Polymer light-emitting diodes based on a soluble poly(p-phenylene vinylene) with interfaces modified by self-assembly

We report on the characteristics of light-emitting diodes, LEDs, based on a soluble polymer - poly({2-[(2-ethylhexyl)oxy]-5-methoxy-1,4-phenylene} vinylene), MEH-PPV - having either the anode/polymer or the polymer/cathode interfaces modified by self-assembly. In particular, we observe that the grafting of polar molecules at the indium-tin oxide anode surface can significantly reduce the turn-on voltage, while the reverse is observed when ionic polymers are self-assembled on top of the luminescent polymer surface prior to the cathode deposition.