Investigation on the energy conversion of dye-sensitized solar cells based on TiO2 core/shell using metal oxide as a barrier layer

Photo-electrochemical solar cells based on a core-shell structure including ZnO shell and TiO2 cove, have been fabricated with ruthenium bipyridyl complex (N719) as the sensitizer. Compared with the pure anatase TiO2, the ZnO-covered TiO2 film possesses outstanding ability to transport electrons with an overall power conversion efficiency of 3.72. Electrochemical study shows that surface modification of TiO2 film with ZnO can increase the concentration of free electrons in the conduction band of TiO2. This remit implies that the charge recombination is reduced in process of electron transport through the TiO2 porous film, which can decrease the photocurrent loss and hence improve Dye-Sensitized solar cells (DSSCs) efficiency. This result indicates that optimization of TiO2 porous network fabrication condition is efficient, for the improvement of TiO2 based DSSC's performances. (authors)