Hybrid photovoltaic cell with well-ordered nanoporous titania–P3HT by nanoimprinting lithography

We have made bulk heterojunction hybrid photovoltaic cells with highly ordered nanoporous titania (TiO2)–poly(3-hexylthiophene) (P3HT). The nanostructured titania, which has a periodic hexagonal hole array with 80–90 nm diameter, was fabricated by the nanoimprinting technique. The nanoporous titania was synthesized by coating the sol–gel mixture of titanium ethoxide (IV), HCl, and 2-propanol on indium tin oxide (ITO) surface. The coated surface was then embossed with an array of PMMA nanopoles, which was produced using a nanoporous alumina (Al2O3) template. The photovoltaic cells with nanostructured titania have a higher power conversion efficiency of 0.16% compared to conventional thin-film titania, under air mass 1.5 (100 mW/cm2) global illumination.