I was trying to do two step sequential deposition, and even for stirring at 70C for overnight it do not dissolve completely. Eventually, after spin coating i see grains of PbI2 which are obvious even after making the full perovskite. Any suggestions?
PbI2 is more soluble in DMF when MAI is in the solution as well. That being said, you should be able to make up to a 1M solution reasonably easy. The PbI2 must by dry in order to dissolve well - this is critical, we have had brand new PbI2 bottles that didn't make good solutions because of too much adsorbed H2O. Even with dry PbI2, typically there is some slight cloudiness to it after stirring for 30 min to 1hr at 70C. Filter this through a syringe filter and it should be nice and clear yellow.
Jeffrey, thanks for the great point about the presence of water, I will dry that and try to get the solution again. Yes you right PbI2 is more soluble in the presence of MAI.
However for 1M solution, filtered through the syringe, does the final (less than 1M) concentration have effect on the perovskite? after adding MAI solution.
Be careful about the idea of "totally soluble", totally soluble means all mixtures of A nd B will form a homogenous solution. Ethanol and water are totally soluble in each other as are hexane and heptane.
Mark, thanks for feedback. Purpose is just to get PbI2 dissolved enough to get grain free perovskite.
I did tried the syringe with filter and was able to get clear yellow solution which i used afterwards for perovskite crystallization and got awesome results.
please can you explain it clearly. "Even with dry PbI2, typically there is some slight cloudiness to it after stirring for 30 min to 1hr at 70C."
We never tried, but you can filter with filtering syringe the DMF solution of PbI2 to get a clear, saturated solution for further process.
Anyone ever use Butylamine for dissolving PbI2 or PbCl2?
Many thanks for help
Best!
@Jeffrey, Thanks for your answer. Wouldn't the concentration of PbI2 changes(reduces) when the solution is filtered out from the cloudy powders?
Those interested at this discussion may possibly find useful to check the following somewhat related discussion: https://www.researchgate.net/post/Which_organic_solvents_can_be_used_to_disolve_PbI2_or_PbCl3_crystals
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