A simple theoretical approach to the band gaps of conjugated polymers

Abstract

Engineering the band gap of a conjugated polymer is an effective way to improve the performance of the corresponding photoelectric device. In this study, a repeating unit of a conjugated polymer is reduced to a phenylene, a vinylene/ethynylene or a combination of them according to the characteristics of the atoms and the bonds. And the trends of the band gaps of polyphenylene, polyvinylene/polyethynylene, their substituted derivatives and alternating copolymers are given by using Hückel molecular orbital method with the parameters for the electron-withdrawing powers and the strengths of the bonding interactions of atoms. The approximation for complex structures and the trends of simple structures make it very convenient to analyse and predict the band gap of a conjugated polymer qualitatively.

Keywords::

• conjugated polymer
• band gap
• simplification
• Hückel molecular orbital
• repeating unit

Notes

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