (gate insulator, p- and n-channel semiconductors) that results in very linear frequency changes with control gate potential. Our use of a double layer top dielectric consisting of a combination of solution processed P(VDF-TrFE) and Al2O3 deposited by atomic layer deposition leads to low operating voltages and near-optimal device characteristics from a circuit standpoint. Such functional blocks will enable the realization of printed voltage-controlled oscillator-based analog-to-digital converters.
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Affiliation(s)
- Bongjun Kim
- †Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, United States
- ‡Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jaeyoung Park
- ‡Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Michael L Geier
- §Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- §Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Ananth Dodabalapur
- †Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758, United States
- ‡Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
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219
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Chiang N, Jiang N, Chulhai DV, Pozzi EA, Hersam MC, Jensen L, Seideman T, Van Duyne RP. Molecular-Resolution Interrogation of a Porphyrin Monolayer by Ultrahigh Vacuum Tip-Enhanced Raman and Fluorescence Spectroscopy. Nano Lett 2015; 15:4114-20. [PMID: 25938625 DOI: 10.1021/acs.nanolett.5b01225] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Tip-enhanced Raman scattering (TERS) and optically excited tip-enhanced fluorescence (TEF) of a self-assembled porphyrin monolayer on Ag(111) are studied using an ultrahigh vacuum scanning tunneling microscope (UHV-STM). Through selectively exciting different Q-bands of meso-tetrakis- (3,5-ditertiarybutylphenyl)-porphyrin (H2TBPP), chemical information regarding different vibronic excited states is revealed by a combination of theory and experiment; namely, TERS and time-dependent density functional theory (TDDFT) simulations. The observed TEF spectra suggest a weak coupling of H2TBPP to the substrate due to the bulky t-butyl groups and a possible alternative excited state decay path. This work demonstrates the potential of combining TERS and TEF for studying surface-mounted porphyins on substrates, thus providing insight into porphyrin-sensitized solar cells and catalysis.
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Affiliation(s)
| | | | - Dhabih V Chulhai
- ⊥Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | | | | | - Lasse Jensen
- ⊥Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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220
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Rickert K, Pozzi EA, Khanal R, Onoue M, Trimarchi G, Medvedeva JE, Hersam MC, Van Duyne RP, Poeppelmeier KR. Selective Crystal Growth and Structural, Optical, and Electronic Studies of Mn3Ta2O8. Inorg Chem 2015; 54:6513-9. [DOI: 10.1021/acs.inorgchem.5b00853] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - Rabi Khanal
- Department of Physics, Missouri University of Science & Technology, Rolla, Missouri 65409, United States
| | | | | | - Julia E. Medvedeva
- Department of Physics, Missouri University of Science & Technology, Rolla, Missouri 65409, United States
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221
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222
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Sangwan VK, Jariwala D, Kim IS, Chen KS, Marks TJ, Lauhon LJ, Hersam MC. Gate-tunable memristive phenomena mediated by grain boundaries in single-layer MoS2. Nat Nanotechnol 2015; 10:403-6. [PMID: 25849785 DOI: 10.1038/nnano.2015.56] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 02/23/2015] [Indexed: 05/09/2023]
Abstract
Continued progress in high-speed computing depends on breakthroughs in both materials synthesis and device architectures. The performance of logic and memory can be enhanced significantly by introducing a memristor, a two-terminal device with internal resistance that depends on the history of the external bias voltage. State-of-the-art memristors, based on metal-insulator-metal (MIM) structures with insulating oxides, such as TiO₂, are limited by a lack of control over the filament formation and external control of the switching voltage. Here, we report a class of memristors based on grain boundaries (GBs) in single-layer MoS₂ devices. Specifically, the resistance of GBs emerging from contacts can be easily and repeatedly modulated, with switching ratios up to ∼10(3) and a dynamic negative differential resistance (NDR). Furthermore, the atomically thin nature of MoS₂ enables tuning of the set voltage by a third gate terminal in a field-effect geometry, which provides new functionality that is not observed in other known memristive devices.
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Affiliation(s)
- Vinod K Sangwan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Deep Jariwala
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - In Soo Kim
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Kan-Sheng Chen
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Tobin J Marks
- 1] Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA [2] Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Lincoln J Lauhon
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Mark C Hersam
- 1] Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA [2] Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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223
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224
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Kang J, Wood JD, Wells SA, Lee JH, Liu X, Chen KS, Hersam MC. Solvent exfoliation of electronic-grade, two-dimensional black phosphorus. ACS Nano 2015; 9:3596-604. [PMID: 25785299 DOI: 10.1021/acsnano.5b01143] [Citation(s) in RCA: 323] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Solution dispersions of two-dimensional (2D) black phosphorus (BP)--often referred to as phosphorene--are achieved by solvent exfoliation. These pristine, electronic-grade BP dispersions are produced with anhydrous organic solvents in a sealed-tip ultrasonication system, which circumvents BP degradation that would otherwise occur via solvated O2 or H2O. Among conventional solvents, N-methylpyrrolidone (NMP) is found to provide stable, highly concentrated (∼0.4 mg/mL) BP dispersions. Atomic force microscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy show that the structure and chemistry of solvent-exfoliated BP nanosheets are comparable to mechanically exfoliated BP flakes. Additionally, residual NMP from the liquid-phase processing suppresses the rate of BP oxidation in ambient conditions. Solvent-exfoliated BP nanosheet field-effect transistors exhibit ambipolar behavior with current on/off ratios and mobilities up to ∼10(4) and ∼50 cm(2) V(-1) s(-1), respectively. Overall, this study shows that stable, highly concentrated, electronic-grade 2D BP dispersions can be realized by scalable solvent exfoliation, thereby presenting opportunities for large-area, high-performance BP device applications.
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Affiliation(s)
- Joohoon Kang
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua D Wood
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Spencer A Wells
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Jae-Hyeok Lee
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Xiaolong Liu
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Kan-Sheng Chen
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
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225
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Howell SL, Jariwala D, Wu CC, Chen KS, Sangwan VK, Kang J, Marks TJ, Hersam MC, Lauhon LJ. Investigation of band-offsets at monolayer-multilayer MoS₂ junctions by scanning photocurrent microscopy. Nano Lett 2015; 15:2278-84. [PMID: 25807012 DOI: 10.1021/nl504311p] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The thickness-dependent band structure of MoS2 implies that discontinuities in energy bands exist at the interface of monolayer (1L) and multilayer (ML) thin films. The characteristics of such heterojunctions are analyzed here using current versus voltage measurements, scanning photocurrent microscopy, and finite element simulations of charge carrier transport. Rectifying I-V curves are consistently observed between contacts on opposite sides of 1L/ML junctions, and a strong bias-dependent photocurrent is observed at the junction. Finite element device simulations with varying carrier concentrations and electron affinities show that a type II band alignment at single layer/multilayer junctions reproduces both the rectifying electrical characteristics and the photocurrent response under bias. However, the zero-bias junction photocurrent and its energy dependence are not explained by conventional photovoltaic and photothermoelectric mechanisms, indicating the contributions of hot carriers.
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Affiliation(s)
- Sarah L Howell
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Deep Jariwala
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Chung-Chiang Wu
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Kan-Sheng Chen
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinod K Sangwan
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Junmo Kang
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Tobin J Marks
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Lincoln J Lauhon
- †Department of Materials Science and Engineering, ‡Department of Chemistry, §Department of Medicine, and ∥Materials Research Center, Northwestern University, Evanston, Illinois 60208, United States
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226
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Gong M, Shastry TA, Cui Q, Kohlmeyer RR, Luck KA, Rowberg A, Marks TJ, Durstock MF, Zhao H, Hersam MC, Ren S. Understanding charge transfer in carbon nanotube-fullerene bulk heterojunctions. ACS Appl Mater Interfaces 2015; 7:7428-7435. [PMID: 25797180 DOI: 10.1021/acsami.5b01536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Semiconducting single-walled carbon nanotube/fullerene bulk heterojunctions exhibit unique optoelectronic properties highly suitable for flexible, efficient, and robust photovoltaics and photodetectors. We investigate charge-transfer dynamics in inverted devices featuring a polyethylenimine-coated ZnO nanowire array infiltrated with these blends and find that trap-assisted recombination dominates transport within the blend and at the active layer/nanowire interface. We find that electrode modifiers suppress this recombination, leading to high performance.
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Affiliation(s)
| | | | | | - Ryan R Kohlmeyer
- ∥National Research Council, Washington, D.C. 20001, United States
- ⊥Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
| | | | | | | | - Michael F Durstock
- ⊥Soft Matter Materials Branch, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson Air Force Base, Ohio 45433, United States
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227
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Wang X, Duch MC, Mansukhani N, Ji Z, Liao YP, Wang M, Zhang H, Sun B, Chang CH, Li R, Lin S, Meng H, Xia T, Hersam MC, Nel AE. Use of a pro-fibrogenic mechanism-based predictive toxicological approach for tiered testing and decision analysis of carbonaceous nanomaterials. ACS Nano 2015; 9:3032-43. [PMID: 25646681 PMCID: PMC4539018 DOI: 10.1021/nn507243w] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Engineered carbonaceous nanomaterials (ECNs), including single-wall carbon nanotubes (SWCNTs), multiwall carbon nanotubes (MWCNTs), graphene, and graphene oxide (GO), are potentially hazardous to the lung. With incremental experience in the use of predictive toxicological approaches, seeking to relate ECN physicochemical properties to adverse outcome pathways (AOPs), it is logical to explore the existence of a common AOP that allows comparative analysis of broad ECN categories. We established an ECN library comprising three different types of SWCNTs, graphene, and graphene oxide (two sizes) for comparative analysis according to a cell-based AOP that also plays a role in the pathogenesis of pulmonary fibrosis. SWCNTs synthesized by Hipco, arc discharge and Co-Mo catalyst (CoMoCAT) methods were obtained in their as-prepared (AP) state, following which they were further purified (PD) or coated with Pluronic F108 (PF108) or bovine serum albumin (BSA) to improve dispersal and colloidal stability. GO was prepared as two sizes, GO-small (S) and GO-large (L), while the graphene samples were coated with BSA and PF108 to enable dispersion in aqueous solution. In vitro screening showed that AP- and PD-SWCNTs, irrespective of the method of synthesis, as well as graphene (BSA) and GO (S and L) could trigger interleukin-1β (IL-1β) and transforming growth factor-β1 (TGF-β1) production in myeloid (THP-1) and epithelial (BEAS-2B) cell lines, respectively. Oropharyngeal aspiration in mice confirmed that AP-Hipco tubes, graphene (BSA-dispersed), GO-S and GO-L could induce IL-1β and TGF-β1 production in the lung in parallel with lung fibrosis. Notably, GO-L was the most pro-fibrogenic material based on rapid kinetics of pulmonary injury. In contrast, PF108-dispersed SWCNTs and -graphene failed to exert fibrogenic effects. Collectively, these data indicate that the dispersal state and surface reactivity of ECNs play key roles in triggering a pro-fibrogenic AOP, which could prove helpful for hazard ranking and a proposed tiered testing approach for large ECN categories.
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Affiliation(s)
- Xiang Wang
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Matthew C. Duch
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Nikhita Mansukhani
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Zhaoxia Ji
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Yu-Pei Liao
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
| | - Meiying Wang
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
| | - Haiyuan Zhang
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Bingbing Sun
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
| | - Chong Hyun Chang
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Ruibin Li
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
| | - Sijie Lin
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Huan Meng
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Tian Xia
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
| | - Mark C. Hersam
- Departments of Materials Science and Engineering, Chemistry, and Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - André E. Nel
- Division of NanoMedicine, Department of Medicine, University of California, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, United States
- Corresponding Author: André E. Nel, M.D./Ph.D., Department of Medicine, Division of NanoMedicine, UCLA School of Medicine, 52-175 CHS, 10833 Le Conte Ave, Los Angeles, CA 90095-1680. Tel: (310) 825-6620, Fax: (310) 206-8107,
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228
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Abstract
We report on the dynamics of spatial temperature distributions in aligned semiconducting carbon nanotube array devices with submicrometer channel lengths. By using high-resolution optical microscopy in combination with electrical transport measurements, we observe under steady state bias conditions the emergence of time-variable, local temperature maxima with dimensions below 300 nm, and temperatures above 400 K. On the basis of time domain cross-correlation analysis, we investigate how the intensity fluctuations of the thermal radiation patterns are correlated with the overall device current. The analysis reveals the interdependence of electrical current fluctuations and time-variable hot spot formation that limits the overall device performance and, ultimately, may cause device degradation. The findings have implications for the future development of carbon nanotube-based technologies.
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Affiliation(s)
- Michael Engel
- IBM Thomas J. Watson Research Center , Yorktown Heights, New York 10598, United States
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229
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Abstract
With a semiconducting band gap and high charge carrier mobility, two-dimensional (2D) black phosphorus (BP)—often referred to as phosphorene—holds significant promise for next generation electronics and optoelectronics. However, as a 2D material, it possesses a higher surface area to volume ratio than bulk BP, suggesting that its chemical and thermal stability will be modified. Herein, an atomic-scale microscopic and spectroscopic study is performed to characterize the thermal degradation of mechanically exfoliated 2D BP. From in situ scanning/transmission electron microscopy, decomposition of 2D BP is observed to occur at ∼400 °C in vacuum, in contrast to the 550 °C bulk BP sublimation temperature. This decomposition initiates via eye-shaped cracks along the [001] direction and then continues until only a thin, amorphous red phosphorus like skeleton remains. In situ electron energy loss spectroscopy, energy-dispersive X-ray spectroscopy, and energy-loss near-edge structure changes provide quantitative insight into this chemical transformation process.
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Affiliation(s)
- Xiaolong Liu
- †Graduate Program in Applied Physics, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua D Wood
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Kan-Sheng Chen
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - EunKyung Cho
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Graduate Program in Applied Physics, Northwestern University, Evanston, Illinois 60208, United States
- ‡Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- §Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- ∥Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
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230
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Abstract
Carbon and post-carbon nanomaterials present desirable electrical, optical, chemical, and mechanical attributes for printed electronics, offering low-cost, large-area functionality on flexible substrates. In this Perspective, recent developments in carbon nanomaterial inks are highlighted. Monodisperse semiconducting single-walled carbon nanotubes compatible with inkjet and aerosol jet printing are ideal channels for thin-film transistors, while inkjet, gravure, and screen-printable graphene-based inks are better-suited for electrodes and interconnects. Despite the high performance achieved in prototype devices, additional effort is required to address materials integration issues encountered in more complex systems. In this regard, post-carbon nanomaterial inks (e.g., electrically insulating boron nitride and optically active transition-metal dichalcogenides) present promising opportunities. Finally, emerging work to extend these nanomaterial inks to three-dimensional printing provides a path toward nonplanar devices. Overall, the superlative properties of these materials, coupled with versatile assembly by printing techniques, offer a powerful platform for next-generation printed electronics.
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Affiliation(s)
- Ethan B Secor
- †Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Materials Science and Engineering, ‡Department of Chemistry, and §Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
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231
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Lanphere JD, Luth CJ, Guiney LM, Mansukhani ND, Hersam MC, Walker SL. Fate and Transport of Molybdenum Disulfide Nanomaterials in Sand Columns. Environ Eng Sci 2015; 32:163-173. [PMID: 25741176 PMCID: PMC4323112 DOI: 10.1089/ees.2014.0335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/26/2014] [Indexed: 05/26/2023]
Abstract
Research and development of two-dimensional transition metal dichalcogenides (TMDC) (e.g., molybdenum disulfide [MoS2]) in electronic, optical, and catalytic applications has been growing rapidly. However, there is little known regarding the behavior of these particles once released into aquatic environments. Therefore, an in-depth study regarding the fate and transport of two popular types of MoS2 nanomaterials, lithiated (MoS2-Li) and Pluronic PF-87 dispersed (MoS2-PL), was conducted in saturated porous media (quartz sand) to identify which form would be least mobile in aquatic environments. The electrokinetic properties and hydrodynamic diameters of MoS2 as a function of ionic strength and pH were determined using a zeta potential analyzer and dynamic light scattering techniques. Results suggest that the stability is significantly decreased beginning at 10 and 31.6 mM KCl, for MoS2-PL and MoS2-Li, respectively. Transport study results from breakthrough curves, column dissections, and release experiments suggest that MoS2-PL exhibits a greater affinity to be irreversibly bound to quartz surfaces as compared with the MoS2-Li at a similar ionic strength. Derjaguin-Landau-Verwey-Overbeek theory was used to help explain the unique interactions between the MoS2-PL and MoS2-Li surfaces between particles and with the quartz collectors. Overall, the results suggest that the fate and transport of MoS2 is dependent on the type of MoS2 that enters the environment, where MoS2-PL will be least mobile and more likely be deposited in porous media from pluronic-quartz interactions, whereas MoS2-Li will travel greater distances and have a greater tendency to be remobilized in sand columns.
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Affiliation(s)
- Jacob D Lanphere
- Department of Chemical and Environmental Engineering, University of California , Riverside, California
| | - Corey J Luth
- Department of Chemical and Environmental Engineering, University of California , Riverside, California
| | - Linda M Guiney
- Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois
| | - Nikhita D Mansukhani
- Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois
| | - Mark C Hersam
- Department of Material Science and Engineering, Chemistry, and Medicine, Northwestern University , Evanston, Illinois
| | - Sharon L Walker
- Department of Chemical and Environmental Engineering, University of California , Riverside, California
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232
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Qin W, Gong M, Chen X, Shastry TA, Sakidja R, Yuan G, Hersam MC, Wuttig M, Ren S. Multiferroicity of carbon-based charge-transfer magnets. Adv Mater 2015; 27:734-739. [PMID: 25389110 DOI: 10.1002/adma.201403396] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 10/10/2014] [Indexed: 06/04/2023]
Abstract
A new type of carbon charge-transfer magnet, consisting of a fullerene acceptor and single-walled carbon nanotube donor, is demonstrated, which exhibits room temperature ferromagnetism and magnetoelectric (ME) coupling. In addition, external stimuli (electric/magnetic/elastic field) and the concentration of a nanocarbon complex enable the tunabilities of the magnetization and ME coupling due to the control of the charge transfer.
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Affiliation(s)
- Wei Qin
- Department of Chemistry, University of Kansas, Lawrence, KS, 66045, USA
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233
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Jariwala D, Sangwan VK, Seo JWT, Xu W, Smith J, Kim CH, Lauhon LJ, Marks TJ, Hersam MC. Large-area, low-voltage, antiambipolar heterojunctions from solution-processed semiconductors. Nano Lett 2015; 15:416-421. [PMID: 25438195 DOI: 10.1021/nl5037484] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The emergence of semiconducting materials with inert or dangling bond-free surfaces has created opportunities to form van der Waals heterostructures without the constraints of traditional epitaxial growth. For example, layered two-dimensional (2D) semiconductors have been incorporated into heterostructure devices with gate-tunable electronic and optical functionalities. However, 2D materials present processing challenges that have prevented these heterostructures from being produced with sufficient scalability and/or homogeneity to enable their incorporation into large-area integrated circuits. Here, we extend the concept of van der Waals heterojunctions to semiconducting p-type single-walled carbon nanotube (s-SWCNT) and n-type amorphous indium gallium zinc oxide (a-IGZO) thin films that can be solution-processed or sputtered with high spatial uniformity at the wafer scale. The resulting large-area, low-voltage p-n heterojunctions exhibit antiambipolar transfer characteristics with high on/off ratios that are well-suited for electronic, optoelectronic, and telecommunication technologies.
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Affiliation(s)
- Deep Jariwala
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
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234
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Hyun WJ, Secor EB, Hersam MC, Frisbie CD, Francis LF. High-resolution patterning of graphene by screen printing with a silicon stencil for highly flexible printed electronics. Adv Mater 2015; 27:109-15. [PMID: 25377870 DOI: 10.1002/adma.201404133] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 10/07/2014] [Indexed: 05/18/2023]
Abstract
High-resolution screen printing of pristine graphene is introduced for the rapid fabrication of conductive lines on flexible substrates. Well-defined silicon stencils and viscosity-controlled inks facilitate the preparation of high-quality graphene patterns as narrow as 40 μm. This strategy provides an efficient method to produce highly flexible graphene electrodes for printed electronics.
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Affiliation(s)
- Woo Jin Hyun
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. SE, Minneapolis, Minnesota, 55455, USA
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235
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Jakus AE, Secor EB, Rutz AL, Jordan SW, Hersam MC, Shah RN. Three-dimensional printing of high-content graphene scaffolds for electronic and biomedical applications. ACS Nano 2015; 9:4636-48. [PMID: 25858670 DOI: 10.1021/acsnano.5b01179] [Citation(s) in RCA: 302] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The exceptional properties of graphene enable applications in electronics, optoelectronics, energy storage, and structural composites. Here we demonstrate a 3D printable graphene (3DG) composite consisting of majority graphene and minority polylactide-co-glycolide, a biocompatible elastomer, 3D-printed from a liquid ink. This ink can be utilized under ambient conditions via extrusion-based 3D printing to create graphene structures with features as small as 100 μm composed of as few as two layers (<300 μm thick object) or many hundreds of layers (>10 cm thick object). The resulting 3DG material is mechanically robust and flexible while retaining electrical conductivities greater than 800 S/m, an order of magnitude increase over previously reported 3D-printed carbon materials. In vitro experiments in simple growth medium, in the absence of neurogenic stimuli, reveal that 3DG supports human mesenchymal stem cell (hMSC) adhesion, viability, proliferation, and neurogenic differentiation with significant upregulation of glial and neuronal genes. This coincides with hMSCs adopting highly elongated morphologies with features similar to axons and presynaptic terminals. In vivo experiments indicate that 3DG has promising biocompatibility over the course of at least 30 days. Surgical tests using a human cadaver nerve model also illustrate that 3DG has exceptional handling characteristics and can be intraoperatively manipulated and applied to fine surgical procedures. With this unique set of properties, combined with ease of fabrication, 3DG could be applied toward the design and fabrication of a wide range of functional electronic, biological, and bioelectronic medical and nonmedical devices.
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Affiliation(s)
- Adam E Jakus
- †Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
- §Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 East Superior Street, Chicago, Illinois 60611, United States
| | - Ethan B Secor
- †Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Alexandra L Rutz
- ‡Department of Biomedical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- §Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 East Superior Street, Chicago, Illinois 60611, United States
| | - Sumanas W Jordan
- ⊥Department of Surgery, Northwestern University, 251 East Huron Street, Galter 3-150, Illinois 60611, United States
| | - Mark C Hersam
- †Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
- ∥Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston Illinois 60208, United States
| | - Ramille N Shah
- †Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
- §Simpson Querrey Institute for BioNanotechnology, Northwestern University, 303 East Superior Street, Chicago, Illinois 60611, United States
- ⊥Department of Surgery, Northwestern University, 251 East Huron Street, Galter 3-150, Illinois 60611, United States
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236
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Chan WCW, Gogotsi Y, Hafner JH, Hammond PT, Hersam MC, Javey A, Kagan CR, Khademhosseini A, Kotov NA, Lee ST, Möhwald H, Mulvaney PA, Nel AE, Nordlander PJ, Parak WJ, Penner RM, Rogach AL, Schaak RE, Stevens MM, Wee ATS, Willson CG, Weiss PS. A year for nanoscience. ACS Nano 2014; 8:11901-11903. [PMID: 25533169 DOI: 10.1021/nn5070716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
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237
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Song CK, Luck KA, Zhou N, Zeng L, Heitzer HM, Manley EF, Goldman S, Chen LX, Ratner MA, Bedzyk MJ, Chang RPH, Hersam MC, Marks TJ. “Supersaturated” Self-Assembled Charge-Selective Interfacial Layers for Organic Solar Cells. J Am Chem Soc 2014; 136:17762-73. [DOI: 10.1021/ja508453n] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Charles Kiseok Song
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Kyle A. Luck
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Nanjia Zhou
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Li Zeng
- Graduate
Program in Applied Physics, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Henry M. Heitzer
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Eric F. Manley
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Samuel Goldman
- Weinberg
College of Arts and Science, Northwestern University, 1918 Sheridan
Road, Evanston, Illinois 60208, United States
| | - Lin X. Chen
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Mark A. Ratner
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Michael J. Bedzyk
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
- Graduate
Program in Applied Physics, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Robert P. H. Chang
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Mark C. Hersam
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
| | - Tobin J. Marks
- Department
of Chemistry and the Argonne-Northwestern Solar Energy Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department
of Materials Science and Engineering and the Argonne-Northwestern
Solar Energy Research Center, Northwestern University, 2220 Campus
Drive, Evanston, Illinois 60208, United States
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238
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Wood JD, Wells SA, Jariwala D, Chen KS, Cho E, Sangwan VK, Liu X, Lauhon LJ, Marks TJ, Hersam MC. Effective passivation of exfoliated black phosphorus transistors against ambient degradation. Nano Lett 2014; 14:6964-70. [PMID: 25380142 DOI: 10.1021/nl5032293] [Citation(s) in RCA: 677] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Unencapsulated, exfoliated black phosphorus (BP) flakes are found to chemically degrade upon exposure to ambient conditions. Atomic force microscopy, electrostatic force microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy are employed to characterize the structure and chemistry of the degradation process, suggesting that O2 saturated H2O irreversibly reacts with BP to form oxidized phosphorus species. This interpretation is further supported by the observation that BP degradation occurs more rapidly on hydrophobic octadecyltrichlorosilane self-assembled monolayers and on H-Si(111) versus hydrophilic SiO2. For unencapsulated BP field-effect transistors, the ambient degradation causes large increases in threshold voltage after 6 h in ambient, followed by a ∼ 10(3) decrease in FET current on/off ratio and mobility after 48 h. Atomic layer deposited AlOx overlayers effectively suppress ambient degradation, allowing encapsulated BP FETs to maintain high on/off ratios of ∼ 10(3) and mobilities of ∼ 100 cm(2) V(-1) s(-1) for over 2 weeks in ambient conditions. This work shows that the ambient degradation of BP can be managed effectively when the flakes are sufficiently passivated. In turn, our strategy for enhancing BP environmental stability will accelerate efforts to implement BP in electronic and optoelectronic applications.
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Affiliation(s)
- Joshua D Wood
- Department of Materials Science and Engineering, ‡Department of Chemistry, and §Graduate Program in Applied Physics, Northwestern University , Evanston, Illinois 60208, United States
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239
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Hartnett PE, Timalsina A, Matte HSSR, Zhou N, Guo X, Zhao W, Facchetti A, Chang RPH, Hersam MC, Wasielewski MR, Marks TJ. Slip-stacked perylenediimides as an alternative strategy for high efficiency nonfullerene acceptors in organic photovoltaics. J Am Chem Soc 2014; 136:16345-56. [PMID: 25350908 DOI: 10.1021/ja508814z] [Citation(s) in RCA: 297] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Perylenediimide (PDI)-based acceptors offer a potential replacement for fullerenes in bulk-heterojunction (BHJ) organic photovoltaic cells (OPVs). The most promising efforts have focused on creating twisted PDI dimers to disrupt aggregation and thereby suppress excimer formation. Here, we present an alternative strategy for developing high-performance OPVs based on PDI acceptors that promote slip-stacking in the solid state, thus preventing the coupling necessary for rapid excimer formation. This packing structure is accomplished by substitution at the PDI 2,5,8,11-positions ("headland positions"). Using this design principle, three PDI acceptors, N,N-bis(n-octyl)-2,5,8,11-tetra(n-hexyl)-PDI (Hexyl-PDI), N,N-bis(n-octyl)-2,5,8,11-tetraphenethyl-PDI (Phenethyl-PDI), and N,N-bis(n-octyl)-2,5,8,11-tetraphenyl-PDI (Phenyl-PDI), were synthesized, and their molecular and electronic structures were characterized. They were then blended with the donor polymer PBTI3T, and inverted OPVs of the structure ITO/ZnO/Active Layer/MoO3/Ag were fabricated and characterized. Of these, 1:1 PBTI3T:Phenyl-PDI proved to have the best performance with Jsc = 6.56 mA/cm(2), Voc = 1.024 V, FF = 54.59%, and power conversion efficiency (PCE) = 3.67%. Devices fabricated with Phenethyl-PDI and Hexyl-PDI have significantly lower performance. The thin film morphology and the electronic and photophysical properties of the three materials are examined, and although all three materials undergo efficient charge separation, PBTI3T:Phenyl-PDI is found to have the deepest LUMO, intermediate crystallinity, and the most well-mixed domains. This minimizes geminate recombination in Phenyl-PDI OPVs and affords the highest PCE. Thus, slip-stacked PDI strategies represent a promising approach to fullerene replacements in BHJ OPVs.
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Affiliation(s)
- Patrick E Hartnett
- Department of Chemistry and the Materials Research Center, and ‡Department of Materials Science and Engineering and the Materials Research Center, The Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
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240
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Kim IS, Sangwan VK, Jariwala D, Wood JD, Park S, Chen KS, Shi F, Ruiz-Zepeda F, Ponce A, Jose-Yacaman M, Dravid VP, Marks TJ, Hersam MC, Lauhon LJ. Influence of stoichiometry on the optical and electrical properties of chemical vapor deposition derived MoS2. ACS Nano 2014; 8:10551-8. [PMID: 25223821 PMCID: PMC4212723 DOI: 10.1021/nn503988x] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 09/15/2014] [Indexed: 05/19/2023]
Abstract
Ultrathin transition metal dichalcogenides (TMDCs) of Mo and W show great potential for digital electronics and optoelectronic applications. Whereas early studies were limited to mechanically exfoliated flakes, the large-area synthesis of 2D TMDCs has now been realized by chemical vapor deposition (CVD) based on a sulfurization reaction. The optoelectronic properties of CVD grown monolayer MoS2 have been intensively investigated, but the influence of stoichiometry on the electrical and optical properties has been largely overlooked. Here we systematically vary the stoichiometry of monolayer MoS2 during CVD via controlled sulfurization and investigate the associated changes in photoluminescence and electrical properties. X-ray photoelectron spectroscopy is employed to measure relative variations in stoichiometry and the persistence of MoOx species. As MoS2-δ is reduced (increasing δ), the field-effect mobility of monolayer transistors increases while the photoluminescence yield becomes nonuniform. Devices fabricated from monolayers with the lowest sulfur content have negligible hysteresis and a threshold voltage of ∼ 0 V. We conclude that the electrical and optical properties of monolayer MoS2 crystals can be tuned via stoichiometry engineering to meet the requirements of various applications.
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Affiliation(s)
- In Soo Kim
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinod K. Sangwan
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Deep Jariwala
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Joshua D. Wood
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Spencer Park
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Kan-Sheng Chen
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Fengyuan Shi
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Francisco Ruiz-Zepeda
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Arturo Ponce
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Miguel Jose-Yacaman
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Vinayak P. Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- International Institute of Nanotechnology, Northwestern University, Evanston, Illinois 60208, United States
| | - Tobin J. Marks
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C. Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Department of Medicine, Northwestern University, Evanston, Illinois 60208, United States
- Address correspondence to ,
| | - Lincoln J. Lauhon
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Address correspondence to ,
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241
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Hung AH, Holbrook RJ, Rotz MW, Glasscock CJ, Mansukhani ND, MacRenaris KW, Manus LM, Duch MC, Dam KT, Hersam MC, Meade TJ. Graphene oxide enhances cellular delivery of hydrophilic small molecules by co-incubation. ACS Nano 2014; 8:10168-77. [PMID: 25226566 PMCID: PMC4212791 DOI: 10.1021/nn502986e] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/16/2014] [Indexed: 05/22/2023]
Abstract
The delivery of bioactive molecules into cells has broad applications in biology and medicine. Polymer-modified graphene oxide (GO) has recently emerged as a de facto noncovalent vehicle for hydrophobic drugs. Here, we investigate a different approach using native GO to deliver hydrophilic molecules by co-incubation in culture. GO adsorption and delivery were systematically studied with a library of 15 molecules synthesized with Gd(III) labels to enable quantitation. Amines were revealed to be a key chemical group for adsorption, while delivery was shown to be quantitatively predictable by molecular adsorption, GO sedimentation, and GO size. GO co-incubation was shown to enhance delivery by up to 13-fold and allowed for a 100-fold increase in molecular incubation concentration compared to the alternative of nanoconjugation. When tested in the application of Gd(III) cellular MRI, these advantages led to a nearly 10-fold improvement in sensitivity over the state-of-the-art. GO co-incubation is an effective method of cellular delivery that is easily adoptable by researchers across all fields.
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Affiliation(s)
- Andy H. Hung
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Robert J. Holbrook
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Matthew W. Rotz
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Cameron J. Glasscock
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Nikhita D. Mansukhani
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Keith W. MacRenaris
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Lisa M. Manus
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Matthew C. Duch
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
| | - Kevin T. Dam
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Mark C. Hersam
- Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, United States
- Address correspondence to ;
| | - Thomas J. Meade
- Department of Chemistry, Molecular Biosciences, Neurobiology, Biomedical Engineering, and Radiology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
- Address correspondence to ;
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242
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Jaber-Ansari L, Puntambekar KP, Tavassol H, Yildirim H, Kinaci A, Kumar R, Saldaña SJ, Gewirth AA, Greeley JP, Chan MKY, Hersam MC. Defect evolution in graphene upon electrochemical lithiation. ACS Appl Mater Interfaces 2014; 6:17626-36. [PMID: 25265029 DOI: 10.1021/am503715g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Despite rapidly growing interest in the application of graphene in lithium ion batteries, the interaction of the graphene with lithium ions and electrolyte species during electrochemical cycling is not fully understood. In this work, we use Raman spectroscopy in a model system of monolayer graphene transferred on a Si(111) substrate and density functional theory (DFT) to investigate defect formation as a function of lithiation. This model system enables the early stages of defect formation to be probed in a manner previously not possible with commonly used reduced graphene oxide or multilayer graphene substrates. Using ex situ and Ar-atmosphere Raman spectroscopy, we detected a rapid increase in graphene defect level for small increments in the number of lithiation/delithiation cycles until the I(D)/I(G) ratio reaches ∼1.5-2.0 and the 2D peak intensity drops by ∼50%, after which the Raman spectra show minimal changes upon further cycling. Using DFT, the interplay between graphene topological defects and chemical functionalization is explored, thus providing insight into the experimental results. In particular, the DFT results show that defects can act as active sites for species that are present in the electrochemical environment such as Li, O, and F. Furthermore, chemical functionalization with these species lowers subsequent defect formation energies, thus accelerating graphene degradation upon cycling. This positive feedback loop continues until the defect concentration reaches a level where lithium diffusion through the graphene can occur in a relatively unimpeded manner, with minimal further degradation upon extended cycling. Overall, this study provides mechanistic insight into graphene defect formation during lithiation, thus informing ongoing efforts to employ graphene in lithium ion battery technology.
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Affiliation(s)
- Laila Jaber-Ansari
- Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States
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243
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Abstract
Tip-enhanced Raman spectroscopy (TERS) has experienced tremendous growth in the last 5 years. Specifically, TER imaging has provided invaluable insight into the spatial distribution and properties of chemical species on a surface with spatial resolution that is otherwise unattainable by any other analytical method. Additionally, there has been further development in coupling ultrafast spectroscopy with TERS in the hope of obtaining both ultrafast temporal and nanometer-scale spatial resolution. In this Perspective, we discuss several recent advances in TERS, specifically highlighting those in the areas of TER imaging and integrating ultrafast spectroscopy with TERS.
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Affiliation(s)
- Matthew D Sonntag
- †Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Eric A Pozzi
- †Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Nan Jiang
- †Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- ‡Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Richard P Van Duyne
- †Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
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244
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Gong M, Shastry TA, Xie Y, Bernardi M, Jasion D, Luck KA, Marks TJ, Grossman JC, Ren S, Hersam MC. Polychiral semiconducting carbon nanotube-fullerene solar cells. Nano Lett 2014; 14:5308-14. [PMID: 25101896 DOI: 10.1021/nl5027452] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Single-walled carbon nanotubes (SWCNTs) have highly desirable attributes for solution-processable thin-film photovoltaics (TFPVs), such as broadband absorption, high carrier mobility, and environmental stability. However, previous TFPVs incorporating photoactive SWCNTs have utilized architectures that have limited current, voltage, and ultimately power conversion efficiency (PCE). Here, we report a solar cell geometry that maximizes photocurrent using polychiral SWCNTs while retaining high photovoltage, leading to record-high efficiency SWCNT-fullerene solar cells with average NREL certified and champion PCEs of 2.5% and 3.1%, respectively. Moreover, these cells show significant absorption in the near-infrared portion of the solar spectrum that is currently inaccessible by many leading TFPV technologies.
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Affiliation(s)
- Maogang Gong
- Department of Chemistry, University of Kansas , Lawrence, Kansas 66045, United States
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245
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Chowdhury I, Duch MC, Mansukhani ND, Hersam MC, Bouchard D. Interactions of graphene oxide nanomaterials with natural organic matter and metal oxide surfaces. Environ Sci Technol 2014; 48:9382-9390. [PMID: 25026416 DOI: 10.1021/es5020828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Interactions of graphene oxide (GO) nanomaterials with natural organic matter (NOM) and metal oxide surfaces were investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Three different types of NOM were studied: Suwannee River humic and fulvic acids (SRHA and SRFA) and alginate. Aluminum oxide surface was used as a model metal oxide surface. Deposition trends show that GO has the highest attachment on alginate, followed by SRFA, SRHA, and aluminum oxide surfaces, and that GO displayed higher interactions with all investigated surfaces than with silica. Deposition and release behavior of GO on aluminum oxide surface is very similar to positively charged poly-L-lysine-coated surface. Higher interactions of GO with NOM-coated surfaces are attributed to the hydroxyl, epoxy, and carboxyl functional groups of GO; higher deposition on alginate-coated surfaces is attributed to the rougher surface created by the extended conformation of the larger alginate macromolecules. Both ionic strength (IS) and ion valence (Na(+) vs Ca(2+)) had notable impact on interactions of GO with different environmental surfaces. Due to charge screening, increased IS resulted in greater deposition for NOM-coated surfaces. Release behavior of deposited GO varied significantly between different environmental surfaces. All surfaces showed significant release of deposited GO upon introduction of low IS water, indicating that deposition of GO on these surfaces is reversible. Release of GO from NOM-coated surfaces decreased with IS due to charge screening. Release rates of deposited GO from alginate-coated surface were significantly lower than from SRHA and SRFA-coated surfaces due to trapping of GO within the rough surface of the alginate layer.
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Affiliation(s)
- Indranil Chowdhury
- National Research Council Research Associate, Athens, Georgia 30605, United States
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246
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Pozzi EA, Sonntag MD, Jiang N, Chiang N, Seideman T, Hersam MC, Van Duyne RP. Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy with Picosecond Excitation. J Phys Chem Lett 2014; 5:2657-2661. [PMID: 26277959 DOI: 10.1021/jz501239z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Tip-enhanced Raman spectroscopy (TERS) provides chemical information about adsorbates with nanoscale spatial resolution, but developments are still required in order to incorporate ultrafast temporal resolution. In this Letter, we demonstrate that a reliable TER signal of rhodamine 6G (R6G) using picosecond (ps)-pulsed excitation can be obtained in ultrahigh vacuum (UHV). In contrast to our previous observation of irreversible signal loss in ambient TERS ( Klingsporn , J. M. ; Sonntag , M. D. ; Seideman , T. ; Van Duyne , R. P. J. Phys. Chem. Lett. 2014 , 5 , 106 - 110 ), we demonstrate that the UHV environment decreases irreversible signal degradation. As a complement to the TERS experiments, we examined the rate of surface-enhanced Raman (SER) signal decay under picosecond irradiation and found that it is also slowed in UHV compared to that in ambient. Signal decay kinetics suggest that the predominant mechanism responsible for signal loss in ps SERS of R6G is surface diffusion. Both diffusive and reactive phenomena can lead to pulsed excitation TER signal loss, and a UHV environment is advantageous in either scenario.
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Affiliation(s)
- Eric A Pozzi
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Matthew D Sonntag
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Nan Jiang
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Naihao Chiang
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Tamar Seideman
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Mark C Hersam
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Richard P Van Duyne
- †Department of Chemistry, ‡Department of Materials Science and Engineering, and §Applied Physics Program, Northwestern University, Evanston, Illinois 60208, United States
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247
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Abstract
Having fueled the microelectronics industry for over 50 years, silicon is arguably the most studied and influential semiconductor. With the recent emergence of two-dimensional (2D) materials (e.g., graphene, MoS2, phosphorene, etc.), it is natural to contemplate the behavior of Si in the 2D limit. Guided by atomic-scale studies utilizing ultrahigh vacuum (UHV), scanning tunneling microscopy (STM), and spectroscopy (STS), we have investigated the 2D limits of Si growth on Ag(111). In contrast to previous reports of a distinct sp(2)-bonded silicene allotrope, we observe the evolution of apparent surface alloys (ordered 2D silicon-Ag surface phases), which culminate in the precipitation of crystalline, sp(3)-bonded Si(111) nanosheets. These nanosheets are capped with a √3 honeycomb phase that is isostructural to a √3 honeycomb-chained-trimer (HCT) reconstruction of Ag on Si(111). Further investigations reveal evidence for silicon intermixing with the Ag(111) substrate followed by surface precipitation of crystalline, sp(3)-bonded silicon nanosheets. These conclusions are corroborated by ex situ atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Even at the 2D limit, scanning tunneling spectroscopy shows that the sp(3)-bonded silicon nanosheets exhibit semiconducting electronic properties.
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Affiliation(s)
- Andrew J Mannix
- Center for Nanoscale Materials, Argonne National Laboratory , 9700 South Cass Avenue, Building 440, Argonne, Illinois 60439, United States
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248
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Secor EB, Lim S, Zhang H, Frisbie CD, Francis LF, Hersam MC. Gravure printing of graphene for large-area flexible electronics. Adv Mater 2014; 26:4533-8. [PMID: 24782064 DOI: 10.1002/adma.201401052] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 03/26/2014] [Indexed: 05/25/2023]
Abstract
Gravure printing of graphene is demonstrated for the rapid production of conductive patterns on flexible substrates. Development of suitable inks and printing parameters enables the fabrication of patterns with a resolution down to 30 μm. A mild annealing step yields conductive lines with high reliability and uniformity, providing an efficient method for the integration of graphene into large-area printed and flexible electronics.
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Affiliation(s)
- Ethan B Secor
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois, 60208
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249
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Kim B, Jang S, Geier ML, Prabhumirashi PL, Hersam MC, Dodabalapur A. High-speed, inkjet-printed carbon nanotube/zinc tin oxide hybrid complementary ring oscillators. Nano Lett 2014; 14:3683-3687. [PMID: 24849313 DOI: 10.1021/nl5016014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The materials combination of inkjet-printed single-walled carbon nanotubes (SWCNTs) and zinc tin oxide (ZTO) is very promising for large-area thin-film electronics. We compare the characteristics of conventional complementary inverters and ring oscillators measured in air (with SWCNT p-channel field effect transistors (FETs) and ZTO n-channel FETs) with those of ambipolar inverters and ring oscillators comprised of bilayer SWCNT/ZTO FETs. This is the first such comparison between the performance characteristics of ambipolar and conventional inverters and ring oscillators. The measured signal delay per stage of 140 ns for complementary ring oscillators is the fastest for any ring oscillator circuit with printed semiconductors to date.
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Affiliation(s)
- Bongjun Kim
- Microelectronics Research Center, The University of Texas at Austin , Austin, Texas 78758, United States
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250
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Abstract
Recent advances in semiconductor performance made possible by organic π-electron molecules, carbon-based nanomaterials, and metal oxides have been a central scientific and technological research focus over the past decade in the quest for flexible and transparent electronic products. However, advances in semiconductor materials require corresponding advances in compatible gate dielectric materials, which must exhibit excellent electrical properties such as large capacitance, high breakdown strength, low leakage current density, and mechanical flexibility on arbitrary substrates. Historically, conventional silicon dioxide (SiO2) has dominated electronics as the preferred gate dielectric material in complementary metal oxide semiconductor (CMOS) integrated transistor circuitry. However, it does not satisfy many of the performance requirements for the aforementioned semiconductors due to its relatively low dielectric constant and intransigent processability. High-k inorganics such as hafnium dioxide (HfO2) or zirconium dioxide (ZrO2) offer some increases in performance, but scientists have great difficulty depositing these materials as smooth films at temperatures compatible with flexible plastic substrates. While various organic polymers are accessible via chemical synthesis and readily form films from solution, they typically exhibit low capacitances, and the corresponding transistors operate at unacceptably high voltages. More recently, researchers have combined the favorable properties of high-k metal oxides and π-electron organics to form processable, structurally well-defined, and robust self-assembled multilayer nanodielectrics, which enable high-performance transistors with a wide variety of unconventional semiconductors. In this Account, we review recent advances in organic-inorganic hybrid gate dielectrics, fabricated by multilayer self-assembly, and their remarkable synergy with unconventional semiconductors. We first discuss the principals and functional importance of gate dielectric materials in thin-film transistor (TFT) operation. Next, we describe the design, fabrication, properties, and applications of solution-deposited multilayer organic-inorganic hybrid gate dielectrics, using self-assembly techniques, which provide bonding between the organic and inorganic layers. Finally, we discuss approaches for preparing analogous hybrid multilayers by vapor-phase growth and discuss the properties of these materials.
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Affiliation(s)
- Young-Geun Ha
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Chemistry, Kyonggi University, Suwon, Gyeonggi-Do 443-760, Republic of Korea
| | - Ken Everaerts
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Mark C. Hersam
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
| | - Tobin J. Marks
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, United States
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