Abstract
Bilayer poly(3-hexylthiophene):[6,6]-phenylC(61)-butyric acid methyl ester (PC61BM) [P3HT:PC61BM] organic field-effect transistors (OFETs) have been fabricated using a bottom-contact, bottom-gate (BCBG) architecture. By annealing these devices and monitoring the magnitude of the electron field-effect mobility, information about the diffusion properties of PC61BM in P3HT can be obtained. Using a solution to the one-dimensional diffusion equation and an application of percolation theory, a relationship between electron field-effect mobility, diffusion coefficient, and annealing time has been obtained. By applying this model to time-dependent mobility measurements, a rough approximation of 5 nm(2)s(-1) has been made for the diffusion coefficient of PC61BM in P3HT at a temperature of 130 degrees C.