Problem with modeling solar cell voltage distribution

[El Flea]

Hi,

Has anyone tried getting the voltage distribution of a biased solar cell with the poisson equation ( (d"V/dx") = (q/e)*(p-n) ) and electron and hole densities equation
( n = Nc*exp(-(Ec-qV-F)/kT) , p = Nv*(exp(Ev-qV-F)/kT) ) where Nc and Nv are the effective density of states, Ec and Ev are the transport level, F is the fermi level, e is the electric constant and V is the voltage?

I've tried make some guesses on the initial V distribution, and put them in the e-/h+ density equations, then putting the n and p into the poisson equations, and solve V using finite difference method. The voltage I got was in the order of 1x10^3x and the numbers gets bigger and bigger after each itteration. I need to reduce the grid size to 1e-40 in order to get some reasonable voltage. But that means that I can either have an extreamly thin layer or have a grid number that is too big for MATLAB to handle.

I've also found that the bigger my voltage gets at the Boundary, the smaller the grid size need to be.

Has anyone came across problem as such before?

Thanks!

 

[eljose79]

Hello,

I have not personally encountered this specific problem before, but I can offer some suggestions that may help. First, it is important to make sure that all of your equations and constants are accurately represented in your calculations. Double check that you are using the correct values for Nc, Nv, Ec, Ev, F, and e. Additionally, make sure that your units are consistent throughout all equations and calculations.

Another potential issue could be with your initial voltage distribution. It is possible that your initial guesses are not close enough to the actual solution, leading to large discrepancies in subsequent iterations. You may want to try varying your initial guesses and see if that affects the results.

You could also consider using a different numerical method, such as the shooting method, to solve for the voltage distribution. This may provide more accurate results without requiring such a small grid size.

I hope this helps and good luck with your research!

 

[Entropia]

Hi there,

I have not personally encountered this specific problem before, but I can offer some suggestions for troubleshooting and resolving the issue.

First, it may be helpful to double check your equations and make sure they are accurate and appropriate for modeling solar cell voltage distribution. You may also want to consider consulting with other experts in the field or reviewing published literature on similar models to ensure you are using the most accurate and up-to-date equations.

Additionally, it may be beneficial to try different initial V distributions and see if that affects the outcome. You can also try adjusting the grid size incrementally to find a balance between a reasonable voltage and a manageable grid size for your software.

Another option could be to look into using different modeling software that can handle larger grid sizes, or to optimize your code for more efficient computation.

Overall, it seems like there may be some issues with the accuracy or implementation of your equations, so I would recommend reviewing those and seeking input from others in the field to troubleshoot and improve your model. I hope this helps and best of luck with your research!