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%.