| The TiO2compact layer applied in the Dye-sensitized solar cells (DSCs) for improving the efficiency of the solar cell has been extensively studied. Most of reported TiO2compact films were grown by chemistry methods. Interfacial charge recombination is a significant loss mechanism in DSC. Dark current phenomenon exists between the interfaces in the DSC, which has a bad influence on the performance of DSC. In this work, the TiO2passivating layer was grown by DC magnetron sputtering on the FTO electrodes at room temperature using a TiO2ceramic target. From a practical and industrial point of view, DC sputtering is desirable for the large area coating because it is much simpler than RF sputtering and it gives a higher deposition rate. We studied the thickness effect of passivating TiO2layer on the performance of the DSCs.The morphological and microstructural properties of the formed TiO2layers were characterized by scanning electronic microscopy and X-ray diffraction. The DC sputtered TiO2passivating layer showed the better transparency than the RF sputtered TiO2film. The deposition rate of the compact TiO2layer by DC sputtering was much higher than that of RF deposition under the same deposition conditions. Moreover, it was found that the power conversion efficiency of the dye-sensitized solar cells (DSCs) is strongly dependent on the thickness of both RF and DC sputtered TiO2layer inserted between FTO electrode and nanoporous TiO2layer. The thickness of the sputtered TiO2layer was changed from0to200nm. The electrochemical impedance spectroscopy (EIS) technique was employed to evaluate the recombination resistance and electron lifetime in DSCs with differently thick TiO2passivating films. The DSC fabricated on160nm thick TiO2passivating FTO electrode showed the maximum power conversion efficiency of7.90%due to highly effective prevention of the electron transfer to electrolyte. The study demonstrates that the DC sputtered TiO2as dense and compact layers on FTO glass substrates is a promising electrode scheme for highly efficient DSCs, due to its effective prevention of leakage current from FTO to electrolyte as well as its high deposition rate and good transparency. |
