  Using electrically detected magnetic resonance spectroscopy, we demonstrate
that doping the conducting polymer
poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) with
ethylene glycol allows for the control of effective local charge carrier
hyperfine fields through motional narrowing. These results suggest that doping
of organic semiconductors could enable the tuning of macroscopic material
properties dependent on hyperfine fields such as magnetoresistance, the
magneto-optical responses and spin-diffusion.
