Charge Carrier Mobility Measurements

Abstract

An important elementary process in solar cells is the transport of photo-generated charge carriers from the place of their generation through the devices to the electrodes. The transport may have to occur through different material layers, and each layer may have its own transport properties. In a given material, charge transport is macroscopically characterized by the charge carrier mobility as the most important physical quantity. A number of methods exist to determine charge carrier mobility experimentally. This chapter gives a brief introduction to selected methods. Namely, mobility measurements in organic field effect transistors (OFETs) and studies using single carrier diodes are discussed. An important difference between both approaches concerns the direction of the charge transport. In OFETs, charge transport is studied laterally through a thin film on a substrate. In contrast, in a single carrier diode, transport is investigated in the direction perpendicular to the film. Therefore, the methods can be regarded to provide complementary information. © Springer International Publishing Switzerland 2014.