Charge Transport and Thermoelectric Properties of Organic Semiconductors

Organic semiconductors have emerged as an interdisciplinary research field with significant potential across multiple electronic applications, including organic field-effect transistors, organic photovoltaics, organic light-emitting diodes, and organic thermoelectric devices. To facilitate the rational molecular design of high-performance materials and advance these technologies toward practical implementation, elucidating the fundamental properties of organic semiconductors is crucial.
Our research group has focused on the effects of polar side chains on the fundamental physical processes (e.g. charge transfer, separation, and transport), and corresponding thermoelectric properties of n-type organic thermoelectrics. Besides, we also have developed a new model for the charge carrier behaviors in hopping transport. This thesis builds on previous work regarding organic semiconductors in two perspectives: 1) novel organic thermoelectric materials and understanding of the relationship between chemical structures and thermoelectric performance; 2) experimental observations of Coulomb repulsion and collective screen in organic semiconductors to explain the mechanisms governing electrical property evolution and supplement hopping transport.