Thin films of p-type nickel oxide (NiO) were prepared by a sol-gel spin deposition on ITO/TiO2 to fabricate the photoelectrodes and all-solid-state dye-sensitized solar cells. The Ni(OH)(2) sol was formed from nickel (11) acetate tetrahydrate in a mixture of alcohol solution and poly(ethylene glycol), and followed by different heat treatments in air (350-800 degrees C). The formation and composition of NiO thin film was verified by EDX and X-ray diffraction (XRD) analysis, which shows preferred orientation along the (I 1 1) plane. The thickness of the NiO film calcined at 450 degrees C for 1 h is 120.6 nm with average grain size of 22 nm, and high UV transparency (similar to 75%) in the visible region is observed. The electrical properties of the sol-gel NiO films such as hole carrier concentration, sheet resistance and carrier mobility were examined using Hall measurement. Results show that the Hall mobility is dominated by the hole concentration. Furthermore, all-solid-state dye-sensitized solar cells comprising n-TiO2/p-NiO composite electrode were fabricated and the performance was evaluated. The current-voltage (I-V) characteristics of the composite TiO2/NiO electrode in dark demonstrate a good rectifying curve, verifying the p-type behavior of NiO films. Solar cells when sensitized with Ru-dye (N719) demonstrate short-circuit photocurrent (I-SC) of 0.33 mA/cm(2) and open-circuit photovoltage (V-OC) of 210 mV; the overall energy conversion efficiency of the device is about 0.025%. (C) 2009 Elsevier Ltd. All rights reserved.