Monolithic coal-based carbon counter electrodes for highly efficient dye-sensitized solar cells

A novel method for the preparation of monolithic coal-based porous carbon counter electrodes (CEs) for high performance dye-sensitized solar cells has been reported. Rigid monolithic coal-based carbon CE has been synthesized by preferential densification of one side of porous carbon plate formulated by caking bituminous coal powder. The phase, surface composition, and surface micro&nanotexture of the monolithic porous carbon plates have been characterized by X-ray diffraction, X-ray photoelectron energy spectroscopy, nitrogen sorption, scanning electron microscopy, and transmission electron microscopy. The coal-based carbon monolithic CEs exhibit a low internal resistance and high energy conversion efficiency (up to 6.38%). When the surface of the porous substrate was modified with mesoporous carbon as catalytic layer, the energy conversion efficiency can be further enhanced up to 8.73%, which is comparable to that of the platinized fluorine-doped tin oxide glass based device.