AGING AND REGENERATIVE BEHAVIOR THROUGH CYCLIC TEMPERATURE OF NANOSTRUCTURED DYE-SENSITIZED SOLAR CELLS

摘要

We have studied the effect of repeatedly and regularly varying temperature on the performance of bothfresh and aged dye-sensitized solar cells filled with either liquid or semi-solid iodine electrolytes. The temperaturewas varied in cycles 20 °C → 40 °C → 70 °C → 40 °C → 20 °C and the IV-curves and the EIS spectra of the cellswere measured in the abovementioned temperatures on several days over the observation period of ca. one month.The temperature cyclings regenerated the aged cell efficiencies through gains in both short circuit current and opencircuit voltage, to the extent that the overall efficiency drop over the observation period was on average 18 %-unitsmaller for the temperature treated cells, in comparison to the reference cells aged at constant temperature. EISmeasurements showed that the electron lifetimes in the TiO_2 film were longer and the charge transfer resistance onthe counter electrode smaller after the temperature cyclings; both of these effects also having short-term permanence.