Thickness effect of the TiO2 nanofiber scattering layer on the performance of the TiO2 nanoparticle/TiO2 nanofiber-structured dye-sensitized solar cells

TiO₂ nanofibers (NFs) were fabricated by an electrospinning process and were used as scattering layers in dye-sensitized solar cells (DSSCs). The NF-coated photoanodes of the DSSCs were prepared with a variety of scattering layer thicknesses. The thickness effect of the scattering layer on the double-layered TiO₂ nanoparticle (NP)/TiO₂ NF structure was investigated through structural, morphological, and optical measurements. In the double-layered photoanode, the TiO₂ NP layer plays a major role in dye adsorption and light transmission, and the TiO₂ NF scattering layer improves the absorption of visible light due to the light scattering effects. The scattering effect of TiO₂ NFs layer was examined by the incident monochromatic photon-to-electron conversion efficiency (IPCE) and UV–Vis spectrometry. The conversion efficiency for the 12 μm-thick photoanode composed of a 2 μm-thick TiO₂ NF layer and 10 μm-thick TiO₂ NP layer was higher than that of DSSCs with only TiO₂ NPs photoanode by approximately 33%.