Study of Quantum Dot/Inorganic Layer/Dye Molecule Sandwich Structure for Electrochemical Solar Cells

A highly efficient quantum dot (QD)/inorganic layer/dye molecule sandwich structure was designed and applied in electrochemical QD-sensitized solar cells. The key component TiO₂/CdS/ZnS/N719 hybrid photoanode with ZnS insertion between the two types of sensitizers was demonstrated not only to efficiently extend the light absorption but also to suppress the charge recombination from either TiO₂ or CdS QDs to electrolyte redox species, yielding a photocurrent density of 11.04 mA cm^–2, an open-circuit voltage of 713 mV, a fill factor of 0.559, and an impressive overall energy conversion efficiency of 4.4%. More importantly, the cell exhibited enhanced photostability with the help of the synergistic stabilizing effect of both the organic and the inorganic passivation layers in the presence of a corrosive electrolyte.