Investigation of Cation Effects in the Electrolytes for Dye-Sensitized Solar Cells
(English)Article in journal (Other academic) Submitted
A comparison of the effects of the cations of lithium, sodium and guanidinium in electrolytes for dye-sensitized solar cells have been investigated. Upon addition of cations to the reference electrolyte, short-circuit currents are generally found to be significantly enhanced, largely due to the positive shift of the conduction band edge (CB) in the TiO2. This probably results in an increase of the electron injection yield from the excited state of the sensitizing dye to the CB of TiO2. The open-circuit voltages for electrolytes incorporating lithium and sodium cations, however, are found to be slightly lower in comparison to the reference electrolyte. This may be attributed to the more positive shift of the conduction band edge in the TiO2. On the contrary, a slight improvement of the open-circuit voltage for electrolytes containing higher concentrations of guanidinium cations is observed relative to the reference electrolyte. This can most likely be ascribed to the collective effect of a much longer electron lifetime in the TiO2 and less positive shift of the CB. The electrolyte higher concentrations of guanidinium cations exhibits the optimal overall conversion efficiency among all the electrolytes investigated. the optimal performance can be attributed to the dual gain in both short-circuit current and open-circuit voltage with respect to the reference electrolyte.
IdentifiersURN: urn:nbn:se:kth:diva-63827OAI: oai:DiVA.org:kth-63827DiVA: diva2:482777
QS 20122012-01-242012-01-242012-01-24Bibliographically approved