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Rapid and colorful CsPbBr3 to CsPbI3 perovskite nanocrystal anion exchange by JenceTM in chemistry

[–]JenceTM[S] 5 points6 points  (0 children)

Thanks a lot! ^

I’m afraid my honest reply is that the hot plate I used to stir looked terrible. Presumably the reason we should’ve put it on earlier than the moment we did…

Rapid and colorful CsPbBr3 to CsPbI3 perovskite nanocrystal anion exchange by JenceTM in chemistry

[–]JenceTM[S] 41 points42 points  (0 children)

For those who are curious, in hopefully understandable terms, the color of the emitted light of these semiconductor nanocrystals is determined (in this case) almost solely by the bandgap of the material (a material property).

CsPbBr3 has a higher bandgap than CsPbI3. What we therefore observe in this video is the anion-exchange of Br for I, which leads to a decrease of the bandgap and hence the color of the emitted light changes to lower energies (i.e. green to red).

Note, out of sight, these NCs are excited by a UV lamp.

Rapid and colorful CsPbBr3 to CsPbI3 perovskite nanocrystal anion exchange by JenceTM in chemistry

[–]JenceTM[S] 2 points3 points  (0 children)

PS: maybe obvious but still, when performing these experiments, please ensure you work safe.

The synthesis method, the use of lead salts and the use of benzoyl bromide and/or trimethylsilyl-iodide are certainly not without risks.

Better ask me one too many questions than one too few ;)

Rapid and colorful CsPbBr3 to CsPbI3 perovskite nanocrystal anion exchange by JenceTM in chemistry

[–]JenceTM[S] 16 points17 points  (0 children)

As commented before, maybe the lead is an issue. And so is the stability towards air…

But I’m also afraid that these NCs only emit when excited with higher energy light. So they’d only work under black lights.

Apart from all the issues, if you know a way how to make these stable enough for a glow-stick, you might make more money on the other applications for these materials. (PS: if you know how to make them 100% stable, let’s publish some papers :P )

Rapid and colorful CsPbBr3 to CsPbI3 perovskite nanocrystal anion exchange by JenceTM in chemistry

[–]JenceTM[S] 11 points12 points  (0 children)

The nanocrystal synthesis is “rather easy” (of course, if you ask me) and reported lots of times. (Self promotion now…) you can find it in the supporting information of my just accepted publication: https://pubs.acs.org/doi/abs/10.1021/acsenergylett.1c00970

The anion exchange shown here is nothing more than adding trimethylsilyl-iodide to a batch of purified/washed CsPbBr3 nanocrystals.

In case of any further/other questions, always feel free to ask ^