Charge Transport in Non-Diluted Conjugated Polymers
  We present a unified calculation method for variable range hopping transport with a varying charge concentration and a varying applied electrical field. We demonstrate that the major differences between the transport properties measured at high concentration and low concentration can be explained within this framework. In particular the difference between the measured mobility, and mobility activation energy in polymer field effect transistors and polymer light emitting diodes is explained. A theoretical method to extract the charge carrier density of state from the transport measurements of non-diluted materials is proposed. 
Yohai Roichman and Nir Tessler