Hi
I am fabricating the standard organic solar cells using the structure ITO/PEDOT:PSS/P3HT:PC61BM/Ca/Al.
Using the standard and well known procedure steps in the papers, I got the standard results previously (last year). (Isc was about 300uA for my device area and Voc=0.6 , Eff about 3%)
The problem is that using the same procedure and materials I don't get the same results anymore. (Isc is 5uA now!, Voc remains unchanged).
To Identify the problem, I have fabricated devices using the inverted structure (ITO/TiO2/P3HT:PCBM/MoO3/Ag) to see if the problem is with one of the injection/blocking layers. But the devices are not working this way either (Again Isc=5uA).
My question is, in these situations how can one identify the problem?
How can I interpret the J-V to find out the problem? Or is there any other test to do?
Thanks
Dear Muhammad,
Do you use the same batch of the active layer of P3HT or PCBM? Bear in mind that organic materials have degradation from time to time if not stored properly ( Say in an inert gas environment ). You mentioned that you made OPVs with diffetent structures, but the shirt circuit current are the same regardless device structures. This could be something wrong with your testing equipment. Please check the source current unit to see whether it works well. You could get an inorganic photodiode to test against different light intensities. Hope it helps.
Xuhua
Xuhua Wang Thanks for your answer. My SMU is a Keithley 2400, and I have checked its functionality with a silicon solar cell, had no problem.
Yes I used the same batch of active layer materials. About degradation time I agree with you, that's possible, despite that I have kept them properly sealed and wrapped with aluminium foil to prevent the light from entering, they have been kept in air.
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