We describe a one-pot chemical synthesis to produce TiO2-x(OH)(2x) colloidal solutions that are suitable to be deposited, at 150 degrees C only, as interfacial electron transporting layer, in inverted organic solar cells. The crystallized nanoparticles were synthesized from the hydrolysis of [Ti8O12(H2O)(24)]Cl8HCl center dot 7H(2)O in organic solvent, using solvothermal method at 120 degrees C. The UV-illumination of TiO2 colloidal solutions, before the deposition process, was found to improve the initial performance of solar cells. Compared to the usual sol-gel TiOx layer, no kink shape of the I/V curve is observed, indicating the good quality of the interfacial contact with the P3HT:PCBM blend of polymer. Additionally it is worth noting the significant improvement of the solar cells stability, characterized by a loss of power conversion efficiency limited to 17% after 6500 h over continuous AM 1.5 illumination. (C) 2013 Elsevier B.V. All rights reserved.