We studied the charge mobility characteristics of a series of new poly (p-phenylenevinylene) PPV derivatives, with different substituents (CF3, OCH3, F) on their biphenylyl side chains, using a conventional time of flight (TOF) photoconductivity technique. The TOF hole transients at 295 K showed a non dispersive nature of transport and the dependence of hole mobility with applied electric field follows Pool-Frenkel relation. The present results indicate that the charge mobility characteristics can be fine-tuned by varying the size of the substitutents on the biphenylyl side chains, which is in good agreement with the PLED device performance. (c) 2005 Elsevier B.V. All rights reserved.