Dear Harikesh P C

we will demonstrate the unlike contrast

when we have a divergence in the energy level between the different layers of the PSCs ,

the carriers they need more energy and time to achieve the other layers , and with the migration of the ions and its accumilation at the interfaces, this issue they will more influence.

this lead to more acceleration of the hysteresis phenomenen.

Dear cl leagues,

This is really a good question. It is my pleasure to share this question with you. When one knows exactly the origin of the hysteresis in perovskite solar cells, it could be reduced by the appropriate design and structure of the solar cells.

Here i would like to assume that the hystersis is due to the movement of the positive ions and negative ions of the perovskite molecules. The question is how these ions are formed. In fact one has to reduce the the formation of these ions during fabrication. This may be the the most effective way to solve this problem.

Let us revert to the original question if it is possible by matching the energy bands at the interfaces of the HTL and the ETL with the perovskite that one reduce the severity of the hysteresis?

The htl is slected such that it rejects the electrons and extracts the holes. The ETL is selected to extract the electrons and reject the holes.

If the ions are formed in the active region they will move as their similarly charged mobile charges, which means that the positive ions will move in the direction of holes and the negative ions in the direction of electrons under the influence of the built in electric field. While the oles can be attracted to the HTL and enter it while the positive ion may be not able to move in the HTL accumulating at the interface.

The same holds for the negative ions. While the interface encourage them to move further in the ETL they will most probably stick at the ETL interface. The active material will polarized and cause lowering the built in electric field and detracting the collection operation of the photgenerated electrons hole pairs.

I think one of the solutions is to free the active layer by from the electric field and affect collection by diffusion.

This can be accomplished by using either p or n pervoskite and using the concept of the Schottky solar cell junction.

Accordingly one expect that i- perovskite is more subjected to the p or n perovskite.

These are some thought concerning the formation of hysteresis in the perovskite solar cells.

Best wishes

dear Harikesh P C

thanks for your help

all the best.

Dimeh.

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