Improvement of photoelectrochemical and optical characteristics of MEH-PPV using titanium dioxide nanoparticles

The use of bulk heterojunctions can increase the efficiency of exciton dissociation in polymer-based photovoltaics. We prepared and characterized bulk heterojunctions of poly[2-methoxy-5-(2′-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) and titanium dioxide nanoparticles deposited by spin coating on indium tin oxide substrates. The surface morphology of the MEH-PPV+TiO2 composite films revealed that addition of TiO2 nanoparticles increased the film roughness. The effect of TiO2 nanoparticles on the photoelectrochemical and optical characteristics of MEH-PPV polymer heterojunctions was studied. Addition of TiO2 nanoparticles improved the absorbance of MEH-PPV composite films. Moreover, the photocurrent of the composite devices increased with the TiO2 nanoparticle concentration. These observations provide an insight into new approaches to improve the light collection efficiency in photoconductive polymers.