Colloidal TiO2 Nanocrystals/MEH-PPV Nanocomposites: Photo(electro)chemical Study

An extensive optical and photoelectrochemical study of blended systems composed of organic-capped TiO2 nanocrystals with either a spherical or rodlike morphology and a conjugated polymer, MEH-PPV, is presented. The absorption and emission properties of the heterojunctions have been characterized both in solution and in thin films. The blended structures deposited onto conductive substrates have been employed as active layers in photoelectrochemical systems. The investigation has been focused on the photoinduced charge transfer and recombination processes at the interface between the two components, as a function of the nanocrystal shape and surface coating, and of the film thickness. The presence of a large number of interfaces available for charge transfer is believed to play a fundamental role in enhancing the photoelectrochemical performances of the dispersed heterojunctions. The reported results suggest that such MEH-PPV/TiO2 heterojunctions may be exploited as potential active layers in future photovoltaic and photoelectrochemical devices.