Solid state hybrid solar cells with hybrid organolead halide perovskites (CH 3 NH 3 PbBr 3 and CH 3 NH 3 PbI 3 ) as light harvesters and p-type polymer poly[N-9-hepta-decanyl-2,7-carbazole-alt-3,6-bis-(thiophen-5-yl)-2,5-dioctyl-2,5-di-hydropyrrolo [3,4-]pyrrole-1,4-dione](PCBTDPP) as a hole transporting material were studied. The Great attention has recently been drawn to developing costeffective, high efficiency solar cells to meet the ever increasing demand for clean energy. Dye/semiconductor sensitized solar cells, 1-11 organic solar cells, 12-15 and inorganic-organic hybrid solar cells [16][17][18][19][20][21] show promise among the novel photovoltaic devices. However, liquid electrolyte-based sensitized solar cells suffer from solvent leakage, and organic solar cells have the problem of short life-time. Hybrid solar cells present a possibility to overcome these disadvantages by using solid-state ptype hole transporting materials (HTM) in lieu of the liquid electrolyte.22-28 Most recently, research in this eld has achieved great progress: PCEs exceeding 5% have been obtained for solar cells consisting of Sb 2 S 3 nanocrystals as the sensitizer, mesoscopic TiO 2 as the n-type electron transporting material (ETM) and p-type polymers as the HTM. 29,30Hybrid organolead halide perovskites are a class of semiconductors with ABX 3 (X ¼ Cl À , Br À , and I À ) structures consisting of lead cations in 6-fold coordination (B site), surrounded by an octahedron of halide anions (X site, face centered) together with the organic components in 12-fold cuboctahedral coordination (A site) (Fig. 1a). Their intrinsic properties can easily be tuned by tailoring the chemistry of the organic and inorganic components. 31,32 These hybrid perovskites have a direct band gap, a large absorption coefficient as well as high carrier mobility. Especially notable is that they can be synthesized by simple solution approaches, a very attractive characteristic for fabricating cost-effective solar cells. Miyasaka et al. 33 have pioneered their application in sensitized solar cells in a liquid electrolyte system, and a high efficiency of 6.5% was reported later. Unfortunately the performance of the solar cells degraded very rapidly due to the dissolution of perovskite sensitizers in the liquid electrolyte.34 A breakthrough was