Generation rate shifted and low current




I am new to the software and i am working on a solar cell basic structure.
The generation rate while imported from FDTD to CHARGE appears to be shifted. I tried to adjust the dimensions to fit the semiconductor regions but i am getting very low emitter current values (range of 10e-19). the result is not affected by any changes.
knowing that i am not using any doping, as I am using organic materials which are already internally blended and doped.
could you please assist in this.


Hi @kh.asma, the imported generation data should not be shifted automatically and should not require any manual shifting. One sure way to check this will be to calculate the mesh only and then look at the result (grid) available in the solver region. The result will contain the generation rate (Goptext) that is getting applied to your device and you will be able to verify whether it is getting applied properly or not. Since you are getting a small current, my guess would be that your manual shifting has placed the imported data outside the simulation region and that the generation rate is not getting included in the simulation.

Since you mentioned that you are using organic material in your device I am curious as to how you are modeling the organic material since DEVICE does not support simulation with organic materials by default. May be your organic material model is not getting defined properly which is causing this issue?


Thank you for the reply. I managed to get the generation rate placed in the (x,y,z) zero center also with my structure centered in zero. Thus, no shifting occurs, but i still get the size of the generation rate smaller than the one in FDTD.

For the materials, i am just trying to find the proper parameters of the organic materials and add the new materials to DEVICE library. Do you think this will work with organic materials or not as i did not find any example that has been done with any of the organic materials.


Hi @kh.asma, The CHARGE solver in DEVICE was designed for crystalline semiconductors and uses a specific type of energy band profile (DOS) to model the semiconductors. The band profile of organic materials are quite different from that of a crystalline material, also the scattering mechanisms are much more complicated which cannot be modeled with the scattering models available in DEVICE. Therefore, unfortunately you will not be able to model electrical transport in organic materials using the CHARGE solver. My guess is that this is why you are not seeing any significant photo-current since your model for the organic material is not working and it is not working as you might expect.

Perovskite Solar Cells
Electrical simulation for organic solar cells
How to deal with "Initialization failed to converge charge update"

Thank you aalam for the clarification.