Photovoltaic Properties of Nano-particulate and Nanorod Array ZnO Electrodes for Dye-Sensitized Solar Cell

The nanorod array ZnO electrode showed stable photovoltaic properties compared with nano-particulate electrode despite the small adsorption of dye-molecules. The well-crystallized surface of nanorod should reduce significantly the formation of Zn2+-dye aggregates. The nanorod array electrode is also favorable for electrolyte diffusion since the diffusion channel is highly spacious and hardly blocked by Zn2+-dye aggregates within the electrode, while the complicated nano-pore channels in nano-particulate electrode can be easily blocked. Graetzel-type dye-sensitized solar cell (DSSC) has been considered as a new candidate for the next solar cell device in the near future. Its distinct colorful and transparent features as well as the possibility of low-price production allow much extended applications of DSSC compared to conventional silicon solar cells. Nanocrystalline semiconducting electrode in DSSC, usually made of anatase TiO2, is the one of essential component of this device, which serves as a supporting transparent film for dye-molecules and then receives the photoelectrons injected from dye-molecules and furnishes them adequate diffusion path to the back-contact. Among various kinds of semiconducting materials with photovoltaic properties, anatase TiO2 has been known as the best due to good matching of conduction band (CB) edge with LUMO level of ruthenium dye-molecule