Kindly explain the proper procedure for cleaning and etching FTO and ITO substrates prior to ETL coating to achieve higher power conversion efficiency (PCE%). Additionally, please clarify which substrate thickness is most suitable to ensure high optical transmittance and efficient electron–hole pair generation from the perovskite layer.
Hello Theertharaman Govindasamy
There are hundreds of different combinations of film thickness published in literature. The most important about these are that the layers must be as much uniform as possible. To achieve this, you have to be careful at the very beginning with etching and washing.
1 - Make sure your etching was successful. If you don't use the proper acid concentration, it can etch some of the ITO/FTO, but not everything, then you will have a partially etched surface. I covered the surface with Zn powder and used a 2M HCl. Only HCl works too.
2 - Washing with sonication: 20 minutes of destiled water with detergent, followed by 20 minutes of acetone and 20 minutes of Isopropyl alcohol. I didn't have a glovebox or a UV plasma, so after sonication with Isopropyl, I put the substrates in hot plate at 110 degrees Celsius until deposition time.
The most important is the solution dispersion. There are incredibly easy solutions to deposit, like PCBM layer as HTL. PEDOT:PSS as ETL is not as easy to deposit, but definitely not the hardest.
You will have to try what fits for you. If you have organic cation perovskite, don't waste time letting it on the substrate, drop it, spin quickly, and put in annealing.
Please, let me know if you manage this
Best regards,
Dr. Ricardo Tadeu
Hii Dr. Ricardo Tadeu
Thank you for your response to my comment. Meanwhile, I am happy to have found this message. I now understand the complications involved in the ETL fabrication process. If you happen to have any ideas for achieving a pinhole-free film using the spin coating process in a simpler way, kindly let me know, sir. Thank you.
Hello Theertharaman Govindasamy
You can follow any methodology you want according to what resources you have. I managed to make good depositions of PEDOT:PSS by spin coating, without a glovebox or UV Plasma. Check this paper:
Article Increasing efficiency in perovskite solar cells through ener...
But as I told you, there are many methodologies, and you must seek for film uniformity when you do it. Don't give up, it can take a few tries. And feel free to message in private if you want detailed help.
Best regards
Dr. Ricardo Tadeu
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