Laplacian PL Image Evaluation Implying Correction of Photon Scattering in the Luminescence Detector

Abstract

Photoluminescence (PL) imaging is an established characterization method for investigating local inhomogeneities in solar cells. Conventional evaluation methods are based on the model of independent diodes, leading to wrong results of the local saturation current density J₀₁. The Laplacian-based PL evaluation method does not rely on this model and has the potential to image J₀₁ correctly. First attempts for using this method to evaluate PL images failed. In this contribution it is shown that the main reason for this failure was due to the light scattering effect occurring in the luminescence detector. Implying an image deconvolution procedure to the PL images with the correct point spread function, the result of the Laplacian-based evaluation method nearly shows the correct J₀₁ distribution. It will be shown that the Laplacian-based method has also the potential to image the different dark current contributions (J₀₁, J₀₂ and ohmic) separately, as DLIT can do it already now.