Ti doped MoO2 nanoparticles with high BET surface area of 135 m(2)/g were synthesized via scalable solvothermal cracking of polycrystalline MoO3 microparticles prepared by ultrasonic spray pyrolysis. The pristine MoO2 and Ti doped MoO2 nanoparticles showed metallic conductivity, whereas the MoO3 microparticles had semi-conducting behavior. In addition, the Ti doping in MoO2 nanoparticles formed stronger Mo-O bond than the pristine MoO2 and consequently exhibited improved stability against humidity. Accordingly, the p-i-n type planar CH3NH3PbI3 perovskite solar cells with Ti doped MoO2 inorganic hole transporting material showed 15.8% of power conversion efficiency at 1 Sun condition (100 mW/cm(2)) and significantly improved humidity stability.