On Monday, October 28, 2013, Alberto Morpugo of University of Geneva will give his talk:
Organic semiconductors are a broad class of materials that have incredible potential for applications. TV screens based on organic molecules are already commercially available, large area solar cell panels are being researched intensively, and organic transistors are developed to target flexible electronic applications as well as low-cost disposable devices. Despite their technological relevance, the basic electronic properties of organic semiconductors are only very poorly understood. To a large part, this is because most research has focused on low-cost applications, based on materials prepared with simple methods, whose electronic properties are fully dominated by disorder and imperfections. In this talk I will discuss our research on field-effect transistors realized using high-quality single-crystals of different molecules. In these devices the amount of disorder is limited, and it is possible to observe experimentally the intrinsic properties of the materials. I will present an overview of some of our findings, focusing in particular on the role of the interfacial electronic properties. I will discuss –for instance- how the proximity of an insulator can strongly affect the carrier mobility at the surface of an organic crystal, or how the interface between two insulating organic semiconductors can have metallic conductivity. I will also discuss some aspects of the relation between the material structure and its electronic transport properties, that are just starting to be understood now.