Growth of three-dimensional ZnO nanorods by electrochemical method for quantum dots-sensitized solar cells

There-dimensional (3D) superstructure was expected to fabricate high performance photoelectrodes of quantum dot-sensitized solar cells (QDSCs). In this paper, the ZnO 3D superstructure with multi-layer structure (3D ZnO nanorods) was grown on ITO glass by a novel electrochemical method at low temperature (60–90 °C). The 3D ZnO nanorods were composed of close-packed ZnO nanorod bundles with wide dimension distribution ranging from hundreds of nanometers to several micrometers. The effects of some important parameters, such as concentration of Zn(NO3)2, deposition temperature and concentration of ZnO nanoparticles (served as growth seeds for ZnO nanorods), on the morphology of 3D ZnO nanorods were also studied by scanning electron microscopy. Once being applied in QDSCs, the 3D ZnO nanorods showed more superior photoelectrochemical performance to ZnO nanorod array. The conversion efficiency of 1.42% achieved by the QDSC based on 3D ZnO nanorods was a very promising value for the QDSCs based on ZnO electrodes.

► ZnO there-dimensional (3D) superstructure with multi-layer structure (3D ZnO nanorods) was grown by a novel electrochemical method.
► The photoelectrode based on 3D ZnO nanorods was prepared by depositing CdS QDs on 3D ZnO nanorods.
► The QDSC based on 3D ZnO nanorods showed more superior performance to that based on ZnO nanorod array.