Investigation of Polymeric Composite Films Using Modified TiO2 Nanoparticles for Organic Light Emitting Diodes

Nanocomposite films for hole transport and emitting layer were prepared from poly(3,4-ethylenedioxythiophene), poly(styrenesulfonate), and poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] - as MEH-PPV - incorporated with anatase (TiO2) nanoparticles dispersed in oleic acid. The precursor for the sol was a solution of tetraiso-propyl orthotitanate [Ti(iso-OC3H7)4]. The research showed that both the electrical and spectral properties of the conjugated polymers were enhanced due to the incorporation of anatase. The best volume ratio between the oleic acid precursor and tetraiso-propyl orthotitanate was found to be of 10. Current-voltage characteristics of organic light emitting diodes made from these nanocomposite films were considerably enhanced in comparison with those made from pure polymers. The luminous efficiency is reported. Mechanical properties of the nanocomposite materials, (in particular for MEH-PPV-TiO2) were found to be dependent on constituent organic and inorganic materials and on the geometric position of constituents. It was concluded that such composite organic light emitting diodes can exhibit larger performance efficiency and longer lifetimes than classical light emitting diodes.