Some publications now report effect of dry air storage over night for efficient results? such as Solar EnergyMaterials&SolarCells134(2015)60–63, any experience?
You need to put the spiro films in dry air for couple of hours to dope them before evaporating metal electrode. Look at these two papers for reference-
1. Science 338, 643–647 (2012)
2. Nature 501, 395–398 (2013)
After spin on one has to dry the spin on film from the solvents. In addition one has to subject it in a dry oxygen rich environment to develop the hole conduction in the film to perform its intended function better. This is what i got from the paper in the Link: www.researchgate.net/.../54db59340cf2ba88a68fe1d4.pdf
If i understood you, you want to shorten the exposure time to dry air. Can this be made shorter by post heat treatment at appreciable higher temperature than the environment under dry air! The process of exposure to dry air is necessary to enhance the performance of the layer.
I have worked personally on this:
you need to expose the doped spiro-MeOTAD (spiro) to AMBIENT AIR, and humidity is very important for the dopants to diffuse across the spiro film, without the Humidity the Li-TFSI dopants will stay at the bottom of the spiro film. spiro film suffers from very low conductivity alone, and Li-TFSI enhances the conductivity a lot, (specifically after at least 3 hrs of ambient air exposure, i have tried synthetic air, and dry air, and O2 alone, but it didn't work (non published results) ).
unfortunately, moisture is bad for perovskite (PS) solar cells, so if you are using the spiro for PS solar cells, you should be careful, don't expose it too long.
gold evaporation (or metal evaporation):
after the air exposure it is fine to do thermal evaporation, but make sure that your spiro samples (or your devices with the spiro) are far enough from the evaporation source, to avoid any heating effects, or damaging the interfaces
please check my following reference:
https://www.researchgate.net/publication/270996191_Air-Exposure_Induced_Dopant_Redistribution_and_Energy_Level_Shifts_in_Spin-Coated_Spiro-MeOTAD_Films
(http://pubs.acs.org/doi/abs/10.1021/cm504022q)
good luck and don't hesitate to ask me more questions if you need any help with spiro.
Article Air-Exposure Induced Dopant Redistribution and Energy Level ...
Dear Zafer,
Thanks for sharing your experience and work, i will definitely go through the data.
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