Search results for "Molecular wire"
showing 10 items of 18 documents
Effect of Metal Complexation on the Conductance of Single-Molecular Wires Measured at Room Temperature
2014
The present work aims to give insight into the effect that metal coordination has on the room-temperature conductance of molecular wires. For that purpose, we have designed a family of rigid, highly conductive ligands functionalized with different terminations (acetylthiols, pyridines, and ethynyl groups), in which the conformational changes induced by metal coordination are negligible. The single-molecule conductance features of this series of molecular wires and their corresponding Cu(I) complexes have been measured in break-junction setups at room temperature. Experimental and theoretical data show that no matter the anchoring group, in all cases metal coordination leads to a shift towar…
Tetrathiafulvalene-based molecular nanowires.
2008
A new molecular wire suitably functionalized with sulfur atoms at terminal positions and endowed with a central redox active TTF unit has been synthesized and inserted within two atomic-sized Au electrodes; electrical transport measurements have been performed in STM and MCBJ set-ups in a liquid environment and reveal conductance values around 10(-2) G0 for a single molecule.
Disorder and dephasing effects on electron transport through conjugated molecular wires in molecular junctions
2012
Understanding electron transport processes in molecular wires connected between contacts is a central focus in the field of molecular electronics. Especially, the dephasing effect causing tunneling-to-hopping transition has great importance from both applicational and fundamental points of view. We analyzed coherent and incoherent electron transmission through conjugated molecular wires by means of density-functional tight-binding theory within the D'Amato-Pastawski model. Our approach can study explicitly the structure/transport relationship in molecular junctions in a dephasing environmental condition using only single dephasing parameter. We investigated the length dependence and the inf…
Intrinsic electrical conductivity of nanostructured metal-organic polymer chains
2012
One-dimensional conductive polymers are attractive materials because of their potential in flexible and transparent electronics. Despite years of research, on the macro- and nano-scale, structural disorder represents the major hurdle in achieving high conductivities. Here we report measurements of highly ordered metal-organic nanoribbons, whose intrinsic (defect-free) conductivity is found to be 104 S m−1, three orders of magnitude higher than that of our macroscopic crystals. This magnitude is preserved for distances as large as 300 nm. Above this length, the presence of structural defects (~ 0.5%) gives rise to an inter-fibre-mediated charge transport similar to that of macroscopic crysta…
Two-terminal nanoelectromechanical bistable switches based on molybdenum–sulfur–iodine molecular wire bundles
2010
We demonstrate the application of Mo(6)S(3)I(6) molecular wire bundles for electrically controllable two-terminal on-off switches. We investigate how changes in the contact electrode material and geometry influence the device characteristics, hysteretic switching behavior and device stability. We also determine the device operating parameters, particularly the Young's moduli (40-270 GPa), operating current densities (3.2 x 10(5)-7 x 10(6) A m(-2)) and force constants. Although qualitatively, the properties of Mo(6)S(3)I(6) nanowires in nanoelectromechanical (NEM) switches are similar to those of carbon nanotubes (CNTs), their lower friction coefficient, higher mechanical stability and highe…
Phenothiazine dye featuring encapsulated insulated molecular wire as auxiliary donor for high photovoltage of dye-sensitized solar cells by suppressi…
2019
Abstract Two efficient dye-sensitized solar cells have been fabricated by two novel D–D–π–A phenothiazine-based organic dyes (PH2 and PH3) with an encapsulated insulated molecular wire (EIMW) as an auxiliary donor. The cell sensitized by PH2 with EIMW as an auxiliary donor shows a much higher photovoltage (Voc) relative to the reference dye PH1 without EIMW, because the former dye can inhibit dye aggregation and suppress the charge recombination effectively. The results show that the cell sensitized by PH2 with co-adsorption of chenodeoxycholic acid obtains a high power conversion efficiency, even higher than that of the cell based on N719. Thus, an effective way to increase the photovoltag…
Coordination Chemistry of 6-Thioguanine Derivatives with Cobalt: Toward Formation of Electrical Conductive One-Dimensional Coordination Polymers
2013
In this work we have synthetized and characterized by X-ray diffraction five cobalt complexes with 6-thioguanine (6-ThioGH), 6-thioguanosine (6-ThioGuoH), or 2'-deoxy-6-thioguanosine (2'-d-6-ThioGuoH) ligands. In all cases, these ligands coordinate to cobalt via N7 and S6 forming a chelate ring. However, independently of reagents ratio, 6-ThioGH provided monodimensional cobalt(II) coordination polymers, in which the 6-ThioG(-) acts as bridging ligand. However, for 2'-d-6-ThioGuoH and 6-ThioGuoH, the structure directing effect of the sugar residue gives rise to mononuclear cobalt complexes which form extensive H-bond interactions to generate 3D supramolecular networks. Furthermore, with 2'-d…
Buckyballs
2013
Buckyballs represent a new and fascinating molecular allotropic form of carbon that has received a lot of attention by the chemical community during the last two decades. The unabating interest on this singular family of highly strained carbon spheres has allowed the establishing of the fundamental chemical reactivity of these carbon cages and, therefore, a huge variety of fullerene derivatives involving [60] and [70]fullerenes, higher fullerenes, and endohedral fullerenes have been prepared. Much less is known, however, of the chemistry of the uncommon non-IPR fullerenes which currently represent a scientific curiosity and which could pave the way to a range of new fullerenes. In this revi…
Large Conductance Switching in a Single-Molecule Device through Room Temperature Spin-Dependent Transport
2016
Controlling the spin of electrons in nanoscale electronic devices is one of the most promising topics aiming at developing devices with rapid and high density information storage capabilities. The interface magnetism or spinterface resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, has become a key ingredient in creating nanoscale molecular devices with novel functionalities. Here, we present a single-molecule wire that displays large (>10000%) conductance switching by controlling the spin-dependent transport under ambient conditions (room temperature in a liquid cell). The molecular wire is built by trapping individual spin crossover Fe-II comple…
S-shaped decanuclear heterometallic [Ni8Ln2] complexes [Ln(iii) = Gd, Tb, Dy and Ho]: theoretical modeling of the magnetic properties of the gadolini…
2014
The reaction of 8-quinolinol-2-carboaldoxime (LH2) with Ni(II) and Ln(III) salts afforded the heterometallic decanuclear compounds [Ni8Dy2(μ3-OH)2(L)8(LH)2(H2O)6](ClO4)2·16H2O (1), [Ni8Gd2(μ3-OH)2(L)8(LH)2(H2O)4(MeOH)2](NO3)2·12H2O (2), [Ni8Ho2(μ3-OH)2(L)8(LH)2(H2O)4(MeOH)2](ClO4)2·2MeOH·12H2O (3) and [Ni8Tb2 (μ3-OH)2(L)8(LH)2(MeOH)4(OMe)2]·2CH2Cl2·8H2O (4). While compounds 1-3 are dicationic, compound 4 is neutral. These compounds possess an S-shaped architecture and comprise a long chain of metal ions bound to each other. In all the complexes, the eight Ni(II) and two Ln(III) ions of the multimetallic ensemble are hold together by two μ3-OH, eight dianionic (L(2-)) and two monoanionic oxi…