I am working on fabrication and simulation of perovskite solar cells (PSCs). I am using Spiro( HOMO level =5.22) as a hole transport layer for 2D perovskites which works for MaPbI3 , Pb4I13 and Pb3I10 have valence bands of 5.46 , 5.43 and 5.38 respectively. (BA)2(MA)Pb2I7 has the Valence band of 4.88 and PbI4 has VB 4.55 so i need a hole transport layer whose HOMO level is greater than that perovskite valence band. If anyone please let me know which HTL i will use in this case? I will be grateful.
Thanks and Regards
Dear Hassan,
Please have a look at these two articles, which report most of the hole transport materials used in perovskite solar cells. it may help
https://onlinelibrary.wiley.com/doi/full/10.1002/admi.201800882?casa_token=ao1nNWXxJnMAAAAA%3Ay1B_Y8AapakMXpDtJnksYjjpAoQt4NTnMfy8wsvFJBA3aPniY_DuynqW24F4J0X9opakWPsjTMArmRw
Article Advances in hole transport materials engineering for stable ...
Greetings
M.Elshorbagy
Dear Hassan Shahid,
Hope you are well!
It is so for the HTL to work well it must have a valence band edge Ev or a homolevel lying higher than that of the perovskite valence band such that the holes in the Perrovskite can be extracted easily from the perovskite. In the energy level diagram one represents the electron energy as function of the distance among the device.
The other condition is that Its conduction band edge must lye above that of the perovskite. This is to reflect the electrons back towards the ETL.
The last condition is that this material must be rich with holes to have low ohmic resistance.
So your material, it will function properly.
On the other side the contact difference of potential = EfETL- EFHTL.
Shifting EvHTL upwards may decrease the contact difference of potential which can reduce the opencircuit voltage.
For more information about the energy level diagram of such devices can be found in the link: Conference Paper Generic Analytical Models for Organic and Perovskite Solar Cells
Best wishes