Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Band bending and structure dependent HOMO energy at the ZnO(0001)-titanyl phthalocyanine interface
KTH, School of Information and Communication Technology (ICT), Material Physics.
KTH, School of Information and Communication Technology (ICT), Material Physics.
KTH, School of Information and Communication Technology (ICT), Material Physics.
KTH, School of Information and Communication Technology (ICT), Material Physics.
Show others and affiliations
2007 (English)In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 601, no 18, 4222-4226 p.Article in journal (Refereed) Published
Abstract [en]

We have investigated the initial stages of titanyl phthalocyanine (TiOPc) growth on single crystalline ZnO(0 0 0 1). This organic-semiconductor interface is self-organizing as a 2 x 1 pattern appears in a low energy electron diffraction upon deposition of the molecules. To achieve this pattern, the TiOPc is suggested to adsorb standing with the edge of the molecule along the substrate atomic rows. Photoelectron spectroscopy is used to further analyze the interface; a relatively large upwards band bending amounting to 0.5 eV is found and a splitting of the molecules highest occupied molecular orbital occurs after thermal treatment, indicating that the molecules are lying down.

Place, publisher, year, edition, pages
2007. Vol. 601, no 18, 4222-4226 p.
Keyword [en]
Single crystal; Synchrotron radiation photoelectron spectroscopy; Titanyl phthalocyanine; ZnO; Crystal growth; Photoelectron spectroscopy; Single crystals; Synchrotron radiation; Titanium compounds; Zinc oxide; Band bending; Synchrotron radiation photoelectron spectroscopy; Titanyl phthalocyanine; Interfaces (materials)
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
URN: urn:nbn:se:kth:diva-7779DOI: 10.1016/j.susc.2007.04.113ISI: 000250414600117Scopus ID: 2-s2.0-34548810178OAI: oai:DiVA.org:kth-7779DiVA: diva2:12906
Note
QC 20100812Available from: 2007-12-10 Created: 2007-12-10 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Phthalocyanine interfaces: the monolayer region
Open this publication in new window or tab >>Phthalocyanine interfaces: the monolayer region
2007 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Organic molecules adsorbed on inorganic substrates are the topics of interest in this thesis. Interfaces of this kind are found in dye sensitized solar cells that convert solar energy to electricity, a promising environmentally friendly energy source which might provide a route to replace fossil fuels. Another field where these interfaces play a role is in molecular electronics, an approach to solve the down scaling in the ever increasing hunt for miniaturized electronic devices. The motivation for this work lies among other in these applications and surface science is a suitable approach to investigate the electronic and morphologic properties of the interfaces as it provides detailed knowledge on an atomic level.

Phthalocyanines are the organic molecules investigated and the inorganic substrates range from wide band gap via narrow band gap semiconductors to metals. Photoelectron and X-ray spectroscopy experiments are performed to shed light on the electronic properties of the adsorbed molecules and the substrate, as well as the chemical interaction between adsorbate and substrate at the interface. The ordering of the adsorbate at the interface is important as ordered molecular thin films may have other properties than amorphous films due to the anisotropic electronic properties of the organic molecules; this is investigated using scanning tunneling microscopy.

We find that the phthalocyanines are affected by adsorption when the substrate is TiO2 or Ag, where charge transfer from the molecule occurs or an interface state is formed respectively. The molecules are adsorbed flat on these surfaces giving a large contact area and a relatively strong bond. On Ag, ordered structures appear with different symmetry depending on initial coverage. The reactivity of the TiO2 surface is not ideal in the solar cell application and by modifying the surface with a thin organic layer, the negative influence on the adsorbed phthalocyanine is reduced. ZnO is not as reactive as TiO2, thanks maybe to the upright adsorption mode of the phthalocyanines. The semiconductor InSb is less reactive leading to self-assembled molecular structures on the (001) surface, either homogenously distributed in a one monolayer thick film or in strands along the reconstruction rows. InAs on the other hand has a larger influence on the adsorbed molecules resulting in a metallic film upon thermal treatment.

Place, publisher, year, edition, pages
Stockholm: KTH, 2007. 68 p.
Series
Trita-ICT/MAP, 2007:10
Keyword
phthalocyanine, III-V semiconductor, transition metal oxides, adsorption, self-assembly
National Category
Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:kth:diva-4571 (URN)978-91-7178-784-2 (ISBN)
Public defence
2007-12-18, N2, electrum 3, Isafjordsgatan 28, Kista, 10:00
Opponent
Supervisors
Note
QC 20100812Available from: 2007-12-10 Created: 2007-12-10 Last updated: 2010-08-12

Open Access in DiVA

No full text

Other links

Publisher's full textScopusScienceDirect

Authority records BETA

Tjernberg, Oscar

Search in DiVA

By author/editor
Palmgren, PålClaesson, ThomasÖnsten, AnneliAgnarsson, BjörnMånsson, MartinTjernberg, OscarGöthelid, Mats
By organisation
Material Physics
In the same journal
Surface Science
Other Engineering and Technologies not elsewhere specified

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 85 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf