Conjugated, rod-like viologen oligomers: correlation of oligomer length with conductivity and photoconductivity

Chen, Long, Vivier, Elodie, Eling, Charlotte J, Babra, Tahkur S, Bouillard, Jean-Sebastien G, Adawi, Ali M, Benoit, David M, Hartl, František, Colquhoun, Howard M, Efremova, Olga A and Greenland, Barnaby W (2018) Conjugated, rod-like viologen oligomers: correlation of oligomer length with conductivity and photoconductivity. Synthetic Metals, 241. pp. 31-38. ISSN 0379-6779

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Abstract

An iterative synthesis has been used to produce conjugated, monodisperse, viologen-based aromatic oligomers containing up to 12 aromatic/heterocyclic rings. The methoxy-substituted oligomers were soluble in common organic solvents and could be processed by spin coating. The conductivities of the resulting films (30 to 221 nm thick) increased by more than an order of magnitude as the oligomer length increased from unimer (1, 2.20×10-11 S cm-1) through dimer (2) to trimer (3, 6.87×10-10 S cm-1). The bandgaps of the materials were estimated from the absorption spectra of these thin films. The longest oligomer, 3, exhibited a noticeably narrower bandgap (2.3 eV) than the shorter oligomers (1 and 2 both 2.7 eV). Oligomer 3 also showed photoconductivity under irradiation across a wide range of wavelengths in the visible spectral region. In conjunction with DFT calculations of these systems our results suggest that structurally related viologen-type oligomers may find use in optoelectronic devices.

Item Type: Article
Schools and Departments: School of Life Sciences > Chemistry
Subjects: Q Science > QD Chemistry
Depositing User: Barnaby Greenland
Date Deposited: 10 Apr 2018 08:12
Last Modified: 10 Apr 2018 12:03
URI: http://sro.sussex.ac.uk/id/eprint/74959

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