Enhancement of the hole transport in poly(p-phenylene vinylene) based light-emitting diodes

The hole transport in various polyp-phenylene vinylene (PPV) derivatives has been investigated in hole-only diodes as function of temperature T and applied electric field E. A difference of three decades has been found in the hole mobility between a random copolymer with asymmetric sidechains and a PPV-derivative with symmetric sidechains. The temperature dependence of the hole mobility has been analysed within the correlated Gaussian disorder model. The large differences in the mobility values of these PPV derivatives are governed by a strong decrease of the energetic disorder. The high mobility PPV-based polymers are interesting candidates for being used as hole transport layers in heterojunction light-emitting diodes.