p-type dye sensitized solar cells (p-DSCs) derived from nickel oxide (NiO) photocathodes have been obtained via rapid discharge sintering (RDS) of parent metal oxide nanoparticles deposited onto differently treated substrates utilizing a plasma atmosphere with microwave radiation as heat source. This method produces NiO thin films (0.6<l<6 μm) with mesoporous features and large surface areas as required for efficient dye-loading and high photocurrents. Erythrosine B (ERY) was used to sensitize the oxide in the visible spectrum. We have analyzed and compared the photoelectrochemical performances of the p-DSCs assembled with the various types of NiO samples prepared by RDS techniques with different treatments of the supporting substrate prior to, or during, spray deposition of the NiO nanoparticles. The best photovoltaic performances were obtained when the transparent conducting substrate (TCS) was heated during spraying. We believe that this is because the charge transfer through the NiO film and the charge collection at the TCS/NiO film interface were the most efficient with this sample. To our knowledge, the photovoltaic performances reported here are the best achieved with the commercial dye ERY as sensitizer.