Inorganic-organic hybrid structures have become innovative alternatives for next-generation dye-sensitized solar cells, because they combine the advantages of both systems. Here, we introduce a layered sandwich-type architecture, the core of which comprises a bicontinuous three-dimensional nanocomposite of mesoporous (mp)-TiO2, with CH(3)NH(3)Pbl(3) perovskite as light harvester, as well as a polymeric hole conductor. This platform creates new opportunities for the development of low-cost, solution-processed, high-efficiency solar cells. The use of a polymeric hole conductor, especially poly-triarylamine, substantially improves the open-circuit voltage V-oc and fill factor of the cells. Solar cells based on these inorganic-organic hybrids exhibit a short-circuit current density J(sc) of 16.5 mA cm(-2), V-oc of 0.997 V and fill factor of 0.727, yielding a power conversion efficiency of 12.0% under standard AM 1.5 conditions.