Fabrication and evaluation of dye-sensitized solar cells with photoanodes based on electrospun TiO2 nanotubes

Two types of electrospun TiO2 nanotubes were prepared by the technique of co-axial electrospinning followed by pyrolysis of electrospun core-shell nanofibers at 500 °C. The SEM/TEM images showed that both types of TiO2 nanotubes were polycrystalline with diameters of ~400-500 nm and crystallite/grain sizes of ~10 nm. The XRD results indicated that the TiO2 nanotubes possessed the anatase crystalline phase/structure. Upon sonication, both types of TiO2 nanotubes could be shortened; whereas the average lengths were different (i.e., shorter and longer TiO2 nanotubes). The dye-sensitized solar cell (DSSC) with photoanode based on the shorter TiO2 nanotubes had higher short-circuit current density and device efficiency while lower open-circuit voltage than the DSSC with photoanode based on the longer TiO2 nanotubes. The results are discussed in terms of dye loading amount and electron recombination lifetime.