Mechanism of photoinduced charge transfer at MEH-PPV and titanium dioxide nanoparticle interface

Abstract

In this study, we investigated mechanisms of photoinduced electron transfer from a conjugated polymer (poly(2-methoxy-5-(2-ethylhexyloxy) 1,4-phenylenevinylene (MEH-PPV) to titanium dioxide (TiO₂) nanoparticles (acceptor) through steady-state photoluminescence (PL) spectroscopy. Since mixed phase TiO₂ has better photocatalytic compared to single phase, it is an efficient charge separation process during photoexcitation of polymer nanocomposites by incorporating the mixed phase TiO₂ nanoparticles into the MEH-PPV polymer matrix through in situ polymerization. Structural characterization revealed only physical interaction between the polymer matrix and dispersed nanoparticles. The absorbance spectra of nanocomposites also indicated the absence of ground state complex formation. Luminescence quenching of polymer nanocomposites compared to pristine MEH-PVV signifies the charge transfer taking place at the MEH-PPV/TiO₂ interfaces. Thus, the MEH-PPV/ mixed phase TiO₂ nanocomposite serves as an active layer for photovoltaic application.