Finite element simulation of inhomogeneous solar cells based on lock-in thermography and luminescence imaging

This work presents a method to extract the spatial distributions of local two-diode parameters, contact resistance, grid resistance, and emitter resistance of a solar cell, based on spatial data obtained by lock-in thermography, 4-point probing, electroluminescence, and photoluminescence imaging. The extracted parameters are input into Griddler, a finite-element simulator, to calculate the cell plane voltage distributions as a test of the goodness of fit. This Griddler model then can be used to predict the cell properties under conditions not measured before, e.g. at different temperatures, biasing, and illumination conditions, and it can be used to evaluate the influence of certain defects on the cell efficiency by excluding them in the simulation.