The efficiency of Grätzel cell can be further improved by the anchoring groups, such as
COOH to be adsorbed onto the TiO2 surface with a large electronic coupling. Some of the
most efficient sensitizers are synthetic dyes including transition metal coordination
compounds such as Ruthenium polypyridyl complexes because of their highly efficient metal-
to-ligand charge transfer, suitable ground and excited state energy levels with respect to
titanium dioxide conduction band energy. They also have intense and wide range …