1
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Esteki K, Curic D, Manning HG, Sheerin E, Ferreira MS, Boland JJ, Rocha CG. Thermo-electro-optical properties of seamless metallic nanowire networks for transparent conductor applications. Nanoscale 2023. [PMID: 37294276 DOI: 10.1039/d3nr01130e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Rapid reaction time, high attainable temperatures, minimum operating voltage, excellent optical transmittance, and tunable sheet resistance are all desirable properties of transparent conductors, which are important thin-film components in numerous electronic devices. A seamless nanowire network (NWN) refers to a structure composed of nanowires that lack interwire contact junctions, resulting in a continuous and uninterrupted network arrangement. This seamless nature leads to unique properties, including high conductivity and surface area-to-volume ratios, which make it a promising candidate for a vast application range in nanotechnology. Here, we have conducted an in-depth computational investigation to study the thermo-electro-optical properties of seamless nanowire networks and understand their geometrical features using in-house computational implementations and a coupled electrothermal model built in COMSOL Multiphysics software. Sheet resistance calculations were performed using Ohm's law combined with Kirchhoff circuit laws for a random resistor network and compared with those obtained employing COMSOL. In this work, aluminium, gold, copper, and silver nanowires are the materials of choice for testing the transparent conduction performance of our systems. We have studied a wide range of tuning parameters, including the network area fraction, the width-to-depth aspect ratio, and the length of the nanowire segments. We obtained corresponding figures of merit (optical transmittance versus sheet resistance) and temperature distributions to provide a complete characterization of the performance of real-world transparent conductors idealized with seamless NWNs. Our analysis accounted for the thermo-electro-optical responses of the NWNs and the inspection of various controlling parameters depending on system design considerations to shed light on how the electrical transport, optical qualities, and thermal management of these systems can be optimized.
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Affiliation(s)
- K Esteki
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
| | - D Curic
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
| | - H G Manning
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - E Sheerin
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - M S Ferreira
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - J J Boland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - C G Rocha
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
- Institute for Quantum Science and Technology, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
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2
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Lynes AD, Lovitt JI, Rotella C, Boland JJ, Gunnlaugsson T, Hawes CS. Crystal engineering studies of a series of pyridine-3,5-dicarboxamide ligands possessing alkyl ester arms, and their coordination chemistry. Results in Chemistry 2022. [DOI: 10.1016/j.rechem.2022.100679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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3
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Li D, Sheerin ED, Shi Y, Xiao L, Yang L, Boland JJ, Wang JJ. Alcohol Pretreatment to Eliminate the Interference of Micro Additive Particles in the Identification of Microplastics Using Raman Spectroscopy. Environ Sci Technol 2022; 56:12158-12168. [PMID: 36006854 PMCID: PMC9454250 DOI: 10.1021/acs.est.2c01551] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 08/10/2022] [Accepted: 08/10/2022] [Indexed: 06/15/2023]
Abstract
Raman spectroscopy is an indispensable tool in the analysis of microplastics smaller than 20 μm. However, due to its limitation, Raman spectroscopy may be incapable of effectively distinguishing microplastics from micro additive particles. To validate this hypothesis, we characterized and compared the Raman spectra of six typical slip additives with polyethylene and found that their hit quality index values (0.93-0.96) are much higher than the accepted threshold value (0.70) used to identify microplastics. To prevent this interference, a new protocol involving an alcohol treatment step was introduced to successfully eliminate additive particles and accurately identify microplastics. Tests using the new protocol showed that three typical plastic products (polyethylene pellets, polyethylene bottle caps, and polypropylene food containers) can simultaneously release microplastic-like additive particles and microplastics regardless of the plastic type, daily-use scenario, or service duration. Micro additive particles can also adsorb onto and modify the surfaces of microplastics in a manner that may potentially increase their health risks. This study not only reveals the hidden problem associated with the substantial interference of additive particles in microplastic detection but also provides a cost-effective method to eliminate this interference and a rigorous basis to quantify the risks associated with microplastic exposure.
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Affiliation(s)
- Dunzhu Li
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
- Department
of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Emmet D. Sheerin
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
- School
of Chemistry, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Yunhong Shi
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
- Department
of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Liwen Xiao
- Department
of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin D02 PN40, Ireland
- TrinityHaus, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Luming Yang
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
- Department
of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - John J. Boland
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
- School
of Chemistry, Trinity College Dublin, Dublin D02 PN40, Ireland
| | - Jing Jing Wang
- AMBER
Research Centre and Centre for Research on Adaptive Nanostructures
and Nanodevices (CRANN), Trinity College
Dublin, Dublin D02 PN40, Ireland
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4
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Shi Y, Li D, Xiao L, Sheerin ED, Mullarkey D, Yang L, Bai X, Shvets IV, Boland JJ, Wang JJ. The influence of drinking water constituents on the level of microplastic release from plastic kettles. J Hazard Mater 2022; 425:127997. [PMID: 34986566 DOI: 10.1016/j.jhazmat.2021.127997] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [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: 08/12/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Microplastic (MP) release from household plastic products has become a global concern due to the high recorded levels of microplastic and the direct risk of human exposure. However, the most widely used MP measurement protocol, which involves the use of deionized (DI) water, fails to account for the ions and particles present in real drinking water. In this paper, the influence of typical ions (Ca2+/HCO3-, Fe3+, Cu2+) and particles (Fe2O3 particles) on MP release was systematically investigated by conducting a 100-day study using plastic kettles. Surprisingly, after 40 days, all ions resulted in a greater than 89.0% reduction in MP release while Fe2O3 particles showed no significant effect compared to the DI water control. The MP reduction efficiency ranking is Fe3+ ≈ Cu2+ > Ca2+/HCO3- > > Fe2O3 particles ≈ DI water. Physical and chemical characterization using SEM-EDX, AFM, XPS and Raman spectroscopy confirmed Ca2+/HCO3-, Cu2+ and Fe3+ ions are transformed into passivating films of CaCO3, CuO, and Fe2O3, respectively, which are barriers to MP release. In contrast, there was no film formed when the plastic was exposed to Fe2O3 particles. Studies also confirmed that films with different chemical compositions form naturally in kettles during real life due to the different ions present in local regional water supplies. All films identified in this study can substantially reduce the levels of MP release while withstanding the repeated adverse conditions associated with daily use. This study underscores the potential for regional variations in human MP exposure due to the substantial impact water constituents have on the formation of passivating film formation and the subsequent release of MPs.
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Affiliation(s)
- Yunhong Shi
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Dunzhu Li
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Liwen Xiao
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland; TrinityHaus, Trinity College Dublin, Dublin 2, Ireland.
| | - Emmet D Sheerin
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Daragh Mullarkey
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Luming Yang
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin, Dublin 2, Ireland
| | - Xue Bai
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Igor V Shvets
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - John J Boland
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland; School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
| | - Jing Jing Wang
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
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5
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Esteki K, Manning HG, Sheerin E, Ferreira MS, Boland JJ, Gomes da Rocha C. Tuning the electro-optical properties of nanowire networks. Nanoscale 2021; 13:15369-15379. [PMID: 34498659 DOI: 10.1039/d1nr03944j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Conductive and transparent metallic nanowire networks are regarded as promising alternatives to Indium-Tin-Oxides (ITOs) in emerging flexible next-generation technologies due to their prominent optoelectronic properties and low-cost fabrication. The performance of such systems closely relies on many geometrical, physical, and intrinsic properties of the nanowire materials as well as the device-layout. A comprehensive computational study is essential to model and quantify the device's optical and electrical responses prior to fabrication. Here, we present a computational toolkit that exploits the electro-optical specifications of distinct device-layouts, namely standard random nanowire network and transparent mesh pattern structures. The target materials for transparent conducting electrodes of this study are aluminium, gold, copper, and silver nanowires. We have examined a variety of tunable parameters including network area fraction, length to diameter aspect ratio, and nanowires angular orientations under different device designs. Moreover, the optical extinction efficiency factors of each material are estimated by two approaches: Mie light scattering theory and finite element method (FEM) algorithm implemented in COMSOL®Multiphysics software. We studied various nanowire network structures and calculated their respective figures of merit (optical transmittance versus sheet resistance) from which insights on the design of next-generation transparent conductor devices can be inferred.
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Affiliation(s)
- Koorosh Esteki
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
| | - Hugh G Manning
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Emmet Sheerin
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Mauro S Ferreira
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - John J Boland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Claudia Gomes da Rocha
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
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6
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Li D, Yang L, Kavanagh R, Xiao L, Shi Y, Kehoe DK, Sheerin ED, Gun'ko YK, Boland JJ, Wang JJ. Sampling, Identification and Characterization of Microplastics Release from Polypropylene Baby Feeding Bottle during Daily Use. J Vis Exp 2021. [PMID: 34369927 DOI: 10.3791/62545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Microplastics (MPs) are becoming a global concern due to the potential risk to human health. Case studies of plastic products (i.e., plastic single-use cups and kettles) indicate that MP release during daily use can be extremely high. Precisely determining the MP release level is a crucial step to identify and quantify the exposure source and assess/control the corresponding risks stemming from this exposure. Though protocols for measuring MP levels in marine or freshwater has been well developed, the conditions experienced by household plastic products can vary widely. Many plastic products are exposed to frequent high temperatures (up to 100 °C) and are cooled back to room temperature during daily use. It is therefore crucial to develop a sampling protocol that mimics the actual daily-use scenario for each particular product. This study focused on widely used polypropylene-based baby feeding bottles to develop a cost-effective protocol for MP release studies of many plastic products. The protocol developed here enables: 1) prevention of the potential contamination during sampling and detection; 2) realistic implementation of daily-use scenarios and accurate collection of the MPs released from baby feeding bottles based on WHO guidelines; and 3) cost-effective chemical determination and physical topography mapping of MPs released from baby feeding bottles. Based on this protocol, the recovery percentage using standard polystyrene MP (diameter of 2 µm) was 92.4-101.2% while the detected size was around 102.2% of the designed size. The protocol detailed here provides a reliable and cost-effective method for MP sample preparation and detection, which can substantially benefit future studies of MP release from plastic products.
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Affiliation(s)
- Dunzhu Li
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin
| | - Luming Yang
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin
| | - Rachel Kavanagh
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin
| | - Liwen Xiao
- Department of Civil, Structural and Environmental Engineering, Trinity College Dublin; TrinityHaus, Trinity College Dublin;
| | - Yunhong Shi
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin; Department of Civil, Structural and Environmental Engineering, Trinity College Dublin
| | - Daniel K Kehoe
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin
| | - Emmet D Sheerin
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin; School of Chemistry, Trinity College Dublin
| | - Yurii K Gun'ko
- School of Chemistry, Trinity College Dublin; BEACON, Bioeconomy SFI Research Centre, University College Dublin
| | - John J Boland
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin; School of Chemistry, Trinity College Dublin;
| | - Jing Jing Wang
- AMBER Research Centre and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin;
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7
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Biswas S, Doherty J, Galluccio E, Manning HG, Conroy M, Duffy R, Bangert U, Boland JJ, Holmes JD. Stretching the Equilibrium Limit of Sn in Ge 1-x Sn x Nanowires: Implications for Field Effect Transistors. ACS Appl Nano Mater 2021; 4:1048-1056. [PMID: 34056558 PMCID: PMC8153542 DOI: 10.1021/acsanm.0c02569] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/25/2021] [Indexed: 06/12/2023]
Abstract
Ge1-x Sn x nanowires incorporating a large amount of Sn would be useful for mobility enhancement in nanoelectronic devices, a definitive transition to a direct bandgap for application in optoelectronic devices and to increase the efficiency of the GeSn-based photonic devices. Here we report the catalytic bottom-up fabrication of Ge1-x Sn x nanowires with very high Sn incorporation (x > 0.3). These nanowires are grown in supercritical toluene under high pressure (21 MPa). The introduction of high pressure in the vapor-liquid-solid (VLS) like growth regime resulted in a substantial increase of Sn incorporation in the nanowires, with a Sn content ranging between 10 and 35 atom %. The incorporation of Sn in the nanowires was found to be inversely related to nanowire diameter; a high Sn content of 35 atom % was achieved in very thin Ge1-x Sn x nanowires with diameters close to 20 nm. Sn was found to be homogeneously distributed throughout the body of the nanowires, without apparent clustering or segregation. The large inclusion of Sn in the nanowires could be attributed to the nanowire growth kinetics and small nanowire diameters, resulting in increased solubility of Sn in Ge at the metastable liquid-solid interface under high pressure. Electrical investigation of the Ge1-x Sn x (x = 0.10) nanowires synthesized by the supercritical fluid approach revealed their potential in nanoelectronics and sensor-based applications.
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Affiliation(s)
- Subhajit Biswas
- School
of Chemistry and Advanced Materials and Bioengineering Research (AMBER)
Centre, University College Cork, Cork T12 YN60, Ireland
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | - Jessica Doherty
- School
of Chemistry and Advanced Materials and Bioengineering Research (AMBER)
Centre, University College Cork, Cork T12 YN60, Ireland
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | | | - Hugh G. Manning
- School
of Chemistry and AMBER, Trinity College
Dublin, Dublin 2, Ireland
| | - Michele Conroy
- TEMUL,
Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - Ray Duffy
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
| | - Ursel Bangert
- TEMUL,
Department of Physics, Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
| | - John J. Boland
- School
of Chemistry and AMBER, Trinity College
Dublin, Dublin 2, Ireland
| | - Justin D. Holmes
- School
of Chemistry and Advanced Materials and Bioengineering Research (AMBER)
Centre, University College Cork, Cork T12 YN60, Ireland
- Tyndall
National Institute, University College Cork, Cork T12 R5CP, Ireland
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8
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Alialy S, Esteki K, Ferreira MS, Boland JJ, Gomes da Rocha C. Nonlinear ion drift-diffusion memristance description of TiO 2 RRAM devices. Nanoscale Adv 2020; 2:2514-2524. [PMID: 36133364 PMCID: PMC9419089 DOI: 10.1039/d0na00195c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 04/20/2020] [Indexed: 06/16/2023]
Abstract
The nature and direction of the hysteresis in memristive devices is critical to device operation and performance and the ability to realise their potential in neuromorphic applications. TiO2 is a prototypical memristive device material and is known to show hysteresis loops with both clockwise switching and counter-clockwise switching and in many instances evidence of negative differential resistance (NDR) behaviour. Here we study the electrical response of a device composed of a single nanowire channel Au-Ti/TiO2/Ti-Au both in air and under vacuum and simulate the I-V characteristics in each case using the Schottky barrier and an ohmic-like transport memristive model which capture nonlinear diffusion and migration of ions within the wire. The dynamics of this complex charge conduction phenomenon is obtained by fitting the nonlinear ion-drift equations with the experimental data. Our experimental results support a nonlinear drift of oxygen vacancies acting as shallow donors under vacuum conditions. Simulations show that dopant diffusion under bias creates a depletion region along the channel which results in NDR behaviour, but it is overcome at higher applied bias due to oxygen vacancy generation at the anode. The model allows the motion of the charged dopants to be visualised during device operation in air and under vacuum and predicts the elimination of the NDR under low bias operation, in agreement with experiments.
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Affiliation(s)
- Sahar Alialy
- School of Chemistry, Trinity College Dublin Dublin 2 Dublin Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Advanced Materials and Bioengineering Research (AMBER) Research Centre, Trinity College Dublin Dublin 2 Dublin Ireland
| | - Koorosh Esteki
- Department of Physics and Astronomy, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
| | - Mauro S Ferreira
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Advanced Materials and Bioengineering Research (AMBER) Research Centre, Trinity College Dublin Dublin 2 Dublin Ireland
- School of Physics, Trinity College Dublin Dublin 2 Dublin Ireland
| | - John J Boland
- School of Chemistry, Trinity College Dublin Dublin 2 Dublin Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Advanced Materials and Bioengineering Research (AMBER) Research Centre, Trinity College Dublin Dublin 2 Dublin Ireland
| | - Claudia Gomes da Rocha
- Department of Physics and Astronomy, University of Calgary 2500 University Drive NW Calgary Alberta T2N 1N4 Canada
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9
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Jadwiszczak J, Keane D, Maguire P, Cullen CP, Zhou Y, Song H, Downing C, Fox D, McEvoy N, Zhu R, Xu J, Duesberg GS, Liao ZM, Boland JJ, Zhang H. MoS 2 Memtransistors Fabricated by Localized Helium Ion Beam Irradiation. ACS Nano 2019; 13:14262-14273. [PMID: 31790198 DOI: 10.1021/acsnano.9b07421] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [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
Two-dimensional (2D) layered semiconductors have recently emerged as attractive building blocks for next-generation low-power nonvolatile memories. However, challenges remain in the controllable fabrication of bipolar resistive switching circuit components from these materials. Here, the experimental realization of lateral memtransistors from monolayer single-crystal molybdenum disulfide (MoS2) utilizing a focused helium ion beam is reported. Site-specific irradiation with the focused probe of a helium ion microscope creates a nanometer-scale defect-rich region, bisecting the MoS2 lattice. The reversible drift of these defects in the applied electric field modulates the resistance of the channel, enabling versatile memristive functionality. The device can reliably retain its resistance ratios and set/reset biases for 1180 switching cycles. Long-term potentiation and depression with sharp habituation are demonstrated. This work establishes the feasibility of ion irradiation for controllable fabrication of 2D memristive devices with promising key performance parameters, such as low power consumption. The applicability of these devices for synaptic emulation may address the demands of future neuromorphic architectures.
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Affiliation(s)
- Jakub Jadwiszczak
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Physics , Trinity College Dublin , Dublin 2 , Ireland
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , People's Republic of China
- School of Material Science and Engineering , Nanchang University , Youxun W Road , Xinjian Qu, Nanchang Shi , Jiangxi Sheng 330031 , People's Republic of China
| | - Darragh Keane
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Pierce Maguire
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| | - Conor P Cullen
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Yangbo Zhou
- School of Material Science and Engineering , Nanchang University , Youxun W Road , Xinjian Qu, Nanchang Shi , Jiangxi Sheng 330031 , People's Republic of China
| | - Huading Song
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , People's Republic of China
| | - Clive Downing
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Daniel Fox
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Physics , Trinity College Dublin , Dublin 2 , Ireland
| | - Niall McEvoy
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Rui Zhu
- Electron Microscopy Laboratory, School of Physics , Peking University , Beijing 100871 , People's Republic of China
| | - Jun Xu
- Electron Microscopy Laboratory, School of Physics , Peking University , Beijing 100871 , People's Republic of China
| | - Georg S Duesberg
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
- State Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology , Universität der Bundeswehr München , Werner-Heisenberg-Weg 39 , Neubiberg 85577 , Germany
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics, School of Physics , Peking University , Beijing 100871 , People's Republic of China
- Collaborative Innovation Center of Quantum Matter , Beijing 100871 , People's Republic of China
| | - John J Boland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Hongzhou Zhang
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER) Research Centers , Trinity College Dublin , Dublin 2 , Ireland
- School of Physics , Trinity College Dublin , Dublin 2 , Ireland
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10
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Alialy S, Gabriel M, Davitt F, Holmes JD, Boland JJ. Switching at the contacts in Ge 9Sb 1Te 5 phase-change nanowire devices. Nanotechnology 2019; 30:335706. [PMID: 31026844 DOI: 10.1088/1361-6528/ab1cf8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phase-change random access memory is a promising approach to non-volatile memory. However, the inability to secure consistent, reliable switching on a nanometre scale may limit its practical use for high density applications. Here, we report on the switching behaviour of PCRAM cells comprised of single crystalline Ge9Sb1Te5 (GST) nanowires. We show that device switching is dominated by the contacts and does not result in a resistance change within the bulk of the wire. For the devices studied, the typical contact resistance was ∼30 kΩ, whereas the resistance of the GST channel was 1.8 kΩ. The applied voltage was predominately dropped across the passivating oxide on the surface of the GST nanowires, resulting in local resistive switching at the contacts and local power dissipation, which limited the endurance of the devices produced. The optimal device must balance low resistance contacts with a more resistive channel, to facilitate phase change switching within the nanowires. These results highlight the importance of contact formation on the switching properties in phase change devices and help guide the future design of more reliable neuromorphic devices.
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Affiliation(s)
- Sahar Alialy
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland. Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
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11
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Manning HG, da Rocha CG, Callaghan CO, Ferreira MS, Boland JJ. The Electro-Optical Performance of Silver Nanowire Networks. Sci Rep 2019; 9:11550. [PMID: 31399603 PMCID: PMC6689048 DOI: 10.1038/s41598-019-47777-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/23/2019] [Indexed: 11/09/2022] Open
Abstract
Networks of metallic nanowires have the potential to meet the needs of next-generation device technologies that require flexible transparent conductors. At present, there does not exist a first principles model capable of predicting the electro-optical performance of a nanowire network. Here we combine an electrical model derived from fundamental material properties and electrical equations with an optical model based on Mie theory scattering of light by small particles. This approach enables the generation of analogues for any nanowire network and then accurately predicts, without the use of fitting factors, the optical transmittance and sheet resistance of the transparent electrode. Predictions are validated using experimental data from the literature of networks comprised of a wide range of aspect ratios (nanowire length/diameter). The separation of the contributions of the material resistance and the junction resistance allows the effectiveness of post-deposition processing methods to be evaluated and provides a benchmark for the minimum attainable sheet resistance. The predictive power of this model enables a material-by-design approach, whereby suitable systems can be prescribed for targeted technology applications.
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Affiliation(s)
- Hugh G Manning
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland.
| | - Claudia Gomes da Rocha
- Department of Physics and Astronomy, University of Calgary, 2500 University Drive NW Calgary, Alberta, T2N 1N4, Canada
| | - Colin O' Callaghan
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Mauro S Ferreira
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - John J Boland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
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12
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Boland JJ. Corrigendum: Material characterisation of nanowires with Intrinsic stress (2017 Nanotechnology 28 355706). Nanotechnology 2019. [PMID: 31247603 DOI: 10.1088/1361-6528/ab2d37] [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: 06/09/2023]
Abstract
This is to provide a correction to the acknowledgement section of the previously published paper: Mills, S., Sader, J.E., Boland, J.J. "Material characterisation of nanowires with Intrinsic stress" Nanotechnology 28(35), Article No: 355706, 01 September 2017. DOI: 10.1088/1361-6528/aa7c31.
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Affiliation(s)
- John J Boland
- Department of Chemistry, Trinity College Dublin, Trinity College, Dublin, Dublin, IRELAND
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13
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Mills S, Rotella C, McCarthy EK, Hill DJ, Wang JJ, Donegan JF, Cahoon JF, Sader JE, Boland JJ. Solvent-Engineered Stress in Nanoscale Materials. ACS Appl Mater Interfaces 2018; 10:44183-44189. [PMID: 30460845 DOI: 10.1021/acsami.8b17201] [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: 06/09/2023]
Abstract
Nanoscale materials are frequently coated with surface stabilization layers during growth that prevent flocculation in solution and facilitate processing technologies such as ink-jet device printing. Here, we show that few-nanometer-thick stabilization layers typically used swell in the presence of certain solvents and impart significant stresses to the nanomaterial that remains even after the solvent has evaporated. Solvent swelling of the surface layer dramatically enhances nanomaterial-substrate adhesion via the collapse of the stabilization layer during solvent evaporation, preventing stress relaxation. We demonstrate the stress modulation of Ag, Au, and Si nanowires functionalised with surface polymers and surfactant layers and detect strain levels between 0.1 and 0.6% using atomic force microscopy mechanical measurement and Raman spectroscopy. Dry-transferred nanowires exhibit poor adhesion and show no evidence of incorporated stress but become stressed immediately following solvent exposure. Strain engineering is demonstrated by coating nanowires with few-nanometer-thick solvent-responsive polymer layers.
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Affiliation(s)
| | | | | | - David J Hill
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599-3290 , United States
| | | | | | - James F Cahoon
- Department of Chemistry , University of North Carolina at Chapel Hill , Chapel Hill , North Carolina 27599-3290 , United States
| | - John E Sader
- ARC Centre of Excellence in Exciton Science, School of Mathematics and Statistics , University of Melbourne , Parkville , Victoria 3010 , Australia
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14
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Manning HG, Niosi F, da Rocha CG, Bellew AT, O'Callaghan C, Biswas S, Flowers PF, Wiley BJ, Holmes JD, Ferreira MS, Boland JJ. Emergence of winner-takes-all connectivity paths in random nanowire networks. Nat Commun 2018; 9:3219. [PMID: 30104665 PMCID: PMC6089893 DOI: 10.1038/s41467-018-05517-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 07/10/2018] [Indexed: 11/09/2022] Open
Abstract
Nanowire networks are promising memristive architectures for neuromorphic applications due to their connectivity and neurosynaptic-like behaviours. Here, we demonstrate a self-similar scaling of the conductance of networks and the junctions that comprise them. We show this behavior is an emergent property of any junction-dominated network. A particular class of junctions naturally leads to the emergence of conductance plateaus and a "winner-takes-all" conducting path that spans the entire network, and which we show corresponds to the lowest-energy connectivity path. The memory stored in the conductance state is distributed across the network but encoded in specific connectivity pathways, similar to that found in biological systems. These results are expected to have important implications for development of neuromorphic devices based on reservoir computing.
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Affiliation(s)
- Hugh G Manning
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Fabio Niosi
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Claudia Gomes da Rocha
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Allen T Bellew
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Colin O'Callaghan
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Subhajit Biswas
- Materials Chemistry & Analysis Group, School of Chemistry and the Tyndall National Institute, University College Cork, Cork, Ireland
| | - Patrick F Flowers
- Department of Chemistry, Duke University, Durham, 27708, North Carolina, USA
| | - Benjamin J Wiley
- Department of Chemistry, Duke University, Durham, 27708, North Carolina, USA
| | - Justin D Holmes
- Materials Chemistry & Analysis Group, School of Chemistry and the Tyndall National Institute, University College Cork, Cork, Ireland
| | - Mauro S Ferreira
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - John J Boland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & Advanced Materials and Bioengineering Research (AMBER) Centre, Trinity College Dublin, Dublin 2, Ireland.
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15
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Naydenov B, Torsney S, Bonilla AS, El Garah M, Ciesielski A, Gualandi A, Mengozzi L, Cozzi PG, Gutierrez R, Samorì P, Cuniberti G, Boland JJ. Self-Assembled Two-Dimensional Supramolecular Networks Characterized by Scanning Tunneling Microscopy and Spectroscopy in Air and under Vacuum. Langmuir 2018; 34:7698-7707. [PMID: 29889539 DOI: 10.1021/acs.langmuir.8b01374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We combine ambient (air) and ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) and spectroscopy (STS) investigations together with density functional theory (DFT) calculations to gain a subnanometer insight into the structure and dynamic of two-dimensional (2D) surface-supported molecular networks. The planar tetraferrocene-porphyrin molecules employed in this study undergo spontaneous self-assembly via the formation of hydrogen bonded networks at the gold substrate-solution interface. To mimic liquid phase ambient deposition conditions, film formation was accomplished in UHV by electro-spraying a solution of the molecule in chloroform onto an Au(111) substrate, thereby providing access to the full spectroscopic capabilities of STM that can be hardly attained under ambient conditions. We show that molecular assembly on Au (111) is identical in films prepared under the two different conditions, and in good agreement with the theoretical predictions. However, we observe the contrast found for a given STM bias condition to be different in ambient and UHV conditions despite the similarity of the structures, and we propose possible origins of the different imaging contrast. This approach could be valuable for the thorough characterization of surface systems that involve large molecules and are prepared mainly in ambient conditions.
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Affiliation(s)
- Borislav Naydenov
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Samuel Torsney
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
| | - Alejandro Santana Bonilla
- Institute for Materials Sciences and Max Bergmann Center of Biomaterials , TU Dresden , 01062 Dresden , Germany
| | - Mohamed El Garah
- Université de Strasbourg, CNRS, ISIS , 8 alleé Gaspard Monge , 67000 Strasbourg France
| | - Artur Ciesielski
- Université de Strasbourg, CNRS, ISIS , 8 alleé Gaspard Monge , 67000 Strasbourg France
| | - Andrea Gualandi
- Dipartimento di Chimica "G. Ciamician" , Alma Mater Studiorum Università di Bologna , Via Selmi 2 , 40126 Bologna , Italy
| | - Luca Mengozzi
- Dipartimento di Chimica "G. Ciamician" , Alma Mater Studiorum Università di Bologna , Via Selmi 2 , 40126 Bologna , Italy
| | - Pier Giorgio Cozzi
- Dipartimento di Chimica "G. Ciamician" , Alma Mater Studiorum Università di Bologna , Via Selmi 2 , 40126 Bologna , Italy
| | - Rafael Gutierrez
- Institute for Materials Sciences and Max Bergmann Center of Biomaterials , TU Dresden , 01062 Dresden , Germany
| | - Paolo Samorì
- Université de Strasbourg, CNRS, ISIS , 8 alleé Gaspard Monge , 67000 Strasbourg France
| | - Gianaurelio Cuniberti
- Institute for Materials Sciences and Max Bergmann Center of Biomaterials , TU Dresden , 01062 Dresden , Germany
- Dresden Center for Computational Materials Science (DCCMS) , TU Dresden , 01062 Dresden , Germany
- Center for Advancing Electronics Dresden , TU Dresden , 01062 Dresden , Germany
| | - John J Boland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) & School of Chemistry , Trinity College Dublin , Dublin 2 , Ireland
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16
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Hossain M, Kumar GS, Barimar Prabhava SN, Sheerin ED, McCloskey D, Acharya S, Rao KDM, Boland JJ. Transparent, Flexible Silicon Nanostructured Wire Networks with Seamless Junctions for High-Performance Photodetector Applications. ACS Nano 2018; 12:4727-4735. [PMID: 29726674 DOI: 10.1021/acsnano.8b01387] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Optically transparent photodetectors are crucial in next-generation optoelectronic applications including smart windows and transparent image sensors. Designing photodetectors with high transparency, photoresponsivity, and robust mechanical flexibility remains a significant challenge, as is managing the inevitable trade-off between high transparency and strong photoresponse. Here we report a scalable method to produce flexible crystalline Si nanostructured wire (NW) networks fabricated from silicon-on-insulator (SOI) with seamless junctions and highly responsive porous Si segments that combine to deliver exceptional performance. These networks show high transparency (∼92% at 550 nm), broadband photodetection (350 to 950 nm) with excellent responsivity (25 A/W), optical response time (0.58 ms), and mechanical flexibility (1000 cycles). Temperature-dependent photocurrent measurements indicate the presence of localized electronic states in the porous Si segments, which play a crucial role in light harvesting and photocarrier generation. The scalable low-cost approach based on SOI has the potential to deliver new classes of flexible optoelectronic devices, including next-generation photodetectors and solar cells.
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Affiliation(s)
- Mozakkar Hossain
- Technical Research Centre , Indian Association for the Cultivation of Science , Jadavpur , Kolkata - 700032 , India
| | - Gundam Sandeep Kumar
- Centre for Advanced Materials , Indian Association for the Cultivation of Science , Jadavpur , Kolkata - 700032 , India
| | - S N Barimar Prabhava
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) , Trinity College Dublin , College Green, Dublin 2 , Ireland
| | - Emmet D Sheerin
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) , Trinity College Dublin , College Green, Dublin 2 , Ireland
| | - David McCloskey
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) , Trinity College Dublin , College Green, Dublin 2 , Ireland
| | - Somobrata Acharya
- Centre for Advanced Materials , Indian Association for the Cultivation of Science , Jadavpur , Kolkata - 700032 , India
| | - K D M Rao
- Technical Research Centre , Indian Association for the Cultivation of Science , Jadavpur , Kolkata - 700032 , India
| | - John J Boland
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) , Trinity College Dublin , College Green, Dublin 2 , Ireland
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17
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Jadwiszczak J, O’Callaghan C, Zhou Y, Fox DS, Weitz E, Keane D, Cullen CP, O’Reilly I, Downing C, Shmeliov A, Maguire P, Gough JJ, McGuinness C, Ferreira MS, Bradley AL, Boland JJ, Duesberg GS, Nicolosi V, Zhang H. Oxide-mediated recovery of field-effect mobility in plasma-treated MoS 2. Sci Adv 2018; 4:eaao5031. [PMID: 29511736 PMCID: PMC5837433 DOI: 10.1126/sciadv.aao5031] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 01/24/2018] [Indexed: 05/22/2023]
Abstract
Precise tunability of electronic properties of two-dimensional (2D) nanomaterials is a key goal of current research in this field of materials science. Chemical modification of layered transition metal dichalcogenides leads to the creation of heterostructures of low-dimensional variants of these materials. In particular, the effect of oxygen-containing plasma treatment on molybdenum disulfide (MoS2) has long been thought to be detrimental to the electrical performance of the material. We show that the mobility and conductivity of MoS2 can be precisely controlled and improved by systematic exposure to oxygen/argon plasma and characterize the material using advanced spectroscopy and microscopy. Through complementary theoretical modeling, which confirms conductivity enhancement, we infer the role of a transient 2D substoichiometric phase of molybdenum trioxide (2D-MoO x ) in modulating the electronic behavior of the material. Deduction of the beneficial role of MoO x will serve to open the field to new approaches with regard to the tunability of 2D semiconductors by their low-dimensional oxides in nano-modified heterostructures.
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Affiliation(s)
- Jakub Jadwiszczak
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Colin O’Callaghan
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Yangbo Zhou
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Materials Science and Engineering, Nanchang University, 999 Xuefu Road, Nanchang, Jiangxi 330031, China
| | - Daniel S. Fox
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Eamonn Weitz
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Darragh Keane
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Conor P. Cullen
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Ian O’Reilly
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
| | - Clive Downing
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - Aleksey Shmeliov
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Pierce Maguire
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - John J. Gough
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
| | - Cormac McGuinness
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
| | - Mauro S. Ferreira
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
| | - A. Louise Bradley
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
| | - John J. Boland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Georg S. Duesberg
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
- Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85577 Neubiberg, Germany
| | - Valeria Nicolosi
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland
| | - Hongzhou Zhang
- School of Physics, Trinity College Dublin, Dublin 2, Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland
- Advanced Materials and BioEngineering Research Centre, Trinity College Dublin, Dublin 2, Ireland
- Corresponding author.
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18
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Abstract
Nonpolar resistive switching (RS), a combination of bipolar and unipolar RS, is demonstrated for the first time in a single nanowire (NW) system. Exploiting Ag@TiO2 core-shell (CS) NWs synthesized by postgrowth shell formation, the switching mode is controlled by adjusting the current compliance effectively, tailoring the electrical polarity response. We demonstrate ON/OFF ratios of 105 and 107 for bipolar and unipolar modes, respectively. In the bipolar regime, retention times could be controlled up to 103 s, and in the unipolar mode, >106 s was recorded. We show how the unique dual-mode switching behavior is enabled by the defect-rich polycrystalline material structure of the TiO2 shell and the interaction between the Ag core and the Ag electrodes. These results provide a foundation for engineering nonpolar RS behaviors for memory storage and neuromorphic applications in CSNW structures.
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Affiliation(s)
| | - Subhajit Biswas
- School of Chemistry, University College Cork , Cork T12 YN60, Ireland
| | - Justin D Holmes
- School of Chemistry, University College Cork , Cork T12 YN60, Ireland
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19
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Mills S, Sader JE, Boland JJ. Material characterisation of nanowires with intrinsic stress. Nanotechnology 2017; 28:355706. [PMID: 28656901 DOI: 10.1088/1361-6528/aa7c31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
When fabricating nanowires (NWs) in a doubly-clamped beam configuration it is possible for a residual axial stress to be generated. Here, we show that material characterisation of metal and semiconductor NWs subjected to residual axial stress can be problematic. Benchmark measurements of the Young's modulus of NWs are performed by sectioning a doubly-clamped NW into two cantilevered wires, eliminating residual axial stress. Use of models for doubly-clamped beams that incorporate the effects of residual stress are found to lead to ambiguity in the extracted Young's modulus as a function of displacement fit range, even for NWs with no residual stress. This is due to coupling of bending and axial stress effects at small displacements, and the limited displacement range of force curves prior to fracture or plastic deformation. This study highlights the importance of fabricating metal and semiconductor NWs that exhibit little or no residual axial stress for materials characterisation.
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Affiliation(s)
- S Mills
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland. Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
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20
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Zhang X, Han J, Plombon JJ, Sutton AP, Srolovitz DJ, Boland JJ. Nanocrystalline copper films are never flat. Science 2017; 357:397-400. [DOI: 10.1126/science.aan4797] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/21/2017] [Indexed: 11/02/2022]
Affiliation(s)
- Xiaopu Zhang
- School of Chemistry, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER), Trinity College Dublin, Dublin 2, Ireland
| | - Jian Han
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John J. Plombon
- Components Research, Intel Corporation, Hillsboro, OR 97124, USA
| | - Adrian P. Sutton
- Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, UK
| | - David J. Srolovitz
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - John J. Boland
- School of Chemistry, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials and Bioengineering Research (AMBER), Trinity College Dublin, Dublin 2, Ireland
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21
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Dangi MB, Schoenberger E, Boland JJ. Assessment of environmental policy implementation in solid waste management in Kathmandu, Nepal. Waste Manag Res 2017; 35:618-626. [PMID: 28393635 DOI: 10.1177/0734242x17699683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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: 05/21/2023]
Abstract
In Nepal, full-fledged environmental legislation was rare before the democratic constitution of 1990. The first law covering the environment and sustainability was the Environment Protection Act 1997. While the Solid Waste Act was introduced in 1987, the problem of solid waste management still surfaces in Kathmandu. In order to understand the bedrock of this unrelenting failure in solid waste management, the manuscript digs deeper into policy implementation by dissecting solid waste rules, environmental legislations, relevant local laws, and solid waste management practices in Kathmandu, Nepal. A very rich field study that included surveys, interviews, site visits, and literature review provided the basis for the article. The study shows that volumes of new Nepalese rules are crafted without effective enforcement of their predecessors and there is a frequent power struggle between local government bodies and central authority in implementing the codes and allocating resources in solid waste management. The study concludes that Kathmandu does not require any new instrument to address solid waste problems; instead, it needs creation of local resources, execution of local codes, and commitment from central government to allow free exercise of these policies.
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Affiliation(s)
- Mohan B Dangi
- Department of Geography and Environmental Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Erica Schoenberger
- Department of Geography and Environmental Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - John J Boland
- Department of Geography and Environmental Engineering, The Johns Hopkins University, Baltimore, MD, USA
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22
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Fairfield JA, Rocha CG, O'Callaghan C, Ferreira MS, Boland JJ. Co-percolation to tune conductive behaviour in dynamical metallic nanowire networks. Nanoscale 2016; 8:18516-18523. [PMID: 27782246 DOI: 10.1039/c6nr06276h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nanowire networks act as self-healing smart materials, whose sheet resistance can be tuned via an externally applied voltage stimulus. This memristive response occurs due to modification of junction resistances to form a connectivity path across the lowest barrier junctions in the network. While most network studies have been performed on expensive noble metal nanowires like silver, networks of inexpensive nickel nanowires with a nickel oxide coating can also demonstrate resistive switching, a common feature of metal oxides with filamentary conduction. However, networks made from solely nickel nanowires have high operation voltages which prohibit large-scale material applications. Here we show, using both experiment and simulation, that a heterogeneous network of nickel and silver nanowires allows optimization of the activation voltage, as well as tuning of the conduction behavior to be either resistive switching, memristive, or a combination of both. Small percentages of silver nanowires, below the percolation threshold, induce these changes in electrical behaviour, even for low area coverage and hence very transparent films. Silver nanowires act as current concentrators, amplifying conductivity locally as shown in our computational dynamical activation framework for networks of junctions. These results demonstrate that a heterogeneous nanowire network can act as a cost-effective adaptive material with minimal use of noble metal nanowires, without losing memristive behaviour that is essential for smart sensing and neuromorphic applications.
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Affiliation(s)
- J A Fairfield
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
| | - C G Rocha
- School of Physics, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
| | - C O'Callaghan
- School of Physics, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
| | - M S Ferreira
- School of Physics, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
| | - J J Boland
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland.
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23
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Abstract
We demonstrate templating of functional materials with unexpected and intricate micro- and nanostructures by controlling the condensation, packing, and evaporation of water droplets on a polymer solution. Spontaneous evaporation of a polymer solution induces cooling of the liquid surface and water microdroplet condensation from the ambient vapor. These droplets pack together and act as a template to imprint an entangled polymer film. This breath figure (BF) phenomenon is an example of self-organization that involves the long-range ordering of droplets. Equilibrium-based analysis provides many insights into contact angles and drop stability of individual drops, but the BF phenomenon remains poorly understood thus far, preventing translation to real applications. Here we investigate the dynamics of this phenomenon to separate out the competing influences and then introduce a modulation scheme to ultimately manipulate the water vapor-liquid equilibrium independently from the solvent evaporation. This approach to BF control provides insights into the mechanism, a rationale for microstructure design, and evidence for the benefits of dynamical control of self-organization systems. We finally present dramatically different porous architectures from this approach reminiscent of microscale Petri dishes, conical flasks, and test tubes.
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Affiliation(s)
| | - John E Sader
- School of Mathematics and Statistics, The University of Melbourne , Victoria 3010, Australia
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24
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O'Callaghan C, Gomes da Rocha C, Manning HG, Boland JJ, Ferreira MS. Effective medium theory for the conductivity of disordered metallic nanowire networks. Phys Chem Chem Phys 2016; 18:27564-27571. [DOI: 10.1039/c6cp05187a] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An analytical model with dependance on all important underlying parameters to calculate the electrical properties of nanowire networks is presented.
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Affiliation(s)
- Colin O'Callaghan
- School of Physics
- Trinity College Dublin
- Dublin 2
- Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
| | - Claudia Gomes da Rocha
- School of Physics
- Trinity College Dublin
- Dublin 2
- Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
| | - Hugh G. Manning
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
- Trinity College Dublin
- Dublin 2
- Ireland
- AMBER Research Centre
| | - John J. Boland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
- Trinity College Dublin
- Dublin 2
- Ireland
- AMBER Research Centre
| | - Mauro S. Ferreira
- School of Physics
- Trinity College Dublin
- Dublin 2
- Ireland
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN)
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25
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Bellew AT, Manning HG, Gomes da Rocha C, Ferreira MS, Boland JJ. Resistance of Single Ag Nanowire Junctions and Their Role in the Conductivity of Nanowire Networks. ACS Nano 2015; 9:11422-11429. [PMID: 26448205 DOI: 10.1021/acsnano.5b05469] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [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
Networks of silver nanowires appear set to replace expensive indium tin oxide as the transparent conducting electrode material in next generation devices. The success of this approach depends on optimizing the material conductivity, which until now has largely focused on minimizing the junction resistance between wires. However, there have been no detailed reports on what the junction resistance is, nor is there a known benchmark for the minimum attainable sheet resistance of an optimized network. In this paper, we present junction resistance measurements of individual silver nanowire junctions, producing for the first time a distribution of junction resistance values and conclusively demonstrating that the junction contribution to the overall resistance can be reduced beyond that of the wires through standard processing techniques. We find that this distribution shows the presence of a small percentage (6%) of high-resistance junctions, and we show how these may impact the performance of network-based materials. Finally, through combining experiment with a rigorous model, we demonstrate the important role played by the network skeleton and the specific connectivity of the network in determining network performance.
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Affiliation(s)
- Allen T Bellew
- School of Chemistry, ‡School of Physics, and §Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin , College Green, Dublin 2, Ireland
| | - Hugh G Manning
- School of Chemistry, ‡School of Physics, and §Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin , College Green, Dublin 2, Ireland
| | - Claudia Gomes da Rocha
- School of Chemistry, ‡School of Physics, and §Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin , College Green, Dublin 2, Ireland
| | - Mauro S Ferreira
- School of Chemistry, ‡School of Physics, and §Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin , College Green, Dublin 2, Ireland
| | - John J Boland
- School of Chemistry, ‡School of Physics, and §Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin , College Green, Dublin 2, Ireland
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26
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Gomes da Rocha C, Manning HG, O'Callaghan C, Ritter C, Bellew AT, Boland JJ, Ferreira MS. Ultimate conductivity performance in metallic nanowire networks. Nanoscale 2015; 7:13011-6. [PMID: 26169222 DOI: 10.1039/c5nr03905c] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In this work, we introduce a combined experimental and computational approach to describe the conductivity of metallic nanowire networks. Due to their highly disordered nature, these materials are typically described by simplified models in which network junctions control the overall conductivity. Here, we introduce a combined experimental and simulation approach that involves a wire-by-wire junction-by-junction simulation of an actual network. Rather than dealing with computer-generated networks, we use a computational approach that captures the precise spatial distribution of wires from an SEM analysis of a real network. In this way, we fully account for all geometric aspects of the network, i.e. for the properties of the junctions and wire segments. Our model predicts characteristic junction resistances that are smaller than those found by earlier simplified models. The model outputs characteristic values that depend on the detailed connectivity of the network, which can be used to compare the performance of different networks and to predict the optimum performance of any network and its scope for improvement.
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27
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Kotova O, Daly R, dos Santos CMG, Kruger PE, Boland JJ, Gunnlaugsson T. Cross-Linking the Fibers of Supramolecular Gels Formed from a Tripodal Terpyridine Derived Ligand with d-Block Metal Ions. Inorg Chem 2015. [DOI: 10.1021/acs.inorgchem.5b00626] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Oxana Kotova
- School of Chemistry, Trinity Biomedical
Sciences Institute (TBSI), University of Dublin, Trinity College
Dublin, Dublin 2, Ireland
| | - Ronan Daly
- Department of Engineering, University of Cambridge, Charles Babbage
Road, Cambridge CB3 0FS, United Kingdom
| | - Cidália M. G. dos Santos
- School of Chemistry, Trinity Biomedical
Sciences Institute (TBSI), University of Dublin, Trinity College
Dublin, Dublin 2, Ireland
| | - Paul E. Kruger
- MacDiarmid Institute for Advanced Materials
and Nanotechnology, Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
| | - John J. Boland
- School of Chemistry,
Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), University of Dublin, Trinity College Dublin, Dublin 2, Ireland
| | - Thorfinnur Gunnlaugsson
- School of Chemistry, Trinity Biomedical
Sciences Institute (TBSI), University of Dublin, Trinity College
Dublin, Dublin 2, Ireland
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28
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Harte NP, Klyubin I, McCarthy EK, Min S, Garrahy SA, Xie Y, Davey GP, Boland JJ, Rowan MJ, Mok KH. Amyloid Oligomers and Mature Fibrils Prepared from an Innocuous Protein Cause Diverging Cellular Death Mechanisms. J Biol Chem 2015. [PMID: 26221033 DOI: 10.1074/jbc.m115.676072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [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: 12/22/2022] Open
Abstract
Despite significant advances, the molecular identity of the cytotoxic species populated during in vivo amyloid formation crucial for the understanding of neurodegenerative disorders is yet to be revealed. In this study lysozyme prefibrillar oligomers and fibrils in both mature and sonicated states have been isolated through an optimized ultrafiltration/ultracentrifugation method and characterized with various optical spectroscopic techniques, atomic force microscopy, and transmission electron microscopy. We examined their level and mode of toxicity on rat pheochromocytoma (PC12) cells in both differentiated and undifferentiated states. We find that oligomers and fibrils display cytotoxic capabilities toward cultured cells in vitro, with oligomers producing elevated levels of cellular injury toward undifferentiated PC12 cells (PC12(undiff)). Furthermore, dual flow cytometry staining experiments demonstrate that the oligomers and mature fibrils induce divergent cellular death pathways (apoptosis and secondary necrosis, respectively) in these PC12 cells. We have also shown that oligomers but not sonicated mature fibrils inhibit hippocampal long term potentiation, a form of synaptic plasticity implicated in learning and memory, in vivo. We conclude that our in vitro and in vivo findings confer a level of resistance toward amyloid fibrils, and that the PC 12-based comparative cytotoxicity assay can provide insights into toxicity differences between differently aggregated protein species.
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Affiliation(s)
- Níal P Harte
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Igor Klyubin
- Department of Pharmacology and Therapeutics, Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Eoin K McCarthy
- School of Chemistry, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland; Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Soyoung Min
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Sarah Ann Garrahy
- TCIN, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Yongjing Xie
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Gavin P Davey
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland; TCIN, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - John J Boland
- School of Chemistry, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland; Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - Michael J Rowan
- Department of Pharmacology and Therapeutics, Trinity College Institute of Neuroscience (TCIN), Trinity College Dublin, the University of Dublin, Dublin 2, Ireland
| | - K Hun Mok
- Trinity Biomedical Sciences Institute (TBSI), School of Biochemistry and Immunology, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland; Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, the University of Dublin, Dublin 2, Ireland.
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29
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Bell AP, Fairfield JA, McCarthy EK, Mills S, Boland JJ, Baffou G, McCloskey D. Quantitative study of the photothermal properties of metallic nanowire networks. ACS Nano 2015; 9:5551-8. [PMID: 25938797 DOI: 10.1021/acsnano.5b01673] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In this article, we present a comprehensive investigation of the photothermal properties of plasmonic nanowire networks. We measure the local steady-state temperature increase, heat source density, and absorption in Ag, Au, and Ni metallic nanowire networks under optical illumination. This allows direct experimental confirmation of increased heat generation at the junction between two metallic nanowires and stacking-dependent absorption of polarized light. Due to thermal collective effects, the local temperature distribution in a network is shown to be completely delocalized on a micrometer scale, despite the nanoscale features in the heat source density. Comparison of the experimental temperature profile with numerical simulation allows an upper limit for the effective thermal conductivity of a Ag nanowire network to be established at 43 Wm(-1) K(-1) (0.1 κbulk).
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Affiliation(s)
| | | | | | | | | | - Guillaume Baffou
- ∥Institut Fresnel, UMR 7249, CNRS, Aix Marseille Université, Centrale Marseille, 13013 Marseille, France
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30
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Abstract
We describe the fabrication, operation principles, and simulation of a coherent single-atom quantum interference device (QID) structure on Si(100) controlled by the properties of single atoms. The energy and spatial distribution of the wave functions associated with the device are visualized by scanning tunneling spectroscopy and the amplitude and phase of the evanescent wave functions that couple into the quantum well states are directly measured, including the action of an electrostatic gate. Density functional theory simulations were employed to simulate the electronic structure of the device structure, which is in excellent agreement with the measurements. Simulations of device transmission demonstrate that our coherent single-atom QID can have ON-OFF ratios in excess of 10(3) with potentially minimal power dissipation.
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Affiliation(s)
- Borislav Naydenov
- †School of Chemistry, ‡School of Physics, and §Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
| | - Ivan Rungger
- †School of Chemistry, ‡School of Physics, and §Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
| | - Mauro Mantega
- †School of Chemistry, ‡School of Physics, and §Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
| | - Stefano Sanvito
- †School of Chemistry, ‡School of Physics, and §Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
| | - John J Boland
- †School of Chemistry, ‡School of Physics, and §Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
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31
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Martínez-Calvo M, Kotova O, Möbius ME, Bell AP, McCabe T, Boland JJ, Gunnlaugsson T. Healable luminescent self-assembly supramolecular metallogels possessing lanthanide (Eu/Tb) dependent rheological and morphological properties. J Am Chem Soc 2015; 137:1983-92. [PMID: 25590898 DOI: 10.1021/ja511799n] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Herein we present the use of lanthanide directed self-assembly formation (Ln(III) = Eu(III), Tb(III)) in the generation of luminescent supramolecular polymers, that when swelled with methanol give rise to self-healing supramolecular gels. These were analyzed by using luminescent and (1)H NMR titrations studies, allowing for the identification of the various species involved in the subsequent Ln(III)-gel formation. These highly luminescent gels could be mixed to give a variety of luminescent colors depending on their Eu(III):Tb(III) stoichiometric ratios. Imaging and rheological studies showed that these gels prepared using only Eu(III) or only Tb(III) have different morphological and rheological properties, that are also different from those determined upon forming gels by mixing of Eu(III) and Tb(III) gels. Hence, our results demonstrate for the first time the crucial role the lanthanide ions play in the supramolecular polymerization process, which is in principle a host-guest interaction, and consequently in the self-healing properties of the corresponding gels, which are dictated by the same host-guest interactions.
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Affiliation(s)
- Miguel Martínez-Calvo
- School of Chemistry and Trinity Biomedical Sciences Institute (TBSI), Trinity College Dublin, University of Dublin , 152-160 Pearse Street, Dublin 2, Ireland
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32
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Abstract
Nanoscale devices that are sensitive to measurement history enable memory applications, and memristors are currently under intense investigation for robustness and functionality. Here we describe the fabrication and performance of a memristor-like device that comprises a single TiO2 nanowire in contact with Au electrodes, demonstrating both high sensitivity to electrical stimuli and high levels of control. Through an electroforming process, a population of charged dopants is created at the interface between the wire and electrode that can be manipulated to demonstrate a range of device and memristor characteristics. In contrast to conventional two-terminal memristors, our device is essentially a diode that exhibits memristance in the forward bias direction. The device is easily reset to the off state by a single voltage pulse and can be incremented to provide a range of controllable conductance states in the forward direction. Electrochemical modification of the Schottky barrier at the electrodes is proposed as an underlying mechanism, and six-level memory operations are demonstrated on a single nanowire.
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Affiliation(s)
- Curtis O'Kelly
- School of Chemistry and CRANN Institute, Trinity College Dublin , Dublin 2, Ireland
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33
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Fairfield JA, Ritter C, Bellew AT, McCarthy EK, Ferreira MS, Boland JJ. Effective electrode length enhances electrical activation of nanowire networks: experiment and simulation. ACS Nano 2014; 8:9542-9549. [PMID: 25153920 DOI: 10.1021/nn5038515] [Citation(s) in RCA: 7] [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: 06/03/2023]
Abstract
Networks comprised of randomly oriented overlapping nanowires offer the possibility of simple fabrication on a variety of substrates, in contrast with the precise placement required for devices with single or aligned nanowires. Metal nanowires typically have a coating of surfactant or oxide that prevents aggregation, but also prevents electrical connection. Prohibitively high voltages can be required to electrically activate nanowire networks, and even after activation many nanowire junctions remain nonconducting. Nonelectrical activation methods can enhance conductivity but destroy the memristive behavior of the junctions that comprise the network. We show through both simulation and experiment that electrical stimulation, microstructured electrode geometry, and feature scaling can all be used to manipulate the connectivity and thus electrical conductivity of networks of silver nanowires with a nonconducting polymer coating. More generally, these results describe a strategy to integrate nanomaterials into controllable, adaptive macroscale materials.
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34
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Abstract
Electrical connectivity in networks of nanoscale junctions must be better understood if nanowire devices are to be scaled up from single wires to functional material systems. We show that the natural connectivity behaviour found in random nanowire networks presents a new paradigm for creating multi-functional, programmable materials. In devices made from networks of Ni/NiO core-shell nanowires at different length scales, we discover the emergence of distinct behavioural regimes when networks are electrically stressed. We show that a small network, with few nanowire-nanowire junctions, acts as a unipolar resistive switch, demonstrating very high ON/OFF current ratios (>10(5)). However, large networks of nanowires distribute an applied bias across a large number of junctions, and thus respond not by switching but instead by evolving connectivity. We demonstrate that these emergent properties lead to fault-tolerant materials whose resistance may be tuned, and which are capable of adaptively reconfiguring under stress. By combining these two behavioural regimes, we demonstrate that the same nanowire network may be programmed to act both as a metallic interconnect, and a resistive switch device with high ON/OFF ratio. These results enable the fabrication of programmable, multi-functional materials from random nanowire networks.
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Affiliation(s)
- A T Bellew
- School of Chemistry, Trinity College Dublin, Dublin 2, Ireland.
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35
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Byrne JP, Kitchen JA, Kotova O, Leigh V, Bell AP, Boland JJ, Albrecht M, Gunnlaugsson T. Synthesis, structural, photophysical and electrochemical studies of various d-metal complexes of btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] ligands that give rise to the formation of metallo-supramolecular gels. Dalton Trans 2014; 43:196-209. [DOI: 10.1039/c3dt52309h] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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36
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Naydenov B, Boland JJ. Engineering the electronic structure of surface dangling bond nanowires of different size and dimensionality. Nanotechnology 2013; 24:275202. [PMID: 23765570 DOI: 10.1088/0957-4484/24/27/275202] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We demonstrate how the local density of electronic states evolves as the size and dimensionality of surface dangling bond nanowires are modified. These wires were fabricated using the probe of a scanning tunneling microscope on a hydrogen passivated n-type Si(100)-(2 × 1) surface. We demonstrate that by varying the number and arrangement of dangling bonds on the surface it is possible to arbitrarily engineer the electronic characteristic of a surface nanowire from that of a semiconductor with a controllable band gap to that of a metal.
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Affiliation(s)
- Borislav Naydenov
- School of Chemistry and Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College, Dublin 2, Ireland
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37
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Daly R, Kotova O, Boese M, Gunnlaugsson T, Boland JJ. Chemical nano-gardens: growth of salt nanowires from supramolecular self-assembly gels. ACS Nano 2013; 7:4838-4845. [PMID: 23663045 DOI: 10.1021/nn305813y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this article, we examine the phenomenon of single-crystal halide salt wire growth at the surface of porous materials. We report the use of a single-step casting technique with a supramolecular self-assembly gel matrix that upon drying leads to the growth of single-crystal halide (e.g., NaCl, KCl, and KI) nanowires with diameters ~130-200 nm. We demonstrate their formation using electron microscopy and electron-dispersive X-ray spectroscopy, showing that the supramolecular gel stabilizes the growth of these wires by facilitating a diffusion-driven base growth mechanism. Critically, we show that standard non-supramolecular gels are unable to facilitate nanowire growth. We further show that these nanowires can be grown by seeding, forming nanocrystal gardens. This study helps understand the possible prefunctionalization of membranes to stimulate ion-specific filters or salt efflorescence suppressors, while also providing a novel route to nanomaterial growth.
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Affiliation(s)
- Ronan Daly
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), University of Dublin, Trinity College Dublin, Dublin 2, Ireland
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38
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Nirmalraj PN, Bellew AT, Bell AP, Fairfield JA, McCarthy EK, O'Kelly C, Pereira LFC, Sorel S, Morosan D, Coleman JN, Ferreira MS, Boland JJ. Manipulating connectivity and electrical conductivity in metallic nanowire networks. Nano Lett 2012; 12:5966-5971. [PMID: 23062152 DOI: 10.1021/nl303416h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Connectivity in metallic nanowire networks with resistive junctions is manipulated by applying an electric field to create materials with tunable electrical conductivity. In situ electron microscope and electrical measurements visualize the activation and evolution of connectivity within these networks. Modeling nanowire networks, having a distribution of junction breakdown voltages, reveals universal scaling behavior applicable to all network materials. We demonstrate how local connectivity within these networks can be programmed and discuss material and device applications.
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39
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Abstract
Single crystal iron nanocubes are produced by simply heating a bilayer film. This surface energy driven growth (SEDG) method exploits the difference in surface energies of the components (γ(Fe) ~ 2.2 J m(-2) versus γ(Nd) ~ 0.7 J m(-2)) in the binary alloy Fe-Nd system to produce nanocubes of the higher energy Fe component. The dimensions of the cubes range from tens to hundreds of nanometers in size and can be controlled by changing the initial thickness of iron in the deposited Fe-Nd bilayer prior to annealing at 700 °C. The composition and structure of the nanocubes was confirmed by transmission electron microscopy analysis as single crystal bcc iron in the α-phase. The cubes were found to exist as core-shell structures with the α-phase encased by an intermetallic Fe-Nd phase, characteristic of the SEDG growth mechanism.
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Affiliation(s)
- Curtis O'Kelly
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanotechnology (CRANN), Trinity College Dublin, Ireland
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40
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Sheridan JG, Heidelberg A, Brougham DF, Nellist PD, Langford RM, Boland JJ. Self-assembly of LiMo3Se3 nanowire networks from nanoscale building-blocks in solution. Langmuir 2012; 28:15344-15349. [PMID: 23009286 DOI: 10.1021/la301918x] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
LiMo(3)Se(3) is a highly anisotropic solid comprised of a regular pattern of quasi-1-D wire-like structures. Solutions of LiMo(3)Se(3) deposited on substrates and TEM grids reveal the presence of two-dimensional network morphologies. High resolution STEM imaging reveals that the junctions within these networks are not formed by discrete overlying LiMo(3)Se(3) fibers or wires. Rather the junctions are continuous in that the wires are seamlessly interwoven from one bundle to the next. We investigated network formation by dynamic light scattering and AFM and demonstrate that the networks are not pre-existent in solution but rather form via self-assembly of nanoscale building blocks that is driven by solvent evaporation.
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Affiliation(s)
- John G Sheridan
- School of Chemistry and the Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Ireland
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41
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Abstract
Standard surface energy balances using literature values for pure liquids predict that water droplets are unstable at the liquid/air interfaces of many common organic solvents. While the behavior of macroscopic drops in the presence of solvents has been studied, the study of droplets in the micrometer size regime and the possible role of line tension are notably absent. In this article, we experimentally investigate the existence and stability of such micrometer-scale droplets formed at air/solvent interfaces and the possible roles played by partial solubility of organic liquids in water and solvent migration in the lowering of the key air/water surface tension. Three solvents are studied: toluene, butyl acetate, and chloroform, using a technique to optically monitor both condensation and manual deposition of water microdroplets onto air/solvent surfaces. This demonstrates both the existence of stable water droplets and allows measurement of the contact angles at the solvent/water/air interface. Contact angles are shown to be independent of droplet size (diameters: 2-30 μm), ruling out a line tension stabilization mechanism for droplets of radii greater than 1 μm. The interfacial tensions of the deposited water droplets are independently measured using an equivalent macroscopic experiment, which yield results consistent with the partial miscibility of toluene and butyl acetate in water. A discrepancy is observed for chloroform, for which possible mechanisms are discussed.
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Affiliation(s)
- Ronan Daly
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices, Trinity College Dublin, Dublin 2, Ireland.
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42
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Kotova O, Daly R, dos Santos CMG, Boese M, Kruger PE, Boland JJ, Gunnlaugsson T. Europium-Directed Self-Assembly of a Luminescent Supramolecular Gel from a Tripodal Terpyridine-Based Ligand. Angew Chem Int Ed Engl 2012; 51:7208-12. [DOI: 10.1002/anie.201201506] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 04/25/2012] [Indexed: 11/09/2022]
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43
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Ryan PM, Teague LC, Meehan DE, Boland JJ. Stereoselective Cycloaddition of 1,3-Cyclohexadiene on Si(100): A Simple Algorithm for Product Identification Based on Secondary Orbital Interactions. J Am Chem Soc 2011; 133:14287-92. [DOI: 10.1021/ja111539b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Peter M. Ryan
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- National Institute for Nanotechnology,11421 Saskatchewan Drive, Edmonton, Alberta, Canada
| | - Lucile C. Teague
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
- Savannah River National Laboratory, Aiken, South Carolina, United States
| | - David E. Meehan
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
| | - John J. Boland
- School of Chemistry and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
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44
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Abstract
Metal-seeded growth of one-dimensional (1D) semiconductor nanostructures is still a very active field of research, despite the huge progress which has been made in understanding this fundamental phenomenon. Liquid growth promoters allow control of the aspect ratio, diameter, and structure of 1D crystals via external parameters, such as precursor feedstock, temperature, and operating pressure. However the transfer of crystallographic information from a catalytic nanoparticle seed to a growing nanowire has not been described in the literature. Here we define the theoretical requirements for transferring defects from nanoparticle seeds to growing semiconductor nanowires and describe why Ag nanoparticles are ideal candidates for this purpose. We detail in this paper the influence of solid Ag growth seeds on the crystal quality of Ge nanowires, synthesized using a supercritical fluid growth process. Significantly, under certain reaction conditions {111} stacking faults in the Ag seeds can be directly transferred to a high percentage of <112>-oriented Ge nanowires, in the form of radial twins in the semiconductor crystals. Defect transfer from nanoparticles to nanowires could open up the possibility of engineering 1D nanostructures with new and tunable physical properties and morphologies.
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Affiliation(s)
- Sven Barth
- Materials and Supercritical Fluids Group, Department of Chemistry and the Tyndall National Institute, University College Cork, Cork, Ireland
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45
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Jung SJ, Lutz T, Boese M, Holmes JD, Boland JJ. Surface energy driven agglomeration and growth of single crystal metal wires. Nano Lett 2011; 11:1294-1299. [PMID: 21344915 DOI: 10.1021/nl104357e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We introduce a novel wire growth technique that involves simply heating a multilayer film specifically designed to take advantage of the different surface energies of the substrate and film components. In all cases the high surface energy component is extruded as a single crystal nanowire. Moreover we demonstrate that patterning the bilayer film generates localized surface agglomeration waves during the anneal that can be exploited to position the grown wires. Examples of Au and Cu nanowire growth are presented, and the generalization of this method to other systems is discussed.
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Affiliation(s)
- Soon Jung Jung
- School of Chemistry, School of Physics, Trinity College Dublin , Dublin 2, Ireland
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46
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Coleman JN, Lotya M, O'Neill A, Bergin SD, King PJ, Khan U, Young K, Gaucher A, De S, Smith RJ, Shvets IV, Arora SK, Stanton G, Kim HY, Lee K, Kim GT, Duesberg GS, Hallam T, Boland JJ, Wang JJ, Donegan JF, Grunlan JC, Moriarty G, Shmeliov A, Nicholls RJ, Perkins JM, Grieveson EM, Theuwissen K, McComb DW, Nellist PD, Nicolosi V. Two-dimensional nanosheets produced by liquid exfoliation of layered materials. Science 2011; 331:568-71. [PMID: 21292974 DOI: 10.1126/science.1194975] [Citation(s) in RCA: 2968] [Impact Index Per Article: 228.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.
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Affiliation(s)
- Jonathan N Coleman
- School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, D2, Ireland.
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47
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Nirmalraj PN, Lutz T, Kumar S, Duesberg GS, Boland JJ. Nanoscale mapping of electrical resistivity and connectivity in graphene strips and networks. Nano Lett 2011; 11:16-22. [PMID: 21128677 DOI: 10.1021/nl101469d] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this article we map out the thickness dependence of the resistivity of individual graphene strips, from single layer graphene through to the formation of graphitic structures. We report exceptionally low resistivity values for single strips and demonstrate that the resistivity distribution for single strips is anomalously narrow when compared to bi- and trilayer graphene, consistent with the unique electronic properties of single graphene layers. In agreement with theoretical predictions, we show that the transition to bulklike resistivities occurs at seven to eight layers of graphene. Moreover, we demonstrate that the contact resistance between graphene flakes in a graphene network scales with the flake thickness and the implications for transparent conductor applications are discussed.
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48
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Abstract
Due to its low beam current and charge compensation mechanism He-Ion scanning microscopy is a very promising tool for imaging biological cells. However, to obtain relevant information, the method used for sample preparation is also critical. In this work, we have used a Carl Zeiss Orion Plus helium-ion microscope to study the effect of sample gold coating on the morphology of human colorectal adenocarcinoma Caco2 cells. The fixative glutaraldehyde was used and the selective gold coating of the samples was investigated. A comparative study with standard scanning electron microscopy is presented.
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Affiliation(s)
- D Bazou
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and CRANN Advanced Microscopy Laboratory, Trinity College Dublin, Ireland
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49
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50
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Nirmalraj PN, Boland JJ. Selective tuning and optimization of the contacts to metallic and semiconducting single-walled carbon nanotubes. ACS Nano 2010; 4:3801-3806. [PMID: 20560537 DOI: 10.1021/nn100432f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Conductance imaging atomic force microscopy was used to probe the electrical interface between single-walled carbon nanotubes and metal electrodes. The contact resistance was optimized by applying a local voltage pulse (approximately 2 s) using a conductive probe with controlled loading force to the region of the metal electrode contacting the nanotube. Using this technique, we show that Pd forms superior contacts, resulting in contact resistance values that are among the lowest ever reported.
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Affiliation(s)
- Peter N Nirmalraj
- School of Chemistry and Center for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland
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