Effect of polyethyleneimine on the growth of ZnO nanorod arrays and their application in dye-sensitized solar cells

A series of oriented hexagonal wurtzite ZnO nanorod-array films were grown on fluorine-doped tin oxide (FTO) coated glass substrates by chemical process. The effect of polyethyleneimine (PEI) on the structure and micro-morphology of ZnO nanorod array films, as well as the photoelectric conversion properties in dye-sensitized solar cells (DSSCs) was analyzed. It was found that with the addition of PEI in growth solution, the ZnO nanorods became smaller in diameter and longer in length and hence the dye absorption and the photovoltaic performance of DSSCs were improved. A power conversion efficiency of 2.30% had been achieved on a DSSC based on a 7.9 μm-long nanorod array film prepared by a growth solution containing the PEI.

► The influence of polyethyleneimine added in ZnO sol and growth solution, respectively, on the properties of ZnO nanorod arrays and the performance of DSSCs based on ZnO arrays was studied.
► The addition of polyethyleneimine in the growth solution made the ZnO nanorods become smaller in diameter and longer in length.
► A power conversion efficiency of 2.30% has been achieved on a DSSC based on a 7.9 μm-long nanorod array film prepared by a growth solution containing PEI.