Study On The Carbon Counter Electrode Used In Dye-Sensitized Solar Cell

Dye-sensitized solar cell (DSSC) has been attracting considerable attention of the researchers in the world for their simple preparation procedure, low cost and high photovoltaic conversion efficiency. The counter electrode is one of the most important parts in DSSC. Although currently many investigators use the platinum as the counter electrode, the expensive Pt enhances the cost of the DSSC and the limited Pt sources restrict the extensive application of the large solar conversion systems. So it is desirable to develop cheap and high catalytic activity carbon materials to be the counter electrode.In this thesis, we prepared a kind of new carbon material-expanded graphite (EG) used as counter electrodes for the DSSC. The morphology and structure of EG was characterized by SEM, X-ray diffraction, and N2 adsorption. EG was used to the counter electrode with addition of different carbon materials(5B pencil-core powder, acetylene black, carbon nanotubes), which was discussed following five different weight ratios of 1:0, 1:1, 1:2, 2:1, and 0:1. Commercial P25 TiO2 adsorbing dye N719 was used as photoanode and ionic liquid was adopted as electrolyte to compose the cell. Using 25W/m~2 green light and 75W/m~2 white light emitting diode as the light source, I-V curves were taken by the CIMPS-2 system based on an IM6x electrochemical workstation. The good photovoltaic performance and the highest photovoltaic conversion efficiency reached to 4.39% had been recorded when the counter electrode was composed of EG and carbon nanotubes, which was better than Pt counter electrode DSSC. The results indicated that the EG was indeed an ideal kind of carbon counter material at certain mass ratio. It was an important significance on the DSSC practical investigation because of their low cost, corrosion resistance and simple preparation procedure.