Photosensitive heterojunctions of silicon coated with sol-gel derived TiO2 dispersed in poly(3,4-ethylendi oxythiophene)/ poly(styrenesulfonate)

Sol-gel derived aggregates of titania nanocrystals, synthesized starting from alcohol-water solutions of titanium isopropoxide, were characterized by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) measurements. The TiO2 powder was dispersed in aqueous solutions of poly(3,4-ethylendioxythiophene)/poly(styrenesulfonate) (PEDOT-PSS), and the blends were coated on n-doped silicon substrates to achieve simple design heterojunctions. Current versus voltage measurements performed both in the dark and under broad band light irradiation show that the nSi/PEDOT-PSS/TiO2 heterojunctions have remarkable photosensitive behaviour, promising in view of applications as hybrid photovoltaic cells.