Hi everyone.
I've been trying to do calculations of Density Functional Theory in perovskites, using Quantum Espresso. However, the organic-inorganic perovskites, like CH3NH3PbI3 are making me confused, because I don't know how to make a correct input of the structure.
I have this CIF file, but I don't know what to do next.
If you're new to QE and just want a barebones input file with sensible defaults, you can use their input generator on materials cloud. You may want to opt for different/more consistent parameters depending on what you're looking at. https://www.materialscloud.org/work/tools/qeinputgenerator
Mr @Robert Stanton,
Thank you for your reply. I have used this website to make input of other structures, but for this one, I was confused just because the organic cation seems not accurate. When the tool makes the input, in the edges of the structure, there are CH3NH3 splitted in half. In one side there is just CH3, and in other side there is NH3, or even Hidrogens alone. So I just wanted to know how to overcome this.
Hi yes, that's not a problem because QE uses periodic boundary conditions. The visualized splitting of the methylammonium is because of its placement in the unit cell. If you open the cif in a visualizer like Vesta, you can see the MA has the methyl and ammonia groups intersected by planes of the unit cell. This means e.g. that the methyl group will be on one corner and the ammonia group will be on the opposite corner when you visalize your QE input, but this has no negative effect on the calculation.
Whenever this type of thing happens, just blow up the system in the visualizer to a supercell and you will see if it's reproducing the bulk system properly.
Thanks again.
So, this input file was generated by that tool, based in this CIF file attached. Do you think that this is already ready to put in calculation?
Bests
Ricardo
Hi everyone,
Does anyone have an idea to construct the CH3NH3PbI3 unit cell using lammps while considering all parameters like bonds, dihedral, and angle?
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