We have developed a novel method of preparation of homogeneous transparent iron oxide thin films based on the thermal decomposition of iron tris-2,2'-bipyridine complexes. The resulting films were characterized with optical spectroscopy, optical and scanning electron microscopy and their crystal structure was established with X-ray powder diffraction and Raman spectroscopy. The film morphology is defined by the choice of the iron precursor and the method allows for both mono- and multilayer deposition, effectively providing control over film thickness. Addition of tris-2,2'-bipyridine complexes of other metals on the stage of film deposition provides a convenient path towards film doping. Obtained iron oxide films were also tested as photoanodes in dye-sensitized solar cells.