SnO₂, TiO₂ and ZrO₂ nanoparticles were synthesized by a solvothermal reaction, and applied to the fabrication of interfacial layers between transparent conducting electrode and nanocrystalline TiO₂ layer in Dye-Sensitized Solar Cells. The size of the synthesized nanoparticles was determined to 2.5 - 4.5 nm by TEM and XRD. The thickness of each interfacial layer was controlled layer-by-layer by the self-assembly of those nanoparticles. Then, the main TiO₂ layer with a thickness of 10 μm was formed by doctor-blade method. These coupled systems demonstrated higher photovoltaic conversion dfficiency of the dye-sensitized solar cells than the conventional system without thin interfacial layer. Especially, SnO₂/TiO₂ coupled system had a higher short-circuit current (J_sc) than the conventional system without SnO₂ buffer layer. It is suggested that the SnO₂ layer expedites the electron transfer from main TiO₂ layer to FTO glass, and blocks the back-transport of electrons to the electrolyte.