Structural and electronic effects of 1,3,4-thiadiazole units incorporated into polythiophene chains

Hao Pang, Peter Skabara, David J. Crouch, Warren Duffy, Martin Heeney, Iain McCulloch, Simon J. Coles, Peter N. Horton, Michael B. Hursthouse

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

A series of conjugated triaryl compounds have been synthesized, consisting of thiophene or selenophene peripheral units and a central 1,3,4-thiadiazole (TDA) heterocycle. X-ray crystallographic studies on four of the materials reveal that the molecules are planar in the solid state and feature an array of intramolecular (heteroatomic) and intermolecular (heteroatomic and π−π) noncovalent close contacts. Electrochemical oxidative polymerization affords insoluble polymers for EDOT-TDA-EDOT and EDTT-TDA-EDTT. The band gaps of the polymers have been deduced by cyclic voltammetry and electronic absorption spectroscopy and were found to be 1.8−1.9 eV. Both polymers show good stability toward n-doping and the EDTT analogue is more readily reduced than the EDOT-containing system. The enhanced stability toward n-doping, compared with the homopolymers PEDTT and PEDOT, is attributed to the presence of the electron deficient thiadiazole unit. The LUMO of poly(EDTT-TDA-EDTT) is 0.3 eV lower than that of poly(EDOT-TDA-EDOT), demonstrating that the substituent effect of the chalcogen atom is an important contributor to the electronic properties of the polymers.
Original languageUndefined/Unknown
Pages (from-to)6585-6593
Number of pages9
JournalMacromolecules
Volume40
Issue number18
DOIs
Publication statusPublished - 4 Sep 2007

Keywords

  • polymers
  • thiadiazole units
  • triaryl compounds
  • polythiophene chains

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