Highly efficient all solid state dye-sensitized solar cells by the specific interaction of CuI with NCS groups II. Enhancement of the photovoltaic characteristics

Highly efficient all solid state dye-sensitized solar cells (DSSC) were fabricated by the specific interaction of CuI with the NCS groups of the dye molecules and that of the counter electrodes. The counter electrodes were prepared by blending nano size carbon in the PEDOT:PSS dispersion. The counter electrodes were covered with the solution containing guanidine thiocyanate, and heated to give the electrode with larger number of NCS groups. Electrostatic adsorption between PEDOT:PSS and guanidine was investigated by X-ray photoelectron spectroscopy (XPS). DSSC were prepared by connecting the NCS groups of the dye molecule with those of the counter electrode with large surface area. The performances of the resulting DSSC were improved dramatically by the increase of the NCS groups on the counter electrode. It is noteworthy that the performances of the cell were higher than that of the cells prepared by the conventional liquid electrolyte. The highly efficient all solid state DSSC are manufactured with inexpensive and low quality materials, and the practical use is promising.