Farming of ZnO nanorod-arrays via aqueous chemical route for photoelectrochemical solar cell application

A low temperature aqueous chemical route is employed for the synthesis of zinc oxide (ZnO) nanorod arrays onto the soda lime and fluorine-doped tin oxide (FTO) coated glass substrates at various deposition times. Synthesis/farming of ZnO nanorod arrays (ZNRs) consists of the three-step as-ZnO seed forming, ZnO seed sowing followed by ZnO nanorod arrays growing. The length and diameter of ZnO nanorods increased with the reaction time prolonging. The physical, chemical and morphological properties were analyzed by means of X-ray diffraction (XRD), UV–visible spectroscopy (UV–vis), photoluminescence (PL), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) respectively. The XRD pattern revealed wurtzite crystal structures of ZNRs, preferentially orienting in the (002) direction. SEM micrographs show that the ZnO nanorods grew up perpendicular to the substrate and their length increases with increase in deposition time. Finally, the photoelectrochemical (PEC) performance of ZNRs thin films were studied. The junction quality factor upon illumination (n_l), series and shunt resistance (R_s and R_sh), flat-band-potential (V_FB), fill factor (FF) and efficiency (η) have been estimated.