The aim of this study is to prevent back transfer of electrons due to direct contact between the electrolyte and the FTO glass substrate using a TiO2 passivating layer. The TiO2 sol was prepared by a sol-gel method, and the TiO2 was coated on the FTO glass by spin coating method. The crystalline structure was adjusted by various catalyst concentrations: 0.1 mol, 0.5 mol. As With an increase in the catalyst concentration, the crystalline structure of the TiO2 passivating layer become the rutile phase. A nanoporous TiO2 upper layer was deposited by a screen printing method on the TiO2 passivating layer. The optical transmittance and particle size of the TiO2 passivating layer depend on the crystalline structure of the TiO2 passivating layer. The dye-sensitized solar cell was influenced by the crystalline structure of the TiO2 passivating layer. The dye-sensitized solar cell using a TiO2 passivating layer of the rutile phase was measured to have a maximum conversion efficiency of 3.98% due to the effective prevention of an electron recombination to the electrolyte.

Keywords: DSSCs, Passivating layer, TiO2, Spin coating