Impact of Traps on Charge Transport in Organic Semiconductors

• Applicants: Professor Dr.-Ing. Niels Benson; Professor Dr. Carsten Deibel; Professor Dr. Roland Schmechel
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 263376198

The interplay between traps and charge transport is very important for virtually all organic electronic applications, as the charge carrier mobility has a direct impact on the performance of rectifiers, light emitting diodes, transistors, inverters and solar cells. While hole traps are thoroughly investigated, only indirect information has been available on electron traps until recently. Therefore, the main goal of this proposal is to correlate the energetic position and concentration of electron traps in soluble organic semiconductors with their charge transport properties. The properties of these electron trap states will be determined by defect spectroscopy, and the corresponding charge carrier mobility by complementary transient techniques to investigate the transport on trap dependence. Oxygen-related trap states, reported to be common in many conjugated polymer films, are the main focus of our work. This type of trap will be identified by selective polymer thin film oxygen exposure, and controlled directly and indirectly by tuning process conditions as well as doping strategies. By these means, we aim at improving the electron transport, without negatively influencing the hole transport properties.

• DFG Programme: Research Grants