Limitations in the application of the ideal-diode model to the analysis of luminescence from silicon solar cells

On the basis of the ideal-diode model it is straightforward to exploit photo- and electroluminescence results from silicon solar cells. The value of the quasi-Fermi level splitting deduced from experimental luminescence data can be related to the applied voltage under the assumption of homogeneous carrier distributions. We show from numerical simulation and Shockley-diode analysis that in real solar cells discrepancies may exist between the quasi-Fermi level splitting determined from the photoluminescence radiation, which reflects the carrier distributions in the volume of the device, and the applied voltage. Implications are detailed for the construction of current-voltage characteristics from luminescence analysis.