Effect of Al3+ on the growth of ZnO nanograss film and its application in dye-sensitized solar cells

ZnO nanorod arrays were synthesized by an aqueous solution process with Al3+ as an adjusting agent, and their performances as photoanodes of dye-sensitized solar cells (DSSC) were investigated. The ZnO nanorods were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). It was found that adding Al3+ during the growth procedure not only changed the morphology and aspect ratio but also affected the chemical features of the ZnO nanorods. The ZnO nanograss films were evaluated as photoanodes for DSSC. The photovoltaic results showed that the overall conversion efficiency of DSSC based on ZnO nanorods obtained from the growth solution containing 2 at% Al3+ was increased by 55.6% as compared to that without Al3+. This significant improvement was attributed to the reduced charge recombination and enhancement of the electron lifetime.