Hybrid polymer–metal oxide solar cells by in situ chemical polymerization

Abstract

We present a new approach for improving the infiltration of a conjugated polymer into the pores of a nanostructured metal oxide electrode, whereby the polymer is prepared directly inside the porous oxide film by in situ chemical polymerization. We apply this method to the polymerisation of poly[2-methoxy-5-(2 ethylhexyloxy)-1,4-phenylenevinylene (MEH-PPV) inside a nanostructured porous TiO₂ layer by adapting the synthetic route based on the Gilch reaction. Transient and steady state optical studies show that the light absorption and emission properties of the polymer so produced are similar to those of the polymer synthesised ex situ, while the photoinduced charge separation yield is improved by in situpolymerisation. The photocurrent generated by hybrid polymer/metal oxide solar cells prepared by this methodology is enhanced by a factor of two to three relative to devices prepared with pre-synthesised polymer. The improved photocurrent and charge separation yield for the polymer produced in situ are attributed to improved infiltration of the polymer into the metal oxide film.