Charge Carrier Transport in Organic Field-Effect Transistors

Organic optoelectronic devices such as organic field-effect transistors (OFETs) show great promise as competitive alternatives to silicon-based electronics due to demonstrated advantages from a cost and manufacturing standpoint, as well as enabling a new generation of technologies such as flexible integrated optoelectronic devices. However, charge-carrier transport in organic materials is not well-understood, preventing realization of the full potential of organic devices. The objective of this work is to use OFETs with a poly(3-hexylthiophene) (P3HT) active semiconducting layer as a model system for investigating charge-carrier transport in this material. Current-voltage curve measurements of our initial devices show an average charge-carrier mobility of 3.18 x 10^-5 cm²/(V*s), which is about 10x smaller than lowest literature values ranging from 10^-4 to 10^-1 cm²/(V*s). In addition, we have developed a technique called Modulated-Amplitude Reflectance Spectroscopy (MARS) imaging, which can be used to create a spatially resolved map of charge-carrier distribution in the organic, semi-conducting layer of OFETs [1].

[1] A. R. Davis, L. N. Pye, N. Katz, J. A. Hudgings, and K. R. Carter, Adv. Mater. 26, 4539 (2014).