Rocio Aguilar-Sanchez

Publications (3)7.7 Total impact

• Article: From self-assembly to charge transport with single molecules - an electrochemical approach.

  Bo Han, Zhihai Li, Chen Li, Ilya Pobelov, Guijin Su, Rocio Aguilar-Sanchez, Thomas Wandlowski
  [show abstract] [hide abstract]
  ABSTRACT: Structure formation and self-assembly of physisorbed and chemisorbed organic monolayers will be describedon electrified solid-liquid interfaces employing in-situ scanning tunneling microscopy (STM) and surface-enhancedinfrared spectroscopy (SEIRAS) in combination with electrochemical techniques. We present first a casestudy on self-assembly by directional hydrogen bonding and its interplay with the electrode potential choosingaromatic carboxylic acids, with an emphasis on 1,3,5-benzene-tricarboxylic acid (TMA). Structure and electricalcharacteristics of chemisorbed organic monolayers involving the formation of covalent bonds with the substratesurface will be discussed for a series of 4-methyl-4'-(n-mercaptoalkyl)biphenylson Au(111) electrodes. In an attempt to explore single molecule properties, such as charge transport andredox-mediated tunneling, we subsequently introduce an STM-based technique to construct symmetric and asymmetricmetal/(single) molecule/metal junctions. Employing α,ω-alkanedithiols and redox-active derivatives of viologens we demonstratenovel transport and single molecule electrochemical studies, which bear unique novel perspectives for fundamentalas well as applied investigations.
  Topics in current chemistry 01/2009; 287:181-255. · 4.29 Impact Factor
• Source

  Available from: Ilya Pobelov

  Chapter: From Self-Assembly to Charge Transport with Single Molecules – An Electrochemical Approach

  Bo Han, Zhihai Li, Chen Li, Ilya Pobelov, Guijin Su, Rocio Aguilar-Sanchez, Thomas Wandlowski
  [show abstract] [hide abstract]
  ABSTRACT: Structure formation and self-assembly of physisorbed and chemisorbed organic monolayers will be described on electrified solid–liquid interfaces employing in-situ scanning tunneling microscopy (STM) and surface-enhanced infrared spectroscopy (SEIRAS) in combination with electrochemical techniques. We present first acase study on self-assembly by directional hydrogen bonding and its interplay with the electrode potential choosing aromatic carboxylic acids, with an emphasis on 1,3,5-benzene-tricarboxylic acid (TMA). Structure and electrical characteristics of chemisorbed organic monolayers involving the formation of covalent bonds with the substrate surface will be discussed for aseries of 4-methyl-4′-(n-mercaptoalkyl)biphenyls on Au(111) electrodes. In an attempt to explore single molecule properties, such as charge transport and redox-mediated tunneling, we subsequently introduce an STM-based technique to construct symmetric and asymmetric metal/(single) molecule/metal junctions. Employing α,ω-alkanedithiols and redox-active derivatives of viologens we demonstrate novel transport and single molecule electrochemical studies, which bear unique novel perspectives for fundamental as well as applied investigations.
  10/2008: pages 181-255;
• Source

  Available from: Ilya Pobelov

  Article: Scanning tunneling microscopy and spectroscopy studies of 4-methyl- 4'-(n-mercaptoalkyl)biphenyls on Au(111)-(1x1).

  Gujin J Su, Rocio Aguilar-Sanchez, Zhihai Li, Ilya Pobelov, Melanie Homberger, Ulrich Simon, Thomas Wandlowski
  [show abstract] [hide abstract]
  ABSTRACT: 4-methyl-4'-(n-mercaptoalkyl)biphenyl (CH3-C6H4-C6H4-(CH2)n-SH, n=3-6, BPn) monolayers assembled on Au(111)-(1x1) in 1,3,5,-trimethylbenzene (TMB) at various temperatures are studied by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). High resolution STM images reveal that BP3 and BP5 form a (sqrt 3x2sqrt 3) repeating motif superimposed on a temperature-dependent Moire pattern. BP4 and BP6 adlayers are characterized by a coexisting (2sqrt 3x5sqrt 3) majority phase and a temperature-dependent (3xpsqrt 3) minority phase. Assembly at 60 degrees C or 90 degrees C leads to p=5. Compression of the adlayer was found at higher temperatures. Combined with high-resolution structure experiments, the electronic characteristics of BP3 and BP4 self-assembled monolayers (SAMs) were studied by monitoring current-distance (iT-Deltaz) and current-voltage (iT-Ebias) characteristics in TMB employing a gold STM tip|BPn|Au(111)-(1x1) configuration. The semilogarithmic (iT-Deltaz) plots yielded three linear regions in the range 10 pA<or=iT<or=20 microA, which were attributed to the different positions of the STM tip with respect to the molecular adlayer (I outside, II in contact with and/or within the adlayer, and III just before the formation of Au-Au nanocontacts). The effective decay constants kappaeff and the corresponding barrier heights phi(eff) decrease with decreasing tip-substrate distance. The iT-Ebias curves at low bias voltages are represented by the Simmons tunneling model. Based on measurements in the high current limit, the electric field strength of the dielectric breakdown was estimated to range between |0.85+/-0.05|x10(9) V m-1 and |1.5+/-0.1|x10(9) V m-1.
  ChemPhysChem 05/2007; 8(7):1037-48. · 3.41 Impact Factor