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. Elctrochemical 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 ceils (DSSCs) efficiency. This result indicates that optimization of TiO₂ porous network fabrication condition is efficient, for the improvement of TiO₂ based DSSC’s performances.