High-efficiency ZnO/NiO composite photoanodes with Zn(Ac)2 ethanol solution-processed for dye-sensitized solar cells

ZnO/NiO composite photoanodes for dye-sensitized solar cells (DSSCs) were synthesized by an all solid state mothed. The effect of as-prepared NiO with NiCl2·6H2O and Ni(NO3)2·6H2O precusor was investigated using X-ray diffraction (XRD), field-emission scaning electron microscope (FESEM), energy dispersive X-ray analysis (EDAX), UV-visible absorption spectra (UV-vis), electrochemical impedance spectroscopy (EIS), and open circuit voltage decay (OCVD) characterization techniques. NiO enhanced the performance of DSSCs because of the energy level potential difference between NiO and ZnO, which accelerated the electron transfer at the ZnO/dye/electrolyte interface. Using ZnO/NiO composite photoanodes attained the maximum power conversion efficiency (PCE) of 6.60% in DSSCs. Moreover, saturated Zn(Ac)2 ethanol solution-processed ZnO/NiO composite photoanodes showed excellent optical characteristic and prolonged carrier lifetime to contrast unprocessed ones. This post-processed photoanodes exhibited a short-circuit current density (JSC) of 22.34 mA cm−2 and a PCE of 7.01%, and these values were higher than those of the isolated ZnO/NiO photoanodes. These results pave the way to further improve the performance and potential application of DSSCs.