Preparation of a nanostructured composite of titanium dioxide and polythiophene: a new route towards 3D heterojunction solar cells

Using an aerosol technique, in which ultrasonically formed droplets of titanium tetraisopropoxide are pyrolysed, thin films of nanosized particles of anatase TiO2 can be deposited. The size of the particles and the film morphology are strongly dependent on deposition parameters like reaction temperature, concentration of the precursor, and gas flow. At best, films can be formed consisting of homogeneous, stoichiometric anatase TiO2 particles with a size of about 50 nm. With these films, solar cells have been constructed by spin casting poly (3-octyl) thiophe ne (P3OT) on top. Cell characteristics of the devices with a 300 nm film of TiO2 and an equivalence of 30 nm of PT inside the pores are I-sc = 0.25 mA/cm(2), V-oc = 0.72 V, FF = 0.35 and eta = 0.06% using white light with an intensity of 1000 W/m(2) (not AM 1.5). The IPCE is 2.5% at 488 nm. (C) 2003 Elsevier Science B.V All rights reserved.