Structure-property relation in highly luminescent organic semiconductors with high charge carrier mobilities

• Applicant: Professorin Dr. Katharina Broch
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 251536402

Organic semiconductors (OSCs) are compounds, containing carbon, hydrogen and possibly other elements and exhibit temperature dependent electrical conductivity. They find applications in optoelectronic devices such as organic light emitting diodes (OLEDs). The working principle of OLEDs is based on the radiative recombination of electrons and unoccupied electronic states (holes) at an interface in the material. In order to optimize the performance of such a device, two properties of the material are of high relevance. First, a high charge carrier mobility, assuring that all injected charge carriers reach an interface to recombine. This requires a material with high structural order and only a few defects which may scatter and slow down the motion of the charge carriers. Second, an efficient emission, which means, in the ideal case all injected charge carriers should recombine and contribute to the emission of light. Preliminary experiments demonstrated the importance of the structural properties not only for the charge carrier mobility but also for the emission of light. This structure property relation is not yet completely understood from a fundamental point of view.Therefore, the project will focus on a study of the interplay between structure of the material, chemical composition, charge carrier mobilities and optical properties, in particular emission, of a class of OSCs which exhibit high charge carrier mobilities and highly efficient luminescence. Possible applications of these OSCs will be tested in devices.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Dr. Henning Sirringhaus