The measurement and understanding the conductivity/ mobility of an organic semiconductor is one of the most critical issues in organic electronics including organic solar cells. The standard “JV-approach” using space-charge-limited current model has clear drawbacks in evaluating the transport properties. In this chapter, we introduce an alternative transport characterization tool—admittance spectroscopy (AS), to extract charge carrier mobility in semiconducting polymers. The complex impedance of the polymer is obtained by exciting the sample (a thin film (~200–500 nm) sandwiched by two electrodes) with an ac voltage source and the analysis of measured time dependent current of the sample allows the extraction of carrier mobility. Examples of applications of AS to OPV polymers and their bulk heterojunction blends will be provided. The reliability of AS technique in OPV polymers will be compared to time-of-flight (TOF) method.
Scopus Subject Areas
- Physics and Astronomy (miscellaneous)