Fabrication, characterization and application of $TiO_2$ photo-anode for dye sensitized solar cell

Abstract

Dye-sensitized solar cell (DSSC) is one of the most promising candidates for photo-voltaic systems due to its cost effective, use of eco friendly material and simple fabrication process. The conventional photoanode in DSSC is $TiO_2$ nanoparticle for large surface area. It offers, however, many defects on nanoparticle surface, causing recombination. To enhance the photoanode property, 1-D nanostructure is investigated. The electron transferred from excited dye can rapidly transport into $TiO_2$ conduction band with low recombination rate. It is expected the open circuit voltage increases due to low electron loss in $TiO_2$ rather than $TiO_2$ nanoparticle. Herein, we fabricated $TiO_2$ nanowire via electrospinning process on FTO glass with different structures to compare each property. The structures such as particle, wire, and particle on wire structure on FTO glass, are investigated to reveal electron transportation ability in $TiO_2$ nanowire compared to nanoparticle structure. 1-D structure such as nanofibers with 5 μm thickness interconnected network results in the increase of open circuit voltage due to low recombination compared to nanoparticle structure with same thickness. However, since wire is high porous network structure, it leads to low short circuit current due to small surface area. To enhance current density of wire structure, we fabricate double layer structure composed with particle and wire. It is expected that the property is improved. We found that the voltage is, however, significantly decreased due to high resistance between particle and wire despite of the increase of current density of double layer as shown in EIS profile. In this regard, the efficiency of double layer structure slightly more decreases than wire structure. Therefore, nanowire structure should be more deeply investigated to have large surface area for high current density as much as nanoparticle structure to obtain high performance of DSSC with nanowire structure. The...