Research on TiO_2 thin film electrode grown in situ prepared by micro plasma method

TiO2 thin film electrode grown in situ for dye sensitized solar cells was prepared using the micro plasma oxidation method.The electrolyte was filtrated according to the photoelectric properties of the TiO2 thin film electrode.The effects of electrolyte on the surface morphology,phase composition and internal impedance are investigated by scan electron microscopy(SEM),X-ray diffraction(XRD) and electrochemical impedance spectroscopy(EIS).The interaction between dye and the surface of TiO2 thin film is studied by X-ray photoelectron spectroscopy(XPS) ans infrared absorption(IR).The results show that the TiO2 film electrode has higher photoelectric performance using(NH4)2SO4 as electrolyte than that using other electrolytes.The open circuit voltage,short circuit current and photoelectric efficiency are 149 μA/cm2,652 mV and 0.095%,respectively.The prepared TiO2 films consist of a large amount of rutile and a small amount of anatase and titanium,and the content of TiO2 prepared with(NH4)2SO4 is higher than that prepared with H2SO4.Also,the membrane layer is thicker,about 7.5 μm.The internal impedance of the TiO2 film is relatively small.The XPS of the TiO2 film after being sensitized by the dye cis-Ru(dcbpy)2(NCS)2 presents the cis peak of the O=C-O group,which indicates that the dye can be adsorbed on the TiO2 film surface.The infrared spectrum has an absorption peak at 1 737 nm induced by the vibration of carbonyl in ester bond.It can be inferred that the link between dye and TiO2 surface is realized by the analogous ester bond.