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Room temperature single-step synthesis of metal decorated boron-rich nanowires via laser ablation
Mark H. Rummeli,Barbara Trzebicka,Gianaurelio Cuniberti,Thomas Gemming,Alicja Bachmatiuk,Ignacio G. Gonzalez-Martine 나노기술연구협의회 2019 Nano Convergence Vol.6 No.14
Hybrid nanostructures, such as those with nanoparticles anchored on the surface of nanowires, or decorated nanowires, have a large number of potential and tested applications such as: gas sensing, catalysis, plasmonic waveguides, supercapacitors and more. The downside of these nanostructures is their production. Generally, multi-step synthesis procedures are used, with the nanowires and the nanoparticles typically produced separately and then integrated. The few existent single-step methods are lengthy or necessitate highly dedicated setups. In this paper we report a single-step and rapid (ca. 1 min) laser ablation synthesis method which produces a wide variety of boron-rich decorated nanowires. Furthermore, the method is carried at room temperature. The synthesis process consists on a filamentary jet ejection process driven by pressure gradients generated by the ablation plume on the rims of the irradiation crater. Simultaneously nanoparticles are nucleated and deposited on the filaments thus producing hybrid decorated nanowires.
Electrical Conductance in Biological Molecules
Waleed Shinwari, M.,Jamal Deen, M.,Starikov, Evgeni B.,Cuniberti, Gianaurelio WILEY-VCH Verlag 2010 Advanced Functional Materials Vol.20 No.12
<P>Nucleic acids and proteins are not only biologically important polymers. They have recently been recognized as novel functional materials surpassing conventional materials in many aspects. Although Herculean efforts have been undertaken to unravel fine functioning mechanisms of the biopolymers in question, there is still much more to be done. Here the topic of biomolecular charge transport is presented with a particular focus on charge transfer/transport in DNA and protein molecules. The experimentally revealed details, as well as the presently available theories, of charge transfer/transport along these biopolymers are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations.</P> <B>Graphic Abstract</B> <P>Biomolecular charge transport is presented, with a particular focus on charge transfer/transport in DNA and protein molecules. The experimental data, as well as the presently available theories, are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations. <img src='wiley_img_2010/1616301X-2010-20-12-ADFM200902066-content.gif' alt='wiley_img_2010/1616301X-2010-20-12-ADFM200902066-content'> </P>
Bandgap engineering of Cd(x)Zn(1-x)Te nanowires.
Davami, Keivan,Pohl, Judith,Shaygan, Mehrdad,Kheirabi, Nazli,Faryabi, Hamid,Cuniberti, Gianaurelio,Lee, Jeong-Soo,Meyyappan, M RSC Pub 2013 Nanoscale Vol.5 No.3
<P>Bandgap engineering of single-crystalline alloy Cd(x)Zn(1-x)Te (0 x 1) nanowires is achieved successfully through control of growth temperature and a two zone source system in a vapor-liquid-solid process. Extensive characterization using electron microscopy, Raman spectroscopy and photoluminescence shows highly crystalline alloy nanowires with precise tuning of the bandgap. It is well known that bulk Cd(x)Zn(1-x)Te is popular for construction of radiation detectors and availability of a nanowire form of this material would help to improve detection sensitivity and miniaturization. This is a step forward towards the accomplishment of tunable and predetermined bandgap emissions for various applications.</P>
Popov, Alexey A.,Schiemenz, Sandra,Avdoshenko, Stanislav M.,Yang, Shangfeng,Cuniberti, Gianaurelio,Dunsch, Lothar American Chemical Society 2011 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.115 No.31
<P>While the role of asymmetric nitride clusters on the cage size and symmetry in fullerene-based structures is already well-known, the role of the asymmetric arrangement of metals in nitride clusters on the nitrogen is studied in detail in this work. It is discovered that asymmetric mixed-metal nitride clusters give sufficiently narrow <SUP>14</SUP>N NMR signals to make NMR the method of choice to characterize the endohedral cluster from the inside. In the series of mixed-metal nitride clusterfullerenes Lu<SUB><I>x</I></SUB>Sc<SUB>3–<I>x</I></SUB>N@C<SUB>80</SUB> and Lu<SUB><I>x</I></SUB>Y<SUB>3–<I>x</I></SUB>N@C<SUB>80</SUB> (<I>x</I> = 0–3) the δ(<SUP>14</SUP>N) values are found to be linear functions of <I>x</I> showing that <SUP>14</SUP>N chemical shifts are additive values with specific increment for each kind of metal atoms. Density functional theory calculations are performed to interpret the experimentally measured spectra. To reveal the main factors affecting <SUP>14</SUP>N chemical shifts in nitride clusterfullerenes, shielding tensor components are analyzed in terms of Ramsey theory both in localized and canonical molecular orbitals. <SUP>14</SUP>N chemical shifts in M<SUB>3</SUB>N@C<SUB>80</SUB> and related systems are shown to be determined solely by nitrogen-localized orbitals and in particular by the p<SUB><I>x,y,z</I></SUB> atomic orbitals of nitrogen. As a result, the peculiarities of the nitrogen shielding in nitride clusterfullerenes can be interpreted by the simple analysis of the nitrogen-projected density of states and its variation in different chemical environments.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2011/jpccck.2011.115.issue-31/jp204290f/production/images/medium/jp-2011-04290f_0004.gif'></P>
SCC-DFTB Parametrizationfor Boron and Boranes
Grundkö,tter-Stock, Bernhard,Bezugly, Viktor,Kunstmann, Jens,Cuniberti, Gianaurelio,Frauenheim, Thomas,Niehaus, Thomas A. American Chemical Society 2012 Journal of chemical theory and computation Vol.8 No.3
<P>We present the results of our recent parametrization of the boron boron and boron, hydrogen interactions for the self-consistent charge density-functional-based tight-binding (SCC-DFTB) method. To evaluate the performance, we compare SCC-DFTB to full density functional theory (DFT) and wave-function-based semiempirical methods (AM1 and MNDO). Since the advantages of SCC-DFTB emerge especially for large systems, we calculated molecular systems of boranes and pure boron nanostructures. Computed bond lengths, bond angles, and vibrational frequencies are close to DFT predictions. We find that the proposed parametrization provides a transferable and balanced description of both finite and periodic systems.</P>
Control of Thermal and Electronic Transport in Defect-Engineered Graphene Nanoribbons
Haskins, Justin,Kınacı, Alper,Sevik, Cem,Sevinç,li, Hâ,ldun,Cuniberti, Gianaurelio,Ç,ağ,ın, Tahir American Chemical Society 2011 ACS NANO Vol.5 No.5
<P>The influence of the structural detail and defects on the thermal and electronic transport properties of graphene nanoribbons (GNRs) is explored by molecular dynamics and non-equilibrium Green’s function methods. A variety of randomly oriented and distributed defects, single and double vacancies, Stone−Wales defects, as well as two types of edge form (armchair and zigzag) and different edge roughnesses are studied for model systems similar in sizes to experiments (>100 nm long and >15 nm wide). We observe substantial reduction in thermal conductivity due to all forms of defects, whereas electrical conductance reveals a peculiar defect-type-dependent response. We find that a 0.1% single vacancy concentration and a 0.23% double vacancy or Stone−Wales concentration lead to a drastic reduction in thermal conductivity of GNRs, namely, an 80% reduction from the pristine one of the same width. Edge roughness with an rms value of 7.28 Å leads to a similar reduction in thermal conductivity. Randomly distributed bulk vacancies are also found to strongly suppress the ballistic nature of electrons and reduce the conductance by 2 orders of magnitude. However, we have identified that defects close to the edges and relatively small values of edge roughness preserve the quasi-ballistic nature of electronic transport. This presents a route of independently controlling electrical and thermal transport by judicious engineering of the defect distribution; we discuss the implications of this for thermoelectric performance.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-5/nn200114p/production/images/medium/nn-2011-00114p_0005.gif'></P>