Molecular ordering in monolayers of an alkyl-Substituted perylene-bisimide dye by attenuated total reflectance ultraviolet-visible spectroscopy

Walter J. Doherty, Adam G. Simmonds, Sergio B. Mendes, Neal R. Armstrong, S. Scott Saavedra

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Surface-relative orientational parameters were determined for monolayer films of N, N'-ditridecylperylenetetracarboxylic dianhydridediimide (C 13-PTCDI) in terms of the relative electronic transition dipole strengths, providing a three-dimensional view of the absorption dipole distribution. In order to obtain a macroscopically ordered film, C 13-PTCDI was deposited by (1) horizontal Langmuir-Blodgett (LB) transfer onto methyl- and phenyl-silanized glass, and (2) vapor deposition onto oriented films of poly(tetrafluoroethylene) (PTFE) on glass. Films of LB-deposited C 13-PTCDI were found to be completely Isotropic prior to annealing. After annealing, these films remained isotropic in the plane of the substrate while the out-of-plane anisotropy was significantly enhanced. In contrast, films of C 13-PTCDI vapor deposited onto oriented poly(tetrafluoroethylene) (PTFE)-modified substrates yielded films with a high degree of both in- and out-of-plane anisotropy. Atomic force microscopy (AFM) images of both the LB- and vapor-deposited films show substantial differences in film morphology and long-range order. These results demonstrate that molecular orientation in C 13-PTCDI films can be controlled by varying substrate surface chemistry and post-deposition processing.

Original languageEnglish (US)
Pages (from-to)1248-1256
Number of pages9
JournalApplied Spectroscopy
Volume59
Issue number10
DOIs
StatePublished - Oct 1 2005

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Keywords

  • ATR
  • Attenuated total reflection
  • Molecular orientation
  • Perylene

ASJC Scopus subject areas

  • Instrumentation
  • Spectroscopy

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