Enhancement of the electrical properties of poly(p-phenylene vinylene) by the incorporation of silicon dioxide nanoparticles

The electrical properties of a poly(p-phenyl-ene vinylene) (PPV) conjugated polymer using silver (Ag) as a cathode were improved by the incorporation of silicon dioxide (SiO₂) nanoparticles. The current density of the Ag-PPV/SiO₂ nanocomposite system was higher than that of Ag-PPV. A lower level of interfacial oxidation was found in the Ag-PPV/SiO₂ nanocomposite than in Ag-PPV, confirming that a more complete elimination of residue occurred in the nanocomposite. This was due to the relatively large surface area of the PPV/SiO₂ nanocomposite film and the hydrophilic surface of the SiO₂ nano-particles. The lower level of oxidation contributed to an improvement in the material's current-voltage characteristics. Morphology-dependent current-voltage characteristics were enhanced by a large variation in the thickness of the Ag-PPV/SiO₂ nanocomposite film because an increased effective field strength could be induced in the thinner regions of the film. The incorporation of SiO₂ nanoparticles altered the effective film thickness and the amount of residue in the interior of the PPV without disrupting the structure of the conjugated polymer. The Ag cathode created a stable interface with the PPV film layer without causing the formation of an organic-metal complex, which would have obstructed electron injection.