Terahertz mobility measurements on poly-3-hexylthiophene films: Device comparison, molecular weight, and film processing effects

We directly compare relative carrier mobilities in semiconducting organic polymer films measured using noncontact optical pump terahertz (THz) probe spectroscopy to those reported in electrical device studies. Relative transient signal amplitude measurements of photoinjected carrier mobility as a function of poly-3-hexylthiophene (P3HT) molecular weight correlate directly with electrical device test values, indicating that the THz method shows promise as a rapid material screening approach. We also present measurements on P3HT conducting films as a function of structural regularity, dispersing solvent, addition of C-60 electron traps, sample temperature, and other growth parameters relevant to device manufacture. (c) 2008 American Institute of Physics.