Synthesis, characterisation and application in electronic devices of low band gap materials based on thiophene derivatives

Abstract

Recent years have seen the increased use of organic materials for electronic applications as photovoltaic cells and field-effect transistors (FETs). Such applications require the use of conjugated polymers with a sufficiently high quality, purity and molecular weight (Mw > 30 000). This dissertation deals with the search for possible synthetic routes leading to low band gap (LBG) materials, conjugated polymers with a small energy gap between the valence and conduction band. Those materials show interesting properties which make them extremely attractive for applications in plastic electronics. The processability of these materials here is very important. This can be obtained either by introducing long chains or by the use of a precursor route. In this dissertation especially the latter is dealt with. Here first a soluble precursor polymer is synthesised which, after thermal treatment, gives rise to the conjugated polymer. We aim at efficient synthetical pathways in order to obtain well defined polymer materials. In cooperation with other research groups, different materials were characterised en tested with an eye to further applications. ...