Molecular conformation and electronic properties of Protoporphyrin-IX self assembled monolayers adsorbed on a Pt(111) surface

Christophe Humbert, Cedric Volcke, Yannick Sartenaer, André Peremans, Paul Thiry, Laurent Dreesen

Research output: Contribution to journalArticle

Abstract

Monolayers of protoporphyrinIX molecules are prepared on a Pt(111) surface by self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning Tunneling Microscopy (STM) and Two-Colour Sum-Frequency Generation (2C-SFG) are performed ex situ at ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800-3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)ProtoporphyrinIX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. All these results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety.
Original languageEnglish
Pages (from-to)3702-3709
Number of pages8
JournalSurface Science
Volume600
Issue number18
Publication statusPublished - 2006

Fingerprint

Self assembled monolayers
Electronic properties
Conformations
Scanning tunneling microscopy
scanning tunneling microscopy
Monolayers
electronics
methylidyne
Molecules
Porphyrins
Chain length
porphyrins
Gold
red shift
Self assembly
Stretching
metal surfaces
Metal ions
self assembly
molecules

Keywords

  • sum-frequency generation
  • mercaptoporphyrins
  • protoporphyrins
  • Scanning tunneling microscopy
  • monolayers

Cite this

Humbert, Christophe ; Volcke, Cedric ; Sartenaer, Yannick ; Peremans, André ; Thiry, Paul ; Dreesen, Laurent. / Molecular conformation and electronic properties of Protoporphyrin-IX self assembled monolayers adsorbed on a Pt(111) surface. In: Surface Science. 2006 ; Vol. 600, No. 18. pp. 3702-3709.
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abstract = "Monolayers of protoporphyrinIX molecules are prepared on a Pt(111) surface by self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning Tunneling Microscopy (STM) and Two-Colour Sum-Frequency Generation (2C-SFG) are performed ex situ at ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800-3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)ProtoporphyrinIX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. All these results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety.",
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Humbert, C, Volcke, C, Sartenaer, Y, Peremans, A, Thiry, P & Dreesen, L 2006, 'Molecular conformation and electronic properties of Protoporphyrin-IX self assembled monolayers adsorbed on a Pt(111) surface', Surface Science, vol. 600, no. 18, pp. 3702-3709.

Molecular conformation and electronic properties of Protoporphyrin-IX self assembled monolayers adsorbed on a Pt(111) surface. / Humbert, Christophe; Volcke, Cedric; Sartenaer, Yannick; Peremans, André; Thiry, Paul; Dreesen, Laurent.

In: Surface Science, Vol. 600, No. 18, 2006, p. 3702-3709.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Molecular conformation and electronic properties of Protoporphyrin-IX self assembled monolayers adsorbed on a Pt(111) surface

AU - Humbert, Christophe

AU - Volcke, Cedric

AU - Sartenaer, Yannick

AU - Peremans, André

AU - Thiry, Paul

AU - Dreesen, Laurent

PY - 2006

Y1 - 2006

N2 - Monolayers of protoporphyrinIX molecules are prepared on a Pt(111) surface by self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning Tunneling Microscopy (STM) and Two-Colour Sum-Frequency Generation (2C-SFG) are performed ex situ at ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800-3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)ProtoporphyrinIX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. All these results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety.

AB - Monolayers of protoporphyrinIX molecules are prepared on a Pt(111) surface by self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning Tunneling Microscopy (STM) and Two-Colour Sum-Frequency Generation (2C-SFG) are performed ex situ at ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800-3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)ProtoporphyrinIX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. All these results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety.

KW - sum-frequency generation

KW - mercaptoporphyrins

KW - protoporphyrins

KW - Scanning tunneling microscopy

KW - monolayers

M3 - Article

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SP - 3702

EP - 3709

JO - Surface Science

JF - Surface Science

SN - 0039-6028

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