Structure-Property Relationships In Organogels of Polythiophenes

Conjugated polymers, such as polythiophenes (PTs), are known to form fibrillar structures when solvent quality is reduced. At high concentrations, PTs will self-assemble and form semiconducting elastic networks of interconnected fibers. The interconnectivity of these networks lead to a continuous, 3-dimensional path for charge transport which is ideal for the bulk heterojunction structure of organic photovoltaic devices. This talk will describe our recent systematic evaluation of these networks over multiple length scales (0.1 – 10,000 nm) using small angle neutron scattering (SANS). SANS is used in combination with in situ rheology (Rheo-SANS) and in situ electrochemical analysis (Dielectric-SANS) to characterize the development of structural, mechanical and electrical properties. This allows us to formulate additional structure-property relationships for this important class of materials. This talk will also address the implications of our findings on the development of novel photovoltaic technology.