Dye-sensitized solar cells (DSSCs) have drawn extensive attention
because of their relatively low cost and high photoelectrical conversion
efficiency potential [1]. Since the pioneer work of O'Regan and Grätzel
[2], DSSCs have been intensively studied during the past two decades.
Although 13% conversion efficiency was obtained recently [3], further
improvements are still necessary. In general, DSSCs are comprised of
photoanode (the most frequently used material is anatase TiO2) decorated
by a monolayer of dye molecules (sensitizers), a platinized counter
electrode, and an electrolyte solutionwith a dissolved iodide ion/triiodide
ion redox couple between the electrodes. The transport progress
of photogenerated electrons across the TiO2 nanoparticle network becomes
the major bottleneck of improving the conversion efficiency of
DSSCs [4,5]. If the photogenerated electrons couldn't accomplish the
transportation, they will recombine with the holes and get annihilated
in the TiO2 nanoparticle network [6]. To enhance electron transfer ability
and suppress the recombination, some charge carriers materials are
introduced into photoanode to the direct photo electrons