Electrospun TiO2 nanowires for hybrid photovoltaic cells

A simple and controllable fabrication of TiO2 nanowires by electrospinning and their applications to the electron transporting layer for hybrid organic-inorganic photovoltaic cells are reported. TiO2 nanowires were directly electrospun onto an indium tin oxide on glass substrate from a solution in methanol of polyvinylpyrrolidone, titanium(IV) butoxide, and acetylacetone. The nanowire electrode obtained was consequently subjected to calcination at 450 degrees C. Solution of blended [6,6]-phenyl-C-61-butyric acid methyl ester and poly(3-hexylthiophene) was spin coated on the TiO2 nanowire electrode, followed by thermal annealing and deposition of Au electrode. Hybrid organic-inorganic photovoltaic cells made of TiO2 nanowires exhibited remarkable improvement of the cell efficiencies in terms of photocurrent density and open-circuit voltage as compared with those of references, TiO2 flat films. Maximum energy conversion efficiency of hybrid organic-inorganic photovoltaic cells made of TiO2 nanowires of 1.27% was achieved.