LAUSR

Summary Effect of ZnO nanorod surface on fabricating the perovskite solar cell and its performance were studied. Varied thickness of ZnO nanorod arrays with rough surface condition were achieved through the control of hydrothermal growth time and acid treatment. Samples based on modified ZnO nanorod arrays exhibit an impressive increase on the open-circuit voltage (Voc) and fill factor (FF) compared with the untreated ones. Further research onto the surface topography and electrochemical impedance spectroscopy test indicates that the improvement should be attributed to the suppression of the charge recombination rate at the ZnO nanorod/CH3NH3PbI3 interface. In order to enhance the short-circuit current density (Jsc) performance one step further, Cl-doped perovskite crystal was introduced into the cell. Because of its longer electron diffusion length, an impressive Jsc is received. The final combination of the two methods with the optimized thickness of the ZnO nanorod brought a total power conversion efficiency of 13.3% together with Voc~0.92 V, Jsc~23.1 mA/cm2, and FF~63%. This work highlights the importance of the surface morphology of the electron transport layer and its interface contact with the light absorbing layer in a solar cell structure. Copyright © 2017 John Wiley & Sons, Ltd.