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Intrinsic electrical conductivity of nanostructured metal-organic polymer chains.

Hermosa C, Vicente Álvarez J, Azani MR, Gómez-García CJ, Fritz M, Soler JM, Gómez-Herrero J, Gómez-Navarro C, Zamora F - Nat Commun (2013)

Bottom Line: This magnitude is preserved for distances as large as 300 nm.We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds.Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Inorgánica, Universidad Autónoma de Madrid, Madrid 28049, Spain.

ABSTRACT
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 10(4) 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 crystals. We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds. Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices.

No MeSH data available.


Electrical characterisation of conventional MMX crystals.Comparison of IV curves for the nanoribbons and macrocrystals. (a) Resistance versus length curve acquired on a crystal with dimensions of 350 × 10 × 10 μm3, where, in contrast to the nanoribbons case, a linear behaviour is observed. The inset shows an optical microscopy image of a crystal contacted by two gold probes. (b) Experimental I/V curves obtained for nanoribbons (green), and crystals both for longitudinal transport (blue) and for transversal transport (red). The light blue empty circles show the fitting to theoretical Expression (2) of the main text.
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f3: Electrical characterisation of conventional MMX crystals.Comparison of IV curves for the nanoribbons and macrocrystals. (a) Resistance versus length curve acquired on a crystal with dimensions of 350 × 10 × 10 μm3, where, in contrast to the nanoribbons case, a linear behaviour is observed. The inset shows an optical microscopy image of a crystal contacted by two gold probes. (b) Experimental I/V curves obtained for nanoribbons (green), and crystals both for longitudinal transport (blue) and for transversal transport (red). The light blue empty circles show the fitting to theoretical Expression (2) of the main text.

Mentions: With the aim of a full characterization of the material, the measurements were extended to conventional (micro-scaled) monocrystals of the same compound with typical dimensions of 350 × 10 × 10 μm3. Measurements of several crystals, in four-probe configuration, gave longitudinal conductivity values of 10–80 S m−1, three or four orders of magnitude lower than those obtained for the intrinsic value of the polymeric chains. In contrast with the exponential R(L) dependence of the nanoribbons, the electrical resistance of the crystal as a function of the length (Fig. 3a) showed a linear dependence. In addition, the curves showed a marked non-linear behaviour (Fig. 3b), clearly indicating a change in the electrical transport mechanism from the nanoribbons to the crystals. Two-terminal transversal conductivity measurements (perpendicular to the polymer chains axis) resulted in values of 10−4–10−3 S m−1, reflecting the very high electrical anisotropy in the electrical properties of these crystals.


Intrinsic electrical conductivity of nanostructured metal-organic polymer chains.

Hermosa C, Vicente Álvarez J, Azani MR, Gómez-García CJ, Fritz M, Soler JM, Gómez-Herrero J, Gómez-Navarro C, Zamora F - Nat Commun (2013)

Electrical characterisation of conventional MMX crystals.Comparison of IV curves for the nanoribbons and macrocrystals. (a) Resistance versus length curve acquired on a crystal with dimensions of 350 × 10 × 10 μm3, where, in contrast to the nanoribbons case, a linear behaviour is observed. The inset shows an optical microscopy image of a crystal contacted by two gold probes. (b) Experimental I/V curves obtained for nanoribbons (green), and crystals both for longitudinal transport (blue) and for transversal transport (red). The light blue empty circles show the fitting to theoretical Expression (2) of the main text.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3644075&req=5

f3: Electrical characterisation of conventional MMX crystals.Comparison of IV curves for the nanoribbons and macrocrystals. (a) Resistance versus length curve acquired on a crystal with dimensions of 350 × 10 × 10 μm3, where, in contrast to the nanoribbons case, a linear behaviour is observed. The inset shows an optical microscopy image of a crystal contacted by two gold probes. (b) Experimental I/V curves obtained for nanoribbons (green), and crystals both for longitudinal transport (blue) and for transversal transport (red). The light blue empty circles show the fitting to theoretical Expression (2) of the main text.
Mentions: With the aim of a full characterization of the material, the measurements were extended to conventional (micro-scaled) monocrystals of the same compound with typical dimensions of 350 × 10 × 10 μm3. Measurements of several crystals, in four-probe configuration, gave longitudinal conductivity values of 10–80 S m−1, three or four orders of magnitude lower than those obtained for the intrinsic value of the polymeric chains. In contrast with the exponential R(L) dependence of the nanoribbons, the electrical resistance of the crystal as a function of the length (Fig. 3a) showed a linear dependence. In addition, the curves showed a marked non-linear behaviour (Fig. 3b), clearly indicating a change in the electrical transport mechanism from the nanoribbons to the crystals. Two-terminal transversal conductivity measurements (perpendicular to the polymer chains axis) resulted in values of 10−4–10−3 S m−1, reflecting the very high electrical anisotropy in the electrical properties of these crystals.

Bottom Line: This magnitude is preserved for distances as large as 300 nm.We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds.Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Química Inorgánica, Universidad Autónoma de Madrid, Madrid 28049, Spain.

ABSTRACT
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 10(4) 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 crystals. We provide the first direct experimental evidence of the gapless electronic structure predicted for these compounds. Our results postulate metal-organic molecular wires as good metallic interconnectors in nanodevices.

No MeSH data available.