Hybrid organic / inorganic perovskite solar cells (PSCs) are among the most competitive emerging photovoltaic technologies and its efficiency has increased considerably in the last few years. In this context, inorganic hole transport materials (HTMs) that replace more expensive spiro-OMeTAD had become an intense research area. NiO has been used as HTM due to its high hole mobility, broad Eg and good stability. Nevertheless, it requires an inverted solar cell architecture due to the nature of the sol-gel deposition method, which is incompatible with deposition onto perovskite. In this work, P3HT:NiO nanocomposites were prepared and optimized to be used as HTM in the conventional architecture: glass/TCO/compact TiO2/ mesoporous TiO2/ Perovskite/P3HT: NiO/Au. The nanocomposite P3HT: NiO is formed with functionalized and as-obtained NiO nanoparticles, using chlorobenzene as a common solvent. The concentration of NiO in the composite was optimized in order to improve the efficiency of the PSCs. P3HT: NiO films were morphologically and electrically characterized by SEM, XRD, and conductivity studies. PSCs elaborated with P3HT: NiO as HTM were characterized by surface photovoltage spectroscopy (SPS) and impedance spectroscopy, as well as J-V and external quantum efficiency curves. Improved conductivity was observed in both types of nanocomposites relative to P3HT, and doping of P3HT by functionalized NiO could be inferred from the different film colors.