A rapid microwave-assisted hydrothermal synthetic method is reported for the fabrication of TiO2 nanoparticles. Their photovoltaic activities are performed in dye-sensitized and perovskite-based solar cells. Power conversion efficiencies using microwave-assisted synthesized TiO2 are relatively similar compared with those employed TiO2 nanoparticles made of conventional hydrothermal process. The reaction time that is typically 12 h (literature value) was greatly reduced to only 25 min using microwave-heating process for TiO2 nanoparticles formation, which provides an energy-saving and cost-effective method for making the building blocks of photoactive TiO2 nanocrystallines. The material properties of the microwave-synthesized TiO2 nanoparticles are characterized in details by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy and photoluminescence emission spectra. An optimal dye-sensitized solar cell with impressive power conversion efficiency of 8.2% was achieved using microwave-synthesized nanoparticles in combination with commercial paste (CCIC HPW-400) as scattering layer. A mesoscopic perovskite-based solar cell employing microwave-assisted synthesized TiO2 nanopartides obtained power conversion efficiency over 10%. (C) 2015 Elsevier Ltd. All rights reserved.