Enhanced omnidirectional light harvesting in dye-sensitized solar cells with periodic ZnO nanoflower photoelectrodes

In this study, two-dimensional ZnO nanoflower photoelectrodes were prepared using a chemical solution method and applied to dye-sensitised solar cells. By growing ZnO nanoflowers with different lengths on the photoelectrodes, the effects of the ZnO nanoflowers on the omnidirectional light-harvesting and broadband of dye-sensitised solar cells were investigated. According to the field emission scanning electron microscope and UV–Vis-NIR measurements of the prepared ZnO nanoflowers at different lengths, it can be determined that the amount of dye adsorption and degree of light scattering are affected by the lengths of the nanoflowers. A finite difference time-domain simulation was used to verify whether the degree of light scattering was affected by the lengths of the ZnO nanoflowers. In addition, the prepared ZnO nanoflower photoelectrodes of different lengths were applied to dye-sensitised solar cells. The photoelectric element efficiency, carrier life cycle, and element characteristics under wide-angle measurements were investigated through electrochemical impedance spectroscopy, the monochromic incident photon-to-electronic conversion efficiency, and a solar simulator. At high angles, the difference in efficiency of multi-directional incident light was reduced from 46% to 12%, which effectively improved the capturing characteristics of the multi-directional incident light during light scattering.