Resolving structural defects in push-pull type conjugated polymers as a leverage for commercialization of organic electronics (R-10233)

Push-pull type conjugated polymers have become a dominating class of active materials in the field of organic electronics. Their adjustable light-harvesting, charge transfer and transport characteristics have been beneficially applied in organic solar cells, photodetectors, lightemitting diodes and transistors. The conventional synthetic approach toward these polymers is based on Suzuki or Stille cross-coupling of complementary functionalized heterocyclic precursors. In the ideal world, this gives rise to a perfect alternation of the employed building blocks throughout the polymer backbone, which leads to a substantial decrease of the bandgap. In recent years, however, it has become increasingly clear that the 'real' structure of these polymers is often quite different from the projected one. Structural imperfections can for instance result from homocoupling of two identical building blocks. Furthermore, the end groups often deviate from the expected ones. These structural defects generally have a negative impact on the device performance and should therefore be avoided during material production. Batch-to-batch variations in material quality are recognized as one of the main issues hindering commercialization (in particular for organic photovoltaics). In the presented project, this challenge will be addressed by systematic evaluation and optimization of the structures of prototype push-pull polymers, providing a leverage for commercialization of this fascinating technology.

Keywords:homocoupling, organic photovoltaics, push-pull type conjugated polymers, structural purity

Disciplines:Synthesis of materials, Macromolecular and materials chemistry not elsewhere classified, Organic chemical synthesis, Physical organic chemistry, Molecular and organic electronics