In the present work we report the synthesis of highly meso- and macro-porous thin TiO2 films as efficient scaffolds for improved performance of heterojunction solid state perovskite solar cells made in Fambient air. TiO2 films were prepared using sol-gel process and Pluronic P-123 block copolymer as organic template while they were formed on conductive glass substrates by spin-coating method. The films were employed to the construction of very efficient perovskite solar cells made at ambient conditions where CH3NH3PbI3-xClx mixed halide perovskite was used as light harvester and P3HT polymer as hole conductor. The very rough and highly porous TiO2 films proved to be an excellent host material for perovskite growth. The structural properties of the TiO2 electron transport layer, thickness, particle size and porosity, strongly affected the overall conversion efficiency. The optimal structure and materials composition exhibited a notably high current density J(sc) of 23.8 mA/cm(2), V-oc of 0.995 V and fill factor of 0.58. These solar cells prepared under ambient conditions yielded an average power conversion efficiency of 13.7% among the best ever recorded with P3HT polymer as hole conducting material. (C) 2016 Elsevier B.V. All rights reserved.