Home > Community > How can I increase the solubility of PbI2 in DMF?
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+ Inorganic chemistry
+ Solubility
+ Analytical chemistry techniques
+ Solubilization theory and practice
+ Solubility enhancement
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Oluwafemi Ogungbemiro Owen

How can I increase the solubility of PbI2 in DMF?

Bill Cameron  Follow

1 M (460 mg) of PbI2 is fully soluble in 1 ml DMF at 700C  for over night stirring. PbI2 in DMF is transparent yellowish solution at 70C but at room temperature it,s converted into gel like appearance but after heating it again converted into transparent solution. I have prepared this solution many times for the 2 step perovskite coating. In your case I think there is problem with PbI2 purity. I am using PbI2 of sigma (98% Purity). 

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Colin Little  Follow

@Arindam Thank you. Will try this.



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Dare Robertson  Follow

For perovskite solar cell I dissolve ~700 mg PbI2 in 800ul DMF+200uL DMSO and heat it @150 C for 5 mins.... It works nicely.....You can try it without DMSO.

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Blair Blakely  Follow

Can PbBr2 be completely dissolved in DMF? I tried to make a solution of PbBr2 in DMF by keep it in stirring for the period of 15 hrs at room temperature.but it didn't dissolve well.then i kept the solution at 70C ,slowly it got dissolved but after half an hour stirring it was precipitated in white colour. why this happened?How can I get a solution of PbBr2 in DMF?

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Danilo Renzi  Follow

As your research work is just focus on improvement of solubility of  PbI2 in DMF, so you cant add any external excipients to improve solubility. If addition of other ingredients or co-solvents is permited then you can use sodium lauryl asulphate, Tweeen 80, SPan 80, or any other cosolvent slike DMSO.If addition of other excipients not permitted then agitation, sonication will improve solubility, But scuh appraoaches cant improve solubility from 40% to 100%.

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David Currey  Follow

It will not be fully soluble, since it depends on many parameters. Supplier, dmf it self, dryness of PbI2 etc. Since there are so many methods published now, for perovskite, getting the clear bright yellow solution of PbI2 is the main point, before spin coating.  At the end of solubility period (70C, 1hr), from mostly hazy solution, you can use syringe filter (2 micrometer) to get clear bright yellow solution. 

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Danu Novmanu  Follow

Griffiths Sir, you are right, By mistake 460 gm was mentioned..it is 460 mg PbI2 in 1ml DMF.

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Attraction & Success  Follow

I think that R K Singh, in his first line means mol NOT ml.

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Cotondog1116  Follow

The  solubility of ionic compounds is generally related to the dielectric constant of the solvent, the higher the better.  Water is 78 but DMF is 36.7.  Below 10 and few ionic compounds are soluble to any significant extent.  PbI2 in DMF will be ionised, with four DMF molecules datively associated or bound to each Pb2+.  Thus you can pull more PbI2 into solution if a suitable ligand is present or added.
Some salts need more than gentle heat and time to reach a saturated solution.  Place your DMF and lead iodide  in an ultrasonic bath for an hour or more.  This method gets sparingly soluble salts to become a saturated solution in an hour that otherwise would take two weeks of standing or shaking.

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Biniam Berhane  Follow

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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Dale Henderson  Follow

Check this paper. 
"Reproducible Fabrication of Efficient Perovskite-based Solar Cells: X-ray Crystallographic Studies on the Formation of CH3NH3PbI3 Layers "
 - Chem. Lett. 2014, 43, 711–713 | doi:10.1246/cl.140074 
The dehydrated PbI2 dissolved easily in DMF. 
or you can get the PbI2/dmf solution if increase the temperature until 100oC.

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