In this study, dye-sensitized solar cells (DSSCs) were fabricated using double-layer photoanodes consisting of TiO2 nanoparticles (NPs) and Zn-doped TiO2 hollow fibers (HFs). The TiO2 HFs were prepared by co-axial electrospinning and used as the light-scattering layer in the DSSC. The thickness variations of the TiO2 NP and Zn-doped TiO2 HF photoanode layers affect the performance of the DSSC, especially the short-circuit photocurrent density. The thickness of the TiO2 NP layer significantly affected the absorbance of photons and N719 dye molecules in the double-layer photoanode, while that of the Zn-doped TiO2 HF layer affected the scattering of light, as indicated by the low light transmittance in the photoanode. Conventional DSSCs consist of single-layer photoanodes, and exhibit relatively low efficiency, i.e., 1.293% and 0.89% for TiO2 NP and Zn-doped TiO2 HF, respectively. However, herein, the highest efficiency of the DSSC (3.122%) was achieved with a 15 μm NP-5 μm HF photoanode, for which the short-circuit photocurrent density, open-circuit photovoltage, and fill factor were 15.81 mA/cm2, 0.566 V, and 34.91%, respectively.
Effect of ZnO Double Layer as Anti-Reflection Coating Layer in ZnO Dye-Sensitized Solar Cells