Unified View of Charge Transport in Organic Semiconductors

This lecture presents a unified understanding of charge transport in organic semiconductors, focusing on the generalized Einstein relation (GER) that integrates various transport models. The instructor discusses the characteristic features of organic semiconductors, including the Einstein-Smoluchowski relationship and the implications of charge carrier concentration on mobility. The lecture highlights the significance of the density of states (DOS) and its Gaussian distribution in determining charge transport behavior. The GER is introduced as a framework that can predict charge transport across different crystallinities and conditions, allowing for a coherent comparison of transport mechanisms. The instructor explains how the degree of delocalization and energetic disorder influence mobility and transport regimes, including band-like transport and variable range hopping. The lecture concludes with a discussion on the practical applications of these concepts in organic field-effect transistors and photovoltaic devices, emphasizing the importance of understanding these mechanisms for advancing organic electronics.