I am working on perovskite solar cells with inverted structure. My device structure is ITO/PedotPSS/ Perovskite/ PC70BM/ZnO/Al. I am frequently getting very bad dark IV characteristics near the shunt region. While there is no problem with the SCLC region and series resistance.This mainly happens when sweeping the voltage forward. In reverse sweep the whole curve shift towards positive X-Axis by ~0.25V. The light IV characteristics are pretty decent with efficiencies of >12%. Here in I am attaching my dark IV for you to see. Can anyone suggest me some possibilities of how to rectify it?
Would you please plot the dark I-V in a linear scale? The vertical scale is not clearly labeled. I would expect there is some aging effects and stability problems directly after the fabrication process. I would propose in order to stabilize and normalize cell you may stress it for sufficient time. The cells may require some form of aging process to stabilize them.
Best wishes
Dear Dr. Zekry,
I am attaching the same plot below in the linear scale. I am not sure if you are talking about stressing the device against light. If so, I've illuminated the device continuously for 15 min and again taken the measurement in dark but, still I'm getting similar plots. I am also attaching those plots comparing before stressing and after stressing.
Dear Sathy,
welcome,
I saw your curves, i have the feeling that light stress has changed the I-V curve much. Also, the region near zero in forward bias was altered such that current alternations became smaller. I do not know if more dressing time will bring an additional changes. I would investigate this effect more.
However,
There are some other reasons:
You have to be sure that your solar cell is contacted to the accessing electrodes.
You have to see the effect of the rate of the scanning on the I-V curve and choose scanning speed to measure the static characteristics of the device.
Best wishes
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