Characterization of Transport Properties of Organic Semiconductors Using Impedance Spectroscopy

Summary

The transport properties of organic devices can be studied using impedance spectroscopy (IS). This chapter describes the theoretical basis and experimental results for the measurement of drift mobilities, localized‐state distributions and deep trapping lifetimes of organic semiconducting materials. In addition, it reviews conventional methods for measuring these transport properties before describing and highlighting the advantages of IS. Unfortunately, IS cannot be always successfully applied to the characterization of the transport properties of OPVs because organic solar cells (OSCs) are not double‐injection devices but charge‐carrier extraction devices. The transport properties of OSCs can easily be determined using modulated photocurrent techniques. IS measurements for the characterization of transport properties can be carried out in a variety of insulating semiconductors such as hydrogenated amorphous silicon and oxide semiconductors, not restricted to organic semiconductors because the theories for IS are based on trap‐controlled band transport.