In this study, the effect of the incorporation of ZnO nanoparticles into poly(3-hexylthiophene) (P3HT) on the electronic properties of P3HT films was examined. Conductivity proportional to ZnO doping was observed. The improvement of conductivity is considered to mainly come from a mobility enhancement. The carrier mobility in P3HT (ZnO-doped P3HT) samples exhibits unexpected temperature dependence, implying the dominance of tunneling in the temperature range of 280-330 K. Hall-effect analysis by using the polaron theory revealed that ZnO doping might lead to an increased spacing between molecules, thus enhancing the carrier mobility. (C) 2013 Elsevier B. V. All rights reserved.