CdSe quantum dots and N719-dye decorated hierarchical TiO2 nanorods for the construction of efficient co-sensitized solar cells.

Three-dimensional hierarchical TiO2 nanorods (HTNs) decorated with the N719 dye and 3-mercaptopropionic or oleic acid capped CdSe quantum dots (QDs) in photoanodes for the construction of TiO2 nanorod-based efficient co-sensitized solar cells are reported. These HTN co-sensitized solar cells showed a maximum power-conversion efficiency of 3.93 %, and a higher open-circuit voltage and fill factor for the photoanode with 3-mercaptopropionic acid capped CdSe QDs due to the strong electronic interactions between CdSe QDs, N719 dye and HTNs, and the superior light-harvesting features of the HTNs. An electrochemical impedance analysis indicated that the superior charge-collection efficiency and electron diffusion length of the CdSe QD-coated HTNs improved the photovoltaic performance of these HTN co-sensitized solar cells.