| Summary: | 碩士 === 國立中央大學 === 化學研究所 === 99 === Dye-Sensitized Solar Cells (DSSCs) are attractive the third generation thin film solar cells due to their low cost, light weight, colorful, fabricated easily and flexible. Generally, platinum is employed as a catalyst for the cathode in DSSC to catalyze the reduction reaction (I3- to 3I-) of the electrolyte. However, platinum is one of the most expensive materials on the earth. The preparation of Pt counter electrode at high temperature also increases the cost and difficulty in fabricating large-size device. Therefore, extensive studies have been carried out for developing other cheaper materials to replace Pt in DSSC. In this study, we investigated the performance of DSSCs using polyaniline (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT) as a catalyst on the counter electrode. We found that HFIP (Hexafluoroisopropanol) is a very good solvent for PANI and PEDOT powder. PANI and PEDOT counter electrode with large surface area and good conductivity can be made from PANI/HFIP and PEDOT/HFIP solution simply by spin coating at room pemperature, and the heating process is unnecessary. DSSC uses PANI/ FTO as a counter electrode exhibits an efficiency of 7.77 % with CYC-B11 as a sensitizer ( Pt：8.83 % ). Nevertheless, the efficiency of DSSC used PANI-SO4-HFIP CE (made from the H2SO4-Doped PANI/HFIP solution by spin coating the film on FTO) as counter elctrode achieves the highest efficiency of 8.76 %，which is comparable to that (8.83 %) of Pt-based DSSC under the same fabrication and measurement conditions. Furthermore, dispersing of PEDOT powder in HFIP was also used to prepare PEDOT counter electrode (PEDOT CE) by spin coating. The efficiency of PEDOT CE-based DSSC with CYC-B11 as sensitizer is 8.98 % ( Pt：8.74 % ). The results proved that conjugated polymers are good materials for replacing Pt as a counter electrode catalyst for DSSC.
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