Frequency dependence of the charge carrier mobility in DH4T

The charge carrier mobility in bulk samples of alpha,omega -dihexylquaterth iophene has been determined as a function of temperature using the Pulse-Ra diolysis Time-Resolved-Microwave-Conductivity and Thin Film Transistor (TFT ) techniques. The mobility values obtained at room temperature were approxi mate to0.01 cm(2)/Vs for both methods However upon cooling to 150 K the FET mobility decreases by an order of magnitude whereas the TRMC mobility rema ins almost constant. This behaviour is interpreted as an effect of the freq uency of the electric field that is used in the experiments and could be de scribed theoretically using an over-the-barrier hopping model for the mobil ity.