Effects of perfluorination on thiophene and pyrrole oligomers

Date
2010
Authors
Salzner, U.
Advisor
Instructor
Source Title
Journal of Physical Chemistry A
Print ISSN
1089-5639
Electronic ISSN
1520-5215
Publisher
Volume
114
Issue
16
Pages
5397 - 5405
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

The effect of perfluorination on thiophene and pyrrole oligomers in neutral, cationic, and anionic states was investigated with density functional theory at the (TD)B3P86-30%/6-31G* level. For the title compounds fluorination leads to planarization. For pyrroles a band gap reduction of 0.58 eV results, as unsubstituted pyrroles are nonplanar and disordered in the solid state. For thiophene the band gap is slightly increased as long thiophene oligomers are almost planar. Ionization energies and electron affinities increase upon fluorination by 0.65 and 0.60 eV for polythiophene and by 0.45 and 0.90 eV for polypyrrole. Conduction band widths increase by 0.5 for polythiophene and by 0.7 eV for polypyrrole. Spectra of charged (doped) forms are almost identical to those of the parent systems. Like parent systems, fluorinated oligomers with chain lengths of more than six rings develop a third UV absorption that increases in strength and decreases in energy upon chain length increase.

Course
Other identifiers
Book Title
Keywords
Anionic state, Band gap reduction, Band gaps, Fluorinated oligomer, Ionization energies, Perfluorination, Planarization, Poly-thiophene, Thiophene oligomers, Title compounds, UV absorption, Chain length, Density functional theory, Dyes, Electron mobility, Energy gap, Fluorination, Fluorine, Halogenation, Nitrogen compounds, Oligomers, Polypyrroles, Potassium compounds, Pyrrole derivative, Thiophene derivative, Chemical model, Chemistry, Synthesis, Models, Chemical, Pyrroles, Quantum Theory, Thiophenes
Citation
Published Version (Please cite this version)