Hierarchically assembled nanostructures and their photovoltaic properties

Abstract In this study, the effect of morphology and defect density of ZnO nanostructures on photovoltaic performance and electron transport properties of Dye-sensitized solar cells (DSSCs) have been investigated by using highly stable electrolytes which consist of high boiling organic solvents and a mixture of ionic liquids with relatively low viscosity. Two different ZnO nanoarrays with rod and sheet morphologies were fabricated and assembled for photovoltaic and electron transport study of the DSSCs. A photoluminescence spectra study indicated that nanosheets had more defect density compared to nanorods, which resulted in a lower open circuit photovoltage. Electrochemical impedance spectroscopy (EIS) and dye absorption amount analysis further explained the high short-circuit current density (J_sc) of the DSSC with ZnO nanosheet structure based on the dye-loading amount, effective electron lifetime and electron density.