Approximated analytical model for dark and Jsc—Voccharacteristics of p+-i-n+solar cells

The current-voltage characteristics of p
⁺
-i-n
⁺
solar cells is analyzed and an approximated two-exponential model for the dark and
J_{sc}-V_{oc}
operation is presented. It is shown that this two-exponential model and the superposition principle can be used as a first approximation and as a means of attaining further insight on the basic mechanisms actually occurring in the cell. However, some care should be taken when trying to determine the physical solar cell parameters from experimental data through fitting techniques. All this facts are illustrated and confirmed with theoretical examples and measured current-voltage characteristics of six different devices.