Influence of $$\hbox {TiO}₂$$ TiO 2 particle size and conductivity of the CuCrO $$₂$$ 2 nanoparticles on the performance of solid-state dye-sensitized solar cells

Solid-state dye-sensitized solar cells have been fabricated with mesoporous (hbox {TiO}₂ ) photoanode and N719 dye as photosensitizer. First, (hbox {TiO}₂) and non-doped, Zn- and Mg-doped CuCrO(₂) nanoparticles have been synthesized by sol–gel method. In addition, the (hbox {TiO}₂) pastes have been prepared through Pechini-type sol–gel method. The effect of (hbox {TiO}₂) particle size, mesoporous (hbox {TiO}₂) photoanode thickness and solid-state electrolyte thickness on the efficiency of the fabricated devices has been investigated. Our results show that in spite of the low amount of dye loading for photoanode with large (hbox {TiO}₂) nanoparticles (80–180 nm), the dye-sensitized solar cell made from it has higher efficiency than that constructed from the photoanode comprising of small particles about 10–15 nm in size. The higher efficiency is attributed to the longer diffusion length of electrons because of a better electron transport and penetration of a large amount of (hbox {CuCrO}₂ ) nanoparticles in the porous structure of (hbox {TiO}₂) photoanode. By using the doped (hbox {CuCrO}₂) nanoparticles, the efficiency has been increased from 0.027% for (hbox {TiO}₂)/N719 dye/CuCrO(₂) to 0.033% for (hbox {TiO}₂)/N719 dye/CuCrO(₂):Zn and further increased to 0.042% for (hbox {TiO}₂)/N719 dye/CuCrO(₂):Mg. The efficiency enhancement by doping is ascribed to the conductivity improvement due to the presence of impurity atoms.