AIST has developed a ternary material with a core-shell structure consisting of multi-walled carbon nanotubes, an ionic liquid, and a conducting polymer. It was found that, when used as the counter electrode of dye-sensitized solar cells (DSCs), the material exhibits photoelectric conversion efficiency as high as that of platinum counter electrodes. DSCs are in the development stage and platinum, one of rare metals, is considered to be a promising material of counter electrodes. However, because of the rapidly increasing use of platinum as catalysts in vehicles and fuel cells, there is concern that the supply and demand balance of platinum may be affected. If the new ternary material, which is produced by using simple processes, can replace platinum, then its use would help reduce the consumption of platinum. It would also enable a cost reduction and an increase in the area of DSCs.