A solid state solar cell using sol–gel processed material and a polymer

Abstract We present a heterojunction photovoltaic cell, fabricated from sol–gel TiO 2 anatase and poly[2-methoxy-5-(2 ′ -ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH–PPV). The solid state cell has a peak power conversion efficiency of 1.6% when illuminated with monochromatic light at 500 nm. At this wavelength the fill factor of the device is 0.67 and the incident photon to current conversion efficiency is 9.5%. The open circuit voltage of the device under these conditions is 0.63 V, similar to the value calculated using capacitance techniques. The anatase TiO 2 thin film was prepared by sol–gel processing and dip-coating techniques, whereas the soluble conjugated polymer film, MEH–PPV, was spin coated on top of the TiO 2 anatase film. Layer thicknesses of 50 and 80 nm were obtained for TiO 2 and MEH–PPV, respectively, and cross section TEM photographs of the TiO 2 layer shown the dense nature of the polycrystalline anatase structure with crystallite sizes ranging from 5 to 20 nm.