Charge Transport Mechanisms in Organic Semiconductors

This lecture discusses the mechanisms of charge transport in organic semiconductors, focusing on band transport and transient localization. It begins with an overview of band transport, explaining how charge carriers move through materials via Bloch waves in a periodic lattice. The instructor outlines the conditions necessary for effective band transport, including the dominance of interaction energy over disorder. The lecture further explores the temperature dependence of charge mobility and the significance of mobility thresholds for band transport. Examples of band transport in low-temperature systems and organic field-effect transistors are presented, illustrating the practical implications of these concepts. The discussion transitions to transient localization, where charge transport resembles band transport but is influenced by dynamic disorder. The instructor emphasizes the importance of understanding these transport mechanisms for the development of efficient organic electronic devices, highlighting the challenges posed by impurities and structural disorder. The lecture concludes with a summary of the key factors affecting charge transport in organic materials.