Fabrication of anthocyanin-sensitized nanocrystalline titanium dioxide solar cells using supercritical carbon dioxide

- Low surface tension characteristics of supercritical carbon dioxide could be dyed nanocrystalline titanium dioxide photoelectrodes with anthocyanin.
- Supercritical dyeing process produced a deeper color in the TiO2 photoelectrode.
- Supercritical dyeing time can be shortened to 1/10 that of the traditional dip process under total absorption equivalent.

This study describes an inexpensive, facile process for fabricating dye-sensitized solar cell (DSSC) using nanocrystalline titanium dioxide as the photoelectrode. The results of this work showed that the low surface tension characteristics of supercritical carbon dioxide could save dyeing time when used as a medium to dye nanocrystalline titanium dioxide photoelectrodes with anthocyanin. Metallographic microscopy observations of the dyed photoelectrodes revealed that the supercritical dyeing process produced a deeper color in the TiO2 photoelectrode than did dip dyeing. The absorption spectrum of the product showed that the supercritical dyeing time can be shortened to 1/10 that of the traditional dip process under total absorption equivalent. In addition, the I-V characteristics of the dyed photoelectrode exhibited a critical surplus of current and voltage, which was another indication of the superiority of the supercritical dyeing process. The supercritical dye-sensitized photoelectrodes showed improved values of Isc (1.2 mA) and Voc (290 mV).