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Posted Date: December 8, 2017

Reference:
The Journal of Chemical Physics 144, 194703 (2016); doi: 10.1063/1.4949765

FIG. 2. Model of 8T and 7T molecules from Fig. 1 matched to the Au(111) surface lattice. ((a)-(d)) STM images [set point 100 mV, 5 pA] of sub-areas from Figs. 1(a)-1(c). ((e)-(h)) Models of oligothiophene molecules from (a)-(d) overlaid on the Au(111) lattice. Crystallographic directions are indi- cated. Black dashed circles indicate the van der Waals radii of the hydrogen atoms. Red dashed circles for the highlighted molecules indicate S atoms on or near Au top-sites (as opposed to bridging or hollow sites).

FIG. 2. Model of 8T and 7T molecules from Fig. 1 matched to the Au(111) surface lattice. ((a)-(d)) STM images [set point 100 mV, 5 pA] of sub-areas from Figs. 1(a)-1(c). ((e)-(h)) Models of oligothiophene molecules from (a)-(d) overlaid on the Au(111) lattice. Crystallographic directions are indi- cated. Black dashed circles indicate the van der Waals radii of the hydrogen atoms. Red dashed circles for the highlighted molecules indicate S atoms on or near Au top-sites (as opposed to bridging or hollow sites).

Abstract
We present scanning tunneling microscopy and spectroscopy (STM/STS) investigations of the electronic structures of di erent alkyl-substituted oligothiophenes on the Au(111) surface. STM imaging showed that on Au(111), oligothiophenes adopted distinct straight and bent conformations. By combining STS maps with STM images, we visualize, in real space, particle-in-a-box-like oligothiophene molecular orbitals. We demonstrate that di erent planar conformers with signi cant geometrical distortions of oligothiophene backbones surprisingly exhibit very similar electronic structures, indicating a low degree of conformation-induced electronic disorder. The agreement of these results with gas-phase density functional theory calculations implies that the oligothiophene interaction with the Au(111) surface is generally insensitive to molecular conformation.

Reference:
The Journal of Chemical Physics 144, 194703 (2016); doi: 10.1063/1.4949765

Credits:
Benjamen N. Taber,1 Dmitry A. Kislitsyn,1 Christian F. Gervasi,1 Jon M. Mills,1 Ariel E. Rosenfield,1 Lei Zhang,2 Stefan C. B. Mannsfeld,3 James S. Prell,1 Alejandro L. Briseno,2 and George V. Nazin1

1. Department of Chemistry and Biochemistry, Materials Science Institute, Oregon Center for Optical, Molecular and Quantum Science, University of Oregon, 1253 University of Oregon, Eugene, Oregon 97403, USA

2. Department of Polymer Science and Engineering, Silvio O. Conte National Center for Polymer Research, University of Massachusetts-Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, USA


3. Center for Advancing Electronics Dresden, Dresden University of Technology, 01062 Dresden, Germany

Microscope:
Customized RHK PanScan Freedom Kit with RHK R9 Controller

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Events
Event Date: November 28, 2017

November 28-30 Boston, MA
2017 MRS Fall Meeting Exhibit
The Conference will be held at the Hynes Convention Center in Boston, MA

http://www.mrs.org/fall2017

RHK will be in Booth #612

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Events
Event Date: November 6, 2017

November 6, 2017
MMM 2017 – 62nd Annual Conference on Magnetism and Magnetic Materials
The Conference will be held at the David L. Lawrence Convention Center in Pittsburgh, PA, USA
http://magnetism.org/

RHK will be in Booth #24

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PRIcon
Image of the Month
Posted Date: November 1, 2017

Reference:
Physical Chemistry Chemical Physics 19.30 (2017): 20281-20289

Fig. 4 Overview of the supramolecular phases and the derived structural models for 2HTPTBP on Cu(111) at different coverages (a–c: relatively low coverage; d–f: medium coverage; g–i: monolayer coverage; all the STM images were measured at RT). The red and yellow ovals indicate the individual molecules with different orientations. The intermolecular T-type-like interactions and p–p stacking interactions in the structural models are highlighted by green lines and black parallel lines, respectively. The van der Waals interactions between the phenyl groups of two neighbouring molecules are marked by green dashed lines. Tunnelling parameters: (a) U = 1.0 V, I = 30 pA; (b) U = 1.6 V, I = 30 pA; (d, e, g and h) U = 1.1 V, I = 30 pA.

Fig. 4 Overview of the supramolecular phases and the derived structural models for 2HTPTBP on Cu(111) at different coverages (a–c: relatively low coverage; d–f: medium coverage; g–i: monolayer coverage; all the STM images were measured at RT). The red and yellow ovals indicate the individual molecules with different orientations. The intermolecular T-type-like interactions and p–p stacking interactions in the structural models are highlighted by green lines and black parallel lines, respectively. The van der Waals interactions between the phenyl groups of two neighbouring molecules are marked by green dashed lines. Tunnelling parameters: (a) U = 1.0 V, I = 30 pA; (b) U = 1.6 V, I = 30 pA; (d, e, g and h) U = 1.1 V, I = 30 pA.

Abstract
The adsorption behaviour of 2H-5,10,15,20-tetraphenyltetrabenzoporphyrin (2HTPTBP) on different metal surfaces, i.e., Ag(111), Cu(111), Cu(110), and Cu(110)–(2 ? 1)O was investigated by scanning tunnelling microscopy at room temperature. The adsorption of 2HTPTBP on Ag(111) leads to the formation of a well- ordered two-dimensional (2D) island structure due to the mutual stabilization through the intermolecular p–p stacking and T-type-like interactions of phenyl and benzene substituents of neighboring molecules. For 2HTPTBP on Cu(111), the formed 2D supramolecular structures exhibit a coverage-dependent behaviour, which can be understood from the interplay of molecule–substrate and molecule–molecule interactions. In contrast, on Cu(110) the 2HTPTBP molecules form dispersed one-dimensional (1D) molecular chains along the [11%0] direction of the substrate due to relatively strong attractive molecule– substrate interactions. Furthermore, we demonstrate that the reconstruction of the Cu(110) surface by oxygen atoms yields a change in dimensionality of the resulting nanostructures from 1D on Cu(110) to 2D on (2 ? 1) oxygen-reconstructed Cu(110), induced by a decreased molecule–substrate interaction combined with attractive molecule–molecule interactions. This comprehensive study on these prototypical systems enables us to deepen the understanding of the particular role of the substrate concerning the adsorption behavior of organic molecules on metal surfaces and thus to tweak the ordering in functional molecular architectures.

Reference:
Physical Chemistry Chemical Physics 19.30 (2017): 20281-20289

Credits:
Liang Zhang, ab Michael Lepper, ab Michael Stark,ab Teresa Menzel,ab
Dominik Lungerich,bc Norbert Jux,bc Wolfgang Hieringer,bd Hans-Peter Steinru ̈ckab and Hubertus Marbach*ab

a Lehrstuhl fu ̈r Physikalische Chemie II, Universita ̈t Erlangen-Nu ̈rnberg, Egerlandstr. 3, 91058 Erlangen, Germany. E-mail: [email protected]

b Interdisciplinary Center for Molecular Materials (ICMM), Universita ̈t Erlangen-Nu ̈rnberg, Germany

c Lehrstuhl fu ̈r Organische Chemie II, Universita ̈t Erlangen-Nu ̈rnberg, Henkestr. 42, 91054 Erlangen, Germany

d Lehrstuhl fu ̈r Theoretische Chemie, Universita ̈t Erlangen-Nu ̈rnberg, Egerlandstr. 3, 91058 Erlangen, Germany

† Electronic supplementary information (ESI) available: The structure models of 2HTPTBP on Cu(111), the STM images of 2HTPTBP on Cu(110) after annealing and the atomic Cartesian coordinates for the calculated gas phase model. See DOI: 10.1039/c7cp03731g

Microscope:
UHV VT Beetle 300

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