RTG 1

Surfaces/Interfaces

Jan Čechal (CEITEC), Ulrike Diebold (TUW), Alexander Vaskevich (WIS)

Interfaces between two materials frequently have a defining role in the function of devices in which they are incorporated. For example, a thin layer organic semiconductor is a crucial part of the organic light-emitting diode that forms a fundamental component of the OLED displays. Here the electric current flow from an electrode to this layer is strongly affected by the interface in between. In other words, the interface may feature very high contact resistance. Therefore, if we engineer the interface properly, we can decrease the power consumption of all the OLED displays and OLED-based illumination. Here even a slight improvement in power consumption will sum up considerable global energy-saving and contribute to a sustainable future.

In particular, we aim at the interface between selected organic semiconductors, copper phthalocyanine (CuPc), and indium oxide. Indium oxide is a prototypical transparent contact material extensively used in a wide range of applications, most prominently in optoelectronic technologies, especially if doped with tin; then it is commonly referred to as indium tin oxide (ITO). In the framework of the SINNCE project, we study the adsorption position of CuPc, its growth from single molecules to thin films, and the electronic level alignment, which essentially defines the contact resistance. These results will provide the understanding required for the design of advanced devices comprising organic molecular semiconductors.