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Scanning tunneling microscopy study of metal-free phthalocyanine monolayer structures on graphite

Nilson, Katharina; Ahlund, John; Brena, Barbara; Gothelid, Emmanuelle; Schiessling, Joachim LU ; Martensson, Nils and Puglia, Carla (2007) In Journal of Chemical Physics 127(11).
Abstract
Low temperature scanning tunneling microscopy (STM) studies of metal-free phthalocyanine (H2Pc) adsorbed on highly oriented pyrolytic graphite (HOPG) have shown ordered arrangement of molecules for low coverages up to 1 ML. Evaporation of H2Pc onto HOPG and annealing of the sample to 670 K result in a densely packed structure of the molecules. Arrangements of submonolayer, monolayer, and monolayer with additional adsorbed molecules have been investigated. The high resolution of our investigations has permitted us to image single molecule orientation. The molecular plane is found to be oriented parallel to the substrate surface and a square adsorption unit cell of the molecules is reported. In addition, depending on the bias voltage,... (More)
Low temperature scanning tunneling microscopy (STM) studies of metal-free phthalocyanine (H2Pc) adsorbed on highly oriented pyrolytic graphite (HOPG) have shown ordered arrangement of molecules for low coverages up to 1 ML. Evaporation of H2Pc onto HOPG and annealing of the sample to 670 K result in a densely packed structure of the molecules. Arrangements of submonolayer, monolayer, and monolayer with additional adsorbed molecules have been investigated. The high resolution of our investigations has permitted us to image single molecule orientation. The molecular plane is found to be oriented parallel to the substrate surface and a square adsorption unit cell of the molecules is reported. In addition, depending on the bias voltage, different electronic states of the molecules have been probed. The characterized molecular states are in excellent agreement with density functional theory ground state simulations of a single molecule. Additional molecules adsorbed on the monolayer structures have been observed, and it is found that the second layer molecules adsorb flat and on top of the molecules in the first layer. All STM measurements presented here have been performed at a sample temperature of 70 K. (Less)
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organization
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type
Contribution to journal
publication status
published
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in
Journal of Chemical Physics
volume
127
issue
11
publisher
American Institute of Physics
external identifiers
  • wos:000249667400050
  • scopus:34648820177
ISSN
0021-9606
DOI
10.1063/1.2770732
language
English
LU publication?
yes
id
a3f141bb-2c5f-4dd5-b5ef-e74a84cb88b2 (old id 656042)
date added to LUP
2007-12-18 16:13:15
date last changed
2017-11-05 03:35:30
@article{a3f141bb-2c5f-4dd5-b5ef-e74a84cb88b2,
  abstract     = {Low temperature scanning tunneling microscopy (STM) studies of metal-free phthalocyanine (H2Pc) adsorbed on highly oriented pyrolytic graphite (HOPG) have shown ordered arrangement of molecules for low coverages up to 1 ML. Evaporation of H2Pc onto HOPG and annealing of the sample to 670 K result in a densely packed structure of the molecules. Arrangements of submonolayer, monolayer, and monolayer with additional adsorbed molecules have been investigated. The high resolution of our investigations has permitted us to image single molecule orientation. The molecular plane is found to be oriented parallel to the substrate surface and a square adsorption unit cell of the molecules is reported. In addition, depending on the bias voltage, different electronic states of the molecules have been probed. The characterized molecular states are in excellent agreement with density functional theory ground state simulations of a single molecule. Additional molecules adsorbed on the monolayer structures have been observed, and it is found that the second layer molecules adsorb flat and on top of the molecules in the first layer. All STM measurements presented here have been performed at a sample temperature of 70 K.},
  author       = {Nilson, Katharina and Ahlund, John and Brena, Barbara and Gothelid, Emmanuelle and Schiessling, Joachim and Martensson, Nils and Puglia, Carla},
  issn         = {0021-9606},
  language     = {eng},
  number       = {11},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Scanning tunneling microscopy study of metal-free phthalocyanine monolayer structures on graphite},
  url          = {http://dx.doi.org/10.1063/1.2770732},
  volume       = {127},
  year         = {2007},
}