Can we discuss about the correct procedure to be followed while measuring perovskite solar cells. Including the ambient atmosphere, the scan rate, the light soaking , masking etc.
What effects have you observed by altering these parameters ?
Dear Harikesh,
Since the solar cells must work on diverse environment with varying temperature and humidity and other weather conditions they must be tested after encapsulation in solar modules where the cells will be sealed against the leak of air and moisture from reaching the cells.
As for the testing the solar cells during the fabrication and after the fabrication when they are encapsulated, one has to see for testing environment which will not detract the solar cells and fully preserve them fully operating.
As for the perovskite solar cells there is an optimum moisture conditions[1]
May be one of the most important test conditions is the scan rate which must be sufficiently slow to avoid formation of hysteresis. This condition can be experimentally determined by reducing the scan rate such that the forward and backward scan coincide almost with each others.
As for the test conditions for qualifying the solar cells they must be measured under standard test conditions of room temperature and pressure with SPECIFIC AIR MASS.
[1] https://ieeexplore.ieee.org/document/8362049
Best wishes
Hi Harikesh,
This is a very important topic in the field of halide perovskite optoelectronics due to the complicated, mixed ionic electronic, nature of conduction in these materials.
From the phrasing of your question it seems like you are already familar with some of the important details of the measurement.
Given that perovskites have mobile ionic species that respond to external biases, it is important to give ions time to equilibrate before recording a current measurement at a given bias, so slow scan rates are preferred. This is further complicated by the hysteretic nature of current-voltage scans in perovskite solar cells, that the short circuit-open circuit scan will be different to open circuit-short circuit scan, most likely due to differences in accumulation of ions at interfaces. (https://pubs.rsc.org/en/content/articlehtml/2014/ee/c4ee02465f ) So both directions of the scan should be reported. If your material has been light soaked beforehand, it is critical to report this and the exact conditions that it was performed in, particularly in relation to your question about the ambient conditions - different environmental conditions can cause different light soaking effects. ( Article Metal Halide Perovskite Polycrystalline Films Exhibiting Pro...
) Masking is also important as one might imagine.In reality, the best method to determine the performance is to measure the stabilised power output at the max power point. JV curves in perovskite devices require a lot of caveats to make claims about them. Stabilised power output does what it claims to do, no caveats required!
Kyle
Abdelhalim abdelnaby Zekry Kyle Frohna
It seems MPPT is the better way to go..But we rarely see good papers with proper MPPT measurements on perovskites..
Hi, Harikesh
The emerging PV, DSSC, PSC, ..., have the capacity effect and hysteresis effect. Therefore, I-V of the device show forward/backward can't overlap.
If you want to improve accuracy under I-V or IPCE measurement, some test method can refer from
https://www.researchgate.net/project/Performance-rating-measurement-of-emerging-PV-for-Outdoor-Solar-AM15G-and-Indoor-lighting/update/5a1ccc354cde267c3e6f269a
or
https://www.researchgate.net/project/Performance-rating-measurement-of-emerging-PV-for-Outdoor-Solar-AM15G-and-Indoor-lighting
Thank you.
Best wishes
Mickey
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