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Wani, I. H., Jafri, S. H., Wärnå, J., Hayat, A., Li, H., Shukla, V. A., . . . Leifer, K. (2019). A sub 20 nm metal-conjugated molecule junction acting as a nitrogen dioxide sensor. Nanoscale, 11(14), 6571-6575
Open this publication in new window or tab >>A sub 20 nm metal-conjugated molecule junction acting as a nitrogen dioxide sensor
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2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 14, p. 6571-6575Article in journal (Refereed) Published
Abstract [en]

The interaction of a gas molecule with a sensing material causes the highest change in the electronic structure of the latter, when this material consists of only a few atoms. If the sensing material consists of a short, conductive molecule, the sensing action can be furthermore probed by connecting such molecules to nanoelectrodes. Here, we report that NO2 molecules that adhere to 4,4'-biphenyldithiol (BPDT) bound to Au surfaces lead to a change of the electrical transmission of the BPDT. The related device shows reproducible, stable measurements and is so far the smallest (<20 nm) gas sensor. It demonstrates modulation of charge transport through molecules upon exposure to nitrogen dioxide down to concentrations of 55 ppb. We have evaluated several devices and exposure conditions and obtained a close to linear dependence of the sensor response on the gas concentration.

National Category
Nano Technology
Identifiers
urn:nbn:se:uu:diva-381056 (URN)10.1039/c8nr08417c (DOI)000464454400007 ()30916070 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationGöran Gustafsson Foundation for Research in Natural Sciences and MedicineCarl Tryggers foundation Swedish Energy AgencySwedish Foundation for Strategic Research
Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-05-03Bibliographically approved
Shukla, V., Grigoriev, A., Jena, N. K. & Ahuja, R. (2018). Strain controlled electronic and transport anisotropies in two-dimensional borophene sheets. Physical Chemistry, Chemical Physics - PCCP, 20(35), 22952-22960
Open this publication in new window or tab >>Strain controlled electronic and transport anisotropies in two-dimensional borophene sheets
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 35, p. 22952-22960Article in journal (Refereed) Published
Abstract [en]

Two recent reports on realization of an elemental 2D analogue of graphene:borophene (Science, 2015, 350, 1513-1516; Nat. Chem., 2016, 8, 563-568) focus on the inherent anisotropy and directional dependence of the electronic properties of borophene polymorphs. Achieving stable 2D borophene structures may lead to some degree of strain in the system because of the substrate-lattice mismatch. We use first principles density functional theory (DFT) calculations to study the structural, electronic and transport properties of (12) and -borophene polymorphs. We verified the directional dependency and found the tunable anisotropic behavior of the transport properties in these two polymorphs. We find that strain as low as 6% brings remarkable changes in the properties of these two structures. We further investigate current-voltage (I-V) characteristics in the low bias regime after applying a strain to see how the anisotropy of the current is affected. Such observations like the sizeable tuning of transport and I-V characteristics at the expense of minimal strain suggest the suitability of 2D borophene for futuristic device applications.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-363428 (URN)10.1039/c8cp03815e (DOI)000445220500055 ()30156222 (PubMedID)
Funder
Swedish Research CouncilSwedish National Infrastructure for Computing (SNIC), SNIC2017-11-28 SNIC2017-5-8 SNIC2017-1-237
Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2019-01-05Bibliographically approved
Parlak, O., Mishra, Y. K., Grigoriev, A., Mecklenburg, M., Luo, W., Keene, S., . . . Tiwari, A. (2017). Hierarchical Aerographite nano-microtubular tetrapodal networks based electrodes as lightweight supercapacitor. Nano Energy, 34, 570-577
Open this publication in new window or tab >>Hierarchical Aerographite nano-microtubular tetrapodal networks based electrodes as lightweight supercapacitor
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2017 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 34, p. 570-577Article in journal (Refereed) Published
Abstract [en]

A great deal of interest has been paid to the application of carbon-based nano-and microstructured materials as electrodes due to their relatively low-cost production, abundance, large surface area, high chemical stability, wide operating temperature range, and ease of processing including many more excellent features. The nanostructured carbon materials usually offer various micro-textures due to their varying degrees of graphitisation, a rich variety in terms of dimensionality as well as morphologies, extremely large surface accessibility and high electrical conductivity, etc. The possibilities of activating them by chemical and physical methods allow these materials to be produced with further higher surface area and controlled distribution of pores from nanoscale upto macroscopic dimensions, which actually play the most crucial role towards construction of the efficient electrode/electrolyte interfaces for capacitive processes in energy storage applications. Development of new carbon materials with extremely high surface areas could exhibit significant potential in this context and motivated by this in present work, we report for the first time the utilization of ultralight and extremely porous nano-microtubular Aerographite tetrapodal network as a functional interface to probe the electrochemical properties for capacitive energy storage. A simple and robust electrode fabrication strategy based on surface functionalized Aerographite with optimum porosity leads to significantly high specific capacitance (640 F/g) with high energy (14.2 Wh/kg) and power densities (9.67x103 W/kg) which has been discussed in detail.

Keywords
Hierarchical nanocarbons, Tubular Aerographite, Electrodes, Porous interfaces, Supercapacitors
National Category
Materials Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-322849 (URN)10.1016/j.nanoen.2017.03.004 (DOI)000400383300061 ()
Funder
Knut and Alice Wallenberg Foundation, KAW 2014.0387German Research Foundation (DFG), AD 183/17-1German Research Foundation (DFG), AD 183/20-2German Research Foundation (DFG), SFB 986M3 TP B1Swedish Research Council, VR-2016-06014
Available from: 2017-06-07 Created: 2017-06-07 Last updated: 2017-06-07Bibliographically approved
Parlak, O., Kumar Mishra, Y., Grigoriev, A., Mecklenburg, M., Luo, W., Keene, S., . . . Tiwari, A. (2017). Hierarchical Aerographite nano-microtubular tetrapodal networks based electrodes as lightweight supercapacitor. Nano Energy, 34(April), 570-577
Open this publication in new window or tab >>Hierarchical Aerographite nano-microtubular tetrapodal networks based electrodes as lightweight supercapacitor
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2017 (English)In: Nano Energy, Vol. 34, no April, p. 570-577Article in journal (Refereed) Published
Abstract [en]

A great deal of interest has been paid to the application of carbon-based nano- and microstructured materials as electrodes due to their relatively low-cost production, abundance, large surface area, high chemical stability, wide operating temperature range, and ease of processing including many more excellent features. The nanostructured carbon materials usually offer various micro-textures due to their varying degrees of graphitisation, a rich variety in terms of dimensionality as well as morphologies, extremely large surface accessibility and high electrical conductivity, etc. The possibilities of activating them by chemical and physical methods allow these materials to be produced with further higher surface area and controlled distribution of pores from nanoscale upto macroscopic dimensions, which actually play the most crucial role towards construction of the efficient electrode/electrolyte interfaces for capacitive processes in energy storage applications. Development of new carbon materials with extremely high surface areas could exhibit significant potential in this context and motivated by this in present work, we report for the first time the utilization of ultralight and extremely porous nano-microtubular Aerographite tetrapodal network as a functional interface to probe the electrochemical properties for capacitive energy storage. A simple and robust electrode fabrication strategy based on surface functionalized Aerographite with optimum porosity leads to significantly high specific capacitance (640 F/g) with high energy (14.2 Wh/kg) and power densities (9.67×103 W/kg) which has been discussed in detail.

National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:uu:diva-381063 (URN)10.1016/j.nanoen.2017.03.004 (DOI)
Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-09-02Bibliographically approved
Shukla, V., Jena, N. K., Grigoriev, A. & Ahuja, R. (2017). Prospects of Graphene-hBN Heterostructure Nanogap for DNA Sequencing. ACS Applied Materials and Interfaces, 9(46), 39945-39952
Open this publication in new window or tab >>Prospects of Graphene-hBN Heterostructure Nanogap for DNA Sequencing
2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 46, p. 39945-39952Article in journal (Refereed) Published
Abstract [en]

Recent advances in solid-state nano-device-based DNA sequencing are at the helm of the development of a new paradigm, commonly referred to as personalized medicines. Paying heed to a timely need for standardizing robust nanodevices for cheap, fast, and scalable DNA detection, in this article, the nanogap formed by the lateral heterostructure of graphene and hexagonal boron nitride (hBN) is explored as a potential architecture. These heterostructures have been realized experimentally, and our study boasts the idea that the passivation of the edge of the graphene electrode with hBN will solve many of practical problems, such as high reactivity of the graphene edge and difficulty in controlled engineering of the graphene edge structure, while retaining the nanogap setup as a useful nanodevice for sensing applications. Employing first-principle density-functional-theory-based nonequilibrium Greens function methods, we identify that the DNA building blocks, nucleobases, uniquely couple with the states of the nanogap, and the resulting induced states can be attributed as leaving a fingerprint of the DNA sequence in the computed current-voltage (I-V) characteristic. Two bias windows are put forward: lower (1-1.2 V) and higher (2.7-3 V), where unique identification of all four bases is possible from the current traces, although higher sensitivity is obtained at the higher voltage window. Our study can be a practical guide for experimentalists toward development of a nanodevice DNA sensor based on graphene-hBN heterostructures.

Keywords
DNA sequencing, graphene-hBN heterostructure, nonequilibrium Green's function, density functional theory, I-V characteristics
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-343317 (URN)10.1021/acsami.7b06827 (DOI)000416614600012 ()
Funder
Swedish Research CouncilStandUpCarl Tryggers foundation
Available from: 2018-03-13 Created: 2018-03-13 Last updated: 2019-01-05Bibliographically approved
Shukla, V., Wärnå, J., Jena, N. K., Grigoriev, A. & Ahuja, R. (2017). Toward the Realization of 2D Borophene Based Gas Sensor. The Journal of Physical Chemistry C, 121(48), 26869-26876
Open this publication in new window or tab >>Toward the Realization of 2D Borophene Based Gas Sensor
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2017 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 121, no 48, p. 26869-26876Article in journal (Refereed) Published
Abstract [en]

To the league of rapidly expanding 2D materials, borophene is a recent addition. Herein, a combination of ab initio density functional theory (DFT) and nonequilibrium Green's function (NEGF) based methods is used to estimate the prospects of this promising elemental 2D material for gas sensing applications. We note that the binding of target gas molecules such as CO, NO, NO2, NH3, and CO2 is quite strong on the borophene surface. Interestingly, our computed binding energies are far stronger than several other reported 2D materials like graphene, MoS2, and phosphorene. Further rationalization of stronger binding is made with the help of charge transfer analysis. The sensitivity of the borophene for these gases is also interpreted in terms of computing the vibrational spectra of the adsorbed gases on top of borophene, which show dramatic shift from their gas phase reference values. The metallic nature of borophene enables us to devise a setup considering the same substrate as electrodes. From the computation of the transmission function of system (gas + borophene), appreciable changes in the transmission functions are noted compared to pristine borophene surface. The measurements of current-voltage (I-V) characteristics unambiguously demonstrate the presence and absence of gas molecules (acting as ON and OFF states), strengthening the plausibility of a borophene based gas sensing device. As we extol the extraordinary sensitivity of borophene, we assert that this elemental 2D material is likely to attract subsequent interest.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-340255 (URN)10.1021/acs.jpcc.7b09552 (DOI)000417671500032 ()
Funder
Swedish National Infrastructure for Computing (SNIC)Swedish Research CouncilCarl Tryggers foundation StandUp
Available from: 2018-01-30 Created: 2018-01-30 Last updated: 2019-04-13Bibliographically approved
Renault, S., Oltean, V. A., Araujo, C. M., Grigoriev, A., Edström, K. & Brandell, D. (2016). Superlithiation of Organic Electrode Materials: The Case of Dilithium Benzenedipropiolate. Chemistry of Materials, 28(6), 1920-1926
Open this publication in new window or tab >>Superlithiation of Organic Electrode Materials: The Case of Dilithium Benzenedipropiolate
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2016 (English)In: Chemistry of Materials, Vol. 28, no 6, p. 1920-1926Article in journal (Refereed) Published
Abstract [en]

Dilithium benzenedipropiolate was prepared and investigated as a potential negative electrode material for secondary lithium-ion batteries. In addition to the expected reduction of its carbonyls, this material can reduce and reversibly oxidize its unsaturated carbon–carbon bonds leading to a Li/C ratio of 1/1 and a specific capacity as high as 1363 mAh g–1: the highest ever reported for a lithium carboxylate. Density functional theory calculations suggest that the lithiation is preferential on the propiolate carbons.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-283396 (URN)10.1021/acs.chemmater.6b00267 (DOI)000372856600038 ()
Funder
StandUpSwedish Foundation for Strategic Research
Available from: 2016-04-12 Created: 2016-04-12 Last updated: 2017-12-30
Orthaber, A., Löfås, H., Öberg, E., Grigoriev, A., Wallner, A., Jafri, S. M., . . . Ott, S. (2015). Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes [Letter to the editor]. Angewandte Chemie International Edition, 54(36), 10634-10638
Open this publication in new window or tab >>Cooperative Gold Nanoparticle Stabilization by Acetylenic Phosphaalkenes
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2015 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, no 36, p. 10634-10638Article in journal, Letter (Refereed) Published
National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:uu:diva-259963 (URN)10.1002/anie.201504834 (DOI)000360312800045 ()26211907 (PubMedID)
Funder
Swedish Research Council
Available from: 2015-08-13 Created: 2015-08-13 Last updated: 2019-04-24Bibliographically approved
Jafri, S. H., Löfås, H., Blom, T., Wallner, A., Grigoriev, A., Ahuja, R., . . . Leifer, K. (2015). Nano-fabrication of molecular electronic junctions by targeted modification of metal-molecule bonds. Scientific Reports, 5, Article ID 14431.
Open this publication in new window or tab >>Nano-fabrication of molecular electronic junctions by targeted modification of metal-molecule bonds
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2015 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 14431Article in journal (Refereed) Published
Abstract [en]

Reproducibility, stability and the coupling between electrical and molecular properties are central challenges in the field of molecular electronics. The field not only needs devices that fulfill these criteria but they also need to be up-scalable to application size. In this work, few-molecule based electronics devices with reproducible electrical characteristics are demonstrated. Our previously reported 5 nm gold nanoparticles (AuNP) coated with omega-triphenylmethyl (trityl) protected 1,8-octanedithiol molecules are trapped in between sub-20 nm gap spacing gold nanoelectrodes forming AuNP-molecule network. When the trityl groups are removed, reproducible devices and stable Au-thiol junctions are established on both ends of the alkane segment. The resistance of more than 50 devices is reduced by orders of magnitude as well as a reduction of the spread in the resistance histogram is observed. By density functional theory calculations the orders of magnitude decrease in resistance can be explained and supported by TEM observations thus indicating that the resistance changes and strongly improved resistance spread are related to the establishment of reproducible and stable metal-molecule bonds. The same experimental sequence is carried out using 1,6-hexanedithiol functionalized AuNPs. The average resistances as a function of molecular length, demonstrated herein, are comparable to the one found in single molecule devices.

National Category
Other Engineering and Technologies
Identifiers
urn:nbn:se:uu:diva-264841 (URN)10.1038/srep14431 (DOI)000361596000001 ()26395225 (PubMedID)
Funder
Swedish Research CouncilKnut and Alice Wallenberg FoundationCarl Tryggers foundation Swedish Energy AgencySwedish Foundation for Strategic Research
Available from: 2015-10-19 Created: 2015-10-19 Last updated: 2019-04-24Bibliographically approved
Dahlstrand, C., Jahn, B. O., Grigoriev, A., Villaume, S., Ahuja, R. & Ottosson, H. (2015). Polyfulvenes: Polymers with "Handles" That Enable Extensive Electronic Structure Tuning. The Journal of Physical Chemistry C, 119(46), 25726-25737
Open this publication in new window or tab >>Polyfulvenes: Polymers with "Handles" That Enable Extensive Electronic Structure Tuning
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2015 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 46, p. 25726-25737Article in journal (Refereed) Published
Abstract [en]

The fundamental electronic structure properties of substituted poly(penta)fulvenes and pentafulvene-based polymers are analyzed through qualitative molecular orbital (MO) theory combined with calculations at the B3LYP and HSE06 hybrid density functional theory (DFT) levels. We argue that the pentafulvene monomer unit has a unique character because electron density in the exocyclic C=C double bond can be polarized into and out of the five-membered ring, a feature that is not available to other more commonly used monomers. It is investigated how the energy gaps between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively), as approximate band gaps, are influenced by exocyclic substitution, introduction of linker groups, benzannulation, and ring substitution. In particular, the exocyclic positions of the fulvene act as handles by which the electronic structure of the polymer can be tuned between the quinoid and fulvenoid valence bond isomers; electron-withdrawing exocyclic substituents lead to polyfulvenes in the quinoid form while those with electron-donating substituents prefer the fulvenoid. Taken together, the HOMO-LUMO gaps of polyfulvenes can be tuned extensively, varying in ranges 0.77-2.44 eV (B3LYP) and 0.35-2.00 eV (HSE06) suggesting that they are a class of polymers with highly interesting, yet nearly unexplored, properties.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-271022 (URN)10.1021/acs.jpcc.5b08042 (DOI)000365463000006 ()
Funder
Wenner-Gren FoundationsCarl Tryggers foundation Swedish Research CouncilSwedish Foundation for Strategic Research
Available from: 2016-01-05 Created: 2016-01-05 Last updated: 2017-12-01Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0001-5389-2469

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