Alternative routes for the preparation of a Zr-doped TiO2 anode for dye-sensitized solar cells (DSCs)

Mesoporous film-based dye-sensitized solar cells (DSCs) have recently received considerable attention as practical solar energy conversion devices [1]. A DSC is commonly composed by a few micrometer-thick film consisting of nanocrystalline oxide covered with a monolayer of ruthenium-based charge-transfer dye, a redox electrolyte and a platinized counter electrode. Although dye-sensitization can be achieved with porous films of other semiconductors [2], none of cells has ever been reported to be as efficient as the TiO2 cells reported by O'Regan and Grätzel [1]. Thus, in order to improve the cell performances, several research groups attempted to tune the electrode properties modifying the microstructure of TiO2-anode or promoting an increase in the conduction band energy level of the materials used. One of the most promising way is the doping of TiO2 with a definite mol% of Zr. In this work, the doping of TiO2 with 1 mol% of Zrwas done thorough three different methods and the resulting products were used to produce anodes for DSC. The obtained results, in terms of efficiency and structural morphology, were compared with the ones coming from a traditional cell with a pure TiO2-anode. All the electrodes were realized by screen-printing and the obtained films were characterized by compositional (XRD), morphological (FE-SEM) and electrochemical (CV-EIS) analysis and tested with a solar simulator after the production of the complete cell. These analyses allowed to evaluate the correlation between the doping processes and the final performances of the DSC and to evaluate the most efficient and economical one.