The optical properties of ZnO sheets electrodeposited on ITO glass

Large-scale hexagonal ZnO sheets were grown on ITO glass by cathodic electrodeposition in an aqueous zinc nitrate/potassium chloride solution at 60 °C and annealing at 350 °C for an hour. The sheets are about 3 μm in dimension and 100-300 nm in thickness. The ZnO sheets show many nano-pits on the surface and produce intense green luminescence at room temperature under femtosecond (fs) pulse ultraviolet (UV) light excitation. Both power-dependent photoluminescence spectra and time-resolved spectra were measured with varied excitation powers. Lasing phenomena occur at above 500 μJ/cm² and the stimulated emission occurs with lifetime of less than 30 ps over 600 μJ/cm². Additionally, the open-circuit photovoltage spectra indicate that the light-absorbing dye of RuL₂(NCS)₂ (N3) can be well adsorbed on the surface of ZnO sheets, which is useful for the dye-sensitized solar cells(DSSC).