Calculation of the TCO sheet resistance in thin film modules using electroluminescence imaging

Here we present a method for calculating the TCO sheet resistance of complete thin film modules using EL imaging. The method uses the characteristic decay of the junction voltage over the width of a cell stripe to derive four simple analytic equations for the TCO sheet resistance and the internal and contact resistances. Experimentally, only the module dark JV curve, Jsc-Voc curve, and electroluminescence imaging is required. Unlike previous methods, the internal and contact resistances of the modules are accounted for, and the method does not require curve fitting. The TCO sheet resistances of four 10cm × 10cm amorphous silicon modules are calculated and show excellent agreement with the experimentally measured values.