Modification of dye-sensitized solar cell working electrode using TiO_2 nanoparticle/N-doped TiO_2 nanofiber composites

摘要

Nanocomposite films of N-doped TiO_2 nanofibers (NFs) and commercial-grade TiO_2 nanoparticles Degussa (P25) were utilized as working electrode of typical dye-sensitized solar cells (DSSCs). N-doped TiO_2 NFs were fabricated via electrospinning method using ammonium acetate (CH_3COONH_4) as nitrogen source and titanium (Ⅳ) isoprop-oxide (TiP) in ethanol as starting precursor in combination with calcinations process. The electrospun NFs were characterized by XRD, Raman spectroscopy, XPS, SEM, and TEM. The photoelectric conversion performance of the DSSCs with composite film electrode was compared to the device using pure P25 film. The result shows that as calcination temperature increases, the anatase-to-rutile phase transformation and the fiber size reduction of NFs were observed. The energy conversion efficiency (η) of the device tends to increase with increasing calcined temperature with specific nanofiber loading content, indicating the significant enhancement in the device performance by the incorporation of the NFs. This enhancement of DSSCs may attribute to high surface area, higher light scattering and light harvesting, low charge recombination, and fast electron-transfer rate by loaded NFs.