Photoelectrochemical properties of nanocrystalline TiO/sub 2/ electrodes sensitized by porphyrin derivatives with different functional groups

Porous semiconductor TiO/sub 2/ electrode was prepared by coating a conducting glass support. The photoelectrochemical properties of the nanocrystalline TiO/sub 2/ electrodes sensitized by porphyrin derivatives with different functional groups, e.g., carboxyl, sulfonate and phenyl were investigated. It was found that the all porphyrin derivatives used in this study had sensitization effect. The interaction between the porphyrin and the TiO/sub 2/ surface is determined and compared using UV-vis spectra. The adsorption behavior of the porphyrin on the TiO/sub 2/ electrode surface was discussed. Furthermore, we examined the photoelectrochemical properties of a free base porphyrin with only one carboxylate group (H/sub 2/TC1PP), the result obtained was compared with that of porphyrin with four carboxyl groups (H/sub 2/TC4PP). It reveals that the higher photocurrent intensity of H/sub 2/TC4PP can be obtained than that of H/sub 2/TC1PP, and the energy conversion efficiency of the solar cell is very dependent on the structure of porphyrin. These results indicate that the binding state between the dye and semiconductor is an important factor affecting the properties of the dye-sensitized solar cell.