It was reported that the extracting solvent has an effect
on the efficiency of DSSCs [5]. The efficiency of the DSSCs
was found to increase immensely when ethanol was used for
extracting anthocyanin from aged Jaboticaba skin [5].In
this study, similar finding was also obtained. As shown in
Table 3, the just finished assembling DSSC using ethanol as
solvent shows a higher efficiency than that of using water,
reported at 0.71% and 0.52%, respectively. This might owe
the fact that anthocyanin is more soluble in ethanol [17],
and hence, the aggregation of dye molecules is less as
expected. A good dispersion of dye molecules on the oxide
surface could in fact improve the efficiency of the system.
Unfortunately, the efficiency of ethanol system was
found to be diminished after being exposed to the
simulated sunlight for 3 h while there was only a slight
decrease in the efficiency for the case of using water as an
extract solvent. This might be due to the photocatalytic
decomposition of anthocyanin by TiO
in the presence of
ethanol as observed by the color of the anode to become
paler after exposed to the simulated sunlight. As shown in
Fig. 6, the absorption spectrum of the irradiated TiO
photoanode adsorbed rosella ethanol extract is rather flat
showing no light absorption compares to those of other
conditions. This makes the DSSC prepared from the
rosella ethanol extract unable to function just after a short
operating period. Therefore, ethanol is not suitable as an
anthocyanin extracting solvent for DSSC application.