*1.5.3 Recombination*

**Figure 1** presents the possible ways of recombination: (1) electron injection from dye-excited state to the conduction band of photoanode, (2) regeneration of dye cation by electron transfer from the redox couple, (3) charge recombination to the cation of dye, (4) recombination to the redox couple, and (5) excited-state decay to the ground state. The photo-injected electrons in the photoanode can have

**Figure 1.** *Plausible electron recombination processes in the DSSCs.*

two possible recombination pathways: direct recombination with the oxidized dyes or with the I3 <sup>−</sup> in the electrolyte (**Figure 1**). The latter process is dominant and has thoroughly been studied in the literature by many researches.
