The aim of this work is to prevent short-circuits in the solar cells and back transfer of electrons due to direct contact between the electrolyte and the conductive substrate. A thin passivating TiO2 under layer was deposited on SnO2:F coated glass substrate by facing target sputtering technique with different sputtering pressures: 0.1, 1.0 and 2.0 Pa. An upper nanoporous TiO2 layer was deposited by conventional sol-gel technique with 2.0 g of polyethylene glycol. The variation of photoelectric conversion efficiency of the solar cells with different TiO2 passivating layers is discussed with the analysis of crystallographic and microstructural properties of passivating and upper nanoporous TiO2 layers. (C) 2008 Elsevier B.V. All rights reserved.