Electron transport in a gold nanoparticle assembly structure stabilized by a physisorbed porphyrin derivative

Yuki Noda, Shin Ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura

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21 Citations (Scopus)

Abstract

Gold nanoparticles stabilized by meso-5,10,15,20-tetrakis(2-thienyl) porphyrin (2T) via physisorption (2T-AuNP) were synthesized, and the electronic transport of assemblies of these films was studied. The adsorption mechanism of 2T on gold nanoparticles was examined using UV-vis-NIR, IR, Raman, and H1 -NMR spectroscopy, which showed no evidence of any covalent bonding between 2T and the gold nanoparticles. In temperature-dependent resistivity measurements, a crossover from thermally assisted hopping to Efros-Shklovskii-type variable-range hopping (ES-VRH) was observed around 50 K on decreasing the temperature. At higher temperatures, the 2T-AuNP assembly structure followed an Arrhenius plot (EA =15 meV) with ohmic I-V characteristics at each measurement point. On the other hand, the activation energy at lower temperatures decreased nonlinearly in a T-1 plot, and the logarithm of the resistance obeyed a T-1/2 law, corresponding to an ES-VRH mechanism, which is predicted for disordered materials as a variable-range hopping mechanism influenced by strong Coulomb interactions. ES-VRH behavior has been observed previously in saturated molecule/gold nanoparticle assemblies and was confirmed in our 2T-AuNP assembly. Electronically active conjugated molecules were successfully incorporated between the nanoparticles, keeping the electronic structure of the gold nanoparticle and 2T moieties isolated from each other.

Original languageEnglish
Article number205420
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume82
Issue number20
DOIs
Publication statusPublished - 2010 Nov 12

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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