Gratzel cell viscosity

Figure 15.6 shows the relationship between Jsc of the Gratzel cell and the viscosity of various liquid media under the same conditions [21]. The Jsc of the DSSC system depends simply on the viscosity of the liquid media. However, as described above, the Jsc of iodide-based RTILs is much higher even where viscosity is higher than 200 mPas at 25°C. As shown in the figure, the amount of iodine (I2) affects the improvement in Jsc- This implies that the diffusion coefficient of the iodide... 

Papageorgiou et al. reported the first example of an RTIL-based dye-sensitized solar cell system (Gratzel ceU). They found that l-hexyl-3-methylimidazolium iodide, denoted as HMI-I, melts at room temperature [8]. However, the viscosity of HMI-I is very high, at over 1000 mPas at room temperature. Therefore the /sc of DSSC when HMI-I is used (0.75 mA cm at the irradiation of 120,000 Lux [= 1 sun]) is much lower than that when an organic solvent is used (over 15 mA cm at 1 sun). This indicates that the slow diffusion of the iodide/triiodide redox... 

Other viscosity studies in ionic liquids were carried out by Gratzel et al. as part of a research program for the application of ionic liquids as solvents for a dye-sensitized nanocrystalline solar cell. 

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