You can check the following articles...........

1. https://pubs.rsc.org/en/content/articlehtml/2022/ra/d2ra06734j

2. Article SCAPS simulation and DFT study of lead-free perovskite solar...

3. Article Numerical Analysis in DFT and SCAPS-1D on the Influence of D...

Dear Syeda Rahimon Naher,

You cannot perform DFT calculatation using SCAPS-1D. I think you are using one of the code for DFT calculation. SCAPS is for device simulation not DFT calcualtion.

In DFT calculation, you need to check first cut-off energy convergence not k-points. After finding good cut-off energy, then you need to find optimal k points by using optimal cut-off energy. Optimal reange of k points is depend on material type, crystal structure and other factors. For example for metals k points should be more dense than in semiconductors.

In DFT you can find material properties like band gap, mobility, complex refractive index (of course some extra post steps should be done) and other. Then you can use enter those material preopertis to scaps to simualte that materiall based solar cell.

Sincerely

Jasurbek Gulomov

I don't understand exactly what you mean by "Still, now I can not optimize the energy"; do you mean the cut-off energy, or are you now trying to find the ground state energy of your solar cell material?

In general, the cut-off energy and k-point convergence are almost independent of each other, provided they are good enough to get the correct qualitative materials behaviour (for example, some semiconductors will become metals if you use very low cut-off energies, and metals require more k-points to converge!). I usually recommend that you start with the "coarse" or "medium" cut-off energy for your pseudopotentials (this is written in the first few lines of each pseudopotential) and then do the k-point convergence with that cut-off.

All the best,

Phil Hasnip

(CASTEP developer)